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Dwarf Spheroidal Galaxies in the M101 Group and Behind it
Karachentsev, I. D.; Makarova, L. N.
We use images from the Hubble Space Telescope to determine the distances to a dozen objects with low surface brightness recently observed around the bright nearby spiral M101. Only two dwarf galaxies, M101-DwA and M101-Dw9, turn out to be actual satellites of M101 at distances of about 7 Mpc. The other objects are probably members of a distant gro…
Interacting galaxies in deep fields of the Hubble Space Telescope
Reshetnikov, V. P.; Mohamed, Y. H.
The morphologies of galaxies in several deep fields (HDF-N, HDF-S, HUDF, GOODS, GEMS) of the Hubble Space Telescope are analyzed visually. Lists are made of the galaxies with tidal structures (tails, bridges) and type M51 galaxies in these fields. Photometric characteristics and estimated redshifts for most of these objects are found in the publis…
Method for analyzing the spatial distribution of galaxies on gigaparsec scales. II. Application to a grid of the HUDF-FDF-COSMOS-HDF surveys
Nabokov, N. V.; Baryshev, Yu. V.
Using the deep fields of COSMOS, FDF, HUDF, and HDF-N as an example, we discuss the prospects for and limitations on the method for searching for superlarge structures in the spatial distribution of galaxies proposed in the preceding article of this series. An analysis of the distribution N(z) of photometric redshifts in a grid of the deep fields …
Observational evidences of multiple shock waves in X-ray selected BL Lacerate objects
Kapanadze, B. Z.
The results of optical R-band photometry of three X-ray selected BL Lacertae objects 1ES 0502+675, 1ES 0806+524 and 1ES 1959+650 from the Einstein Slew Survey are presented. The observations are performed during 1997–2006 with the 70-cm meniscus type telescope of Abastumani Astrophysical Observatory. The objects show clear long-term variability wi…
Multiparametric infrared Tully-Fisher relation as a tool for mapping cosmic flows
Kashibadze, O. G.
The peculiar velocity field for 907 galaxies with heliocentric radial velocities VH ≤ 3000 km/s is examined. The data are divided into three samples, organized according to the principles behind the method for determining the distance to the galaxies: the luminosity of the tip of the red giant branch (TRGB), fluctuations in the surface …
Local dark energy: HST evidence from the vicinity of the M81/M82 galaxy group
Karachentsev, I. D.; Kashibadze, O. G.; Makarov, D. I. +5 more
The Hubble Space Telescope observations of the nearby galaxy group M81/M82 and its vicinity indicate that the dynamics of the expansion outflow around the group is dominated by the antigravity of the dark energy background. The local density of dark energy in the area is estimated to be near the global dark energy density or perhaps exactly equal …
Masses of the local group and of the M81 group estimated from distortions in the local velocity field
Karachentsev, I. D.; Kashibadze, O. G.
Based on high precision measurements of the distances to nearby galaxies with the Hubble telescope, we have determined the radii of the zero velocity spheres for the local group, R0 = 0.96±0.03Mpc, and for the group of galaxies around M 81/M 82, 0.89±0.05Mpc. These yield estimates of MT = (1.29±0.14)· 1012 M⊙<…
Stellar Disks and Halos of Edge-on Spiral Galaxies: NGC 891, NGC 4144, and NGC 4244
Tikhonov, N. A.; Galazutdinova, O. A.
Stellar photometry of images from the ACS and WFPC2 cameras on the Hubble Space Telescope (HST) is used to study the star composition and spatial distribution of stars in three edge-on visible spiral galaxies: NGC 891, NGC 4144, and NGC 4244. Measurements of the surface number density of old stars revealed two stellar subsystems in these galaxies:…
The BM Ori System. I. Anomaly in the Radial Velocity
Klochkova, V. G.; Vitrichenko, E. A.
The radial velocities of the star BM Ori are determined from spectra obtained by the HST and IUE satellites, as well as from spectra obtained with the BTA telescope. An analysis of this data shows that the radial velocities of the main star and its satellite experience an irregular positive shift by ∼20-30 km/s. This fact can only be interpreted i…
Classical Cepheids and the Distances of HST Program Galaxies
Abrahamyan, H. V.
The distances of HST program galaxies are revised using the PL-relations we have obtained previously along with a different method from that employed by Freedman et al. On the average, the resulting distances to these galaxies have higher internal accuracies than those obtained before by others. In addition, we have used no corrections for metalli…