Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AN/327/365
- Title:
- Clusters and groups of galaxies in 2dF
- Short Name:
- J/AN/327/365
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We create a new catalogue of groups and clusters, applying the friends-to-friends method to the 2dF GRS final release. We investigate various selection effects due to the use of a magnitude limited sample. For this purpose we follow the changes in group sizes and mean galaxy number densities within the groups when shifting nearby observed groups to larger distances. We study the distribution of sizes of dark matter haloes in N-body simulations and compare properties of these haloes and the 2dF groups.
1323. Cluster SC2008-57(A3667)
- ID:
- ivo://CDS.VizieR/J/MNRAS/259/233
- Title:
- Cluster SC2008-57(A3667)
- Short Name:
- J/MNRAS/259/233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (Abstract of the paper) We present the results of photometric and spectroscopic observations of the cluster of galaxies SC2008-57 (A3667). The observations have resulted in a catalogue with positions and magnitudes for 203 galaxies, complete at b_25 = 18.0, and radial velocities for 128 galaxies, 91 per cent complete at b_25 = 17.5. The cluster can be classified as type L because its galaxy distribution is highly flattened. It shows two strong concentrations: a main concentration, centred on the cluster brightest galaxy (a D galaxy) and coincident with the peak of X-ray emission, and a substructure around the second brightest galaxy (also a D galaxy). Most of the galaxies in this substructure seem to be bound to the second-brightest galaxy, forming a dynamical subunit inside the cluster. The extreme flattening of the cluster may at least partially be due to the presence of the substructure. The cluster also shows evidence for luminosity segregation, with the brightest galaxies being preferentially found in high galaxy density regions. Most of the luminosity segregation, however, is produced by galaxies associated with the two clumps around the D galaxies, suggesting that dynamical friction is effective in subclusters with low velocity dispersions and may be associated with the formation of D galaxies. The velocity dispersion of SC2008-57 is high, about 1200 km/s, but consistent with the observed X-ray luminosity. The cluster mass, derived using several estimators, is about 2.6 x 10^15 M_solar. Both the cluster mass and velocity dispersion may be overestimates due to the presence of the substructure.
1324. Clusters in GEHRs
- ID:
- ivo://CDS.VizieR/J/AJ/108/1276
- Title:
- Clusters in GEHRs
- Short Name:
- J/AJ/108/1276
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometry in BVR continuum bands and in the emission line of Halpha+ [N II] are presented for a sample of H II complexes in disk, spiral arm and nuclear regions of galaxies NGC 1365, 1566, 2366, 2903, 2997, 3351, 4303, 4449, and 5253. Main sources of errors on H II region photometry are discussed. Errors due to background subtraction are parametrized in terms of background nonuniformity and fractional background contribution and are described separately in the Appendix. Our photometric data are compared with the existing data in the literature. Photometric properties of the sample regions are analyzed statistically and its implications on star formation are briefly discussed. Colors and Halpha+[N II] equivalent widths of nuclear H II regions are found to be distinctly different from disk H II regions, suggesting different star formation histories. We have identified a few high Halpha+[N II] equivalent width regions, which are fainter than average in both emission line and continuum fluxes, thus accounting for the low frequency of occurence of such regions in flux limited samples.
- ID:
- ivo://CDS.VizieR/J/ApJS/199/34
- Title:
- Clusters of galaxies in SDSS-III
- Short Name:
- J/ApJS/199/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the photometric redshifts of galaxies from the Sloan Digital Sky Survey III (SDSS-III), we identify 132684 clusters in the redshift range of 0.05<=z<0.8. Monte Carlo simulations show that the false detection rate is less than 6% for the whole sample. The completeness is more than 95% for clusters with a mass of M_200_>1.0x10^14^M_{sun}_ in the redshift range of 0.05<=z<0.42, while clusters of z>0.42 are less complete and have a biased smaller richness than the real one due to incompleteness of member galaxies. We compare our sample with other cluster samples, and find that more than 90% of previously known rich clusters of 0.05<=z<0.42 are matched with clusters in our sample. Richer clusters tend to have more luminous brightest cluster galaxies (BCGs). Correlating with X-ray and the Planck data, we show that the cluster richness is closely related to the X-ray luminosity, temperature, and Sunyaev-Zel'dovich measurements. Comparison of the BCGs with the SDSS luminous red galaxy (LRG) sample shows that 25% of LRGs are BCGs of our clusters and 36% of LRGs are cluster member galaxies. In our cluster sample, 63% of BCGs of r_petro_<19.5 satisfy the SDSS LRG selection criteria.
- ID:
- ivo://CDS.VizieR/J/A+AS/110/313
- Title:
- Clusters of galaxies properties. II.
- Short Name:
- J/A+AS/110/313
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present F band photometry, from digitized 48-inch Palomar plates, of 1167 galaxies brighter than m_3_ +3 in 10 Abell clusters. For each galaxy, absolute coordinates, magnitude, size, ellipticity and orientation are given. For each cluster we provide finding charts and contour maps of the galaxy surface density.
- ID:
- ivo://CDS.VizieR/J/ApJ/767/51
- Title:
- Clusters of starburst galaxy NGC4214
- Short Name:
- J/ApJ/767/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The production rate of ionizing photons in young (<=8Myr), unresolved stellar clusters in the nearby irregular galaxy NGC 4214 is probed using multi-wavelength Hubble Space Telescope WFC3 data. We normalize the ionizing photon rate by the cluster mass to investigate the upper end of the stellar initial mass function (IMF). We have found that within the uncertainties the upper end of the stellar IMF appears to be universal in this galaxy, and that deviations from a universal IMF can be attributed to stochastic sampling of stars in clusters with masses {<~}10^3^M_{sun}_. Furthermore, we have found that there does not seem to be a dependence of the maximum stellar mass on the cluster mass. We have also found that for massive clusters, feedback may cause an underrepresentation in H{alpha} luminosities, which needs to be taken into account when conducting this type of analysis.
- ID:
- ivo://svo.cab/cmc15
- Title:
- CMC15, Carlsberg Meridian Catalogue
- Short Name:
- CMC15
- Date:
- 03 Jun 2020 15:34:50
- Publisher:
- SVO CAB
- Description:
- CMC15 is an astrometric and photometric catalogue of more than 122.7 million stars in the magnitude range 9 < r' (SDSS) < 17. With a positional accuracy to about 35 mas, the catalogue covers the declination range -40deg to 50deg. The current release comprises all the observations made between March 1999 and March 2011. The catalogue fills the gap between 5h 30m and 10h 30m for declinations south of -15deg of the CMC14 and adds the bans -30deg to -40deg. Some zones north of -30deg have also been re-observed in order to improve their internal errors.
1329. CMD for And III
- ID:
- ivo://CDS.VizieR/J/AJ/106/986
- Title:
- CMD for And III
- Short Name:
- J/AJ/106/986
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The prime focus CCD camera of the KPNO 4 m telescope has been used to image Andromeda III, a dwarf spheroidal galaxy companion to M31, in the V and I bands. The resulting color-magnitude diagram shows a well defined giant branch whose tip luminosity corresponds to that expected for an old metal-poor population at the distance of M31. By comparing these data with the giant branches of metal-poor population at the distance of M31. By comparing these data with the giant branches of Galactic globular clusters, we determine that the abundance of And III is [Fe/H]=-2.0+/-0.15; with this abundance And III lies on the luminosity-abundance relation defined by the Galactic dwarf spheroidal galaxies. There is some evidence for a small (0.16<{sigma}([Fe/H])<0.24) intrinsic abundance dispersion within And III, but we are unable to unambiguously establish its presence. A study of the And III I-band luminosity function yields a distance modulus (m-M)_0_ of 24.4+/-0.2 for this galaxy, and indicates that the fraction of intermediate-age (3 to 10Gyr) population in And III is approximately 10+/-10 percent. In all these aspects And III, like And I, is similar to the Galactic dwarf spheroidal systems, indicating that M31 and the Galaxy provided similar conditions for the evolution of such galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/125/197
- Title:
- CN abundances of the 47 Tuc main sequence
- Short Name:
- J/AJ/125/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a deep spectroscopic survey for star-to-star CN variations along the main sequence (MS) of the globular cluster 47 Tuc with ESO's Very Large Telescope. We find a significant bimodal distribution in the S(3839) index for main-sequence stars in the mass range ~0.85 to 0.65M_{sun}_, or from the main-sequence turnoff down to ~2.5 mag below the main-sequence turnoff. An anticorrelation of CN and CH is evident on the MS. The result is discussed in the context of the ability of faint MS stars to alter their surface composition through internal evolutionary effects. We argue against internal stellar evolution as the only origin for the abundance spread in 47 Tuc; an external origin such as pollution seems to be more likely.
