A far-infrared spectroscopic survey of intermediate redshift (ultra) luminous infrared galaxies

Magdis, Georgios E, Rigopoulou, D, Hopwood, R, Huang, J-S, Farrah, D, Pearson, C, Alonso-Herrero, A, Bock, J J, Clements, D, Cooray, A, Griffin, M J, Oliver, S, Perez Fournon, I, Riechers, D, Swinyard, B M, Scott, D, Thatte, N, Valtchanov, I and Vaccari, M (2014) A far-infrared spectroscopic survey of intermediate redshift (ultra) luminous infrared galaxies. Astrophysical Journal, 796 (1). pp. 63-81. ISSN 1538-4357

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We present Herschel far-IR photometry and spectroscopy as well as ground-based CO observations of an intermediate redshift (0.21 _ z _ 0.88) sample of Herschel-selected (ultra)-luminous infrared galaxies (LIR >1011.5 L_). With these measurements, we trace the dust continuum, far-IR atomic line emission, in particular [C ii] 157.7μm, as well as the molecular gas of z ∼ 0.3 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) and perform a detailed investigation of the interstellar medium of the population. We find that the majority of Herschel-selected intermediate redshift (U)LIRGs have LCii/LFIR ratios that are a factor of about 10 higher than that of local ULIRGs and comparable to that of local normal and high-z star-forming galaxies. Using our sample to bridge local and high-z [C ii] observations, we find that the majority of galaxies at all redshifts and all luminosities follow an LCii−LFIR relation with a slope of unity, from which local ULIRGs and high-z active-galactic-nucleus-dominated sources are clear outliers.We also confirm that the strong anti-correlation between the LCii/LFIR ratio and the far-IR color L60/L100 observed in the local universe holds over a broad range of redshifts and luminosities, in the sense that warmer sources exhibit lower LC ii/LFIR at any epoch. Intermediate redshift ULIRGs are also characterized by large molecular gas reservoirs and by lower star formation efficiencies compared to that of local ULIRGs. The high LC ii/LFIR ratios, the moderate star formation efficiencies (LIR/L _COor LIR/MH2 ), and the relatively low dust temperatures of our sample (which are also common characteristics of high-z star-forming galaxies with ULIRG-like luminosities) indicate that the evolution of the physical properties of (U)LIRGs between the present day and z > 1 is already significant by z ∼ 0.3.

Item Type: Article
Keywords: galaxies: evolution – galaxies: star formation – gamma rays: ISM – infrared: galaxies –infrared: general
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy > QB0460 Astrophysics
Depositing User: Richard Chambers
Date Deposited: 15 May 2015 14:21
Last Modified: 07 Mar 2017 07:34
URI: http://sro.sussex.ac.uk/id/eprint/54031

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