共查询到20条相似文献,搜索用时 31 毫秒
1.
Using lists of bright galaxies with and without a bar, as well as the Lyon-Meudon Extragalactic Data Set (LEDA), the surroundings
of SB and SA galaxies have been investigated and some differences between them have been found.
Translated from Astrofizika, Vol. 42, No. 4, pp. 579–588, October–December, 1999. 相似文献
2.
The radio and xray properties of spiral galaxies with and without a bar are discussed on the basis of complete samples that
we have compiled. The two types of spirals are shown not to differ from one another in emission power in the two indicated
ranges. In the case of SB galaxies, the luminosities in the IR, radio, and xray ranges are closely related. The spectral indices
of SB and SA galaxies in the 1.4–5 GHz range are the same, on the average. In the case of barred galaxies, however, a definite
dependence is observed between the spectral index and both the IR and × ray luminosities, i.e., the spectral index increases
as both luminosities increase. It is assumed that this is caused by the bar itself, which stimulates star formation in a barred
galaxy.
Translated from Astrofizika, Vol. 41. No. 4, pp. 599–608, October–December, 1998. 相似文献
3.
Various characteristics of galaxies with and without a bar are compared in two complete samples compiled by the authors. It
is found that the two types of spiral galaxies hardly differ from each other in a number of parameters and properties, such
as nuclear activity and degree of concentration in groups. Star formation evidently occurs more efficiently in barred galaxies,
however. Bars are encountered more often in intermediate and late subtypes of disk galaxies. Barred galaxies in groups are
redder, on the average, than those outside of groups. Luminosity functions are constructed both for galaxies with and without
bars.
Translated from Astrofizika, Vol. 4L No. 2, pp. 185–196, April-June, 1998 相似文献
4.
Kotaro Kohno Koichiro Nakanishi Tomoka Tosaki Kazuyuki Muraoka Rie Miura Hajime Ezawa Ryohei Kawabe 《Astrophysics and Space Science》2008,313(1-3):279-285
Dense molecular medium plays essential roles in galaxies. As demonstrated by the tight and linear correlation between HCN(1–0)
and FIR luminosities among star-forming galaxies, from very nearby to high-z ones, the observation of a dense molecular component
is indispensable to understand the star formation laws in galaxies. In order to obtain a general picture of the global distributions
of dense molecular medium in normal star-forming galaxies, we have conducted an extragalactic CO(3–2) imaging survey of nearby
spiral galaxies using the Atacama Submillimeter Telescope Experiment (ASTE). From the survey (ADIoS; ASTE Dense gas Imaging
of Star-forming galaxies), CO(3–2) images of M 83 and NGC 986 are presented. Emphasis is placed on the correlation between
the CO(3–2)/CO(1–0) ratio and the star formation efficiency in galaxies. In the central regions of some active galaxies, on
the other hand, we often find enhanced or overluminous HCN(1–0) emission. The HCN(1–0)/CO(1–0) and HCN(1–0)/HCO+(1–0) intensities are often enhanced up to ∼0.2–0.3 and ∼2–3, respectively. Such elevated ratios have never been observed
in the nuclear starburst regions. One possible explanation for these high HCN(1–0)/CO(1–0) and HCN(1–0)/HCO+(1–0) ratios is X-ray induced chemistry in X-ray dominated regions (XDRs), i.e., the overabundance of the HCN molecule in
the X-ray irradiated dense molecular tori. If this view is true, the known tight correlation between HCN(1–0) and the star-formation
rate breaks in the vicinity of active nuclei. Although the interpretation of these ratios is still an open question, these
ratios have a great potential for a new diagnostic tool for the energy sources of dusty galaxies in the ALMA era because these
molecular lines are free from dust extinction. 相似文献
5.
A catalog of barred spiral galaxies of types SB and SAB with BT ≤ 13.5 and δ > -10° has been compiled. Some parameters of these galaxies are given.
Translated from Astrofizika, Vol. 4L No. 1, pp. 5–21 January-March. 1998. 相似文献
6.
L. K. Erastova 《Astrophysics》2000,43(2):141-144
The diameters of active galaxies were compared with the diameters of ordinary galaxies. It is shown that, within the same
luminosity limits, they do not differ clearly from each other. Starlike active galaxies in the samples of active galaxies
have any possible luminosities. The parent galaxies of quasars have different diameters and, in accordance with their sizes,
can be either elliptical or spiral.
Translated from Astrofizika, Vol. 43, No. 2, pp. 191-196, April–June, 2000. 相似文献
7.
1200 strongly flattened galaxies with axis ratio b/a ≤ 0.15 were selected from the UGC catalogue, contained in the Abadumani
Merged Catalogue of Galaxies, and their properties were studied. The possibility of using strongly flattened galaxies and
several other samples of galaxies according to their morphological type as a distance indicator has been examined by the Tully-Fisher
relation. The investigation has shown that angular diameters of strongly flattened as well as flat, seen edge-on galaxies
designated as F and L in the MCG catalogue can be used for the estimation of distance moduli with accuracy O.m7. The distribution of absolute magnitudes of strongly flattened galaxies was approximated by analytic Schechter expression
with main parameters M* = -21.m2 and α = -1.0. The statistical method of the nearest companion applied to the apparent distribution of strongly flattened
galaxies has shown that these galaxies are considerably more frequently found in mixed pairs and multiple systems than spirals.
Published in Astrofizika, Vol. 41, No. 1, pp. 23–34, January-March, 1998. 相似文献
8.
V. H. Malumian 《Astrophysics》1997,40(1):22-24
It is shown that objects with steep radio emission spectra occur significantly more often among isolated spiral galaxies than
among spiral members of double galaxies. This, along with some other facts, indicates that members of pairs of galaxies are
at a more active phase of their evolution than isolated galaxies.
Translated fromAstrofizika, Vol. 40, No. 1, pp. 39–43, February, 1997. 相似文献
9.
R. A. Kandalyan A. T. Kalloghlian H. M. K. AI- Naimiy A. M. Khassawneh 《Astrophysics》2000,43(3):299-308
The gas properties of barred and unbarred spiral galaxies are compared in two complete samples. It is found that two types
of spiral galaxies do not differ from each other in atomic and molecular gas contents. On average there is 6 times more HI
than H2 in spiral galaxies and the ratio MH2/MHI decreases from early to late types. The barred and unbarred spirals in general show
a similar behaviors of the gas-to-luminosity relationships, but also there are certain differences between them such as correlation
of two gas phases (HI and H2)for unbarred galaxies. It is suggested that different behaviors of two types galaxies are due to the higher star forming
activity of barred with respect unbarred spirals. The expected values of HI and H2 gas contents have been estimated using blue and far-infrared emission.
Published in Astrofizika, Vol. 43, No. 3, pp. 405-410, July–September, 2000. 相似文献
10.
A. P. Mahtessian 《Astrophysics》1998,41(3):308-321
A list of groups of galaxies, determined on identification principles suggested by the author, and some of their empirical
characteristics are given.
Translated from Astrofizika, Vol. 41, No. 3, pp 473–488, July–September, 1998. 相似文献
11.
A. M. Mickaelian 《Astrophysics》2000,43(3):309-321
A fifth list of objects from the BIG (Byurakan-IRAS galaxies) sample is given: 89 galaxies identified with 59 point sources
from the IRAS Point Source Catalog. The identifications were based on the Digital Sky Survey (DSS), the First Byurakan Survey,
blue and red maps from the Palomar Observatory Sky Survey, and infrared fluxes at 12, 25, 60, and 100 mm in the region of+65°
≤ δ ≤69δ and 5h10m ≤ α ≤9h 15m with an area of 96 deg2. For the identified galaxies the optical coordinates, their departures from the IR coordinates, and the stellar V magnitudes,
morphological types, angular sizes, and position angles were determined. The objects have optical magnitudes in the range
of 14m. 1-21m.5 and angular sizes in the range of 2″-47″. The galaxies are mainly spiral in morphology. Compact galaxies and Seyfert candidates,
interacting pairs, “mergers,” galaxies with companions and superassociations, groups of galaxies (including compact ones),
and others are encountered, which shows the importance of these objects for the study of the relationships among the phenomena
of star formation, activity, and interactions. Finder charts from the DSS are given for these objects. New designations and
numbering are introduced for galaxies in the studied sample.
Translated from Astrofizika, Vol. 43, No. 3, pp. 425-441, July– September, 2000.
The NASA/IPAC Extragalactic Database (NED), operated by the Jet Propulsion Laboratory, California Institute of Technology,
under contract with NASA. 相似文献
12.
P. Amram C. Mendes de Oliveira H. Plana C. Balkowski M. Bolte 《Astrophysics and Space Science》2002,281(1-2):397-400
We present kinematics and photometric evidence for the presence of seven candidate tidal dwarf galaxies in Stephan's Quintet.
The central regions of the two most probable parent galaxies, NGC 7319 and NGC 7318B, contain little or no gas whereas the
intragroup medium and, in particular, the optical tails that seem to be associated with NGC 7318B are rich in cold and ionized
gas. Two tidal dwarf candidates may be located at the edge of a tidal tail, another located within a tail, and for the four
others there is no obvious stellar/gaseous bridge between them and the parent galaxy. Two of the candidates are associated
with H I clouds, one of which is, in addition, associated with a CO cloud. All seven regions have low continuum fluxes and
high Hα luminosity densities [F(Hα) = (1-60) × 10-14 ergs s-1 cm-2]. Their magnitudes (MB = –16.1 to –12.6), sizes (∼ 3.5 h75
-1 kpc), colors (typically B – R = 0.7), and gas velocity gradients (∼ 8 –26 h75 km s-1 kpc-1) are typical for tidal dwarf galaxies. In addition, the ratios between their star formation rates determined from Hα and
from the B-band luminosity are typical of other tidal dwarf galaxies. The masses of the tidal dwarf galaxies in Stephan's
Quintet range from ∼ 2 × 108 to 1010 M⊙, and the median value for their inferred mass-to-light ratios is 7 (M/L)⊙. At least two of the systems may survive possible ‘fallbacks’ or disruption by the parent galaxies and may already be, or
turn into, self-gravitating dwarf galaxies, new members of the group.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
13.
The widely varying dwarf galaxy counts in different environments provide a strong challenge to standard hierarchical clustering
models. The luminosity function is not universal, but seems to be strongly dependent upon environment. In this paper we describe
an automated procedure for detecting and measuring very Low Surface Brightness (LSB) features in deep CCD data. We apply this
procedure to large area CCD survey fields of the Virgo cluster and find 105 dwarf LSB galaxies previously uncatalogued over
an area of ∼14 sq deg. We show that there are many more faint (14≤MB≤–10) LSB galaxies than would be predicted from extrapolation of the Virgo cluster catalogue luminosity function. Over our
limited range of measurement the faint end slope of the luminosity function becomesα=–1.6. Although these galaxies contribute
a small fraction of the total stellar light of the cluster, they may contribute significantly to the mass in galaxies if they
have large mass-to-light ratios similar to those recently measured for Local Group dwarf galaxies. By a comparison with different
environments, the Virgo Cluster seems to be highly `dwarf rich' if considering the dwarf to giant ratio or it's luminosity
function faint end slope.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
The relationship between the rotation curves for the galaxies and the distribution of mass and angular momentum within the
galaxies is examined. The theory of angular momentum transfer is applied to the observed properties of the galaxies. The coupling
between the dynamical mass of a spiral galaxy and its luminosity is studied. Most of the spiral galaxies in subclusters surrounding
NGC 4889, NGC 4874, and NGC 4839 in the Coma cluster are galaxies that have lower luminosities, with MB fainter than −21m.5. These galaxies are characterized by a higher mass-to-luminosity ratio than that of the galaxies with higher luminosities
MB brighter than −21m.5, which suggests the presence of a large fraction of dark matter in the spiral galaxies of the subclusters.
Translated from Astrofizika, Vol. 52, No. 1, pp. 75–84 (February 2009). 相似文献
15.
Results are presented from a spectral, photometric, and morphological study of two compact groups of compact galaxies (CGCG)
from Shahbazian’s list. The observations were made on the 1.5-m ESO telescope and the 2.6-m telescope at the Byurakan Astrophysical
Observatory (BAO) during 1999–2000. These data are compared with data for the Shahbazian compact group 4. A high spatial density
of galaxies, ranging from 10000 to 100000 galaxies per Mpc3, is observed in all the groups that were studied. The discovery of a Seyfert Sy1 galaxy in the Shahbazian 355 compact group
is especially noteworthy. The direct photographs of the CGCGs that were studied contain no signs of merging or tidal interactions
among the members of these groups. This suggests that the galaxies in these dense systems have a common origin.
__________
Translated from Astrofizika, Vol. 50, No. 3, pp. 347–353 (August 2007). 相似文献
16.
It is shown that objects with relatively flat radio emission spectra are mainly encountered among spiral galaxies of morphological
subtypes Sa and Sab (including barred galaxies of these subtypes). Objects both with flat and with steep spectra are encountered
among galaxies of morphological subtypes later than Sab.
Translated from Astrofizika, Vol. 41, No. 1, pp. 35–39, January-March, 1998 相似文献
17.
P. Rautiainen H. Salo E. Laurikainen 《Monthly notices of the Royal Astronomical Society》2008,388(4):1803-1818
We have modelled 38 barred galaxies by using near-infrared and optical data from the Ohio State University Bright Spiral Galaxy Survey. We constructed the gravitational potentials of the galaxies from H -band photometry, assuming a constant mass-to-light ratio. The halo component we choose corresponds to the so-called universal rotation curve. In each case, we used the response of gaseous and stellar particle disc to rigidly rotating potential to determine the pattern speed.
We find that the pattern speed of the bar depends roughly on the morphological type. The average value of corotation resonance radius to bar radius, , increases from 1.15 ± 0.25 in types SB0/a–SBab to 1.44 ± 0.29 in SBb and 1.82 ± 0.63 in SBbc–SBc. Within the error estimates for the pattern speed and bar radius, all galaxies of type SBab or earlier have a fast bar , whereas the bars in later type galaxies include both fast and slow rotators. Of 16 later type galaxies with a nominal value of , there are five cases, where the fast-rotating bar is ruled out by the adopted error estimates.
We also study the correlation between the parameter and other galactic properties. The clearest correlation is with the bar size: the slowest bars are also the shortest bars when compared to the galaxy size. A weaker correlation is seen with bar strength in a sense that slow bars tend to be weaker. These correlations leave room for a possibility that the determined pattern speed in many galaxies corresponds to actually that of the spiral, which rotates more slowly than the bar. No clear correlation is seen with either the galaxy luminosity or the colour. 相似文献
We find that the pattern speed of the bar depends roughly on the morphological type. The average value of corotation resonance radius to bar radius, , increases from 1.15 ± 0.25 in types SB0/a–SBab to 1.44 ± 0.29 in SBb and 1.82 ± 0.63 in SBbc–SBc. Within the error estimates for the pattern speed and bar radius, all galaxies of type SBab or earlier have a fast bar , whereas the bars in later type galaxies include both fast and slow rotators. Of 16 later type galaxies with a nominal value of , there are five cases, where the fast-rotating bar is ruled out by the adopted error estimates.
We also study the correlation between the parameter and other galactic properties. The clearest correlation is with the bar size: the slowest bars are also the shortest bars when compared to the galaxy size. A weaker correlation is seen with bar strength in a sense that slow bars tend to be weaker. These correlations leave room for a possibility that the determined pattern speed in many galaxies corresponds to actually that of the spiral, which rotates more slowly than the bar. No clear correlation is seen with either the galaxy luminosity or the colour. 相似文献
18.
O. V. Melnyk V. E. Karachentseva I. D. Karachentsev D. I. Makarov I. V. Chilingarian 《Astrophysics》2009,52(2):184-191
The radial velocities are measured for 45 galaxies located in the neighborhoods of 29 likely isolated galaxies in a new catalog.
We find that about 85% of these galaxies actually are well isolated objects. 4% of nearby galaxies with V
LG
< 3500 km/s are this kind of cosmic "orphan"
Translated from Astrofizika, Vol. 52, No. 2, pp. 203–210 (May 2009). 相似文献
19.
We analyze the data presented in a previous paper by Gyulzadyan and Petrosian, and discuss the results of a statistical investigation
of the relationship between SBS galaxies and Zwicky clusters. The main results are that SBS galaxies follow the overall galaxy
distribution in clusters and they do not avoid any type of Zwicky cluster. There is a significantly higher probability of
finding SBS galaxies occurring in medium compact clusters than in open clusters. They also follow the well-established morphology-density
relation. Earlier morphological type, higher luminosity, larger linear size, and redder SBS galaxies tend to be found in clusters
with higher compactness, or in more compact regions of the clusters. The number distribution of SBS galaxies in Zwicky open
clusters probably follows the distribution of normal galaxies. The number distribution of SBS galaxies in medium compact and
compact clusters shows two-maxima structure.
Published in Astrofizika, Vol. 52, No. 2, pp. 225–236 (May 2009). 相似文献
20.
A. P. Mahtessian 《Astrophysics》2011,54(2):162-176
The Schmidt method for constructing the luminosity function of galaxies is generalized to include the dependence of the density
of galaxies on distance in the near universe. The logarithmic luminosity function (LLF) of the field galaxies as a function
of morphological type is constructed. It is found that the LLF for all the galaxies, as well as separately for elliptical
and lenticular galaxies, can be represented as a Schechter function within a narrow range of absolute magnitudes. The LLF
for spiral galaxies is a Schechter function over a rather wide range of absolute magnitudes, −21.0 ≤ M ≤ −14 . The parameter
M* varies little over the spiral galaxies. The parameter α in the Schechter function decreases on going from early to later
spirals. On going from elliptical to lenticular galaxies, from early spiral galaxies and onward to later spiral galaxies,
a decrease in the average luminosity of the galaxies is observed in the bright end, −23 ≤ M ≤ −17.8 . The completeness and
average density of the samples are estimated for galaxies of different morphological types. The average number density of
all the galaxies within the range −23 ≤ M ≤ −13 is 0.126 Mpc-3. 相似文献