We describe the far-infrared (far-IR; rest-frame 8-1000-{$μ$}m) properties of a sample of 443 H{$α$}-selected star-forming galaxies in the Cosmic Evolution Survey (COSMOS) and Ultra Deep Survey ... Show moreWe describe the far-infrared (far-IR; rest-frame 8-1000-{$μ$}m) properties of a sample of 443 H{$α$}-selected star-forming galaxies in the Cosmic Evolution Survey (COSMOS) and Ultra Deep Survey (UDS) fields detected by the High-redshift Emission Line Survey (HiZELS) imaging survey. Sources are identified using narrow-band filters in combination with broad-band photometry to uniformly select H{$α$} (and [O II] if available) emitters in a narrow redshift slice at z = 1.47 {\plusmn} 0.02. We use a stacking approach in Spitzer-MIPS mid-IR, Herschel-PACS/SPIRE far-IR [from the PACS Evolutionary Prove (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES)] and AzTEC mm-wave images to describe their typical far-IR properties. We find that HiZELS galaxies with observed H{$α$} luminosities of L(H{$α$})$_{obs}$ {\ap} 10$^{8.1-9.1}$ L$_{⊙}$ ( {\ap} 10$^{41.7-42.7}$ erg s$^{-1}$) have bolometric far-IR luminosities of typical luminous IR galaxies, L(8-1000 {$μ$} m){\ap} 10\^{}$\{$11.41\^{}$\{$+0.04$\}$\_$\{$-0.06$\}$$\}$ L$_{⊙}$. Combining the H{$α$} and far-IR luminosities, we derive median star formation rates (SFRs) of SFR$_{Hα, FIR}$ = 32 {\plusmn} 5 M$_{⊙}$ yr$^{-1}$ and H{$α$} extinctions of A$_{Hα}$ = 1.0 {\plusmn} 0.2 mag. Perhaps surprisingly, little difference is seen in typical HiZELS extinction levels compared to local star-forming galaxies. We confirm previous empirical stellar mass (M$_{*}$) to A$_{Hα}$ relations and the little or no evolution up to z = 1.47. For HiZELS galaxies (or similar samples) we provide an empirical parametrization of the SFR as a function of rest-frame (u - z) colours and 3.6-{$μ$}m photometry - a useful proxy to aid in the absence of far-IR detections in high-z galaxies. We find that the observed H{$α$} luminosity is a dominant SFR tracer when rest-frame (u - z) colours are {\lsim}0.9 mag or when Spitzer-3.6-{$μ$}m photometry is fainter than 22 mag (Vega) or when stellar masses are lower than 10$^{9.7}$ M$_{⊙}$. We do not find any correlation between the [O II]/H{$α$} and far-IR luminosity, suggesting that this emission line ratio does not trace the extinction of the most obscured star-forming regions, especially in massive galaxies where these dominate. The luminosity-limited HiZELS sample tends to lie above of the so-called main sequence for star-forming galaxies, especially at low stellar masses, indicating high star formation efficiencies in these galaxies. This work has implications for SFR indicators and suggests that obscured star formation is linked to the assembly of stellar mass, with deeper potential wells in massive galaxies providing dense, heavily obscured environments in which stars can form rapidly. Show less
In the course of our 870 {$μ$}m APEX/LABOCA follow-up of the Herschel Lensing Survey we have detected a source in AS1063 (RXC J2248.7-4431) that has no counterparts in any of the Herschel PACS... Show moreIn the course of our 870 {$μ$}m APEX/LABOCA follow-up of the Herschel Lensing Survey we have detected a source in AS1063 (RXC J2248.7-4431) that has no counterparts in any of the Herschel PACS/SPIRE bands, it is a Herschel ''drop-out'' with S$_{870}$/S$_{500}$ {ge} 0.5. The 870 {$μ$}m emission is extended and centered on the brightest cluster galaxy, suggesting either a multiply imaged background source or substructure in the Sunyaev-Zel'dovich increment due to inhomogeneities in the hot cluster gas of this merging cluster. We discuss both interpretations with emphasis on the putative lensed source. Based on the observed properties and on our lens model we find that this source may be the first submillimeter galaxy (SMG) with a moderate far-infrared (FIR) luminosity (L$_{FIR}$ {lt} 10$^{12}$ L$_{⊙}$) detected so far at z {gt} 4. In deep HST observations we identified a multiply imaged z ~{} 6 source and measured its spectroscopic redshift to be z = 6.107 with VLT/FORS. This source may be associated with the putative SMG, but it is most likely offset spatially by 10-30 kpc and they may be interacting galaxies. With a FIR luminosity in the range [5-15] { imes} 10$^{11}$ L$_{⊙}$ corresponding to a star formation rate in the range [80-260] M$_{⊙}$ yr$^{-1}$, this SMG would be more representative of the z {gt} 4 dusty galaxies than the extreme starbursts detected so far. With a total magnification of ~{}25 it would open a unique window to the normal dusty galaxies at the end of the epoch of reionization. Show less
