2 research outputs found
The Outer Stellar Halos of Galaxies: how Radial Merger Mass Deposition, Shells and Streams depend on Infall-Orbit Configurations
Galaxy mergers are a fundamental part of galaxy evolution. To study the
resulting mass distributions of different kinds of galaxy mergers, we present a
simulation suite of 36 high-resolution isolated merger simulations, exploring a
wide range of parameter space in terms of mass ratios (mu = 1:5, 1:10, 1:50,
1:100) and orbital parameters. We find that mini mergers deposit a higher
fraction of their mass in the outer halo compared to minor mergers, while their
contribution to the central mass distribution is highly dependent on the
orbital impact parameter: for larger pericentric distances we find that the
centre of the host galaxy is almost not contaminated by merger particles. We
also find that the median of the resulting radial mass distribution for mini
mergers differs significantly from the predictions of simple theoretical
tidal-force models. Furthermore, we find that mini mergers can increase the
size of the host disc significantly without changing the global shape of the
galaxy, if the impact occurs in the disc plane, thus providing a possible
explanation for extended low-surface brightness disks reported in observations.
Finally, we find clear evidence that streams are a strong indication of nearly
circular infall of a satellite (with large angular momentum), whereas the
appearance of shells clearly points to (nearly) radial satellite infall.Comment: 17 pages, 15 figures, published by MNRAS doi: 10.1093/mnras/stz125
Measurement of the evolving galaxy luminosity and mass function using clustering-based redshift inference
We develop a framework for using clustering-based redshift inference (cluster-z ) to measure the evolving galaxy luminosity function (GLF) and galaxy stellar mass function (GSMF) using Wide-field Infrared Survey Explorer W1 (3.4 μm) mid-infrared photometry and positions. We use multiple reference sets from the Galaxy And Mass Assembly survey, Sloan Digital Sky Survey and Baryon Oscillation Spectroscopic Survey. Combining the resulting cluster-z s allows us to enlarge the study area, and by accounting for the specific properties of each reference set, making best use of each reference set to produce the best overall result