q The ISM Properties of distant star forming

q The ISM Properties of distant star -forming galaxies as constrained by the parameter M. Sargent (MPIA) & you (in its various guises) I. update on the (on-going) IR-radio relation work II. disk galaxy opacity at z ~ 0. 7 III. final VLA-COSMOS Joint Catalog COSMOS Team Meeting ‘ 10 | June 10, 2010 June 3, 2010

Intro Radio & 60 m luminosity functions of galaxies in the IRAS 2 Jy-sample (Yun+ ‘ 01): sta rbu rsts ‘monsters’ June 3, 2010 ies galax Non-thermal radio (synchrotron) emission and, in the IR, re-radiated UV light. field Common link due to life cycle of massive stars: 1

Intro - local galaxies (II) Early IRAS results, integrated IR/radio flux (Helou+ ‘ 85) : q = log(SIR/Sradio) log(1. 4 GHz flux [m. Jy]) radio-loud AGN nascent starbursts ‘regular’ star-forming log(FIR flux [Wm-2]) galaxies June 3, 2010 1. 5 kpc regions in individual SINGS galaxies (Murphy+ ‘ 06) … and the transition to integrated IR/radio flux ratios (Yun+ ‘ 01) 2

Intro - Reasons to study the evolution • Calibration of radio continuum emission as a star formation tracer in distant galaxies (see Alex’ talk!) • Does or doesn’t the IR-radio relation evolve with redshift (see somewhat ambiguous results in the literature) ? • Changes in the correlation due to (understandable) external factors could shed light on: - the physical processes shaping the relation (also at low-z) - state of the ISM (magnetic fields, intensity of UV radiation field, dust absorption) • “…for the […] galaxies studied here, luminosity extrapolations based on the radio emission are considerably more reliable than those based on the mid-IR emission” (Magnelli+ ‘ 10) - the calculation of SFRs is affected less by uncertain radio spectral indices than by a sparsely sampled IR-SED - interferometric radio observations have a high spatial resolution, aiding the correct identification and attribution of flux to (multi- ) counterparts June 3, 2010 3

Evolution of the brightest IR-emitters Sargent+ (‘ 10 b) ULIRGs: median 〈q. TIR〉 LIR > 1012 L☉ SFR > 100 M☉/yr 〈q. TIR〉 ∝ (1+z)-0. 01± 0. 06 After compensating for selection biases - NO evolution at z < 2 (implies B ~ 50 G). redshift • volume-limited sample of ULIRGs (rather than comparing most strongly starbursting systems at high z with mixture of high & low luminosity systems at low z) • IR/radio non-detections included with survival analysis • probabilistic (using rest-frame optical colours) classification into SFGs/AGN June 3, 2010 (cf. Smolčić+ ‘ 08) 4

Evolution of less extreme starbursts Sargent+ (‘ 10 d), in prog. No differing behaviour between stacked and high(er) luminosity samples! Alex’ hard work q 70, obs. normalization of starburst template SEDs adopted from direct detections Expected evolution of q 70 for galaxies with IR dust SEDs similar to local galaxies increasing stellar mass redshift • 1. 4 GHz image stacks of reach rms noise of ~400 n. Jy thanks to 100 s of sources in each mass/redshift bin -> statistical detections of LIRG luminosities out to z ~ 3 • Sample based on 3. 6 m IRAC detections in COSMOS field (cf. Sanders+ ‘ 07, Ilbert+ ‘ 09) -> expect unbiased estimate of average IR/radio ratios (as sample not IR- or radio-selected) • Actively star forming galaxies selected with (NUV-r) colours (cf. Ilbert+ ‘ 09) June 3, 2010

Other IR/radio miscellanea… (Sargent+ ‘ 10 a) 〈q〉IR-sel. > 〈q〉radio-sel. June 3, 2010 ➠ At 2. 5 < z < 5: 〈q. TIR〉= 2. 71+0. 09 , -0. 14 consistent with local average. ➠ ➠ At z < 1. 5: many (optically classified) AGN have the same IR/radio ratios as starforming galaxies. Analytical prediction of offset between IR- and radio-selected samples, qbias = ln(10) [ -1] 2, (e. g. Kellermann ‘ 64; Condon ‘ 84) can reconcile discrepancies in the literature. 6

The Effects of Dust… Parametrization of average variation of surface brightness with inclination due to dust attenuation: z~0 opacity increase surface brightness increase z~0. 7 Driver+ (‘ 07) Sargent+ (‘ 10 c) June 3, 2010 7

Attenuation vs. inclination q = b/a ‘real’ distant disk galaxies blue-band surface brightness brighter redshifted local disk galaxies At z~0. 7: less variation between the average sur-face brightness of faceon and edge-on, large disk galaxies. on e c fa n -o e 1 - cosine(inclination angle) g ed • low-z reference galaxies (from Kampczyk+ ‘ 07) show expected (cf. Möllenhoff+ ‘ 06; Driver+ ‘ 07) surface brightness variations also once redshifted; distant galactic disks behave as if (nearly perfectly!) optically thick… • Scant evidence for different extinction laws in distant galaxies (e. g. , Calzetti+ ‘ 01; Conroy+ ‘ 10), a different distribution of attenuating material seems a likely explanation • Correction relative to face-on ‘homogenizes’ population but does not provide the re-sidual face -on attenuation ➠ interpret shape of inclination-dependence with dust models June 3, 2010 8

Summary Evolution of the IR-radio relation: • No compelling evidence for an evolution of the IR-radio relation out to high redshift, also in luminosity ranges in which the observation of evolution would not have been a surprise… • The understanding/awareness of selection effects is essential for the derivation of the correct (non-)evolution • Many optically-selected AGN at z < 1 have similar IR/radio ratios as star forming galaxies Inclination-dependent attenuation in disk galaxies at z ~ 0. 7: • Blue light escapes high- and low-z disk galaxies with a different (3 D-)angular emission pattern, suggesting a different distribution of attenuating material Plus…: • final VLA-COMOS Joint (source catalog from survey components ‘Large’ & ‘Deep’) catalog is available @ IRSA and published as Schinnerer+ ‘ 10, Ap. JS, 188, 384 June 3, 2010 9

Final VLA-COSMOS Joint catalog rms ~30 Jy (irsa. ipac. caltech. edu/data/COSMOS/tables/vla/… …vla-cosmos_dp_sources_20100504. tbl) • central 1 deg 2 (seven pointings) re-imaged for additional 8. 3 hr each • 2865 sources with S/N > 5 • 1. 4 GHz maps @ resolution 1. 5” & 2. 5” available • rms at field centre ~10 Jy • 1/3 spectroscopically followed-up (pre 20 k) • catalog paper accepted to Ap. JS • Counterpart searches ➠ use new Joint catalog • Statistical studies requiring flux-limited samples ➠ use revised Large Project catalog June 3, 2010 10