The software package for astronomical reductions with KMOS: SPARK

The K-band Multi Object Spectrograph (KMOS) is a multi-object near-infrared integral field spectrometer with 24 deployable cryogenic pick-off arms. Inevitably, data processing is a complex task that requires careful calibration and quality control. In this paper we describe all the steps involved in producing science-quality data products from the raw observations. In particular, we focus on the following issues: (i) the calibration scheme which produces maps of the spatial and spectral locations of all illuminated pixels on the detectors; (ii) our concept of minimising the number of interpolations, to the limiting case of a single reconstruction that simultaneously uses raw data from multiple exposures; (iii) a comparison of the various interpolation methods implemented, and an assessment of the performance of true 3D interpolation schemes; (iv) the way in which instrumental flexure is measured and compensated. We finish by presenting some examples of data processed using the pipeline

The Angular Momentum Distribution and Baryon Content of Star-forming Galaxies at z ~ 1-3

We analyze the angular momenta of massive star-forming galaxies (SFGs) at the peak of the cosmic star formation epoch (z ~ 0.8–2.6). Our sample of ~360 log(M */M ⊙) ~ 9.3–11.8 SFGs is mainly based on the KMOS3D and SINS/zC-SINF surveys of Hα kinematics, and collectively provides a representative subset of the massive star-forming population. The inferred halo scale angular momentum distribution is broadly consistent with that theoretically predicted for their dark matter halos, in terms of mean spin parameter $\langle \lambda \rangle$ ~ 0.037 and its dispersion (σ logλ ~ 0.2). Spin parameters correlate with the disk radial scale and with their stellar surface density, but do not depend significantly on halo mass, stellar mass, or redshift. Our data thus support the long-standing assumption that on average, even at high redshifts, the specific angular momentum of disk galaxies reflects that of their dark matter halos (j d = j DM). The lack of correlation between λ × (j d /j DM) and the nuclear stellar density Σ*(1 kpc) favors a scenario where disk-internal angular momentum redistribution leads to "compaction" inside massive high-redshift disks. For our sample, the inferred average stellar to dark matter mass ratio is ~2%, consistent with abundance matching results. Including the molecular gas, the total baryonic disk to dark matter mass ratio is ~5% for halos near 1012 M ⊙, which corresponds to 31% of the cosmologically available baryons, implying that high-redshift disks are strongly baryon dominated

A Consistent Study of Metallicity Evolution at 0.8 < z < 2.6

We present the correlations between stellar mass, star formation rate (SFR), and the [N II]/Hα flux ratio as an indicator of gas-phase metallicity for a sample of 222 galaxies at 0.8 < z < 2.6 and log (M */M ☉) = 9.0-11.5 from the LUCI, SINS/zC-SINF, and KMOS3D surveys. This sample provides a unique analysis of the mass-metallicity relation (MZR) over an extended redshift range using consistent data analysis techniques and a uniform strong-line metallicity indicator. We find a constant slope at the low-mass end of the relation and can fully describe its redshift evolution through the evolution of the characteristic turnover mass where the relation begins to flatten at the asymptotic metallicity. At a fixed mass and redshift, our data do not show a correlation between the [N II]/Hα ratio and SFR, which disagrees with the 0.2-0.3 dex offset in [N II]/Hα predicted by the "fundamental relation" between stellar mass, SFR, and metallicity discussed in recent literature. However, the overall evolution toward lower [N II]/Hα at earlier times does broadly agree with these predictions

Evidence for Wide-spread Active Galactic Nucleus-driven Outflows in the Most Massive z \~ 1-2 Star-forming Galaxies

In this paper, we follow up on our previous detection of nuclear ionized outflows in the most massive (log(M */M ☉) ≥ 10.9) z ~ 1-3 star-forming galaxies by increasing the sample size by a factor of six (to 44 galaxies above log(M */M ☉) ≥ 10.9) from a combination of the SINS/zC-SINF, LUCI, GNIRS, and KMOS3Dspectroscopic surveys. We find a fairly sharp onset of the incidence of broad nuclear emission (FWHM in the Hα, [N II], and [S II] lines ~450-5300 km s–1), with large [N II]/Hα ratios, above log(M */M ☉) ~ 10.9, with about two-thirds of the galaxies in this mass range exhibiting this component. Broad nuclear components near and above the Schechter mass are similarly prevalent above and below the main sequence of star-forming galaxies, and at z ~ 1 and ~2. The line ratios of the nuclear component are fit by excitation from active galactic nuclei (AGNs), or by a combination of shocks and photoionization. The incidence of the most massive galaxies with broad nuclear components is at least as large as that of AGNs identified by X-ray, optical, infrared, or radio indicators. The mass loading of the nuclear outflows is near unity. Our findings provide compelling evidence for powerful, high-duty cycle, AGN-driven outflows near the Schechter mass, and acting across the peak of cosmic galaxy formation