scholarly journals Kinematics, structure and environment of three dwarf spheroidal galaxies

2014 ◽  
Vol 11 (S308) ◽  
pp. 473-474
Author(s):  
M. E. Sharina ◽  
I. D. Karachentsev ◽  
V. E. Karachentseva
Keyword(s):  
Surface Brightness ◽  
Morphological Type ◽  
Virgo Cluster ◽  
Sloan Digital Sky Survey ◽  
Dwarf Spheroidal Galaxies ◽  
Isolated Galaxies ◽  
Environmental Status ◽  
The Moment ◽  
Academy Of Sciences ◽  
Spheroidal Galaxies

AbstractWe explore the environmental status of three low surface brightness dwarf spheroidal galaxies (dSphs) KKH65, KK180 and KK227 using the results of our long slit spectroscopic observations at the 6m telescope of the Russian Academy of Sciences and surface photometry on the Sloan Digital Sky Survey (SDSS) images. The objects were selected by Karachentseva in 2010 as presumably isolated galaxies. The obtained surface brightness profiles demonstrate that our sample dSphs are less centrally concentrated than the objects of the same morphological type in the Virgo cluster (VC). Using the derived kinematic data we searched for possible neighbours of the dSphs within the projected distances from them Rproj > 500 kpc and with the differences in radial velocities |Δ V| > 500 kms−1. We applied the group finding algorithm by Makarov and Karachentsev to the selected sample. Our analysis shows that the dwarf galaxies of our study are not isolated. KKH65 and KK227 belong to the groups NGC3414 and NGC5371, respectively. KK180 is in the VC infall region. We conclude that it is not possible at the moment to justify the existence of isolated dSphs outside the Local Volume. The searches are complicated due to the lack of the accurate distances to the galaxies farther than 10 Mpc.

scholarly journals Low Surface Brightness Dwarf Galaxies in the Bristol – Anglo-Australian Observatory Virgo Cluster Survey

1999 ◽  
Vol 171 ◽  
pp. 84-91
Author(s):  
J.B. Jones ◽  
S. Phillipps ◽  
J.M. Schwartzenberg ◽  
Q.A. Parker
Keyword(s):  
Surface Brightness ◽  
Initial Study ◽  
Virgo Cluster ◽  
Dwarf Spheroidal Galaxies ◽  
Small Areas ◽  
Multiple Exposures ◽  
The United Kingdom ◽  
Large Numbers ◽  
Photographic Survey ◽  
First Time

AbstractWe describe a new, deep photographic survey of the Virgo Cluster which uses multiple exposures on Tech Pan film with the United Kingdom Schmidt Telescope to probe the dwarf population to fainter surface brightness limits than previous surveys. We have identified galaxies having sizes (≥ 3 arcsec scale length) and surface brightnesses (≤ 24.5 R mag arcsec−2) characteristic of those expected for dwarf spheroidal galaxies in the cluster. The survey is providing substantial samples of extremely low luminosity galaxies outside the environment of the Local Group and nearby groups for the first time. An initial study of two small areas has found dwarf spheroidal candidates in large numbers (500 deg−2) which indicate a steep, continuously rising luminosity function at low luminosities.

scholarly journals Surface Photometry of Low-Surface-Brightness Galaxies in the Area of the NGC 972 Group of Galaxies

1994 ◽  
Vol 161 ◽  
pp. 553-555
Author(s):  
J. Vennik ◽  
G.M. Richter
Keyword(s):  
Surface Brightness ◽  
Surface Photometry ◽  
Schmidt Telescope ◽  
Dwarf Spheroidal Galaxies ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies ◽  
Spheroidal Galaxies

A nearby group of galaxies, centred on NGC 972 and conspicuously rich in faint dwarf spheroidal galaxies, has been investigated photometrically on B and V plates obtained with the Tautenburg 2m Schmidt telescope. For six low surface brightness galaxies, the equivalent B- and V-brightness profiles have been extracted, and asymptotic magnitudes and mean colours have been estimated. Their equivalent profiles are well fitted by modified isothermal (King) models.

scholarly journals Deep optical imaging of the dark galaxy candidate AGESVC1 282

2020 ◽  
Vol 642 ◽  
pp. L10
Author(s):  
Michal Bílek ◽  
Oliver Müller ◽  
Ana Vudragović ◽  
Rhys Taylor
Keyword(s):  
Surface Brightness ◽  
Stellar Mass ◽  
Virgo Cluster ◽  
Sloan Digital Sky Survey ◽  
Dark Matter Halos ◽  
Mass Ratio ◽  
Stellar Content ◽  
Dark Clouds ◽  
Sky Survey ◽  
Galaxy Environment

The blind H I survey Arecibo Galaxy Environment Survey (AGES) detected several unresolved sources in the Virgo cluster, which do not have optical counterparts in the Sloan Digital Sky Survey. The origin of these dark clouds is unknown. They might be crucial objects since they could be the so-called dark galaxies, that is, the dark matter halos without stellar content that are expected from cosmological simulations. In order to reveal the nature of the dark clouds, we took a deep optical image of one them, AGESVC1 282, with the newly-commissioned 1.4 m Milanković Telescope. After observing it for 10.4 h in the L-filter, the image reached a surface-brightness limit of about 29.1 mag arcsec−2 in V. No optical counterpart was detected. We placed an upper limit on the V-band luminosity of the object of 1.1 × 107 L⊙, giving a stellar mass below 1.4 × 107 M⊙ and a H I-to-stellar mass ratio above 3.1. By inspecting archival H I observations of the surrounding region, we found that none of the standard explanations for optically dark H I clouds fits the available constraints on this object.

scholarly journals Galaxy Harassment—Interactions for the 90s

1999 ◽  
Vol 186 ◽  
pp. 393-400 ◽  
Author(s):  
George Lake ◽  
Ben Moore
Keyword(s):  
Surface Brightness ◽  
Luminosity Function ◽  
Local Group ◽  
High Surface ◽  
Late Type ◽  
High Surface Brightness ◽  
Dwarf Spheroidal Galaxies ◽  
Central Surface ◽  
Hubble Sequence ◽  
Spheroidal Galaxies

The origin of the Hubble sequence remains a long-standing puzzle in astronomy. Giant galaxies range from slowly-rotating dense ellipticals to thin late-type spiral disks. At the faint end, there are two distinct classes of “ellipticals/spheroids” that are easily separated in plots of nearly any two of their properties, such as central surface brightness versus luminosity (Ferguson and Binggeli 1994; Kormendy 1985). The elliptical class includes the bright giants and extends to the rare high surface brightness “dwarf ellipticals”, M32 being the prototype. The “spheroidal” galaxies have low surface brightnesses and are all ≳3 magnitudes fainter than L∗, the characteristic break in the luminosity function. The dwarf spheroidal galaxies (dSph) in our Local Group of galaxies with magnitudes in the range −8≳MB≳ - 12 are often considered to be the low luminosity extreme of this sequence, but nearly all other known galaxies in this class reside in clusters.

scholarly journals Dwarf Spheroidal Galaxies in the Virgo Cluster

1998 ◽  
Vol 493 (2) ◽  
pp. L59-L62 ◽  
Author(s):  
S. Phillipps ◽  
Q. A. Parker ◽  
J. M. Schwartzenberg ◽  
J. B. Jones
Keyword(s):  
Virgo Cluster ◽  
Dwarf Spheroidal Galaxies ◽  
Spheroidal Galaxies

COMPARING THE DARK MATTER HALOS OF SPIRAL, LOW SURFACE BRIGHTNESS, AND DWARF SPHEROIDAL GALAXIES

2010 ◽  
Vol 717 (2) ◽  
pp. L87-L91 ◽  
Author(s):  
Matthew G. Walker ◽  
Stacy S. McGaugh ◽  
Mario Mateo ◽  
Edward W. Olszewski ◽  
Rachel Kuzio de Naray
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Dark Matter Halos ◽  
Dwarf Spheroidal Galaxies ◽  
Low Surface Brightness ◽  
Spheroidal Galaxies
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