1609.09085
The-wiZZ: clustering redshift estimation for everyone
Morrison, et al
Present The-wiZZ, an open source and user-friendly software for estimating the redshift distributions of photometric galaxies with unknown redshifts by spatially cross-correlating them against a reference sample with known redshifts. The main benefit of The-wiZZ is in separating the angular pair finding and correlation estimation from the computation of the output clustering redshifts allowing anyone to create a clustering redshift for their sample without the intervention of an "expert". It allows the end user of a given surveys to select any sub-sample of photometric galaxies with unknown redshifts, match this sample's catalog indices into a value-added data file, and produce a clustering redshift estimation for this sample in a fraction of the time it would take to run all the angular correlations needed to produce a clustering redshift. Show results with this software using photometric data from the KiDS and spec data from GAMA and SDSS. The results presented for KiDS are consistent with the redshift distributions used in a recent cosmic shear analysis from the survey. Also present results using a hybrid machine learning-clustering redshift analysis that enables the estimation of clustering redshifts for individual galaxies. The-wiZZ can be downloaded at github.com/morriscb/The-wiZZ.
1609.09090
PRIMUS+DEEP2: the dependence of galaxy clustering on stellar mass and specific star formation rate at 0.2<z<1.2
Coil, Mendez, Eisenstein, Moustakas
Present results on the clustering properties of galaxies as a function of both stellar mass and sSFR using data rom PRIMUS and DEEP2 galaxy redshift surveys spanning 0.2<z<1.2. Use spectroscopic redshifts of over 100k galaxies covering an area of 7.2 deg2 over 5 separate fields on the sky, from which cosmic variance errors are calculated. Find that the galaxy clustering amplitude is a stronger function of sSFR than of stellar mass, and that at a given sSFR, it does not depend on stellar mass, within the range probed here. Further find that within the SF population and at a given stellar mass, galaxies above the main sequence of SF with higher sSFR are more clustered than galaxies below the main sequence with lower sSFR. Also find that within the quiescent population, galaxies with higher sSFR are less clustered than galaxies with lower sSFR, at a given stellar mass. Show that the galaxy clustering amplitude smoothly increases with both increasing stellar mass and decreasing sSFR, implying that galaxies likely evolve across the main sequence, not only along it, before galaxies eventually becomes quiescent. These results imply that the stellar mass to halo mass relation which connects galaxies to DM haloes, likely depends on sSFR.
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