The Herschel census of infrared SEDs through cosmic time

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-Smith, N, Shupe, D L, Smith, A J, Valtchanov, I, Wang, L, Xu, C K, Zemcov, M and Wuyts, S (2013) The Herschel census of infrared SEDs through cosmic time. Monthly Notices of the Royal Astronomical Society, 431 (3). pp. 2317-2340. ISSN 0035-8711

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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.

Item Type: Article
Keywords: galaxies: evolution; galaxies: high-redshift; galaxies: starburst; infrared: galaxies; submillimetre: galaxies
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Seb Oliver
Date Deposited: 01 May 2013 06:57
Last Modified: 06 Mar 2017 20:45

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