The Herschel census of infrared SEDs through cosmic time

May 2013 • 2013MNRAS.431.2317S

Authors • Symeonidis, M. • Vaccari, M. • Berta, S. • Page, M. J. • Lutz, D. • Arumugam, V. • Aussel, H. • Bock, J. • Boselli, A. • Buat, V. • Capak, P. L. • Clements, D. L. • Conley, A. • Conversi, L. • Cooray, A. • Dowell, C. D. • Farrah, D. • Franceschini, A. • Giovannoli, E. • Glenn, J. • Griffin, M. • Hatziminaoglou, E. • Hwang, H. -S. • Ibar, E. • Ilbert, O. • Ivison, R. J. • Le Floc'h, E. • Lilly, S. • Kartaltepe, J. S. • Magnelli, B. • Magdis, G. • Marchetti, L. • Nguyen, H. T. • Nordon, R. • O'Halloran, B. • Oliver, S. J. • Omont, A. • Papageorgiou, A. • Patel, H. • Pearson, C. P. • Pérez-Fournon, I. • Pohlen, M. • Popesso, P. • Pozzi, F. • Rigopoulou, D. • Riguccini, L. • Rosario, D. • Roseboom, I. G. • Rowan-Robinson, M. • Salvato, M. • Schulz, B. • Scott, Douglas • Seymour, N. • Shupe, D. L. • Smith, A. J. • Valtchanov, I. • Wang, L. • Xu, C. K. • Zemcov, M. • Wuyts, S.

Abstract • Using Herschel data from the deepest SPIRE and PACS surveys (HerMES and PEP) in COSMOS, GOODS-S and GOODS-N, we examine the dust properties of infrared (IR)-luminous (LIR > 1010 L) galaxies at 0.1 < z < 2 and determine how these evolve with cosmic time. The unique angle of this work is the rigorous analysis of survey selection effects, making this the first study of the star-formation-dominated, IR-luminous population within a framework almost entirely free of selection biases. We find that IR-luminous galaxies have spectral energy distributions (SEDs) with broad far-IR peaks characterized by cool/extended dust emission and average dust temperatures in the 25-45 K range. Hot (T > 45 K) SEDs and cold (T < 25 K), cirrus-dominated SEDs are rare, with most sources being within the range occupied by warm starbursts such as M82 and cool spirals such as M51. We observe a luminosity-temperature (L-T) relation, where the average dust temperature of log [LIR/L] ∼ 12.5 galaxies is about 10 K higher than that of their log [LIR/L] ∼ 10.5 counterparts. However, although the increased dust heating in more luminous systems is the driving factor behind the L-T relation, the increase in dust mass and/or starburst size with luminosity plays a dominant role in shaping it. Our results show that the dust conditions in IR-luminous sources evolve with cosmic time: at high redshift, dust temperatures are on average up to 10 K lower than what is measured locally (z ≲ 0.1). This is manifested as a flattening of the L-T relation, suggesting that (ultra)luminous infrared galaxies [(U)LIRGs] in the early Universe are typically characterized by a more extended dust distribution and/or higher dust masses than local equivalent sources. Interestingly, the evolution in dust temperature is luminosity dependent, with the fraction of LIRGs with T < 35 K showing a two-fold increase from z ∼ 0 to z ∼ 2, whereas that of ULIRGs with T < 35 K shows a six-fold increase. Our results suggest a greater diversity in the IR-luminous population at high redshift, particularly for ULIRGs.


IPAC Authors

Dave Shupe

Senior Scientist