The far-infrared/radio correlation as probed by Herschel
Creators: name: Ivison, R. J.
name: Magnelli, B.
name: Ibar, E.
name: Andreani, P.
name: Elbaz, D.
name: Altieri, B.
name: Amblard, A.
name: Arumugam, V.
name: Auld, R.
name: Aussel, H.
name: Babbedge, T.
name: Berta, S.
name: Blain, A.
name: Bock, J.
name: Bongiovanni, A.
name: Boselli, A.
name: Buat, V.
name: Burgarella, D.
name: Castro, N.
name: Cava, A.
name: Cepa, J.
name: Chanial, P.
name: Cimatti, A.
name: Cirasuolo, M.
name: Clements, D. L.
name: Conley, A.
name: Conversi, L.
name: Cooray, A.
name: Daddi, E.
name: Dominguez, H.
name: Dowell, C. D.
name: Dwek, E.
name: Eales, S.
name: Farrah, D.
name: Fox, M.
name: Franceschini, A.
name: Gear, W.
name: Genzel, R.
name: Glenn, J.
name: Griffin, M.
name: Gruppioni, C.
name: Halpern, M.
name: Hatziminaoglou, E.
name: Isaak, K.
name: Lagache, G.
name: Levenson, L.
name: Lu, N.
name: Lutz, D.
name: Madden, S.
name: Maffei, B.
name: Magdis, G.
name: Mainetti, G.
name: Maiolino, R.
name: Marchetti, L.
name: Morrison, G. E.
name: Mortier, A. M. J.
name: Nguyen, H. T.
name: Nordon, R.
name: O'Halloran, B.
name: Oliver, S. J.
name: Omont, A.
name: Owen, F. N.
name: Page, M. J.
name: Panuzzo, P.
name: Papageorgiou, A.
name: Pearson, C. P.
name: A.
name: Poglitsch, A.
name: Pohlen, M.
name: Popesso, P.
name: Pozzi, F.
name: Rawlings, J. I.
name: Raymond, G.
name: Rigopoulou, D.
name: Riguccini, L.
name: Rizzo, D.
name: Rodighiero, G.
name: Roseboom, I. G.
name: Rowan-Robinson, M.
name: Saintonge, A.
name: Portal, M. Sanchez
name: Santini, P.
name: Schulz, B.
name: Scott, Douglas
name: Seymour, N.
name: Shao, L.
name: Shupe, D. L.
name: Smith, A. J.
name: Stevens, J. A.
name: Sturm, E.
name: Symeonidis, M.
name: Tacconi, L.
name: Trichas, M.
name: Tugwell, K. E.
name: Vaccari, M.
name: Valtchanov, I.
name: Vieira, J.
name: Vigroux, L.
name: Wang, L.
name: Ward, R.
name: Wright, G.
name: Xu, C. K.
name: Zemcov, M.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We set out to determine the ratio, q(IR), of rest-frame 8-1000um flux, S(IR), to monochromatic radio flux, S(1.4GHz), for galaxies selected at far-IR and radio wavelengths, to search for signs that the ratio evolves with redshift, luminosity or dust temperature, and to identify any far-IR-bright outliers - useful laboratories for exploring why the far-IR/radio correlation is generally so tight when the prevailing theory suggests variations are almost inevitable. We use flux-limited 250-um and 1.4-GHz samples, obtained in GOODS-N using Herschel (HerMES; PEP) and the VLA. We determine bolometric IR output using ten bands spanning 24-1250um, exploiting data from PACS and SPIRE, as well as Spitzer, SCUBA, AzTEC and MAMBO. We also explore the properties of an L(IR)-matched sample, designed to reveal evolution of q(IR) with z, spanning log L(IR) = 11-12 L(sun) and z=0-2, by stacking into the radio and far-IR images. For 1.4-GHz-selected galaxies, we see tentative evidence of a break in the flux ratio, q(IR), at L(1.4GHz) ~ 10^22.7 W/Hz, where AGN are starting to dominate the radio power density, and of weaker correlations with z and T(d). From our 250-um-selected sample we identify a small number of far-IR-bright outliers, and see trends of q(IR) with L(1.4GHz), L(IR), T(d) and z, noting that some of these are inter-related. For our L(IR)-matched sample, there is no evidence that q(IR) changes significantly as we move back into the epoch of galaxy formation: we find q(IR) goes as (1+z)^gamma, where gamma = -0.04 +/- 0.03 at z=0-2; however, discounting the least reliable data at z&lt;0.5 we find gamma = -0.26 +/- 0.07, modest evolution which may be related to the radio background seen by ARCADE2, perhaps driven by &lt;10uJy radio activity amongst ordinary star-forming galaxies at z&gt;1.
description: A&amp;A Herschel Special Issue, in press as a Letter. 5 pages