Herschel-ATLAS/GAMA: How does the far-IR luminosity function depend on galaxy group properties?

Guo, Qi; Lacey, Cedric; Norberg, Peder; Cole, Shaun; Baugh, Carlton; Frenk, Carlos; Cooray, Asantha; Dye, Simon; Bourne, N.; Dunne, L.; Eales, S.; Ivison, R.J.; Maddox, S.J.; Alpasan, M.; Baldry, I.; Driver, S.P.; Robotham, A.

Abstract

We use the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) Phase I data to study the conditional luminosity function of far-IR (250 μm) selected galaxies in optically selected galaxy groups from the Galaxy And Mass Assembly (GAMA) spectroscopic survey, as well as environmental effects on the far-IR-to-optical colour. We applied two methods, which gave consistent results for the far-IR conditional luminosity functions. The direct matching method matches H-ATLAS sources to GAMA/SDSS (Sloan Digital Sky Survey) galaxies, then links the optical counterparts to GAMA groups. The stacking method counts the number of far-IR sources within the projected radii of GAMA groups, subtracting the local background. We investigated the dependence of the far-IR (250 μm) luminosity function on group mass in the range 1012 < Mh < 1014 h−1 M⊙ and on redshift in the range 0 < z < 0.4, using a sample of 3000 groups containing H-ATLAS sources with GAMA redshifts over an area of 126 deg2. We find that the characteristic 250 μm luminosity, L*(250), increases with group mass up to Mh ∼ 1013 h−1 M⊙, but is roughly constant above this, while it increases with redshift at high group masses, but less so at low masses. We also find that the group far-IR luminosity-to-mass ratio L(250)/Mh increases with redshift and is higher in low-mass groups. We estimate that around 70 per cent of the 250 μm luminosity density in the local Universe is contributed by groups with Mh > 1012 h−1 M⊙. We also find that the far-IR-to-optical colours of H-ATLAS galaxies are independent of group mass over the range 1012 < Mh < 1014 h−1 M⊙ in the local Universe. We also compare our observational results with recent semi-analytical models, and find that none of these galaxy formation models can reproduce the conditional far-IR luminosity functions of galaxy groups.

Citation

Guo, Q., Lacey, C., Norberg, P., Cole, S., Baugh, C., Frenk, C., …Robotham, A. (2014). Herschel-ATLAS/GAMA: How does the far-IR luminosity function depend on galaxy group properties?. Monthly Notices of the Royal Astronomical Society, 442(3), 2253-2270. https://doi.org/10.1093/mnras/stu962

• Journal Article Type: Article
• Publication Date: Aug 1, 2014
• Deposit Date: Jun 27, 2014
• Publicly Available Date: Jun 27, 2014
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 442
• Issue: 3
• Pages: 2253-2270
• DOI: https://doi.org/10.1093/mnras/stu962
• Keywords: Galaxies: clusters: general, Galaxies: formation, Galaxies: haloes, Galaxies: luminosity function mass function, Cosmology: theory, Infrared: galaxies.
• Public URL: https://durham-repository.worktribe.com/output/1424570