The SAMI Galaxy Survey: Data Release Two with absorption-line physics value-added products

Abstract

We present the second major release of data from the Sydney – Australian Astronomical
\nObservatory Multi-Object Integral Field Spectrograph (SAMI) Galaxy Survey. Data Release
\nTwo includes data for 1559 galaxies, about 50 per cent of the full survey. Galaxies included
\nhave a redshift range 0.004 <z< 0.113 and a large stellar mass range 7.5 < log (M/M) <
\n11.6. The core data for each galaxy consist of two primary spectral cubes covering the blue
\nand red optical wavelength ranges. For each primary cube, we also provide three spatially
\nbinned spectral cubes and a set of standardized aperture spectra. For each core data product,
\nwe provide a set of value-added data products. This includes all emission line value-added
\nproducts from Data Release One, expanded to the larger sample. In addition, we include
\nstellar kinematic and stellar population value-added products derived from absorption line
\nmeasurements. The data are provided online through Australian Astronomical Optics’ Data
\nCentral. We illustrate the potential of this release by presenting the distribution of ∼350 000
\nstellar velocity dispersion measurements from individual spaxels as a function of R/Re, divided
\nin four galaxy mass bins. In the highest stellar mass bin [log (M/M) > 11], the velocity
\ndispersion strongly increases towards the centre, whereas below log (M/M) < 10 we find
\nno evidence for a clear increase in the central velocity dispersion. This suggests a transition
\nmass around log (M/M) ∼ 10 for galaxies with or without a dispersion-dominated bulge.