1302.4895 (Myrto Symeonidis et al.)

The Herschel census of infrared SEDs through cosmic time    [PDF]

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

Using Herschel data from the deepest SPIRE and PACS surveys (HerMES and PEP) in COSMOS and GOODS (N+S), we examine the dust properties of IR-luminous (L_IR>10^10 L_sun) galaxies at 0.145K) SEDs and cold (T<25K), 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[L_IR/L_sun]=12.5 galaxies is about 10K higher than that of their log[L_IR/L_sun]=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 10K lower than what is measured locally. This is manifested as a flattening of the L-T relation, suggesting that (U)LIRGs in the early Universe are typically characterised 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<35K showing a 2-fold increase from z~0 to z~2, whereas that of ULIRGs with T<35K shows a 6-fold increase.

View original: http://arxiv.org/abs/1302.4895