赫歇尔揭示遥远尘埃星系令人费解的均匀性
宇宙学与河外天体物理
2015-05-19 v1
摘要
赫歇尔空间天文台通过直接采样星暴星系和活动星系核（AGN）远红外（IR）发射的峰值，使我们能够精确测量其辐射热输出。在此，我们检验了自z~2.5以来，星系的谱能量分布（SED）和尘埃温度是否发生了强烈演化。我们利用赫歇尔在100至500微米波段的深场河外巡天数据，使用GOODS-North天区（PEP和HerMES关键项目）的PACS和SPIRE仪器，计算了最暗弱星系的总红外光度。我们证明，如果利用更高空间分辨率的信息来识别其流量未被明亮邻居增强的孤立星系，则SPIRE波段的测量结果可用于统计混淆极限以下。在z~1.5以下，对于恒星形成星系，中红外外推是正确的，弥散仅为40%（0.15 dex），因此与z~0的星系相似。考虑到可能影响这些星系SED的物理过程范围，这种狭窄的分布令人费解。仅从160微米、250微米或350微米波段之一进行外推往往会高估总红外光度。这可能是由于本地模板在静止系约150微米及以上波段缺乏远红外约束。我们还注意到，z~1附近明亮红外星系的尘埃温度比其本地对应物略冷10-15%，而z~1.6的超亮红外星系（ULIRG）则冷至20%。在z=1.5以上，发现遥远星系表现出明显更高的中红外与远红外之比，这可能是由于更强的宽发射线或由隐藏AGN加热的暖尘埃连续谱所致。该天区中具有测量红移的三分之二AGN表现出与纯恒星形成星系相同的行为。因此，很大一部分AGN以非常高的恒星形成率（SFR）并在与纯恒星形成星系相似的条件下孕育着恒星形成。
引用
@article{arxiv.1005.2859,
title = {Herschel unveils a puzzling uniformity of distant dusty galaxies},
author = {D. Elbaz and H. S. Hwang and B. Magnelli and E. Daddi and H. Aussel and B. Altieri and A. Amblard and P. Andreani and V. Arumugam and R. Auld and T. Babbedge and S. Berta and A. Blain and J. Bock and A. Bongiovanni and A. Boselli and V. Buat and D. Burgarella and N. Castro-Rodriguez and A. Cava and J. Cepa and P. Chanial and R. -R. Chary and A. Cimatti and D. L. Clements and A. Conley and L. Conversi and A. Cooray and M. Dickinson and H. Dominguez and C. D. Dowell and J. S. Dunlop and E. Dwek and S. Eales and D. Farrah and N. Forster Schreiber and M. Fox and A. Franceschini and W. Gear and R. Genzel and J. Glenn and M. Griffin and C. Gruppioni and M. Halpern and E. Hatziminaoglou and E. Ibar and K. Isaak and R. J. Ivison and G. Lagache and D. Le Borgne and E. Le Floc'h and L. Levenson and N. Lu and D. Lutz and S. Madden and B. Maffei and G. Magdis and G. Mainetti and R. Maiolino and L. Marchetti and A. M. J. Mortier and H. T. Nguyen and R. Nordon and B. O'Halloran and K. Okumura and S. J. Oliver and A. Omont and M. J. Page and P. Panuzzo and A. Papageorgiou and C. P. Pearson and I. Perez Fournon and A. M. Perez Garcıa and A. Poglitsch and M. Pohlen and P. Popesso and F. Pozzi and J. I. Rawlings and D. Rigopoulou and L. Riguccini and D. Rizzo and G. Rodighiero and I. G. Roseboom and M. Rowan-Robinson and A. Saintonge and M. Sanchez-Portal and P. Santini and M. Sauvage and B. Schulz and Douglas Scott and N. Seymour and L. Shao and D. L. Shupe and A. J. Smith and J. A. Stevens and E. Sturm and M. Symeonidis and L. Tacconi and M. Trichas and K. E. Tugwell and M. Vaccari and I. Valtchanov and J. Vieira and L. Vigroux and L. Wang and R. Ward and G. Wright and C. K. Xu and M. Zemcov},
journal= {arXiv preprint arXiv:1005.2859},
year = {2015}
}
备注
Astronomy and Astrophysics, Herschel Special Issue, in press as a Letter; 5 pages