External Galaxies Commons^™

Catalog Of Edge-On Galaxies Using The Pan-Starrs1 Survey Data, Dimitry I. Makarov, S. Savchenko, Alexander V. Mosenkov, Dmitry V. Bizyaev, Vladimir P. Reshetnikov, Alexandra V. Antipova, I. Tikhonenko, P. Usachev, S. Borisov, L. Makarova, Stefan Kautsch, A. Marchuk, E. Rub Edukov, M. Skryabina, P. Smirnova

Chemistry and Physics Faculty Articles

We have created a catalog of edge-on galaxies based on the publicly available DR2 data from the Pan-STARRS survey. The intensive use of an artificial neural network has significantly improved the quality of candidate selection. The catalog provides homogeneous information on astrometry, photometry, and non-parametric morphological statistics for 16551 edge-on galaxies. Our catalog is intended for studying the three-dimensional structure of galaxies with different morphologies and the scaling relations for disks and bulges.

Does The Stellar Disc Flattening Depend On The Galaxy Type, A. V. Mosenkov, N. Ya. Sotnikova, V. P. Reshetnikov, D. V. Bizyaev, Stefan Kautsch

Chemistry and Physics Faculty Articles

We analyse the dependence of the stellar disc flatness on the galaxy morphological type using 2D decomposition of galaxies from the reliable subsample of the Edge-on Galaxies in SDSS catalogue. Combining these data with the retrieved models of the edge-on galaxies from the Two Micron All Sky Survey and the Spitzer Survey of Stellar Structure in Galaxies catalogue, we make the following conclusions.

1. The disc relative thickness z₀/h in the near- and mid-infrared passbands correlates weakly with morphological type and does not correlate with the bulge-to-total luminosity ratio B/T in all studied bands.

2. Applying a 1D photometric …

The Catalog Of Edge-On Disk Galaxies From Sdss. I. The Catalog And The Structural Parameters Of Stellar Disks, D. V. Bizyaev, Stefan Kautsch, A. V. Mosenkov, V. P. Reshetnikov, N. Ya. Sotnikova, N. V. Yablokova

Chemistry and Physics Faculty Articles

We present a catalog of true edge-on disk galaxies automatically selected from the Seventh Data Release of the Sloan Digital Sky Survey (SDSS). A visual inspection of the g, r, and iimages of about 15,000 galaxies allowed us to split the initial sample of edge-on galaxy candidates into 4768 (31.8% of the initial sample) genuine edge-on galaxies, 8350 (55.7%) non-edge-on galaxies, and 1865 (12.5%) edge-on galaxies not suitable for simple automatic analysis because these objects either show signs of interaction and warps, or nearby bright stars project on it. We added more candidate galaxies from RFGC, EFIGI, …

A Search For Young Stars In The S0 Galaxies Of A Super-Group At Z=0.37, Dennis W. Just, Dennis Zaritsky, Kim-Vy H. Tran, Anthony H. Gonzalez, Stefan Kautsch, John Moustakas

Chemistry and Physics Faculty Articles

We analyze Galaxy Evolution Explorer UV data for a system of four gravitationally bound groups at z = 0.37, SG1120, which is destined to merge into a Coma-mass cluster by z = 0, to study how galaxy properties may change during cluster assembly. Of the 38 visually classified S0 galaxies, with masses ranging from log (M *)[M ☉] ≈ 10-11, we detect only one in the near-UV (NUV) channel, a strongly star-forming S0 that is the brightest UV source with a measured redshift placing it in SG1120. Stacking the undetected S0 galaxies (which generally lie on or near …

A Spectroscopically Confirmed Excess Of 24 Μm Sources In A Super Galaxy Group At Z=0.37: Enhanced Dusty Star Formation Relative To The Cluster And Field Environment, Kim-Vy H. Tran, Amelie Saintonge, John Moustakas, Lei Bai, Anthony H. Gonzalez, Bradford P. Holden, Dennis Zaritsky, Stefan Kautsch

Chemistry and Physics Faculty Articles

To trace how dust-obscured star formation varies with environment, we compare the fraction of 24 μm sources in a super galaxy group to the field and a rich galaxy cluster at z ~ 0.35. We draw on multi-wavelength observations that combine Hubble, Chandra, and Spitzer imaging with extensive optical spectroscopy (>1800 redshifts) to isolate galaxies in each environment and thus ensure a uniform analysis. We focus on the four galaxy groups (σ_1D = 303-580 km s^–1) in supergroup 1120-12 that will merge to form a galaxy cluster comparable in mass to Coma. We find …

Forming Early-Type Galaxies In Groups Prior To Cluster Assembly, Stefan Kautsch, Anthony H. Gonzalez, Christian A. Soto, Kim-Vy H. Tran, Dennis Zaritsky, John Moustakas

Chemistry and Physics Faculty Articles

We study a unique protocluster of galaxies, the supergroup SG1120–1202. We quantify the degree to which morphological transformation of cluster galaxies occurs prior to cluster assembly in order to explain the observed early-type fractions in galaxy clusters at z = 0. SG1120–1202 at z ~ 0.37 is composed of four gravitationally bound groups that are expected to coalesce into a single cluster by z = 0. Using HST ACS observations, we compare the morphological fractions of the supergroup galaxies to those found in a range of environments. We find that the morphological fractions of early-type galaxies (~60%) and the ratio …

The Late Stellar Assembly Of Massive Cluster Galaxies Via Major Merging, Kim-Vy H. Tran, John Moustakas, Anthony H. Gonzalez, Lei Bai, Dennis Zaritsky, Stefan Kautsch

Chemistry and Physics Faculty Articles

We present multiwavelength observations of the brightest galaxies in four X-ray-luminous groups at z ~ 0.37 that will merge to form a cluster comparable in mass to Coma. Ordered by increasing stellar mass, the four brightest group galaxies (BGGs) present a time sequence where BGG-1, 2, and 3 are in merging systems and BGG-4 is a massive remnant (M_* = 6.7 × 10¹¹ M_☉). BGG-1 and 2 have bright, gravitationally bound companions and BGG-3 has two nuclei separated by only 2.5 kpc; thus, merging at z < 0.5 increases the BGG mass by ≳40% (t_MGR < 2 Gyr) and V-band luminosity by ~0.4 mag. The …

Initial Mass Function Effects On The Colour Evolution Of Disk Galaxies, P. Westera, M. Samland, Stefan Kautsch, R. Buser, K. Ammon

Chemistry and Physics Faculty Articles

Aims. In this work, we want to find out if the IMF can be determined from colour images, integrated colours, or mass-to-light ratios, especially at high redshift, where galaxies cannot be resolved into individual stars, which would enable us to investigate dependencies of the IMF on cosmological epoch.

Methods. We use chemo-dynamical models to investigate the influence of the Initial Mass Function (IMF) on the evolution of a Milky Way-type disk galaxy, in particular of its colours.

Results. We find that the effect of the IMF on the internal gas absorption is larger than its effect on …

Erratum: A Catalog Of Edge-On Disk Galaxies: From Galaxies With A Bulge To Superthin Galaxies, Stefan Kautsch, E. K. Grebel, F. D. Barazza, J. S. Gallagher

Chemistry and Physics Faculty Articles

Erratum

A Catalog Of Edge-On Disk Galaxies: From Galaxies With A Bulge To Superthin Galaxies, Stefan Kautsch, E. K. Grebel, F. D. Barazza, J. S. Gallagher

Chemistry and Physics Faculty Articles

Spiral galaxies range from bulge-dominated early-type galaxies to late types with little or no bulge. Cosmological models do not predict the formation of disk-dominated, essentially bulgeless galaxies, yet these objects exist. A particularly striking and poorly understood example of bulgeless galaxies are flat or superthin galaxies with large axis ratios. We therefore embarked on a study aimed at a better understanding of these enigmatic objects, starting by compiling a statistically meaningful sample with well-defined properties. The disk axis ratios can be most easily measured when galaxies are seen edge-on. We used data from the Sloan Digital Sky Survey (SDSS) in …

A Search For Pure Disk Galaxies, Stefan Kautsch, Eva K. Grebel

Chemistry and Physics Faculty Proceedings, Presentations, Speeches, Lectures

Flat (or superthin) galaxies are late-type edge-on spiral galaxies that exhibit large axial ratios, small stellar disk scale heights and no distinct spheroidal bulge component. This type of galaxies appears to be a pure disk system with an extended blue stellar disk embedded in a red thick layer. Flat galaxies are very common objects with low star formation rates, low metallicities, low optical surface brightness but high neutral gas fractions. Their rotation curves resemble those of dwarf and irregular galaxies. These simple disk systems offer the unique opportunity to constrain galaxy disk evolution in underevolved galaxies in the nearby Universe. …