Andrew Bunker

Abstract:

We present basic properties of ∼3,300 emission line galaxies detected by the FastSound survey, which are mostly Hα emitters at z ∼ 1.2–1.5 in the total area of about 20 deg2 , with the Hα flux sensitivity limit of ∼ 1.6 × 10−16 erg cm−2 s −1 at 4.5 sigma. This paper presents the catalogs of the FastSound emission lines and galaxies, which is open to the public. We also present basic properties of typical FastSound Hα emitters, which have Hα luminosities of 1041.8–1043.3 erg/s, SFRs of 20–500 M⊙/yr, and stellar masses of 1010.0–1011.3 M⊙. The 3D distribution maps for the four fields of CFHTLS W1–4 are presented, clearly showing large scale clustering of galaxies at the scale of ∼ 100–600 comoving Mpc. Based on 1,105 galaxies with detections of multiple emission lines, we estimate that contamination of non-Hα lines is about 4% in the single-line emission galaxies, which are mostly [OIII]λ5007. This contamination fraction is also confirmed by the stacked spectrum of all the FastSound spectra, in which Hα, [NII]λλ6548,6583, [SII]λλ6717,6731, and [OI]λλ6300,6364 are seen.

Abstract:

We present first results from the KMOS Redshift One Spectroscopic Survey (KROSS), an ongoing large kinematical survey of a thousand, z~1 star forming galaxies, with VLT KMOS. Out of the targeted galaxies (~500 so far), we detect and spatially resolve Ha emission in ~90% and 77% of the sample respectively. Based on the integrated Ha flux measurements and the spatially resolved maps we derive a median star formation rate (SFR) of ~7.0 Msun/yr and a median physical size of = 5.1kpc. We combine the inferred SFRs and effective radii measurements to derive the star formation surface densities ({\Sigma}SFR) and present a "resolved" version of the star formation main sequence (MS) that appears to hold at sub-galactic scales, with similar slope and scatter as the one inferred from galaxy integrated properties. Our data also yield a trend between {\Sigma}SFR and {\Delta}(sSFR) (distance from the MS) suggesting that galaxies with higher sSFR are characterised by denser star formation activity. Similarly, we find evidence for an anti-correlation between the gas phase metallicity (Z) and the {\Delta}(sSFR), suggesting a 0.2dex variation in the metal content of galaxies within the MS and significantly lower metallicities for galaxies above it. The origin of the observed trends between {\Sigma}SFR - {\Sigma}(sSFR) and Z - {\Delta}(sSFR) could be driven by an interplay between variations of the gas fraction or the star formation efficiency of the galaxies along and off the MS. To address this, follow-up observations of the our sample that will allow gas mass estimates are necessary.