Properties of Warm absorbers in Narrow-Line Seyfert 1 galaxies

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(林伟健)

(林伟健)恒星哈勃拍摄的行星状星云NGC7027向我们提供了一个类似太阳的恒星崩溃时的详细资料: 暗蓝色的外围星云气体,巨大的网络状结构横亘内部的红色尘埃中,显著的中心白点,灼热的中央白矮星.星云的这些显著结构详细表达了恒星临死时的活动:在红巨星阶段, 恒星的氧-碳内核已经不再发生热核反应, 即使外壳对核的压力增大,内核也得不到充分的压缩而引起碳-氧继续聚变, 但内核周围的氢层和氦层继续燃烧,并且向外扩展,这种情况下,引力与排斥力开始不稳定, 恒星便开始一鼓一缩的脉动, 红巨星稀薄的包层向外以星风的形式逃逸,形成同心圆结构; 随着红巨星大气的丧失,中心星由于极高的密度和温度产生类似爆发的高速星风, 将剩余的气体与尘埃抛出,形成不规则的块状结构和气泡结构.这张照片是哈勃广角行星镜头拍摄的可见光波段和红外波段的合成图像.NGC7027距离我们3000光年,位于天鹅座.红巨星超新星白矮中子黑洞新恒星诞生恒星世界凡是由炽热气态物质组成，能自行发热发光的球形或接近球形的天体都可以称为恒星。

自古以来，为了便于说明研究对象在天空中的位置，都把天空的星斗划分为若干区域，在我国春秋战国时代，就把星空划分为三垣四象二十八宿，在西方，巴比伦和古希腊把较亮的星划分成若干个星座，并以神话中的人物或动物为星座命名。

1928年国际天文学联合会确定全天分为88个星座。

宇宙空间中估计有数以万亿计的恒星，看上去好象都是差不多大小的亮点，但它们之间有很大的差别，恒星最小的质量大约为太阳的百分之几，最大的约有太阳的几十倍。

由于每颗恒星的表面温度不同，它发出的光的颜色也不同。

科学家们依光谱特征对恒星进行分类，光谱相同的恒星其表面温度和物质构成均相同。

恒星的寿命也不一样，大质量恒星含氢多，它们中心的温度比小质量恒星高的多，其蕴藏的能量消耗比小的更快，故过早地戕折，只能存活100万年，而小质量恒星的寿命要长达一万亿年.恒星有半数以上不是单个存在的，它们往往组成大大小小的集团。

费米选耀变体序列研究

费米选耀变体序列研究王雪品;王兴华;丁楠;李丙郎;李斯;伍林【摘要】收集了129个费米选耀变体的多波段准同时性观测数据,利用对数抛物线拟合其能谱分布(SED),获得同步辐射峰值频率(vs)、同步辐射峰值光度(Ls)及其他相关参数.分析结果表明:Ls与vs之间有明显的负相关性,支持了耀变体演化遵循从FSRQs到LBLs到HBLs的顺序;星系中心存在小质量黑洞导致Ls-vs图中呈现低vs且低Ls的耀变体.【期刊名称】《云南师范大学学报（自然科学版）》【年(卷),期】2016(036)001【总页数】6页(P1-6)【关键词】同步辐射;中心黑洞质量;耀变体序列;相关分析【作者】王雪品;王兴华;丁楠;李丙郎;李斯;伍林【作者单位】云南师范大学物理与电子信息学院,云南昆明650500;云南师范大学物理与电子信息学院,云南昆明650500;云南师范大学物理与电子信息学院,云南昆明650500;云南师范大学物理与电子信息学院,云南昆明650500;云南师范大学物理与电子信息学院,云南昆明650500;云南师范大学物理与电子信息学院,云南昆明650500【正文语种】中文【中图分类】P14耀变体是一类具有高光度、快速光变、高偏振、非热连续辐射、视超速运动等特征的射电噪活动星系核(AGNs).耀变体的辐射光子能量范围从射电到伽马射线，其多波段能谱分布(SED)呈现双峰结构[1-2].低能峰位于从近红外到X射线能段，一般认为其产生于喷流内极端相对论性电子的同步辐射[3-4]；高能峰位于从MeV到GeV γ射线能段，产生的原因目前还存在很大争议.轻子起源模型认为：高能峰产生于极端相对论电子逆康普顿散射自身发射的同步辐射光子(SSC)，或产生于极端相对论电子逆康普顿散射喷流外部的低能光子(EC)[5-6].耀变体分为平谱射电类星体(FSRQs)和蝎虎天体(BL Lacs)，FSRQs有强的发射线，而BL Lacs只有很弱或没有发射线(等值宽度<5 Å)[7].Fossati等人提出一个FSRQs和BL Lacs统一的耀变体能谱演化序列[8]，该演化序列表明：辐射功率越大的源，其SED中同步辐射的峰值频率和逆康普顿散射的峰值频率就越低，而康普顿主导度(CD≡LC/Ls)随着源的功率的增大而增加，同步辐射峰值光度)随着同步辐射峰值频率的增大而减少.Ghisellini等人拟合了51个耀变体的SED，其结果表明高功率耀变体辐射的能量密度较大[9]，且同步峰值频率辐射的电子能量γp和在Thomson散射截面下磁场和辐射场的能量密度存在负相关性[9-13].导致上述结论的原因是：有效的逆康普顿散射导致较低的电子能量和较大的CD，而低能电子发出较低频率的同步辐射光子.通常把vs-Ls和之间的关系叫做耀变体序列.Abdo等人发现伽马射线光度(Lγ)与伽马射线光子谱指数(Γγ)之间具有相关性[14-15].由于光子谱指数与峰值频率之间有相关性,而伽马射线光度可以表示峰值频率大小[15]，因此，Lγ-Γγ关系可用于耀变体演化序列研究.近几年，关于耀变体序列有不同的观点[16-20]，研究者发现了一些射电光度低且同步辐射峰值频率也低的耀变体[21].同时，高同步辐射峰值频率的FSRQs也被找到[18].还有一些研究者认为，耀变体能谱系列可能是多普勒效应造成的，即认为低同步辐射峰频、高同步辐射光度耀变体的多普勒增亮效应更显著.而Ghisellini等的研究认为：(1)低vs、低Ls的耀变体可能偏离观测者视线方向，弱的聚束效应导致了耀变体的频率和光度都较低；(2)低vs、低Ls的耀变体可能对应质量较小的黑洞，因此喷流将在宽线区内耗散能量，电子在低频率部分辐射且冷却效率高[22]. 本文收集了费米选耀变体的中心黑洞质量和准同时性多波段数据，用对数抛物线拟合其SED并研究耀变体序列.文中取哈勃常数H0=70 km·s-1·Mpc-1，物质能量密度ΩM=0.3，无量纲宇宙学常数ΩΛ=0.7.耀变体是一类快速光变的源，因此，使用同时性多波段数据来拟合SED并与理论模型作比对非常重要.由于观测条件限制，只能选择最大样本费米选耀变体准同时性多波段数据.利用ASDC SED Builder*一种基于线上服务的ASI Science Data Center(ASDC)[21]，http://tools.asdc.asi.it/SED/，收集了129个费米耀变体(其中74个FSRQ，55个BL Lacs)在Planck、WISE、Swift和Fermi(2009年8月-2010年6月)等波段的多波段准同时性观测数据.样本不包括Chen的样本[24]中48个费米LAT亮源AGN(LBAS)和4个费米选窄线Seyfert 1(NLS1)源.逆康普顿散射与同步辐射峰值频率由二次多项式y=ax2+bx+c拟合得到，其中y=logvFv，x=logv.在源坐标系下，其峰值光度和频率由以下两个公式计算得到，和vs,C=(1+z)vp_obss,C，dL是光度距离，z是红移.从文献[25-33]中收集了样本源的黑洞质量，如果一个样本源有多个不同的黑洞质量，则对其取平均值.伽马射线光度和伽马射线光子谱指数来源于文献[34].相应的数据详见文献列表*由于样本比较大所以样本数据和SED图在文中没有给出，如有需要请与作者联系.，其中各栏信息如下：(1)名称；(2)和(3)为同步辐射峰值频率和光度；(4)和(5)为逆康普顿散射峰值频率和光度；(6)红移；(7)伽马射线光子谱指数；(8)伽马射线光度；(9)光学类型；(10)和(11)为黑洞质量及参考文献.3.1 拟合结果有效性测试Ackermann等人最近发布了AGN的费米三期数据(3LAC)，采用了一种基于三次多项式拟合非同时性SED来估算同步辐射峰值频率的方法[35].为了测试所拟合的峰频的有效性，从文献[35]中得到92个blazars(40个FSRQs和52 BL Lacs)的同步辐射峰值频率，并把我们的拟合结果与文献[35]中的同步辐射峰值频率作相关分析，结果在图1中给出.左图为FSRQs，右图为BL Lacs，横坐标为文献[35]中同步辐射峰值频率，纵坐标为我们拟合得到的同步辐射峰值频率，图中黑色虚线为y=x，黑色实线为数据最佳拟合结果，斜率分别为0.874和1.03，皮尔逊概率分别为p=4.91×10-9和p<10-20.从图中可以看到，估算得到的FSRQs的峰值频率多数小于文献[35]中的峰值频率，而BL Lacs的峰值频率多数大于文献[35]中的峰值频率.Ackermann等人认为，使用非同时性多波段数据可能由热辐射/吸积盘辐射导致高估FSRQs的同步辐射峰值频率，而寄主星系的贡献可能低估了对BL Lacs的同步辐射峰值频率.因此，我们用准同时性多波段观测数据拟合得到的vpeak是可靠的.3.2 耀变体序列同步峰值频率vs和同步峰值光度Ls间的相关性如图2所示，图中横坐标为logvs，纵坐标logLs.从图中可以看出随着vs的增大Ls减小，blazar演化遵循从FSRQs到LBLs到HBLs的顺序，沿着这个序列，耀变体的峰值光度在减小，峰值频率在增大.上述结论和利用伽马光子谱指数与伽马射线光度得到的演化序列一致[14-15，38].另外，图2中还呈现出一些低vs、低Ls的耀变体.Ghisellini等人认为，视向偏离或中心有小质量黑洞可能导致低vs低Ls耀变体[22].由于康普顿成分主导度CD是一个和红移无关的量，因此其在演化序列研究中是一个重要的参数.Finke等研究了CD与同步辐射峰值频率间的关系，得出康普顿主导度CD随着同步辐射峰值频率的增加而减少[36].我们研究了CD与同步峰值光度Ls间的关系，结果如图3所示.从图3中可以看出CD随着Ls的增大而增大，这与Fossati等人得到的逆康普顿成分的主导度CD随着源功率的增加而增加[8]的结论一致.如果这些耀变体有相对论性大视角，则会偏向较低频率和较低光度.逆康普顿散射峰值频率和同步辐射峰值频率都依赖聚束效应，因此，rCs=vC/vs和CD与视角无关.由于L∝δ4,因此预料rCs和CD将不依赖.将rCs和CD与的相关性分别呈现在图4、图5中.从图中可以看到大的离散，这个结果不支持低vs、低Ls的耀变体是视向偏离.Ghisellini等人认为低vs低Ls耀变体可能是有小质量黑洞，喷流将在宽线区内耗散能量造成电子的有效冷却和引起低频率和低光度.小质量黑洞也引起康普顿主导度偏低[22].为了调查是否是黑洞造成这些低vs低Ls耀变体，我们从样本中找出黑洞质量.图2中给出的最佳拟合是Ls∝vs-0.39±0.046，因此，参数Lsvs0.39和黑洞质量的相关性可以被用来检测低vs、低Ls的耀变体是否有小质量黑洞，相关结果可以从图6中看到，有明显的正相关，尽管有小的离散，但我们的结果支持低vs、低Ls的耀变体有小质量黑洞.因此，证实了Ghisellini等人认为中心有小质量黑洞可能导致低vs低Ls耀变体[20]的观点.在本文中，把BL Lacs天体分为HBLs和LBLs,从图2耀变体的分布中可以看到大部分LBLs落在FSRQs中，除了LBLs没有或只有弱的发射线这一点外，LBLs和FSRQs具有共同特性，Blazar三个子类在它们的谱特性上显示了一致的连续性，形成了一个序列.在讨论费米选耀变体时，人们有时会使用低同步峰值频率耀变体(LSP)、中同步峰值频率耀变体(ISP)和高同步峰值频率耀变体(HSP)代替FSRQs和BL Lacs[13].研究结果与Padoani等人和Chen的结果一致，尽管Padoani等人的研究基于射电波段到X射线波段，而我们样本数据基于射电到γ射线波段，两个结果都呈现出低vs、低Ls的耀变体.由于缺乏γ射线波段数据所以Padoani等人并没有研究康普顿主导度(CD).Ghisellini等人研究了费米选耀变体并且给出了Lγ和Γγ之间的相关性，认为降低γ射线流量阈值将发现陡谱指数耀变体和低同步辐射光度耀变体[38]，Lγ和Γγ之间有明显的正相关[14].图2中看到logv-log(vLs)之间存在负相关之外还呈现一些低vs、低Ls的耀变体，因此当讨论光子谱指数与峰值频率相关性、伽马射线光度与峰值光度之间的相关性时需要多注意.本文收集了56个耀变体的伽马射线光度和伽马射线光子谱指数，Lγ和Γγ的相关性在图7中给出，从图中可以清晰地看到两者明显的正相关，与Ghisellini等人的结果一致.结果表明是由黑洞质量导致低vs和低Ls而不是聚束效应.需要说明的是，图4、图5中可以看到数据点比较分散，这意味着聚束效应也有一定的作用.很多射电星系已被费米认证，在射电噪类星体统一模型下，blazars天体属于射电星系，但射电星系视角大.Abdo等人在研究中给出了伽马射线光子谱指数与伽马射线光度间的相关(包括射电星系)，可以看出射电星系有较低的光度和光谱较平滑，这与视向偏离的耀变体有低vs和低Ls的假设是一致的[15].同步辐射峰值光度Ls和黑洞质量的相关性在图8中给出，从图中可以看到存在正相关，说明同步辐射峰值光度低的耀变体确实有小质量黑洞.总之，费米选耀变体的logv-log(vLs)之间存在负相关性，Ls随着vs的增大而减小，blazar演化遵循从FSRQs到LBLs到HBLs的顺序.呈现出低vs、低Ls的耀变体的原因可能和小质量黑洞有关而不是弱的聚束效应.【相关文献】[1] 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[18]ANTN S,BROWNE I W A.The recognition of blazars and the blazar spectral sequence[J].Monthly Notices of the Royal Astronomical Society,2005,356(1):225-231. [19]NIEPPOLA E,TORNIKOSKI M,VALTAOJA E.Spectral energy distributions of a large sample of BL Lacertae objects[J].Astronomy & Astrophysics,2006,445(2):441-450.[20]PADOVANI P.The blazar sequence: validity and predictions[J].Astrophysics and Space Science,2007,309(1-4):63-71.[21]NIEPPOLA E,TORNIKOSKI M,VALTAOJA E.Spectral energy distributions of a large sample of BL Lacertae objects[J].Astronomy & Astrophysics, 2006,445(2):441-450. [22]GHISELLINI G,TAVECCHIO F.The blazar sequence: a new perspective[J].Monthly Notices of the Royal Astronomical Society,2008,387(4):1669-1680.[23]STRATTA G,CAPALBI M,GIOMMI P,et al.The ASDC SED Builder Tool description and tutorial[J].arXiv preprint arXiv:1103.0749,2011.[24]CHEN L,BAI J M.Implications for the blazar sequence and inverse compton models from Fermi bright blazars[J].The Astrophysical Journal,2011,735(2):108.[25]WOO J H,URRY C M,VAN DER MAREL R P,et al.Black hole masses and host galaxy evolution of radio-loud active galactic nuclei[J].The Astrophysical Journal,2005,631(2):762.[26]XIE G Z,ZHOU S B,LIANG E W.The mass-luminosity relation,accretion rate-luminosity relation, and evolutionary sequence of blazars[J].The Astronomical Journal,2004,127(1):53.[27]LIU Y,JIANG D R,GU M F.The jet power, radio loudness,and black hole mass in radio-loud active galactic nuclei[J].The Astrophysical Journal,2006,637(2):669.[28]ZHANG J,LIANG E W,ZHANG S N,et al.Radiation mechanisms and physical properties of GeV-TeV BL Lac objects[J].The Astrophysical Journal,2012,752(2):157.[29]SBARRATO T,GHISELLINI G,MARASCHI L,et al.Th e relation between broad lines and γ-ray lumi-nosities in Fermi blazars[J].Monthly Notices of the Royal Astronomical Society,2012,421(2):1764-1778.[30]CHAI B,CAO X,GU M.What governs the bulk velocity of the jet components in active galactic nuclei?[J].The Astrophysical Journal,2012,759(2):114.[31]LEN-TAVARES J,VALTAOJA E,CHAVUSHYAN V H,et al.The connection between black hole mass and Doppler boosted emission in BL Lacertae type objects[J].Monthly Notices of the Royal Astronomical Society,2011,411(2):1127-1136.[32]SHEN Y,RICHARDS G T,STRAUSS M A,et al.A catalog of quasar properties from Sloan Digital Sky Survey data release 7[J].The Astrophysical Journal SupplementSeries,2011,194(2):45.[33]SHAW M S,ROMANI R W,COTTER G,et al.Spectroscopy of broad-line blazars from1LAC[J].The Astrophysical Journal,2012,748(1):49.[34]ACKERMANN M,AJELLO M,ALLAFORT A,et al.The second catalog of active galactic nuclei dete-cted by the fermi large area telescope[J].The AstrophysicalJournal,2011,743(2):171.[35]ACKERMANN M,AJELLO M,ATWOOD W,et al.The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope[J].arXiv preprintarXiv:1501.06054,2015.[36]FINKE J pton Dominance and the Blazar Sequence[J].The Astrophysical Journal,2013,763(2):134.[37]TAVECCHIO F,MARASCHI L,GHISELLINI G.Constraints on the physical parameters of TeV blazars[J].The Astrophysical Journal,1998,509(2):608.[38]GHISELLINI G,MARASCHI L,TAVECCHIO F.The Fermi blazars' divide[J].Monthly Notices of the Royal Astronomical Society,2009,396(1):L105-L109.。

Ia

收稿日期：２０１４ — １２ — ０８；修回日期：２０１５ — ０４ — ０９
资助项目：国家自然科学基金（１１３７３０１５）；９７３项目（２０１４ＣＢ８４５７０２）
通讯作者：姜碧沩，ｂｊｉａｎｇ￣ｂｎｕ．ｅｄｕ．ｃｎ
一
，
同时也被用来测量其他宇宙学参数，如哈勃常数凰、宇宙密度参数ＱＭ、Ａ ’ 。Ｓａｕｌ
Ｐｅｒｌｍｕｔｔｅｒ，ＢｒｉａｎＳｃｈｍｉｄｉｔ和ＡｄａｍＲｉｅｓｓ正是基于对Ｉａ型超新星的研究，发现宇宙加速膨胀而获得２０１１年诺贝尔物理奖。 ’
系统误差来源，准确地测量消光才能获得精确的宇宙学参量。事实上，不同Ｉａ型超新星的
消光幅度相差很大，例如在可见光波段，ＳＮ１９９４Ｄ的消光Ａｖ＝０．１８ｍａｇ，ＳＮ２００３ｃｇ的Ａｖ２．３ｍａｇ … ，ＳＮ２００２ｃｖ的Ａｖ７．９ｍａｇ等。所以，要寻找Ｉａ型超新星消光改正的一般规律，以求获得准确的宇宙学距离。
如果绝对星等为常数，且Ａ＝０，可以很容易地从视星等获得距离。但是，在计算距离时，必须进行消光改正，即上式中的（在波段处尘埃所引起的消光量，单位为ｍａｇ），每０．１

Big.Bang.theory笔记S101

Big.Bang.theory笔记S1011. photon 光子2. plane 平面3. slit 裂缝4. There's no point.5. It's a good idea for a t-shirt.6. hang on. 稍等7. Aegean 爱琴海8. Nabokov 俄裔美籍小说家，《Lorita》，不论恋9. a phylum, a family or a species 门、科、种10.Port-au-Prince 太子港（海地Haiti首都）11.high-iq sperm bank12.semi-pro 半职业选手13.genetic 遗传的；起源的14.fraud 欺骗；骗局；诡计；骗子15.there's no guarantee that...16.offspring 子孙，产物，后代17.hostess 女服务员18.Fuddrucker's 快餐店19.fractional 部分的，少量的，碎片的，分数的20.bandwidth 带宽，频宽21.yearn 渴望，怀念，想念22.pin 把...归罪于,把...归咎于23.who's gonna pin her hopes on my sperm. 会把希望寄托在我精子上的24.what if she winds up with a toddler who doesn't know if he should use25.toddler 初学走路的孩子26.wind up 使结束=end upShe wound up her speech with a quotation. 她以一句引言结束她的演讲。

27.integral 积分，整数；整体的，积分的28.differential 差别的，微分的，特定的29.protocol（for doing）n. 议定书, 协议, 处理某问题的方法;草案, 谈判的起草; 礼节, 行为准则;协议, 处理资料传送的标准30.renege (on sth.)/ri'nig/ v.食言; 违约; 背信; 有牌而不跟; 否认, 拒绝, 放弃31.proffer（sperm）提供；贡献；提议32.If the height of a single step is off by as little as two millimeters,most people will trip.33.a series of experiments34.clavicle 锁骨35.boarding school 寄宿学校/doc/bb16077166.html,ser 激光37.evidently 明显地；显然38.significant improvement over the old neighbor39.transvestite [trans'ves·tite |n.异性装扮癖者40.200-pound transvestite with a skin condition41.hall n. 门厅, 会堂, 走廊42.we don't mean to interrupt.we live across the hall.43.heterosexual | ?het?r??'seksl] n.异性恋的人adj.异性的; 异性爱的44.Should we have invited her for lunch?45./doc/bb16077166.html,mentary n.注释, 批评, 评论47.invite someone over 请XX做客 make her feel welcome48.That was wrong of us. 那是我们的不对49.we need to widen our circle.50.that's the beauty of it51.And you say sth appropriate in response52.I know that moving can be stressful53.undergo 遭受，忍受，经历（stress）54.that good food and company can have a comforting effect55.curry 咖喱/doc/bb16077166.html,xative | 'l?ks?t?v] n.泻药, 缓泻药 adj.通便的, 不简洁的57.colon | 'k??l?n] n.结肠58.one less thing to worry about59.luncheon | 'l?nt??n] n.午宴; 正式的午餐 a luncheon invitation60.bowel 肠，同情心61.skip the reference to bowel movements62.masturbate || 'm?st?be?t /-t?rb] v.手淫; 对...行手淫63.this looks like some serious stuff64.quantum [quan·tum ||'kwɑnt?m /'kw?-]n.分配量, 量, 额65.mechanics [m?'k?n?ks]n.力学; 技术性的部分; 机械学; 技术66.quantum mechanics 量子力学67.doodle [doo·dle || 'du?dl]n. 乱写; 蠢人v. 涂鸦, 混时间; 乱涂; 欺骗68.spoof [spu?f]n. 诳骗, 戏弄, 愚弄v. 哄骗; 戏弄…69.approximation [ap·prox·i·ma·tion || ??pr?ks?'me??n]n. 接近; 概算; 近似额; 近似值70.Holy smokes.71.If by"holy smoke", you mean72.derivative [de·riv·a·tive || d?'r?v?t?v]n. 引出之物, 衍生字, 系出物adj. 引出的; 系出的73.restatement [,re'state·ment || ?r??ste?tm?nt]n. 再声明, 重述74.scribble [scrib·ble || 'skr?bl]n. 潦草的写法, 杂文, 潦草写成的东西v. 潦草地书写; 草率地创作; 在...上面乱涂; 潦草书写; 乱涂, 乱画; 草率创作75.Who hasn't seen this differential below "here I sit, broken-hearted"76.dimension [di·men·sion || d?'men?n]n. 维；尺寸, 容积, 次元77.Just make the math come out.78.Do you guys mind if I start.79.That's where I sit.80.Here we go. 开始了81.radiator ['ra·di·a·tor || 're?d?e?t?(r)]n. 暖房装置, 散热器; 辐射体; 冷却器; 发射天线82.In the winter, that seat is close enough to the radiatorTo remain warm, and yet not so close as to cause perspiration.In the summer, it's directly in the path of a cross-breezecreated by opening windows there and there.It faces the television at an angleThat is neither direct, thus discouraging conversationNot so far wide as to create a parallax distortion83.perspiration [per·spi·ra·tion || ?p?rsp?'re??n /?p??-]n. 汗, 努力, 流汗84.breeze [bri?z]n. 微风, 和风#谣传, 传闻; 轻而易举的事; 骚动, 争吵v. 吹着微风; 轻易地通过; 一阵风似地走; 越狱逃走85.cross-breeze86.discourage [dis·cour·age || d?'sk?r?d?]v. 使气馁, 阻碍87.parallax [par·al·la x || 'p?r?l?ks]n. 视差88.distortion [dis·tor·tion || d?'stn]n. 扭曲; 曲解; 变形89."klingon boggle" boggle 拼字游戏90.that has negative social implication91.Sagittarius [Sag·it·ta·ri·us || ?s?d??'te?r??s]n. 射手座; 人马座92.which probably tells you way more than you need to know93.delusion [de·lu·sion || d?'lu??n]n. 迷惑, 错觉, 欺瞒94.relative to 相对于95.arbitrarilyadv. 武断地; 专横地; 任意地96.constellation [con·stel·la·tion || ?k?nst?'le??n]n. 星座, 灿烂的一群97.Scorpio [Scor·pi·o || 'sk??p]n. 天蝎座, 天蝎宫; 蝎属98.Leonard can't process(加工) corn./doc/bb16077166.html,ctose-intolerant100.it takes you 4 years to get through your high school。

第2章夸克与轻子 (2)

第二章夸克与轻子Quarks and leptons2.1 粒子园The particle zoo学习目标Learning objectives：我们怎样发现新粒子？能否预言新粒子？什么是奇异粒子？大纲参考：3.1.1￣太空入侵者宇宙射线是由包括太阳在内的恒星发射而在宇宙空间传播的高能粒子。

如果宇宙射线粒子进入地球大气层，就会产生寿命短暂的新粒子和反粒子以及光子。

所以，就有“太空入侵者”这种戏称。

发现宇宙射线之初，大多数物理学家都认为这种射线不是来自太空，而是来自地球本身的放射性物质。

当时物理学家兼业余气球旅行者维克托·赫斯（Victor Hess）就发现，在5000m高空处宇宙射线的离子效应要比地面显著得多，从而证明这种理论无法成立。

经过进一步研究，表明大多数宇宙射线都是高速运动的质子或较小原子核。

这类粒子与大气中气体原子发生碰撞，产生粒子和反粒子簇射，数量之大在地面都能探测到。

通过云室和其他探测仪，人类发现了寿命短暂的新粒子与其反粒子。

μ介子（muon）或“重电子”（符号μ）。

这是一种带负电的粒子，静止质量是电子的200多倍。

π介子（pion）。

这可以是一种带正电的粒子（π＋）、带负电的粒子（π－）或中性不带电粒子（π0），静止质量大于μ介子但小于质子。

K介子（kaon）。

这可以是一种带正电的粒子（K＋）、带负电的粒子（K－）或中性不带电粒子（K0），静止质量大于π介子但小于质子。

科学探索How Science Works不同寻常的预言An unusual prediction在发现上述三种粒子之前，日本物理学家汤川秀树（Hideki Yukawa）就预言，核子间的强核力存在交换粒子。

他认为交换粒子的作用范围不超过10－15m，并推断其质量在电子与质子之间。

由于这种离子的质量介于电子与质子之间，所以汤川就将这种粒子称为“介子”（mesons）。

一年后，卡尔·安德森拍摄的云室照片显示一条异常轨迹可能就是这类粒子所产生。

[O II] as a tracer of current star formation

a r X i v :a s t r o -p h /0012485v 1 22 D e c 2000The Astrophysical Journal,000:000–000,2001(MS-52562-ApJ)Preprint typeset using L A T E X style emulateapj2[O II]AS A TRACER OF STAR FORMATION the[O ii]/Hαratio on luminosity.The NFGS sample consists of196nearby galax-ies,objectively selected from the CfA redshift catalog(CfA I,Huchra et al.1983)to span a large range of−14to−22in absolute B magnitude without mor-phological bias.The sample should therefore be rep-resentative of the galaxy population in the local uni-verse,subject only to the biases inherent in B selec-tion and the surface brightness limit of the Zwickycatalog.Our data include nuclear and integratedspectrophotometry(covering the range3550–7250at∼6˚A resolution),supplemented by U,B,R surfacephotometry from which we obtained total magni-tudes and colors.For the details of the galaxy se-lection and for the U,B,R photometry,we refer thereader to Jansen et al.(2000a);for a full descriptionof the spectrophotometric data we refer to Jansenet al.(2000b).Of the191normal(non-AGN dominated)galax-ies in the NFGS sample,141show Hαemission in their integrated spectra.We will concentrate,how-ever,on the118galaxies with HαEW≤−10˚A for which the[O ii]/Hαratios are reliable,and on the 85galaxies that also have EW(Hβ)≤−5˚A for which we can derive accurate Balmer decrements to cor-rect the observed emission lineﬂuxes for reddening. Throughout the paper we correct observed emission lineﬂuxes for Galactic extinction,estimated from the H i maps of Burstein&Heiles(1984)and listed in the RC3(de Vaucouleurs et al.1991).The wave-length dependence of the extinction is assumed to follow the optical interstellar extinction law of Nandy et al.(1975)(as tabulated in Seaton1979,but adopt-ing R V=A V/E(B−V)=3.1instead of3.2).Ob-served Balmer emission lineﬂuxes have also been cor-rected for stellar absorption lines.We partially compensated for the stellar absorp-tion underlying the Hβemission by placing the limits of the measurement window well inside the absorp-tion trough,closely bracketing the emission line.We evaluated the residual absorption using the spectra of galaxies with no detectable emission.On average,an additional correction of1˚A(EW)was required.Sim-ilarly,for Hαwe found that a correction of1.5˚A was needed.After correction,aﬁt to the data in a Hβversus Hαplot passes through the origin.Because we restrict our analysis to galaxies with moderate to strong emission lines,we are insensitive to the details of this procedure.This paper is organized as follows.In section2 we evaluate the range in the observed and reddening corrected[O ii]/Hαratio and its dependence on lumi-nosity,and we demonstrate the eﬀect of diﬀerences in the excitation state of the interstellar medium(ISM). In§3we relate the observed[O ii]and Hαﬂuxes Fig.1—The logarithm of the ratio of the observed[O ii] and Hαemission lineﬂuxes versus total absolute B magni-tude.Only data for the118galaxies with strong emission [EW(Hα)<−10˚A]are shown to ensure reliable emission line ratios.The plotting symbols are coded according to morpho-logical type,as indicated.Overlayed is a linear least-squares ﬁt to the data points.The[O ii]/Hαratio decreases systemat-ically from∼1.5at M B=−14to∼0.3at M B=−21.to the ionizingﬂux and show that these results are consistent with previous studies.We brieﬂy discuss the implications for the use of Hβas SFR tracer in §4.We discuss how to improve SFR estimates and present empirical corrections in§5.The implications for evolutionary studies are discussed in§6.We con-clude with a short summary(§7).2.VARIATION IN THE[O ii]/HαRATIOInﬁgure1we plot the ratio of the observed[O ii] and Hαemission lineﬂuxes vs.total absolute B mag-nitude for the118galaxies with EW(Hα)<−10˚A. The Balmer emission lineﬂuxes were corrected for stellar absorption,but neither Hαnor[O ii]are cor-rected for internal interstellar reddening.The ob-served[O ii]/Hαratio decreases systematically with increasing galaxy luminosity,from∼1.5at M B=−14 to∼0.3at M B=−21,but the range is large.At M B=−18,only a magnitude fainter than the char-acteristic absolute magnitude of the local luminos-ity function(M∗∼−19.2,de Lapparent,Geller,& Huchra1989;M∗∼−18.8,Marzke et al.1994),the observed[O ii]/Hαratios vary by a factor of∼7.JANSEN,FRANX,&FABRICANT3Fig.2—(a )Logarithm of the observed [O ii ]/H αratio versus total absolute B magnitude.Here and in the following panels we only include the 85galaxies with EW(H β)<−5˚A ,allowing us to measure the Balmer decrement,H α/H β,reliably.The plotting symbols are coded according to morphological type as in Fig.1.(b )Logarithm of the [O ii ]/H αratio after correction for interstellar reddening versus absolute B magnitude.The dependence on galaxy luminosity is greatly reduced after correction for reddening,and both the total scatter and the scatter around the best linear ﬁt through the data has decreased.(c )Logarithm of the observed [O ii ]/H αratio versus color excess E(B −V ),determined from the observed Balmer decrement.The [O ii ]/H αratio decreases as the reddening increases.The line shows the relation expected for the adopted reddening curve.(d )Color excess E(B −V )versus absolute B rger reddening values tend to correspond to higher galaxy luminosities,although the range in E(B −V )at a given galaxy luminosity is large.A linear least-squares ﬁt to the data points is overlayed.2.1.Eﬀects of Reddening by DustTo evaluate the contribution of extinction to the variation in the [O ii ]/H αratio and to the ratio’s de-pendence on galaxy luminosity,we compute the color excess,E(B −V ),from the observed Balmer decre-ment,H α/H β.We assume an intrinsic ratio of 2.85(the Balmer decrement for case B recombination at T=104K and n e ∼102–104cm −3;Osterbrock 1989)and adopt the optical interstellar extinction law of Nandy et al.(1975)(as tabulated in Seaton 1979,but adopting R V =A V /E(B −V )=3.1instead of 3.2).This procedure results in a lower limit to the actual reddening,as the observed Balmer decrement will be4[O II]AS A TRACER OF STAR FORMATIONweighted to the regions of lowest line-of-sight extinc-tion(Kennicutt1998a).Other studies suggest,how-ever,that this approach gives a reasonable estimate of the extinction(e.g.,Calzetti,Kinney,&Storchi-Bergmann1994;Buat&Xu1996),except for the dustiest regions in a galaxy.Figure2a is the same asﬁgure1except that we include only the85galaxies with EW(Hβ)<−5˚A, where we could measure the Balmer decrement parison ofﬁgures1and2a indicates that exclusion of the galaxies with fainter Hβemission is unlikely to bias our discussion.Inﬁgure2b we present reddening corrected ratios of the[O ii]and Hαemission lineﬂuxes versus ab-solute B magnitude on the same scale asﬁgure2a. The dependence of[O ii]/Hαon galaxy luminosity de-creases markedly after correction for interstellar red-dening:the slope of a linear least-squaresﬁt to the data changes from0.087dex/mag to0.035dex/mag and both the total scatter and the scatter around the ﬁt decrease from0.18to0.09dex and from0.12to 0.08dex1,respectively.This implies that more than half of the observed scatter in[O ii]/Hαmust be due to dust.The total variation in[O ii]/Hαdecreases from a factor∼7to∼3.Ratios of(observed)equivalent widths behave much like extinction correctedﬂux ratios,but their dependence on the stellar continuum introduces a de-pendence on the star formation history of the galaxy. If we use EW ratios rather than reddening corrected ﬂux ratios inﬁgure2b the scatter around the bestﬁt increases(0.11versus0.08dex)and the slope steep-ens slightly(0.043versus0.035dex/mag).To show the eﬀect of reddening on the relative strengths of[O ii]and Hαmore directly,inﬁgure2c we plot the logarithm of the observed[O ii]/Hαratio versus color excess E(B−V).Weﬁnd a clear trend toward lower[O ii]/Hαratios in galaxies with larger interstellar reddening.This trend spans most of the total range in[O ii]/Hα.For reference we overlay the relation expected for the adopted reddening law,as-suming an intrinsic[O ii]/Hαratio of1(i.e.,ﬁxing the zeropoint to log([O ii]/Hα)=0for E(B−V)=0). Although the data points do not exactly follow the expected relation,the correspondence is good.Inﬁgure2d we plot color excess E(B−V)versus absolute B magnitude.More luminous galaxies tend to show more reddening than low luminosity galaxies. The scatter on this trend is very large,however. Theseﬁgures show that galaxy luminosity,internal reddening and the observed[O ii]/Hαline ratios are linked.The trend of[O ii]/Hαwith reddening has the smaller scatter.Reddening,therefore,is an im-portant factor in the observed trend of[O ii]/Hαwith M B,but it is not uniquely related to galaxy luminos-ity.2.2.Eﬀect of Excitation and MetallicityThe luminosity dependence of the[O ii]/Hαratio does not disappear completely after correction for reddening.Might the variation in the reddening cor-rected[O ii]/Hαratios result from diﬀerences in the excitation state and metallicity of the ISM?Diﬀer-ences in excitation and metallicity aﬀect the relative strengths of the[O ii][O iii]and the hydrogen re-combination lines.Figure3a shows the reddening corrected[O ii]/Hβversus[O iii]λλ4959,5007/Hβﬂux ratios for the85 galaxy subsample.Here,we used Hβrather than Hα(note that Hα=2.85Hβafter reddening correction) to allow a direct comparison of the data with the theoretical predictions of McCall,Rybski,&Shields (1985)for the line ratios of H ii regions in galaxies as a function of metallicity.Along the track,the metal-licity is high at the lower left(low excitation)and low at the upper right(high excitation).The small systematic deviations(∼0.1dex)from the model are in the same sense that McCall et al.(1985)reported for their comparison of the model and observations. The scatter of0.06dex of the data around the model track is consistent with the errors in the data points. The residuals from the model track are not corre-lated with either absolute B magnitude,reddening E(B−V),galaxy color,or Hαemission line strength. The tight coupling between[O ii]/Hαand metal-licity can be demonstrated with the metallicity sensi-tive ratio log{([O ii]+[O iii]λλ4959,5007)/Hβ},com-monly denoted as R23(Pagel et al.1979;Edmunds& Pagel1984),which we use as a quantitative indica-tor of the oxygen abundance(Pagel1997;Kennicutt et al.2000).Inﬁgure3b we plot the reddening cor-rected[O ii]/Hαratios versus R23.R23is computed using reddening correctedﬂux ratios.The metallic-ity measurements are degenerate for values of R23= log{([O ii]+[O iii])/Hβ}∼>0.75(metallicities lower than∼0.6times solar when adopting the expansion in R23given by Zaritsky,Kennicutt,&Huchra1994). This is indicated in theﬁgure by a dotted line.The[O ii]/Hαratio is strongly correlated with metallicity.For R23<0.75(where the metallicity de-termination is non-degenerate)we can approximate the dependence on metallicity with a linear relation: log([O ii]/Hα)cor=(0.82±0.03)R23−(0.48±0.02) The scatter around this relation is only0.023dex, consistent with little or no intrinsic error.1Throughout this paper we will express scatter in terms of the Median Absolute Deviation(MAD),deﬁned as1JANSEN,FRANX,&FABRICANT5Fig.3—(a )Reddening corrected [O ii ]/H βversus [O iii ]λλ4959,5007/H βﬂux ratios.The theoretical sequence of McCall et al.(1985)is overlayed.The scatter of the data around the model curve is consistent with the errors in the data points.Low excitations are found at the lower left of the model curve,high excitations at the upper right.(b )Reddening corrected [O ii ]/H αratio versus the metallicity sensitive index R 23=log {([O ii ]+[O iii ])/H β}.The metallicity determination is degenerate for R 23∼>0.75(indicated by the dotted line).The [O ii ]/H αratio and the oxygen abundance are strongly correlated.The data points for R 23<0.75follow a well deﬁned sequence with little or no intrinsic scatter.(c )R 23versus total absolute B magnitude.The dotted line indicates the degeneracy limit R 23=0.75.Thus,we identify metallicity as the underlying cause of the observed range in [O ii ]/H α,aﬀecting this ratio both indirectly through the diﬀerential extinc-tion of the [O ii ]and H αlines,and directly,as shown above.In ﬁgure 3c we plot the metallicity sensitive R 23index versus absolute B magnitude to explicitly show the correlation of metallicity with luminosity.ING [O ii ]AND H αAS TRACERS OF THE SFRIn the following discussion we use the reddening corrected H αﬂux,H αo ,to parameterize the SFR since this H αﬂux is directly proportional to the ion-izing ﬂux,F ion .In ﬁgure 4a we plot the ratio of the observed [O ii ]ﬂux and the ionizing ﬂux (H αo )versus the absolute B magnitude.A clear trend with luminosity is seen:6[O II ]AS A TRACER OF STARFORMATIONFig.4—(a )Logarithm of the ratio of observed [O ii ]ﬂux to ionizing ﬂux versus total absolute B magnitude.The zeropoint on the ordinate is arbitrary (see text).The plotting symbols are coded according to morphological type as in ﬁgure 1.The total range in [O ii ]obs /H αo spans 1.5orders of magnitude.(b )Logarithm of the ratio of observed H αﬂux to ionizing ﬂux versus M B .Imperfect correction for reddening is a much more serious problem when using [O ii ](see ﬁgure 2a )than when using H α.the lowest luminosity galaxies have the largest ratio of [O ii ]to ionizing ﬂux.Near the characteristic absolute B magnitude of the local galaxy luminosity function,M ∗∼−19,the [O ii ]/H αo ratio varies by a factor of ∼10.The total range spans a factor 25.The SFR derived from observed [O ii ]ﬂuxes,in the absence of other information,will be uncertain by a factor of ∼5,if the calibration of Kennicutt (1992)and the median absolute magnitude of his sample is used as a reference (see section 3.1).Using reddening cor-rected instead of observed [O ii ]ﬂuxes (see ﬁgure 2b )greatly reduces both the luminosity dependence and the scatter at a given luminosity:from 0.147to 0.035dex/mag and from 0.19dex to 0.08dex,respectively.The total range of the reddening corrected [O ii ]/H αo ratio spans 0.53dex (0.49dex,if we exclude one out-lying data point).As expected,reddening is a more signiﬁcant source of error if [O ii ]rather than H αﬂux is used as a SFR tracer.In ﬁgure 4b we plot the ratio of the observed H αﬂux and the ionizing ﬂux versus the absolute B magnitude for comparison.The total range in the ratio of the uncorrected and corrected H αﬂux spans 0.65dex (a factor of ∼4.5),less than one-ﬁfth that found for [O ii ].But here as well reddening produces a trend with galaxy luminosity of 0.060dex/mag.parison with the LiteratureWe compare our measurements for the NFGS sam-ple with those of Kennicutt (1992a)in order totie them to previous absolute calibrations of [O ii ]and H αas SFR tracers.In ﬁgure 5we plot ob-served ([O ii ]+[O iii ]λ5007)/H αﬂux ratios versus ob-served [O iii ]λ5007/[O ii ]ﬂux ratios for both samples.Whereas [O iii ]λ5007/[O ii ]is an excitation sensitive ratio,([O ii ]+[O iii ]λ5007)/H αis sensitive mainly to the oxygen abundance.The galaxies in both sam-ples follow similar trends.Gallagher et al.(1989)did not publish [O iii ]λ5007measuments for their sample,so we are unable to make a similar comparison with their sample.We did however compare the observed [O ii ]/H βﬂux ratios versus absolute B magnitude for both the NFGS and the Gallagher et al.(1989)sam-ple and found them to be consistent with one another.Kennicutt (1992a)noted that his SFR calibration for the observed L ([O ii ])emission line luminosity ex-ceeded that of Gallagher et al.(1989)by a factor of 3.Adopting the same IMF and conversion factor from H αto SFR for both samples reduces this diﬀerence to a factor of 1.57(Kennicutt 1998b).The remain-ing discrepancy he ascribed to excitation diﬀerences between the two samples.The median M B of Kennicutt’s sample is −19.3±1.4mag,that of Gallagher et al.is −16.9±2.0.Tak-ing this magnitude diﬀerence at face value,we ex-pect (see §3)a diﬀerence in the logarithm of the [O ii ]/H αo ratio of 2.4mag ·0.147dex/mag =0.353dex,i.e.,a factor of 2.25.This factor has the correct sign,i.e.,the SFR inferred from a given [O ii ]/H αo ratio is higher for Kennicutt’s sample than for the sample of Gallagher et al.The predicted diﬀerenceJANSEN,FRANX,&FABRICANT7Fig.5—Logarithm of the observed ([O ii ]+[O iii ]λ5007)/H αﬂux ratio versus the logarithm of the observed [O iii ]λ5007/[O ii ]ratio in the sample of Kennicutt (1992a)(labeled K’92)and in the NFGS sample (including the 118galaxies with EW(H α)<−10˚A ).The abscissa is an excitation sensitive ratio,whereas the ordinate is sensitive mainly to the oxygen abun-dance.The data points in both samples follow similar trends.Those data points in the present sample with errors in excess of 0.10dex are indicated by upper limits.is,however,somewhat larger than that actually ob-served.This might be due to the large scatter in the trends with M B ,or to the fact that Kennicutt could not account for the systematic variations in absorp-tion.4.IMPLICATIONS FOR H βAS A SFR TRACERIn section 2we showed that the observed [O ii ]/H αratios strongly depend on the amount of interstellar reddening.H βwill be seriously aﬀected by redden-ing as well.Here we test H βas a quantitative star formation indicator.In ﬁgure 6a we plot the ratio of observed H βﬂux and the ionizing ﬂux versus total absolute B mag-nitude for the 85galaxies with reliable H βmeasure-ments.The H β/H αo ratio varies systematically with luminosity,although not as strongly as the [O ii ]/H αo ratio.The slope of a linear ﬁt to the data is 0.090dex/mag and the scatter around the ﬁt is 0.132dex.The H β/H αo ratio decreases from 0.37at M B =−14to ∼0.09at M B =−21.In most cases where H βcan be secured,the [O iii ]λλ4959,5007lines will be available as well.Fig-ure 6b shows the ratio of the observed H βﬂux andthe ionizing ﬂux versus the observed [O iii ]/H βra-tio.It is remarkable that for high values of [O iii ]/H βthe absorption is generally very small.The SFR can therefore be estimated relatively well,with a conver-sion constant very diﬀerent from that for L ∗galax-ies.The scatter increases drastically for lower values of [O iii ]/H β,and the extinction becomes much more signiﬁcant.When no direct reddening measurement is available (e.g.,when none of the other Balmer lines can be measured reliably)the ionizing ﬂux can be re-trieved to ±0.12dex using the observed H βand [O iii ]ﬂuxes for log([O iii ]/H β)∼>0.2.At smaller observed [O iii ]/H βratios ﬁgure 6b will be useful to estimate the likely range in ionizing ﬂux corresponding to a H βmeasurement.5.IMPROVED SFR ESTIMATION AND EMPIRICALCORRECTIONSIn this section our goal is to derive empirical correc-tions to relate the observed [O ii ]emission line ﬂux to the ionizing ﬂux in those cases where H βis not avail-able.We start with the situation where only [O ii ]ﬂuxes are available.As we found above,the correla-tion between absolute magnitude and [O ii ]/H αo (ﬁg-ure 4a )gives an indication of whether a high or low normalization of the [O ii ]–SFR calibration is likely,and may be used to give a relative weight to a set of several normalizations as published in the literature.For instance,at low luminosities the lower normal-ization of Gallagher et al.(1989)for blue irregular galaxies is likely to be more appropriate.Kennicutt’s (1992a)higher normalization,on the other hand,will be a better choice for luminous galaxies.The scat-ter at a given absolute magnitude is a measure of the errors involved in the choice of calibration constant.The [O ii ]equivalent width,EW([O ii ]),can be used to estimate the likely range in the [O ii ]/H αo ratio.In ﬁgure 7a we plot the logarithm of the ratio of the observed [O ii ]ﬂux and the reddening corrected H αﬂux versus the logarithm of (the nega-tive of)the EW([O ii ]).For EW([O ii ])≤−45˚A [i.e.,log {EW([O ii ])}≥1.65]the scatter in [O ii ]/H αo at a given EW([O ii ])is only 0.064dex and the ion-izing ﬂux (and therefore the SFR)can be deter-mined well.The [O ii ]/H αo ratios for these large EW([O ii ])are high (1.04±0.30),and the star forma-tion would be overestimated by a factor of (1.7±0.5)if the SFR normalization for luminous galaxies were used.EW([O ii ])≤−45˚A are found predominantly in the lower luminosity,lower metallicity galaxies.For smaller EW([O ii ])we ﬁnd a trend toward lower [O ii ]/H αo ratios,but the scatter in [O ii ]/H αo in-creases to an order of magnitude.We note that the lack of galaxies with small EW([O ii ])and large8[O II ]AS A TRACER OF STARFORMATIONFig.6—(a )Logarithm of the ratio of observed H βﬂux to the ionizing ﬂux (reddening corrected H αﬂux)versus absolute B magnitude (including the 85galaxies with reliable H βmeasurements).The plotting symbols are coded according to morphological type as in ﬁgure 1.Upper limits are used to indicate data points with errors larger than 0.15dex.A linear least-squares ﬁt to the data points is overlayed.The dotted line indicates the intrinsic Balmer decrement,H α/H β=2.85.As was seen for the [O ii ]/H αo ratio (ﬁgure 4a ),reddening creates a dependence on galaxy luminosity.(b )Logarithm of the ratio of the observed H βﬂux to the ionizing ﬂux versus the logarithm of the observed [O iii ]/H βratio.These data can be used to estimate the ionizing ﬂux and its error when both H βand [O iii ]can be measured reliably,but a direct reddening measurement is not available.For log([O iii ]/H β)∼>0.2little reddening is seen and the ionizing ﬂux can be estimated accurately.[O ii ]/H αo ratios may be due to a selection eﬀect:these galaxies are expected to have small EW(H β)and will drop out of the sample with reliable redden-ing corrections.Therefore,the scatter in [O ii ]/H αo ratio for small EW([O ii ])may be underestimated in ﬁgure 7a .Broadband colors help to distinguish galaxies that are particularly dusty.In ﬁgures 7b and c we plot the logarithm of the ratio of the observed [O ii ]ﬂux to the reddening corrected H αﬂux versus the eﬀec-tive (U −B )and (B −R )color,respectively.Our ef-fective colors are the average colors measured within the half-light radius in B .Whereas the range in [O ii ]/H αo for galaxies bluer than (U −B )e ∼−0.3or (B −R )e ∼0.95is only ∼0.5dex (a scatter of ∼0.12dex),redder galaxies occupy nearly the full range of observed [O ii ]/H αo .Again,the galaxies dominated by star formation have the highest [O ii ]/H αo ratios.The trends shown here are purely empirical,and the correlations do not have direct physical causes.It remains to be seen if they hold at higher redshifts.6.IMPLICATIONS FOR HIGHER REDSHIFTSIntermediate and high redshift spectroscopic studies like the Hawaii Deep Survey (Cowie et al.1994;Songaila et al.1994;Cowie et al.1996)and the Canada-France Redshift Survey (CFRS;Lilly et al.1995;Hammer et al.1997)have shown that the fraction of relatively bright galaxies with EW([O ii ])<−15˚A increases strongly with redshift.Hammer et al.(1997)showed that converting [O ii ]into a SFR using Kennicutt’s (1992)calibration leads to a production of long-lived stars in excess of the number observed at the present ing the Gallagher et al.(1989)calibration for blue galaxies instead implies that 75%of the present-day mass in stars have been produced since z ∼1.The lumi-nosities sampled in the CFRS survey are comparable to those in the present sample.Hammer et al.(1997)speculate that excitation and/or dust play a role,and our results conﬁrm this.Cowie et al.(1997)found remarkably little extinc-tion in the bulk of the blue star forming galaxies at redshifts z >0.8.The results by Pettini et al.(1998)for a small sample of z ∼3Lyman break galaxies are consistent with this general picture,as their UV selected galaxies generally show low absorption com-pared to our L ∗galaxies.The one possible excep-tion,DSF 2237+116C2,is the reddest,most massive galaxy in their sample.These results indicate that the correlation of reddening and excitation with lu-minosity may change with look-back time,but the colors and equivalent widths might well remain eﬀec-tive indicators of reddening.JANSEN,FRANX,&FABRICANT9Fig.7—(a )Logarithm of the ratio of the observed [O ii ]ﬂux to the ionizing ﬂux versus the logarithm of (the negative of)the [O ii ]equivalent width.Plotting symbols are coded according to morphological type as in ﬁgure 1.Upper limits are used to indicate data points with errors larger than 0.15dex.The upper left region may be depleted due to selection eﬀects.(b )Logarithm of the ratio of the observed [O ii ]ﬂux to the ionizing ﬂux versus eﬀective rest-frame (U −B )color.(c )Same as (b )but using eﬀective rest-frame (B −R )color.The uncertainties in the SFR derived from [O ii ]are of the order of a factor of 3if no other information is available.7.SUMMARYWe have used spectrophotometry for 85emission line galaxies from the Nearby Field Galaxy Survey sample to investigate the dependence of the [O ii ]/H αratio on galaxy luminosity.Reddening and excitation diﬀerences are the main cause of the anti-correlation between [O ii ]/H αand galaxy luminosity.Both are strongly correlated with absolute magnitude and are likely caused by systematic variation in metallicity as a function of galaxy luminosity.Excitation models match the dust corrected line ratios within the accu-racy of our data.The total variation in the ratio of the observed [O ii ]ﬂux to the reddening corrected H αﬂux is a factor 25.The observed diﬀerence between the [O ii ]–SFR calibrations of Gallagher et al.(1989)and Kenni-cutt (1992a)is in the sense expected from the diﬀer-ence in galaxy luminosity between the two samples.We conﬁrm the conjecture of Hammer et al.(1997)that systematic variations in reddening by dust play an important role when interpreting emission line strengths in terms of SFRs.When corrections for metallicity and dust are not possible,the use of [O ii ]ﬂuxes to measure star forma-tion rates may result in an overestimate of a factor of 3if local calibrations for luminous galaxies are used.We show that H βis a signiﬁcantly better tracer of star formation than [O ii ],and we discuss some em-pirical trends which may be useful in the high redshift regime.ACKNOWLEDGEMENTSThis work was supported by grants from the Uni-versity of Groningen,the Leiden Kerkhoven-Bosscha Fund,the Netherlands Organisation for Scientiﬁc Re-search (NWO),and by the Smithsonian Institution.We thank the CfA TAC for generously allocating time for this project over three years.R. A.J.thanks the Harvard-Smithsonian Center for Astro-physics and the F.L.Whipple Observatory for hos-pitality during numerous visits,when all of the obser-vations and part of this work were carried out,and ESA’s ESTEC where this work was completed.We thank the referee,Dr.J.S.Gallagher,for his thought-ful comments that helped improve the manuscript.10[O II]AS A TRACER OF STAR FORMATIONREFERENCESBuat,V.,and Xu,C.1996,A&A,306,61Burstein,D.,&Heiles,C.1984,ApJS,54,33Calzetti, D.,Kinney,A.L.,and Storchi-Bergmann,T.1994, ApJ,429,582Cowie,L.L.,Gardner,J.P.,Hu,E.M.,Songaila,A.,Hodapp, K.-W.,&Wainscoat,R.J.1994,ApJ,434,114Cowie,L.L.,Songaila,A.,Hu,E.M.,&Cohen,J.G.1996, AJ,112,839Cowie,L.L.,Hu,E.M.,Songaila,A.,&Egami,E.1997,ApJ, 481,L9de Lapparent,V.,Geller,M.J.,&Huchra,J.P.1989,ApJ, 343,1de Vaucouleurs,G.,de Vaucouleurs,A.,Corwin,H.G.Jr., Buta,R.J.,Paturel,G.,&Fouqu´e,P.1991,Third Refer-ence Catalog of Bright Galaxies,Springer-Verlag,New York (RC3)Edmunds,M.G.,&Pagel,B.E.J.1984,MNRAS,211,507 Gallagher,J.S.,Bushouse,H.,&Hunter,D.A.1989,AJ,97, 700Hammer,F.,Flores,H.,Lilly,S.J.,Crampton,D.,Le F`e vre, O.,Rola,C.,Mallen-Ornelas,G.,Schade,D.,&Tresse,L. 1997,ApJ,481,49Huchra,J.P.,Davis,M.,Latham,D.,&Tonry,J.1983,ApJS, 52,89(CfA I)Jansen,R.A.,Franx,M.,Fabricant,D.G.,&Caldwell,N. 2000a,ApJS,126,271Jansen,R.A.,Fabricant,D.G.,Franx,M.,&Caldwell,N. 2000b,ApJS,126,331Kennicutt,R.C.,Jr.1992a,ApJ,388,310Kennicutt,R.C.,Jr.1992b,ApJS,79,255Kennicutt,R. 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大气科学类词汇小词典

大气科学类词汇小词典Made by superjyq@lilybbs如有疏漏，敬请指正[A]a priori probability 先验机率a priori reason 先验理由A scope (indicator) A示波器Abbe number 阿贝数ABC bucket ABC 吊桶aberration 像差；光行差aberwind 阿卑风ablation 消冰；消冰量ablation area 消冰区abnormal 异常abnormal lapse rate 异常直减率abnormal propagation 异常传播abnormal refraction 异常折射abnormal weather 异常天气abnormality 异常度；距平度above normal 超常Abraham's tree 亚伯拉罕树状卷云abrego 阿勃列戈风abroholos 亚伯落贺颮Abrolhos squalls 亚伯落贺颮abscissa 横坐标absolute 绝对absolute acceleration 绝对加速度absolute altimeter 绝对高度计absolute altitude 绝对高度absolute angular momentum 绝对角动量absolute annual range of temperature 温度绝对年较差absolute black body 绝对黑体absolute ceiling 绝对云幕高absolute coordinate system 绝对坐标系absolute drought 绝对乾旱absolute error 绝对误差absolute extremes 绝对极端值absolute frequency 绝对频率absolute gradient current 绝对梯度流absolute humidity 绝对溼度absolute index of refraction 绝对折射率absolute instability 绝对不稳度absolute instrument 绝对仪器absolute isohypse 绝对等高线absolute linear momentum 绝对线性动量absolute momentum 绝对动量absolute monthly maximum temperature 绝对月最高温absolute monthly minimum temperature 绝对月最低温absolute motion 绝对运动absolute parallax 绝对视差absolute parcel stability 绝对气块稳度absolute potential vorticity 绝对位涡absolute pyrheliometer 绝对日射强度计absolute reference frame 绝对坐标系absolute refractive index 绝对折射率absolute scale 绝对标度absolute scale of temperature 温度绝对标度absolute stability 绝对稳度absolute standard barometer 绝对标準气压计absolute temperature 绝对温度absolute temperature scale 绝对温标absolute topography 绝对地形absolute unit 绝对单位absolute vacuum 绝对真空absolute value 绝对值absolute variability 绝对变率absolute velocity 绝对速度absolute vorticity 绝对涡度absolute zero 绝对零度absorbent solution 吸收溶液absorber 吸收器；吸收体；吸收剂absorbing agent 吸收剂absorbing function 吸收函数absorbing medium 吸收介质absorbing power 吸收能力absorptance 吸收比absorption 吸收absorption band 吸收带absorption coefficient 吸收係数absorption cross-section 吸收截面absorption factor 吸收率absorption function 吸收函数absorption hygrometer 吸收溼度计absorption length 吸收长度absorption line 吸收线absorption liquid 吸收液体absorption spectrometer 吸收分光计absorption spectrum 吸收谱absorptive index 吸收指数absorptive power 吸收率；吸收能力absorptivity 吸收率accelerated erosion 加速侵蚀accelerating force 加速力acceleration 加速度acceleration of gravity 重力加速度acceleration potential 加速位acceleration spectrum 加速谱accelerator 加速器；催速剂accelerometer 加速计acceptance region 容许范围accessory cloud 附属云accidental error 偶然误差acclimate 适应气候acclimation 气候适应acclimatization 气候适应accommodation 调节accommodation coefficient 调节係数accretion 撞冻；撞併accretion efficiency 撞冻效率；撞併效率accumulated temperature 积温accumulated temperature curve 积温曲线accumulation 积冰量accumulation area 积冰区accumulative raingauge 积雨器accuracy 準确度；精密度acdar 声达acicular ice 丝状冰acid deposition 酸性沉降acid fog 酸雾acid fume 酸烟acid mist 酸靄acid precipitation 酸性降水acid rain 酸雨acid-containing soot 含酸煤烟acidification 酸化acidity 酸度aclinic line 磁倾赤道acoustic (echo) sounder 声测器acoustic (echo) sounding 声测acoustic absorption 声吸收acoustic admittance 声导纳acoustic attenuation constant 声衰减常数acoustic cloud 声反射云acoustic detection and ranging (acdar) 声达acoustic Doppler sounder 都卜勒声测器acoustic Doppler system 都卜勒声测系统acoustic emission monitoring 声发射监测acoustic fluctuation 声变差acoustic fog 声雾acoustic frequency generator 音频发生器acoustic navigation system 声导航系统acoustic pollution 声污染acoustic pressure 声压acoustic radar 声达acoustic reflection 声反射acoustic refraction 声折射acoustic scattering 声散射acoustic thermometer 声波温度计acoustic velocity 声速acoustic wave 声波acoustical scintillation 声闪烁acoustic-gravity wave 声重力波acoustic-microwave radar 声微波雷达acoustics 声学acquisition 收集acquisition range 收集范围acrocyanosis 冻疮actinic 光化[性]actinic absorption 光化吸收actinic balance 热辐射计actinic ray 光化射线actinogram 日射自记图actinograph 日射仪actinometer 日射计actinometry 日射测定术actinon 錒射气action center 活动中心activation 活化active (remote sensing) system 主动[遥测]系统active (remote sensing) technique 主动[遥测]法active accumulated temperature 有效积温active anafront 活跃上滑锋active aurora 活跃极光active carbon 活性碳active cavity radiometer (ACR) 主动腔体辐射计active center 活跃中心active day [地磁]扰动日active front 活跃锋active glacier 活冰川active katafront 活跃下滑锋active layer 活冻层active monitoring system 主动监测系统active monitoring technique 主动监测技术active monsoon 活跃季风active permafrost 活跃永冻层active pollution 活性污染active reaction 活性反应active satellite 主动卫星active scattering aerosol spectrometer probe (ASASP) 主动气[悬]胶径谱仪active solar region 太阳活动区active steering 主动驶引active sun 活跃太阳active surface 活动面active volcano 活火山activity of a foyer of atmospherics 天电源强度actual elevation 实际高度actual evapotranspiration 有效蒸散[量]actual flying weather 实际飞行天气actual pressure 实际气压actual time of observation 实际观测时间acute pollution 急性污染adaptation brightness 适应亮度adaptation illuminance 适应亮度adaptation level 适应亮度adaptation luminance 适应亮度adaptation process 适应过程adaptive control 自适应控制adaptive disease 水土病adaptive filtering 自适应滤波adfreezing 冰结adhesion 附著力adiabat 绝热线adiabatic 绝热adiabatic approximation 绝热近似adiabatic ascending 绝热上升adiabatic atmosphere 绝热大气adiabatic change 绝热变化adiabatic chart 绝热图adiabatic compression 绝热压缩adiabatic condensation 绝热凝结adiabatic condensation point 绝热凝结点adiabatic condensation pressure 绝热凝结气压adiabatic condensation temperature 绝热凝结温度adiabatic condition 绝热状态adiabatic cooling 绝热冷却adiabatic curve 绝热曲线adiabatic diagram 绝热图adiabatic effect 绝热效应adiabatic equation 绝热方程adiabatic equilibrium 绝热平衡adiabatic equivalent temperature 绝热相当温度adiabatic expansion 绝热膨胀adiabatic gradient 绝热梯度adiabatic invariant 绝热不变量adiabatic lapse rate 绝热直减率adiabatic law 绝热定律adiabatic liquid water content 绝热液态水含量adiabatic motion 绝热运动adiabatic process 绝热过程adiabatic psychrometer 绝热乾溼计adiabatic region 绝热区adiabatic saturation point 绝热饱和点adiabatic saturation pressure 绝热饱和气压adiabatic saturation temperature 绝热饱和温度adiabatic sinking 绝热下捵沉adiabatic temperature change 绝热温度变化adiabatic trail 绝热凝结尾adiabatic warming 绝热增温adiabatic wet-bulb temperature 绝热溼球温度adjacent field-of-view method 相邻视场法adjoint 伴随adjustable cistern barometer 调槽气压计adjoint method 伴随法adjoint technique 伴随法adjustment 校正；调整adjustment of long wave 长波调整adjustment process 调整过程adjustment time 调整时间admissible error 容许误差adret [山]向阳面adsorbent 吸附剂adsorption 吸附[作用]advanced atmospheric sounding and imaging radiometer (AASIR) 先进大气探测成像辐射计advanced cloud wind system 先进云风系统advanced microwave sounding unit (AMSU) 先进微波探测装置advanced moisture and temperature sounder (AMTS) 先进温溼探测器advanced TIROS-N 先进泰洛斯N 卫星advanced vidicon camera system 先进光电摄影系统advection 平流advection change 平流变化advection effect 平流效应advection effluent 平流流出[量]advection equation 平流方程advection fog 平流雾advection frost 平流霜advection inversion 平流逆温advection jet 平流喷流advection process 平流过程advection propagation 平流传播advection scale 平流尺度advection velocity 平流速度advection-diffusion equation 平流扩散方程advective boundary layer 平流边界层advective change 平流变化advective flux 平流通量advective form 平流形式advective hypothesis 平流假说advective model 平流模式advective pressure tendency 平流气压趋势advective term 平流项advective thunderstorm 平流雷雨；平流雷暴advective time scale 平流时间尺度advective-radiation fog 平流辐射雾adverse factor 有害因子adverse weather 不良天气adverse weather condition 不良气象条件adverse wind 逆风advice 通告advisory area 警示区advisory forecast 警示预报aeolian 风成aeolian anemometer 风声风速计aeolian sounds 风激声aeolian tones 风音aeration 通气aeroclimatology 高空气候学aerial 天空[的]；天线aerial contaminant 空气污染物aerial contamination 空气污染aerial detection 空气检测；空中检测aerial exploration 高空探测aerial fog 气雾aerial gain 天线增益aerial photograph 航空摄影aerial plankton 大气浮游生物aerial reconnaissance 航空侦察AERO code 航空天气电码aerobiology 大气生物学aerochemistry 气体化学aerodrome elevation 机场标高aerodrome forecast 机场[天气]预报aerodrome meteorological minimum 机场最低气象条件aerodynamic [空]气动力[的]aerodynamic balance [空]气动力秤aerodynamic coefficient [空]气动力係数aerodynamic contrail [空]气动力凝结尾aerodynamic force [空]气动力aerodynamic instability [空]气动力不稳度aerodynamic laboratory [空]气动力实验室aerodynamic method [空]气动力法aerodynamic observatory [空]气动力实验室aerodynamic resistance [空]气动力阻力aerodynamic roughness [空]气动力粗糙度aerodynamic smoothness [空]气动力平滑度aerodynamic trail [空]气动力凝结尾aerodynamically rough surface [空]气动力粗糙面aerodynamically smooth surface [空]气动力平滑面aerodynamics [空]气动力学aeroembolism 高空病；气栓症aerogel 气凝胶aerogram 雷氏热力图；高空气象仪图aerograph 高空气象仪aerographical chart 高空气象图aerolite 陨石aerologation 测高航行aerological 高空[的]aerological days 高空气象日aerological station 高空站aerological table 高空报表aerology 高空气象学aeromancy 航空天气预报aerometeorograph 高空气象仪aerometer 气体比重计aeronautical climatology 航空气候[学]aeronautical meteorological service 航空气象服务aeronautical meteorological station 航空气象站aeronautical meteorology 航空气象学aeronautics 航空学aeronomosphere 特高层大气aeronomy 高层大气物理学；气文学aeropause 适航层顶aerophotography 航空摄影学aerophysics 航空物理学aerosol 气[悬]胶aerosol analyzer 气[悬]胶分析仪aerosol climatic effect (ACE) 气[悬]胶气候效应aerosol climatology 气[悬]胶气候[学] aerosol composition 气[悬]胶成分aerosol detector 气[悬]胶侦测仪aerosol electricity 气[悬]胶电[学]aerosol layer 气[悬]胶层aerosol loading 气[悬]胶负载aerosol optical thickness 气[悬]胶光学厚度aerosol particle 气[悬]胶粒子aerosol size distribution 气[悬]胶径谱aerosoloscope 气[悬]胶仪aerosolsonde 气[悬]胶送aerosphere 气界；气圈aerostat 气球；飞艇aerostat meteorograph 气球气象仪aerostatic balance 气静力秤aerostatics 气体静力学aerothermochemistry 空气热力化学aerovane 舵式测风仪aestival 夏季[的]aestivation 夏蛰；夏眠Afer 阿非风afforestation 造林afghanets 阿富汗[强]风African easterly jet (AEJ) 非洲东风喷流African wave 非洲波Africino 阿非风Africo 阿非风Africuo 阿非风Africus veutus 阿非风after image 留像after summer 秋老虎after-exercise chill 运动后寒冷afterglow 餘辉；晚霞afterheat 秋老虎aftershock 餘震ageostrophic 非地转[的]ageostrophic acceleration 非地转加速ageostrophic advection 非地转平流ageostrophic circulation 非地转环流ageostrophic motion 非地转运动ageostrophic wind 非地转风ageostrophic wind component 非地转风分量agglomeration 撞拼agglutination 黏合[作用]aggregation 聚合aggressive biometeorological index 衝击[性]生物气象指数agonic line 无偏线agricultural climatology 农业气候学agricultural meteorological station 农业气象站agricultural meteorology 农业气象学agricultural seasons 农作季[节]agroclimate 农业气候agroclimatic analogy 农业气候类比agroclimatic atlas 农业气候图集agroclimatic classification 农业气候分类agroclimatic demarcation 农业气候区划agroclimatic index 农业气候指数agroclimatic region 农业气候区agroclimatography 农业气候誌agroclimatology 农业气候学agrometeorological forecast 农业气象预报agrometeorological index 农业气象指数agrometeorological station 农业气象站agrometeorological yield forecast 农业气象產量预报agrometeorology 农业气象学agronomy 农艺学agrotopoclimatology 农业地形气候学agueil 阿格伊风Agulhas current 阿古拉斯海流aiguolos 阿格洛斯风air 空气；微风air atomizer 空气雾化器air bubble 气泡air bumps [空气]颠簸air cascade 气瀑air cataracts 气瀑air circulation 空气环流air column 气柱air conditioning 空调air conductivity 空气传导性；空气导电率air current 气流air density 空气密度air discharge 空中放电air drainage 空气洩流air filter 空气过滤器air fountains 气泉air freezing-index 空气结冰指数air hoar 高霜air mass 气团；大气光程air parcel 气块air parcel trajectory 气块轨跡air particle 空气粒子air plankton 大气浮游生物air pocket 气穴air poise 气静力秤air pollutant 空[气]污[染]物air pollution 空[气]污[染]物air pollution alert 空[气]污[染]预警air pollution chemistry 空[气]污[染]化学air pollution code 空[气]污[染]代码air pollution disaster 空[气]污[染]灾害air pollution episode 空[气]污[染]事件air pollution forecasting 空[气]污[染]预报air pollution index 空[气]污[染]指数air-position indicator 空中位置指示器air pollution law 空[气]污[染]法air pollution legislation 空[气]污[染]立法air pollution meteorology 空[气]污[染]气象学air pollution observation station 空[气]污[染][观测]站air pollution potential 空[气]污[染]潜势air pollution regulation 空[气]污[染]法规air pollution source 空[气]污[染]源air pollution standard 空[气]污[染]标準air pressure 气压air quality 空气品质Air Quality Act 空气品质法案air quality control region 空气品质控制区air quality standard 空气品质标準air report 飞机报告air resistance 空气阻力air resource 空气资源air route 航线air route (weather) forecast 航线[天气]预报air sampling rig 空气取样装置air shower 空气射丛air sickness 航空病air stream 气流air temperature 气温air thawing-index 空气解冻指数air thermometer 气温计air torrent 空气急流air trajectory 空气轨跡air trap 气阱air wave 气波airborne 空中浮游[的]；机载[的]；空载[的]airborne (search) radar 机载[搜索]雷达airborne cloud collector 机载云粒收集器airborne dye lidar 机载有色光达airborne laser radar 机载雷射雷达airborne particulate 空中悬浮微粒airborne radiation thermometer 机载辐射温度计airborne spectrometer 机载径谱计；机载分光计aircraft actinometer 机载日射计aircraft ceiling 飞机云幂aircraft drop windsonde (ACDWS) 飞机投落送aircraft electrification 飞机带电[化]aircraft hazard 飞机视障aircraft ice accretion 飞机积冰aircraft icing 飞机积冰aircraft impactor 机载撞击[取样]器aircraft integration data system (AIDS) 飞机资料整合系统aircraft measurement 机载测量[仪器]；航测[记录]aircraft meteorological station 飞机气象站aircraft observation 飞机观测aircraft report 飞机报告aircraft sounding 飞机探空aircraft thermometry 飞机测温术aircraft turbulence 飞机乱流aircraft weather reconnaissance 飞机气象侦察airdrome forecast 机场[天气]预报airdrome pressure 场面气压airdrome special weather report 机场特别天气报告airdrome warning 机场警报air-dropped expendable bathythermograph (AXBT) 空投消耗性深温仪air-earth conduction current 地空传导电流air-earth current 地空电流airflow 气流airflow multimeter 气流综合测量计airfoil section 尾翼截面airframe deicing 飞机除冰airframe icing 飞机积冰airgauge 气压表airglow 气辉；夜光airlight 空中光airlight formula 空中光公式air-mass analysis 气团分析air-mass characteristic 气团特性air-mass classification 气团分类air-mass climatology 气团气候学air-mass fog 气团雾air-mass frequency 气团频率air-mass identification 气团辨认air-mass meteorology 气团气象学air-mass modification 气团变性air-mass precipitation 气团降水air-mass property 气团属性air-mass shower 气团阵雨air-mass source (region) 气团源地air-mass thunderstorm 气团[性]雷雨；气团[性]雷暴air-mass transformation 气团变性air-mass transport 气团传送air-mass-type diagram 气团类型图解airmeter 气流计air-ocean coupled model 气海耦合模式airplane meteorograph 飞机气象仪airplane observation 飞机观测airport elevation 机场标高airport height 机场高度airport surveillance radar 机场监视雷达air-sea boundary process 气海边界过程air-sea coupled model 气海耦合模式air-sea interaction 气海交互作用air-sea interface 气海界面air-sea temperature difference 气海温差airspeed 空速airsphere 气圈air-water interface 气水界面air-water interface scattering 气水界面散射airway 航[空]线airway weather 航线天气airways code 航线电码airways forecast 航线预报airways forecasting 航线预报airways observation 航线观测airways shelter 航空气象仪器罩Airy function 艾瑞函数Airy theory of rainbow 艾瑞虹理论Aitken dust-counter 艾肯计尘器Aitken nuclei 艾肯核Aitken nucleus counter 艾肯计尘器Aitken particle 艾肯粒子Alaska current 阿拉斯加海流Alaska high 阿拉斯加高压Albe 阿尔培风albedo 反照率albedo of the earth 地球反照率albedograph 反照仪albedometer 反照计Alberta low 亚伯达低压alcohol-in-glass thermometer 酒精温度计alcyone days 冬至风静期alee 背风Aleutian current 阿留申海流Aleutian low 阿留申低压Alfven wave 阿尔芬波algorithm 算则aliased spatial frequency 混淆空间频率aliasing error 混淆误差aliasing range 混淆范围alidade 测高仪alienation 异化alignment chart 线规图alimentation 滋冰Alisov's classification of climate 阿利索夫气候分类alkali fume 硷性烟雾alkalinity 硷度All Saints' summer 万圣夏Allard's law 阿拉德定律allerheiligenwind 万圣风Allhallow summer 万圣夏All-hallown summer 万圣夏allobar 变压allobaric 变压[的]allobaric wind 变压风allohypsic wind 变高风allohypsography 变高线型allowable error 容许误差all-sky photometer 全天光度计all-round visibility 全方位能见度all-sky camera 全天照相机all-weather airport 全天候机场all-weather flight 全天候飞行all-weather landing 全天候降落all-weather wind vane and anenometer 全天候风向风速计almanac 天文年历almucantar 地平纬圈almwind 阿姆风aloegoe 阿洛古风along-track scanning 沿轨道扫描alopach 阿卑风aloup de vent 夜落坡风alpenglow 高山辉alpengluhen 高山辉alpha effect; αeffect "阿尔法效应；α效应"alpha ionization; αionization 阿尔法射线电离；α射线电离alpha particle; αparticle 阿尔法粒子；α粒子alpha ray; α-ray 阿尔法射线；α射线alpha scale; αscale 阿尔法尺度；α尺度alphanumeric data 文数资料alpine climate 高山气候alpine glow 高山辉alpine tundra 高山冻原altanus 奥坦风Alter shield 阿泰挡alternate airport 备降机场alternate forecast 备降机场天气预报alternating current 交流电altichamber 压力室alti-electrograph 空中电场仪altigraph 高度仪altimeter 高度计altimeter corrections 高度计订正altimeter setting 高度拨定值altimeter-setting indicator 高度拨定值指示器altimetry 测高术altithermal 高温气候[的]altitude 高度altitude correction 高度订正altitude disease 高空病altitude profile measurement 高度剖线测量alto cloud 中云altocumulus 高积云altocumulus castellanus 堡状高积云altocumulus cumulogenitus 积云性高积云altocumulus duplicatus 重叠高积云altocumulus floccus 絮状高积云altocumulus glomeratus 簇状高积云altocumulus informis 无定状高积云altocumulus lacunosus 网状高积云altocumulus lenticularis 荚状高积云altocumulus nebulosus 雾状高积云altocumulus opacus 蔽光高积云altocumulus perlucidus 漏光高积云altocumulus radiatus 辐状高积云altocumulus stratiformis 层状高积云altocumulus translucidus 透光高积云altocumulus undulatus 波状高积云altostratus 高层云altostratus densus 浓密高层云altostratus duplicatus 重叠高层云altostratus fractus 碎高层云altostratus lenticularis 荚状高积云altostratus maculosus 斑状高层云altostratus opacus 蔽光高层云altostratus precipitus 降水性高层云altostratus radiatus 辐状高层云altostratus translucidus 透光高层云altostratus undulatus 波状高层云amateur forecast 业餘预报amateur weather station 业餘气象台ambient air 环境空气ambient air monitoring 环境空气监测ambient air quality 环境空气品质ambient air quality standard 环境空气品质标準ambient atmosphere 环境空气ambient liquid-water content 环境液态水含量ambient noise 环境噪音ambient noise level 环境噪音级ambient particulate concentration 环境微粒浓度ambient pollution burden 环境污染负荷ambient pressure 环境气压ambient temperature 环境温度Amble diagram 安布尔图amino acid 胺基酸ammonia 氨ammonia cycle 氨循环amorphous 非晶形[的]amorphous cloud 无定形云amorphous frost 无定形霜amorphous sky 混乱天空amorphous snow 无定形雪amphidromic point 无潮点amphidromic region 无潮区amphidromos 转风点amplification factor 放大因子amplification matrix 放大矩阵amplifier 放大器amplitude 振幅amplitude correlation function 振幅相关函数amplitude modulation 调幅amplitude-modulated indicator 调幅指示器anabaric 升压anabatic front 上滑锋anabatic wind 上坡风anaflow 上升气流anafront 上滑锋anallobar 升压线anallobaric 升压[的]anallobaric center 升压中心analog 类比[型]analog method 类比法analogue 类比[型]analysis 分析analysis initialization cycle 分析初始化循环analytical error 解析误差analytical solution 解析解anathermal climatic change 增温期气候变化anchor ice 底冰anchored trough 滞槽Andes glow 安地斯闪Andes lights 安地斯光Andes lightning 安地斯闪andhi 安地尘暴anelastic approximation 非弹性近似anelastic equation 非弹性方程anemobiagraph 压管风速仪anemoclinograph 风倾仪anemoclinometer 风倾计anemogenic curl effect 风生涡度效应anemogram 风速自记线anemograph 风速仪anemology 测风学anemometer 风速计anemometer factor 风速计因子anemometer level 风速计高[度]anemometer mast 测风桿anemometer tower 测风塔anemometer with stopwatch 停錶风速计anemometrograph 风向风速风压计；测风仪anemometry 测风术anemophile 避风植物anemoscope 测风器anemotachometer 风速计anemovane 接触式风向风速器aneroid 空盒[的]；空盒气压计aneroid altimeter 空盒高度计aneroid barograph 空盒气压仪aneroid barometer 空盒气压计aneroid capsule 空盒aneroidogram 空盒气压线aneroidograph 空盒气压仪angel (echo) 异常回波angin 安轻风angin-darat 安轻达拉脱风angin-laut 安轻劳特风angle bracket 尖括弧angle of aperture 孔径角angle of arrival 到达角angle of declination 赤纬度angle of deflection 偏转角angle of deviation 偏角angle of incidence 入射角angle of inclination 倾角angle of minimum deviation 最小偏角angle of pitch 俯仰角angle of reflection 反射角angle of refraction 折射角angle of roll 滚动角angle of view 视角angle of yaw 偏航角angle stem earth thermometer 曲管地温计angle thermometer 曲管湿度计angstrom 埃Angstrom compensation pyrheliometer 埃氏补偿日射强度计Angstrom pyrgeometer 埃氏地面辐射计Angstrom turbidity coefficient 埃氏浊度係数angular displacement 角位移angular distribution 角分布angular divergence 角辐散angular drift 碎石流angular eclipse 环蚀angular field-of-view 角视场angular filter function 角滤波函数angular frequency 角频率angular momentum 角动量angular momentum balance 角动量平衡angular path length [流星]角程长度angular resolution 角解析[度]angular spectrum 角谱angular spreading 角展angular spreading factor 角展因子angular velocity 角速度angular wave number 角波数angular width 角幅anhyetism 缺雨性animal fog 动物雾animal phenology 动物物候学anion 负离子；阴离子anisallobar 等变压零线anisobaric 不等压[的]anisotropic 各向异性[的]anisotropic factor 各向异性因子ankylosis 自由度减损anniversary winds 週年风annual anomaly 年距平annual cycle 年循环annual flood 年洪annual mean 年平均annual range 年较差annual report 年报annual ring 年轮annual variation 年变annulus 环形annulus experiment 环形水槽实验anomalistic period 近点周期anomalous 异常[的]anomalous (cloud) line 异常云线anomalous diffraction 异常绕射anomalous dispersion 异常频散anomalous gradient wind 异常梯度风anomalous high 反常高压anomalous low 反常低压anomalous propagation 异常传播anomaly 异常；距平anomaly correlation 距平相关anomaly of geopotential difference 重力位差距平anomaly of specific volume 比容距平anoxemia 缺氧症anoxia 缺氧antarctic air 南极空气；南极气团antarctic air (mass) 南极气团antarctic anticyclone 南极反气旋Antarctic Circle 南极圈antarctic circumpolar current 绕南极流antarctic climate 南极气候Antarctic Convergence Zone 南极辐合区antarctic front 南极锋antarctic high 南极高压antarctic pole 南极antarctic sea smoke 南极蒸气雾antarctic stratospheric vortex 南极平流层涡旋Antarctic Zone 南极区antecedent precipitation index (API) 雨前指数antenna 天线antenna arcs 反@日弧antenna feed 天线馈antenna gain 天线增益antenna pattern 天线型antenna temperature 天线温度anthelion 反@日anthracometer 二氧化碳测定计anthracometry 二氧化碳测定法anthropecology 人类生态学anthropoclimatic drying power 人為乾燥率anthropogenic climate catastrophe 人為气候突变anthropogenic factor 人為因素antibaric flow 反压流anticlockwise 反鐘向anticorona 反@日华；反月华anticorrelation 反相关anticrepuscular (arch) 反曙暮光[弧]anticrepuscular rays 反曙暮光anticyclogenesis 反[气]旋生[成]anticyclolysis 反[气]旋消[灭]anticyclone 反气旋anticyclonic bora 反旋式布拉风anticyclonic circulation 反旋式环流anticyclonic curvature 反旋式曲率anticyclonic divergence 反旋式辐散anticyclonic eddy 反旋式涡流anticyclonic flow 反旋式气流anticyclone foehn 反气旋焚风anticyclonic gloom 反气旋阴沉[天气]anticyclone movement 反气旋移动anticyclone subsidence 反气旋下沉anticyclonic inversion 反气旋逆温anticyclonic phase 反气旋期anticyclonic ridge 反气旋脊；高压脊anticyclonic rotation 反旋式旋转anticyclonic shear 反旋式风切anticyclonic tornado 反旋式龙捲[风]anticyclonic vortex 反旋式涡旋anticyclonic vorticity 反旋式涡度anticyclonic vorticity advection (AVA) 反旋式涡度平流antifoggant 防雾剂anti-freezing 防冻anti-hail gun 防雹炮anti-hail rocket 防雹火箭anti-icing 防冰Antilles current 安地列斯海流antimonsoon 反季风antineutrino 反微中子antineutron 反中子antiproton 反质子antiselene 反月antisolar point 反@日点anti-symmetric 反对称[的]antitrades 反信风antitriptic wind 摩擦风；滞衡风antitwilight (arch) 反曙暮光[弧]anvil (cloud) 砧状云apartment microclimate 住宅微气候aperiodic 非週期[的]；无振盪[的]aperiodic flow 非周期流aperiodic oscillation 非週期振盪aperiodic signal 非周期信号aperiodic solution 非周期解aperture 孔径；孔apewind 阿卑风aphelion 远日点Apheliotes 阿非料风apob 飞机观测apocenter 远心点apogean tide 远月潮apogean winds 阿波金风apogee 远地点apostilb 阿熙提apparatus 仪器apparent brightness 视亮度apparent diameter 视直径apparent force 视似力apparent freezing point 视凝固点apparent gravity 视重力apparent heat 视热apparent heat source 视热源apparent horizon 视地平apparent luminance 视亮度apparent moisture sink 视水气匯apparent motion of the sun 太阳视运动apparent noon 视午apparent solar day 视太阳日apparent stresses 视应力apparent time 视时apparent velocity 视速度apparent vorticity source 视涡度源apparent wind 视风Appleton layer 阿普顿层applied climatology 应用气候学applied meteorology 应用气象学appointed aerodrome weather report 预约机场天气报告approach visibility 进场能见度approach-light contact height 目视进场高度approximate absolute temperature scale 近似绝对温标approximate value 近似值approximation 近似APT signal simulator 自动图片传送信号模拟器aqueous aerosol 溼气[悬]胶aqueous vapor 水气aquiclude 弱透水层aquifer 供水层aquifuge 绝水层aracaty 阿拉喀风Arago (neutral) point 阿拉哥[中性]点Arago distance 阿拉哥角距Arakawa Jacobian 荒川函数行列式arc cloud 弧状云arc discharge 弧形放电arc line 弧线Arcas rocket 阿卡斯火箭ARCAS-ROBIN system 阿洛火箭探空系统arch twilight 曙暮光弧arched squall 弧形颮Archimedean buoyant force 阿基米得浮力Archimedes principle 阿基米得原理architectural meteorology 建筑气象学archive 档案；存档arcs of contact of halo 晕耳arcs of Lowitz 日珥；罗氏弧arctic air 北极空气；北极气团arctic air mass 北极气团arctic anticyclone 北极反气旋arctic blackout 北极[无线电]衰落[现象]Arctic Circle 北极圈arctic climate 北极气候arctic continental air (mass) 北极大陆气团；北极大陆空气arctic current 北极海流arctic desert 极漠arctic fog 北极雾arctic front 北极锋arctic haze 北极霾arctic high 北极高压arctic mist 北极靄arctic pack 北极陈冰arctic sea smoke 北极蒸气雾arctic smoke 北极蒸气雾arctic stratospheric vortex 北极平流层涡旋arctic treeline 北极树线arctic warming 北极增温arctic whiteout 北极白矇arctic wind 北极风Arctic Zone 北极区arctic-alpine 极性高山区arcticization 北极化；北极装备arcus 弧状[云]ardometer 光测高温计area forecast 区域预报area forecast center 区域预报中心area mean rainfall 面积平均雨量area precipitation 区域降水argon 氬argument of perigee 近地点辐角arid 乾燥arid climate 乾燥气候arid cycle 乾燥週期arid zone 乾旱带aridity 乾燥；乾度aridity factor 乾燥因子aridity index 乾燥指数aridity region 乾[燥]区[域]arifi 阿利非风arithmetic mean 算术平均armoured thermometer 护套水温计arrested topographic wave 截留地形波artesian ground water 自流地下水artificial boundary condition 人造边界条件artificial climate 人造气候artificial cloud 人造云artificial contaminant 人為污染artificial dissipation 人為消散artificial horizon 假地平artificially initiated lightning 人造闪电artificial microclimate 人造微气候artificial nucleation 人造核化[作用]artificial nucleus 人造核artificial precipitation 人造降水artificial radio element 人造放射元素artificial radioactivity 人造放射性artificial rain 人造雨artificial satellite 人造卫星artificial sodium cloud 人造钠云artificial ventilation 人造通风artillery meteorological standard 炮兵气象标準ascendent 升度；负梯度ascending current 上升气流ascending motion 上升运动ascending node 升交点ascending node longitude 升交经度ascending node time 升交时刻ascension rate of balloon 气球上升速率ascending velocity 上升速度ascent 上升ascent curve 上升曲线ash air 含灰空气ash fall 灰沉降ash shower 阵灰ash-gray light 灰色光Asian-Australian monsoon system 亚澳季风系统asifat 阿法风asymmetric circulation pattern 非对称环流型aspect ratio 长宽比；宽高比aspirated electrical capacitor 通风电容仪aspirated quartz-crystal thermometer 通风石英晶体温度计。

专业英语

1.热力学第一定律：the first law of thermodynamicsA :It was stated for a cycle :the net heat transfer is equal to the net work done for a system undergoing a cycle2.热力学第二定律:the second law of thermodynamicsIt is impossible to construct a device that operates in a cycle and whose sole effect is the transfer of heat from a cooler body to a hotter bodyIt is impossible to construct a device that operates in a cycle and produces no other effect than the production of work and the transfer of heat from a single body3.传热学与热力学区别A :heat transfer is the science that seeks to predict the energy transfer that may take place between material bodies as a result of a temperature difference .Thermodynamics teaches that this energy transfer is defined as heat .The science of heat transfer seeks not merely to explain how heat energy may be transferred but also predict the rate at which the exchange will take place under certain specified conditionsThere are three modes of heat transfer1)Conduction heat transfer 2 Convection heat transfer 3 Radiation heat transfer4.锅炉boiler Boilers use heat to convert water into steam for a variety of applications5.热电厂thermal power plantA power station operates using a closed steam power cycle ,where water undergoes various thermodynamic processes in a cyclic process.6.空调air conditioningAir conditioning is a combined process that performs many functions simultaneously .It conditions the air ,transports it and introduces it into the conditioned space ,it also controls and maintains the temperature humidity ,air movement ,air cleanliness .7.制冷原理refrigerationRefrigeration is defined as the process of extracting heat from a lower temperature heat source substance or cooling medium and transferring it to higher temperature heat sink it contains four process ,corresponding four parts .Condenser --expansion valve --evaporator --compressor冰箱的作用：cold storage and preservation二：主关件简介：：压缩机一：Compressor 制冷系统的“心脏”起压缩和输送制冷剂的作用，制冷系统的“心脏”起压缩和输送制冷剂的作用，目前所用为往复活塞式压，缩机。

超大质量黑洞产生的高能中微子探测及巨型中微子射电探测阵列的选址

超大质量黑洞产生的高能中微子探测及巨型中微子射电探测阵列的选址朱春花;翟楠楠;沈冬祥;吕国梁;王兆军;李琳;刘荷蕾;Olivier Martinea-Huynh;Charles Timmermans【摘要】宇宙高能中微子很可能起源于超大质量黑洞与吸积物质的相互作用.这些中微子在传播过程中由于只参与弱相互作用,其轨迹直指起源的特性,使其成为观测宇宙更远的天体的全新窗口.传统的中微子探测方法由于造价高、技术复杂,限制了探测的有效面积和观测时间.巨型中微子射电探测阵列GRAND,由多国共同参与建设,具有造价低、易大面积部署、可全天观测的特点,成为目前最好的选择,通过探测高能中微子寻找超高能宇宙射线的起源.目前在进行GRANDProto300的选址中,我们在内蒙古明安图、新疆巴里坤等地方使用GRANDProto35原型天线进行实地探测.探测结果显示,巴里坤地区具有良好的电磁环境,更加适合该项目的建设.选址探测工作为GRANDProto300的选址及其它射电探测阵列的建设提供了依据.【期刊名称】《新疆大学学报（自然科学版）》【年(卷),期】2019(036)002【总页数】6页(P127-131,152)【关键词】超大质量黑洞;高能中微子;射电探测;超高能宇宙射线;选址探测;射电阵列【作者】朱春花;翟楠楠;沈冬祥;吕国梁;王兆军;李琳;刘荷蕾;Olivier Martinea-Huynh;Charles Timmermans【作者单位】新疆大学物理科学与技术学院,新疆乌鲁木齐830046;新疆大学物理科学与技术学院,新疆乌鲁木齐830046;新疆大学物理科学与技术学院,新疆乌鲁木齐830046;新疆大学物理科学与技术学院,新疆乌鲁木齐830046;新疆大学物理科学与技术学院,新疆乌鲁木齐830046;新疆大学物理科学与技术学院,新疆乌鲁木齐830046;新疆大学物理科学与技术学院,新疆乌鲁木齐830046;索邦大学、巴黎狄德罗大学、巴黎索邦西岱大学,法国;中国科学院国家天文台,北京100012;奈梅亨大学数学、天体物理与粒子物理研究所,荷兰;荷兰国家核物理与高能物理研究所,荷兰【正文语种】中文【中图分类】P161中微子具有不参与电磁相互作用、强相互作用的特性，在传播过程中几乎不改变传播方向，轨迹直指起源地[1].2013年，南极Icecube中微子实验在《Science》发表，声称已经观测到地外高能中微子，这一发现预示着中微子天文学时代的到来[2].去年，Icecube又发现高能中微子就可能起源于正在吸积物质的超大质量黑洞[3].特别是最近，视界望远镜给出了一座质量高达65亿倍太阳质量的超大质量黑洞照片[4].对高能中微子的探测是解决超高能宇宙射线起源问题的重要手段.由于其特性，天文学家可以通过对它的观测了解宇宙中更远的天体.这种特性也导致人们对它的探测十分困难，为得到统计上可观的宇宙中微子事件需要巨大的探测器.目前对中微子的探测主要分为三种方法[5,6]：(1)使用表面粒子探测器.由于高能中微子在传播过程中与周围的分子或原子之间弱的相互作用，引发粒子级联效应，粒子数量增多，可以通过探测大气中粒子的分布来确定初期粒子的到达方向，例如TA(The Telescopes Array)、HAWC(The High-Altiude Water Cherenkov)等.然而，由于粒子探测器造价昂贵限制了有效探测面积；(2）使用光学探测器.中微子在相对透明的介质中相互作用时会产生Cherenkov光或荧光效应，可以通过在介质（例如水，冰等）中部署相关的探测器进行探测这些事件，例如POEMMA(The Probe Of Multi-Messenger Astrophysics)、AMANDA(Muon and Neutrino Detector Array)等，在大气中使用光学探测器，会受天气和光照的严重影响，因此运行时间受限，而建立在冰层、水中的探测器阵列，加大了大面积部署的难度；(3)使用射电阵列.当粒子速度超过介质中光的相速时，会产生不对称的带电粒子分布，进而产生相干的射电辐射，即Cherenkov 辐射，而且宇宙次级带电粒子在地磁场中产生同步辐射，这种辐射波段在射电波段[7]，可以使用射电技术探测.与传统的探测手段比较，具有价格便宜、易于大面积部署、易维护、接近100%的观测时间的优势，例如在南极冰层中部署的IceCube探测器、以及正在建设中的巨型中微子探测射电阵列GRAND(The Giant Radio Array for Neutrino Detection）. GRAND旨在通过探测高能中微子寻找超高能宇宙射线的起源[8]，采用模块式安装，易于维护，可大面积的部署，使用山体当做自然靶标提高探测高能中微子事件效率，其预期灵敏度将比IceCude 要高一个量级，甚至更好.GRAND 计划在10∼15年的时间在200 000 km2的面积上，部署100 000 根天线，GRAND的建成将成为世界上最大的宇宙中微子探测器.GRAND 科学目标分为三个阶段：第一阶段进行快速射电爆、巨型射电脉冲，再电离时代的研究；第二阶段进行超高能宇宙射线的研究工作；第三阶段开启EeV中微子天文学、中微子物理学、超高能伽马射线研究.加速探测高能中微子领域的快速发展[9]，在国内该项目由武向平院士作为带头人，多所科研机构参与，共同推进该项目的设备部署和后续工作的开展.1 GRAND高能中微子探测原理当高能带电粒子、伽马射线或中微子到达地球时，与大气中的原子或分子相互作用产生次级粒子.次级粒子再与周边大气作用，产生更多二级的粒子，以此连续下去产生级联效应，诱发广延大气簇射[10].宇宙射线的直接探测手段，使用天线阵列直接接收粒子在进入大气后产生的射电辐射.第一种射电辐射来自于其本身带有电荷，在地磁场的影响下，运动粒子的簇射前端正负离子发生分离，诱发横向电流，伴有线偏特性的射电辐射[8].该方法不受天气和天光条件的影响，具有较长的有效观测时间.第二种伴随大气簇射发出的射电辐射机制是切伦科夫辐射的低频对应—Askaryan效应—粒子在介质中的运动速度超过光的相速度时诱发次级带电粒子，引发电荷过剩，电荷随时间的变化引发射电辐射.在大气中由于ASkaryan效应比地磁场中的辐射弱数倍，所以在此过程中地磁辐射占据主导地位.GRAND项目通过探测高能中微子在地下相互作用和在大气中相互作用产生的广延簇射事件.在地下稠密的岩石介质增加了中微子在其中发生相互作用的机会，GeV 能级以上的中微子与核子相互作用，通过深度非弹性散射[11,12].在电性流相互作用中，中微子与核子相互作用，吸收一个W 玻色子转变为对应的带电轻子，而末态的轻子类型与相互作用前一致，W 玻色子迅速衰变，即:其中N可以是质子或原子，X代表末态的强子.在中性流相互作用中，中子与核子相互作用，吸收一个Z玻色子转变为相应的中微子，而末态的中微子与相互作用前一致，因此无法区分，即：由于中微子ve 发生电流性相互作用，能量损失通过辐射的方式释放，在岩石介质中的相互作用辐射截面积小，大多数在内部被吸收.因此探测到的概率较低，所以忽略对ve 探测的可能性；中微子vµ 发生电流性相互作用，从岩石表面出射后有较长的轨迹，在天线阵列上端发生簇射的概率低，所以其被探测到的可能性忽略不计；中微子vτ 质量比vµ 和ve 的质量大，发生电流性相互作用辐射能量衰减被进一步抵制，当vτ 穿过岩石介质之后由相互作用产生τ子，τ子会在天线阵列上方发生衰变诱发广延大气簇射，并产生在射电频段内的信号.因此在GRAND的部署和选址工作中，主要目标位置集中在有山脉的无人地区，山体不仅可以增加高能中微子的探测事件概率，还可以屏蔽和吸收由人为造成电磁噪声.图1 不同味中微子的传播示意图Fig 1 Schematic diagram of the propagation of different neutrinos2 选址探测在选址探测过程中使用GRANDProto35天线，其前期已在乌拉斯台试运行，验证了该方案的可行性，并取得较好的探测数据.选址探测设备主要包含三对相互垂直的蝶形天线，可以对三个极化方向进行全方位采样；DAQ(数据采集），采集板初始信号段接有30∼100MHZ的无源模拟滤波器，滤波后的信号通过阈值比较，若满足触发条件则将信号包络通过12 位ADC（模数转换器）以每秒5 000 万次采样数字化，每隔3×3.6 µs 将GPS、时间信息一同打包发送到中央DAQ.此次选址探测是为了推行GRAND阶段中GRANDProto300的实施，该阶段计划在100∼300km2的面积上部署300根天线，目的是对水平簇射的射电探测实验进行验证.为解决由射电信号通过与地面反射波的相互作用强烈衰减带来的水平方向簇射的检测问题，以及到达方向分辨率随着靠近地平线而降低，导致信号难以重建的问题，选择将部分或全部部署在5∼10o的山坡上.选址探测步骤：(1)对周围环境进行视觉检测，查看周围是否有大量人类活动、高压输电线以及山体，评估访问和部署的便利性；(2)将天线X轴对向北方架设天线，测量30∼80MHz频段的瞬态噪声；(3)数据处理画出瞬态噪声图、Fourier变换后的频谱图.以下为在内蒙古、巴里坤地区的探测情况，以及在1KHz、10KHz 基线时，将乌拉斯台数据当作理想数据进行对比，同时通过设置触发阈值可以较好的消除一部分人为噪声.2.1 明安图太阳观测基地在内蒙古明安图太阳观测基地附近，海拔1 300∼1 400m.有较为平缓的山坡，人为活动较少，短距离内有基础的设施.在该地使用两副天线进行瞬态噪声探测，处理数据结果如表1，相比较理想数据而言相差较大.在后面的探测过程中，推测是由于两副天线距离较近产生的射频干涉引起，具体数据见表1.表1 明安图太阳观测基地Tab 1 Mingantu observing station探测编号测量值/理想值测量值/理想值（1kHz）（10kHz）1006.66.2 10210.09.9 10310.514.3 10514.312.8 10617.620.1表2 巴里坤山谷内Tab 2 Within the vally of Balikun探测编号测量值/理想值测量值/理想值（1kHz）（10kHz）B103A7.57.8 B31337.46.8 B31303.03.1B31324.54.6 B31316.26.12.2 巴里坤地区在巴里坤地区的探测，主要可以分为在山谷内、天籁基地附近、戈壁滩周边三部分.巴里坤山谷被大山环绕，地形宽阔平坦，15km左右有个村庄，易于访问和部署.但山谷规模有限，缺乏可用的基础设施.探测结果如表2，从山谷入口的小路旁开始探测，入口处B103A、B3133有较高的噪声，在山谷内部噪声较低，当到达山谷末端时，海拔升高，B3131的噪声也有所提高，具体数据见表2.天籁观测基地处于一个小的山谷中，有较为便利的基础设施和方便的部署和访问条件，但是其面积太小，使用相同的方式，从山谷入口处开始探测直到山谷末端停止探测.其中B3125、B3141几乎在同一地点不同时间进行探测的结果，其他测量结果，比山谷区域的结果稍好，噪声较低.具体数据见表3.在位置靠近大山的路边上，其周围有大面积的开阔区域，人为活动较少，易于访问和部署.对比在路边的两次探测结果，在戈壁路边的结果非常好，噪声较低，具体数据见表4，其中B101、3134巴里坤山谷附近；B3111、103B、3110在巴里坤县附近；B3143天籁基地附近；B3144、3146戈壁路旁.因此与大山相连接的戈壁也是值得GRAND项目考虑的部署区域.3 探测分析对两个探测点B3122、B3111的原始数据进行处理分析（图2、图3）.图2 运行编号B3122测试结果Fig 2 The result of run number B3122图中为三个极化方向各自的经过傅里叶变换后频谱图和噪声频谱图.其中，右侧坐标单位 1 ADC=0.0125mV，左侧图垂直轴单位为mV，图上127 特指数据采集板的编号，三个探极化方向的数据分别对应于C1、C2、C3.图中所示从上往下分别为x轴，y轴，z轴三个极化方向的测量结果，左侧为Fourier变换后频谱图，右侧为对应的瞬态噪声.由于主要考虑到从水平方向来的噪声问题，因此偏重于x轴和y 轴的结果.对于B3122处的a、c、e 图均在30MHz附近出现峰值，其中a、c 两图在其他频率上有一些较小的起伏，而B3111处的探测数据在30∼80MHz频段内存在强烈的干扰信号，尤其是在60MHz、70MHz处存在两个尖锐的峰.b、d、f 图中分别为对应噪声，B3122处探测结果显示，趋势线集中在300ADC 范围内，而B3111处，趋势线变化不均匀，且一直延伸至最大值.在选址中观测两图，频谱图越平缓、噪声图趋势线越窄则证明探测点处没有嘈杂的电磁噪声，可以在较低的触发阈值情况下进行有效的探测，获得更多有用的信息.图3 运行编号B3111测试结果Fig 3 The result of run number B3111表3 天籁观测基地附近Tab 3 Near the Tianlai observing station探测编号测量值/理想值测量值/理想值（1kHz）（10kHz）B312517.610.0 B31414.04.7B31274.75.0 B31222.42.6 B31422.73.2 B31246.23.7 B31284.24.6表4 路边探测Tab 4 Roadside detection探测编号测量值/理想值测量值/理想值（1kHz）（10kHz）B10113.013.1 B31344.65.0 B311114.211.3B103B8.97.4 B31103.53.7 B31434.34.7 B31444.95.7 B31463.33.74 总结探测结果表明在内蒙古探测过程中，两根天线间距较近会严重影响探测结果.在新疆巴里坤地区探测结果显示，在四周环山的区域电磁噪声相对较小其大部分结果都符合选址要求.新疆地区具有优越的地理位置，为GRAND的选址提供了优质的选项.为GRAND 原型阵列的建造，进一步对相关技术进行验证，选址探测为GRANDProto300以及将来建造的射电探测阵列提供了依据.GRAND 的建成将提供大的机遇，开启高能中微子天文学潜力巨大的观测窗口，使我国能在该领域快速发展，使该地区成为国际高能中微子研究的探测中心、学术中心.致谢感谢中国科学院院士武向平老师给予的帮助，使得我能够有这样一个机会接触到该项目，了解目前中微子探测的进展，参与到选址探测的工作中来.感谢国家自然科学基金11763007,11473024,11463005,11863005,11803026 和11503008的支持，也感谢新疆天山雪松基金2017Q014的支持.参考文献：【相关文献】[1]Anchordoqui L A,Barger V,Cholis I.Cosmic neutrino pevatrons:A brand new pathway to astronomy,astrophysics,and particle physics[J].J HEAP,2014,1:1-30.[2]Aartsen M G,Abbasi R,Abdou Y.Evidence for high-energy extraterrestrial neutrinos atthe IceCubedetector[J].Science,2013,342:1242856.[3]Aartsen M G,Abbasi R,Abdou Y.et al.,Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A[J].Science,2018,361:6398.[4]Akiyama K,Alberdi A,Alef W,et al.First M87 Event Horizon Telescope Results.I.The Shadow of the Supermassive Black Hole[J].Ap J,875,1.[5]Cao Z,Xiao G.The status of Ultra high energy neutrino experiments[J].ModPhys,2007,19:18-24.[6]翁路华，施浒立，高超，等.高能宇宙射线射电探测系统接收天线设计[J].电气与仪表技术，2009，4：93-96.[7]张建立，张毅.天山射电实验探测极高能中微子和宇宙射线[J].中国科学，2015，45（11）：119511-1-7.[8]Giant Radio Array for Neutrino Detection:Science and Design.arXiv:1810.09994v1.[9]Waxman E,Bahcall J N.High energy neutrinos from astrophysical sources:An upper bound[J].Phys Rev D,1999,59:023002.[10]O C 阿尔科费尔.宇宙线入门[M].徐春娴，朱清棋，译.北京:科学出版社,1987:3-7.[11]Raj Gandhi,Chris Quigg,Mary Hall Reno,et al.Ultra high-energy neutrino interactions[J].Astroparticle Physics,1996,5:81.[12]Raj Gandhi，Chris Quigg，Mary Hall Reno，et al.Neutrino Interactions at Ultrahigh Energies[J].Physical Review D，1998，58:093009.。

一份关于二维电子气(2DEG)的讲义

Ψ(r, z) = χ(z) ψ(r)
where r is the vector in plane of 2DEG. Throughout our considerations we will assume that all the distances are much larger than interatomic distance and thus we will use the eﬀective
Density of States
The density of states g( ) is deﬁned as number of states per the energy interval , + d . It is clear that
g( ) = δ( − α)
α
where α is the set of quantum numbers characterizing the states. In the present case it includes the subband quantum number n, spin quantum number σ, valley quantum number
v (for n-type materials), and in-plane quasimomentum k. If the spectrum is degenerate
with respect to spin and valleys one can deﬁne the spin degeneracy νs and valley degeneracy
n-AlGaAs i-GaAs
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arXiv:astro-ph/0005172v1 8 May 2000WarmabsorbersinNarrow-LineSeyfert1galaxies

StefanieKomossaaaMax-Planck-Institutf¨urextraterrestrischePhysik,Giessenbachstr.,D-85748

Garching,Germany;email:skomossa@xray.mpe.mpg.de

1DustywarmabsorbersinNLS1galaxiesWarmabsorbers(WAs)areanimportantnewprobeofthephysicalconditionswithinthecentralregionsofactivegalaxies.Theyhavebeenobservedin∼50%ofthewell-studiedSeyfertgalaxiesandhavealsobeendetectedinquiteanumberofNarrow-lineSeyfert1galaxies(seeKomossa2000forareview,andreferencestherein).ThephotoionizationcalculationspresentedbelowwerecarriedoutwithFerland’s(1993)codeCloudy.

DustyWAsweresuggestedtobepresentinseveralNLS1galaxies.ModelcalculationsofdustyWAswereﬁrstappliedtoNGC4051(Komossa&Fink1997a,KF97hereafter).ThebulkofitsWAturnedouttobedust-free.OtherNLS1swerethensuccessfullyﬁtwiththismodel.Tab.1liststheresults,includingalsotypesofAGNotherthanNLS1s.

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PreprintsubmittedtoElsevierPreprint1February2008Table1Summaryofthecandidatesfordustywarmabsorbers,successfullymodeledassuch,listedinthechronologicalorderthattheyweresuggested,andresultsfromspectralﬁts.ValuesoftheionizationparameterUgivenhereandelsewhereinthetextrefertoacontinuumspectrumwithαEUV=−1.4(betweenLyman-limitand0.1keV),ifnotnotedotherwise,andphotonindexΓxaslisted.

3C212‘red’quasar[1]IRAS13349+2438NLquasar–2.9–0.421.21[2],[8]NGC3227Sy1.5–1.9–0.321.8[3]NGC3786Sy1.8–1.9–0.821.7[4]MCG−6-30-15Sy1–2.221.7[5]IRAS17020+4544NLS1–2.80.721.61[6],[9]4C+74.26radioquasar–2.2–0.121.6[7]andtheIRcontinuumstrength.Weﬁndthatinallcases,thelines[FeVII]–[FeXI]remainmuchweakerthanobservedbyseveralordersofmagnitude(seeTab.2inKomossa2000foradetailedlistofpredictedlineratios).Thereasonforthisisthatthewarmabsorberisalwaystoohighlyionized,withato-tallynegligibleamountofFe9+andFe10+ionsinthegas.Therefore,changesincollisionalstrengthsfortherelevantFetransitions,whicharestillpoorlyknown,arenotexpectedtoalterthisresult.WeconcludethatforthecaseofNGC4051thewarmabsorberandthecoronallineregionarenotoneandthesamecomponent,butareofdiﬀerentorigins.ThisisconsistentwiththerecentﬁndingsofNagaoetal.(2000)thatthe[FeXI]emissionofNGC4051isnotconﬁnedtothenucleus,butwidelyextended(outtoatleast∼150pc).

RecentlyPorquetetal.(1999;P99hereafter)presentedaparameterspacestudyofthestrengthsofFecoronallinesthatoriginatefromwarmabsorbers.TheyconcludethatFelinesinlow-densityabsorbers(theystudiedtheden-sityrangelognH=8–12)areover-predictedforpartoftheparameterspace.ComparingourearlierresultsonNGC4051(KF97)withtheirresults,weﬁndtheyareconsistent:forwarmabsorbersdominatedbyOVIIIabsorptionandhighionizationparameters,nooverpredictioninlineemissionoccurs(theirTab.1).Thequestionremainswhetherthe‘OVIIabsorbers’ofP99doindeedoverpredicttheFelinesandthusareinconﬂictwithobservations.WeproposethatmostofthestrongOVIIabsorberslikelycontaindust(whichwasnotin-cludedinthemodelsofP99),assuggestedbythestudyofReynolds(1997).ThestrongdepletionofFeintodustgrainsthenresultsinweakergasphaseemissionintheFecoronallines;seeKomossa2000forfurtherdiscussion.

3TheX-raytransientNLS1RXJ0134−4258TheNarrow-lineSeyfert1galaxyRXJ0134−4258isoneoftheraresourcesthatshoweddramaticspectralvariability.Itsspectrumchangedfromultrasoft(Γx=−4.4)intheROSATall-skysurvey(RASS)toﬂat(Γx=−2.2)inourpointedPSPCobservationmadetwoyearslater,whileitscountrateremainednearlyconstant(Komossa&Meerschweinchen2000,andreferencestherein).Onepossibleexplanationforthiskindofspectralvariabilityisthepresenceofawarmabsorber.

Weﬁndthatawarmly-absorbed,intrinsicallyﬂatpowerlawﬁtstheRASSobservationwell,withlogNw≃1023cm−2(χ2red=0.6).ToaccountthenforthemuchﬂatterspectrumduringthelaterPSPCobservationrequiresachangeinionizationstateofthewarmabsorber.Sincetheintrinsicluminosityofthesourceisnotsigniﬁcantlydiﬀerentbetweenthetwoobservations,itisthenrequiredthattheionizationstateofthewarmabsorberreﬂectsthe(un-observed)historyofthevariabilityintheintrinsicluminosity(seeKM2000

3Fig.1.Left:ResidualsafterﬁttingawarmabsorbertotheRASSspectrum(=‘steep-state’spectrum)ofRXJ0134−4258.Right:ResidualsafterﬁttingapowerlawtothepointedPSPCdata(=‘ﬂat-state’spectrum)ofRXJ0134−4258.

fordetails).Afterallowingfornon-equilibriumeﬀectsintheabsorberand/orarangeindensities,suchawarmabsorberisconsistentwiththelong-andshort-timescalevariabilitybehaviorofRXJ0134−4258.Wedidnotfavorthisexplanation,becauseitintroducesanewlevelofcomplexity(morefreeparam-eters)ascomparedtothesimplercaseofanabsorberinequilibrium.Alterna-tively,acloudofionizedmaterialmayhavepassedthroughourlineofsightduringtheRASSobservation,andmayhave(nearly)disappearedduringthelaterPSPCobservation.Finally,itisinterestingtonotethatthepresenceofhigh-ionizationUVabsorptionlinesinthisobjectwasreportedbyGoodrichatthismeeting.Indeed,recentstudiessuggestanearlyone-to-onematchofthepresenceofUVandX-raywarmabsorbers.ForamoredetaileddiscussionofRXJ0134−4258,includingalternativemodeldescriptions,werefertoKo-mossa&Meerschweinchen2000(andreferencestherein).Acknowledgements:WethankGaryFerlandforprovidingCloudy.Preprintsofthisandrelatedpaperscanberetrievedfromhttp://www.xray.mpe.mpg.de/∼skomossa/