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To investigate the formation and evolution of vertical structures in disk galaxies, we measure global $\operatorname{sech}^2$ scale heights, averaging thin and thick components when present, for 2631 edge-on disk galaxies with $M_*>10^{10}…

Disk scale length and central surface brightness for a sample of about 29955 bright disk galaxies from the Sloan Digital Sky Survey have been analysed. Cross correlation of the SDSS sample with the LEDA catalogue allowed us to investigate…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Kambiz Fathi

Most of the visible mass in a typical spiral galaxy is distributed in a thin disk, with a radial extent much larger than its thickness. While the planar disk structure, including non-axisymmetric features such as spiral structure, has been…

Astrophysics of Galaxies · Physics 2025-07-04 Chanda J. Jog

I review recent SDSS results related to galaxies and large scale structure, including: (1) discovery of coherent, unbound structures in the stellar halo, (2) demonstration that Pal 5 has tidal tails and Draco doesn't, (3) precise…

Astrophysics · Physics 2007-05-23 David H. Weinberg

We have derived disk scale lengths for 30374 non-interacting disk galaxies in all five SDSS bands. Virtual Observatory methods and tools were used to define, retrieve, and analyse the images for this unprecedentedly large sample classified…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-21 Kambiz Fathi , Mark Allen , Thomas Boch , Evanthia Hatziminaoglou , Reynier Peletier

We present an analysis of Galactic halo structure and substructure traced by ~500 RR Lyrae stars in the SDSS stripe 82 region. The main result of this study is a 2D map of the Galactic halo that reaches distances of 100 kpc and traces…

Astrophysics of Galaxies · Physics 2011-05-23 Branimir Sesar

Late-type low surface brightness galaxies (LSBs) are faint disk galaxies with central maximum stellar surface densities below 100 Msun/pc^2. The currently favored scenario for their origin is that LSBs have formed in fast-rotating halos…

Astrophysics of Galaxies · Physics 2013-06-05 Ji-hoon Kim , Jounghun Lee

We have detected over 400 HI clouds in the lower halo of the Galaxy within the pilot region of the Galactic All-Sky Survey (GASS), a region of the fourth quadrant that spans 18 degrees in longitude, 40 degrees in latitude and is centered on…

For the past twenty years, it has been accepted that the vertical scaleheight of the stellar disk in spiral galaxies is constant with radius. However, there is no clear physical explanation for this in the literature. Here we calculate the…

Astrophysics · Physics 2009-11-07 Chaitra A. Narayan , Chanda J. Jog

A generic prediction of hierarchical clustering models is that the mass function of dark haloes in dense regions in the Universe should be top-heavy. We provide a novel test of this prediction using a sample of galaxies drawn from the Sloan…

Astrophysics · Physics 2009-11-11 Ummi Abbas , Ravi K. Sheth

The observed flaring of HI disk in the outer region of galaxies has been used in the past to determine the shape of the dark matter halo. Previous studies based on this concept suggest a slightly oblate halo (axis ratio ~ 0.8) for our…

Astrophysics · Physics 2009-11-11 C. A. Narayan , K. Saha , C. J. Jog

A statistical study of global galaxy parameters can help to improve our understanding of galaxy formation processes. In this paper we present the analysis of global galaxy parameters based on optical and near-infrared observations of a…

Astrophysics · Physics 2009-10-30 R. de Grijs

Based on the Sloan Digital Sky Survey DR6 (SDSS) and Millennium Simulation (MS) we investigate the alignment between galaxies and large-scale structure. For this purpose we develop two new statistical tools, namely the alignment correlation…

Astrophysics · Physics 2009-09-25 A. Faltenbacher , Cheng Li , Simon D. M. White , Y. P. Jing , Shude Mao , Jie Wang

The radial density profiles of stellar galaxy discs can be well approximated as an exponential. Compared to this canonical form, however, the profiles in the majority of disc galaxies show downward or upward breaks at large radii.…

We use 666 blue horizontal branch (BHB) stars from the 2Qz redshift survey to map the Galactic halo in four dimensions (position, distance and velocity). We find that the halo extends to at least 100 kpc in Galactocentric distance, and…

Astrophysics of Galaxies · Physics 2015-05-19 Roberto De Propris , Craig D. Harrison , Peter J. Mares , CTIO , Cornell University

We have used the field stars from the open cluster survey BOCCE, to study three low-latitude fields imaged with the Canada-France-Hawaii telescope (CFHT), with the aim of better understanding the Galactic structure in those directions. Due…

Astrophysics · Physics 2009-11-13 M. Cignoni , M. Tosi , A. Bragaglia , J. S. Kalirai , D. S. Davis

We measure the angular 2-point correlation functions of galaxies in a volume limited, photometrically selected galaxy sample from the fifth data release of the Sloan Digital Sky Survey. We split the sample both by luminosity and galaxy type…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-20 Ashley J Ross , Robert J. Brunner

We estimated the dynamical surface mass density (Sigma) at the solar Galactocentric distance between 2 and 4 kpc from the Galactic plane, as inferred from the observed kinematics of the thick disk. We find Sigma(z=2 kpc)=57.6+-5.8 Mo pc^-2,…

Astrophysics of Galaxies · Physics 2015-05-20 C. Moni Bidin , G. Carraro , R. A. Mendez , W. F. van Altena

We compute the exponential disc scalelength for 686 disc galaxies with spectroscopic redshifts out to redshift 5.8 based on Hubble Space Telescope archival data. We compare the results with our previous measurements based on 30000 nearby…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Kambiz Fathi , Michael Gatchell , Evanthia Hatziminaoglou , Benoit Epinat

Wide-angle, moderately deep redshift surveys such as that conducted as part of the Sloan Digital Sky Survey (SDSS) allow study of the relationship between the structural elements of the large-scale distribution of galaxies -- including…

Astrophysics · Physics 2009-11-10 Michael S. Vogeley , Fiona Hoyle , Randall R. Rojas , David M. Goldberg