416 research outputs found
Tidal Tails and Galaxy Evolution
We review recent results on the tidal structures of spiral galaxies. Topics
included are general characteristics of tails; kinematics of tidal structures
and dark haloes of host galaxies; frequency of tidal distortions at z~1.Comment: 5 pages, "Morphology and Dynamics of Stellar Systems: Star Clusters,
Galactic Arms and Rings", Proc. JENAM-2000, in pres
Effect of the Environment on the Fundamental Plane of Elliptical Galaxies
We present an analysis of interacting E/S0 galaxies location on the
Fundamental Plane. Using the NEMO package, we performed N-body simulations of
close encounters and mergers between two spherical galaxies. We followed how
structural and dynamical parameters (central density, half-mass radius and
velocity dispersion)of galaxies are changed during the encounter. We analysed
the dependence of these changes on initial mass concentration and presence of
dark halo. The results of our simulations are used to discuss the Fundamental
Plane for interacting early-type galaxies.Comment: Poster presented at JENAM-2000 (Joint European and National
Astronomical meeting - S02. Morphology and dynamics of stellar systems: star
clusters, galactic arms and rings
Polar-bulge galaxies
Based on SDSS data, we have selected a sample of nine edge-on spiral galaxies
with bulges whose major axes show a high inclination to the disk plane. Such
objects are called polar-bulge galaxies. They are similar in their morphology
to polar-ring galaxies, but the central objects in them have small size and low
luminosity. We have performed a photometric analysis of the galaxies in the g
and r bands and determined the main characteristics of their bulges and disks.
We show that the disks of such galaxies are typical for the disks of spiral
galaxies of late morphological types. The integrated characteristics of their
bulges are similar to the parameters of normal bulges. The stellar disks of
polar-bulge galaxies often show large-scale warps, which can be explained by
their interaction with neighboring galaxies or external accretion from outside.Comment: 8 pages, 3 figure
Does the stellar disc flattening depend on the galaxy type?
We analyze 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 (EGIS) catalogue. Combining these
data with the retrieved models of the edge-on galaxies from the Two Micron All
Sky Survey (2MASS) and the Spitzer Survey of Stellar Structure in Galaxies
(SG) catalogue, we make the following conclusions:
(1) The disc relative thickness in the near- and mid-infrared
passbands correlates weakly with morphological type and does not correlate with
the bulge-to-total luminosity ratio in all studied bands.
(2) Applying an 1D photometric profile analysis overestimates the disc
thickness in galaxies with large bulges making an illusion of the relationship
between the disc flattening and the ratio .
(3) In our sample the early-type disc galaxies (S0/a) have both flat and
"puffed" discs. The early spirals and intermediate-type galaxies have a large
scatter of the disc flatness, which can be caused by the presence of a bar:
barred galaxies have thicker stellar discs, on average. On the other hand, the
late-type spirals are mostly thin galaxies, whereas irregular galaxies have
puffed stellar discs.Comment: 17 pages, 17 figures, accepted for publication in MNRA
The Catalog of Edge-on Disk Galaxies from SDSS. Part I: the catalog and the Structural Parameters of Stellar Disks
We present a catalog of true edge-on disk galaxies automatically selected
from the Seventh Data Release (DR7) of the Sloan Digital Sky Survey. A visual
inspection of the , and images of about 15000 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-ons, and 1865
(12.5%) edge-on galaxies not suitable for simple automatic analysis because
these objects show signs of interaction, warps, or nearby bright stars project
on it. We added more candidate galaxies from RFGC, EFIGI, RC3, and Galaxy Zoo
catalogs found in the SDSS footprints. Our final sample consists of 5747
genuine edge-on galaxies. We estimate the structural parameters of the stellar
disks (the stellar disk thickness, radial scale length, and central surface
brightness) in the galaxies by analyzing photometric profiles in each of the g,
r, and i images. We also perform simplified 3-D modeling of the light
distribution in the stellar disks of edge-on galaxies from our sample. Our
large sample is intended to be used for studying scaling relations in the
stellar disks and bulges and for estimating parameters of the thick disks in
different types of galaxies via the image stacking. In this paper we present
the sample selection procedure and general description of the sample.Comment: Accepted for publication in Ap
Candidate genes and clinical-laboratory parameters in pregnant women with preeclampsia
They studied the associations of genetic polymorphisms with clinico-laboratory indicators among pregnant women with preeclampsia depending on hereditary complicatio
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