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2361. Group of galaxies in SDSS 5
ID:
ivo://CDS.VizieR/J/A+A/479/927
Title:
Group of galaxies in SDSS 5
Short Name:
J/A+A/479/927
Date:
21 Oct 2021
Publisher:
CDS
Description:
We extract groups of galaxies from the SDSS Data Release 5 to study the supercluster-void network and environmental properties of groups therein. Groups of galaxies as density enhancements can be used to determine the luminosity density field of the supercluster-void network. We use a modified friends-of-friends (FoF) method with slightly variable linking lengths in transverse and radial directions to eliminate selection effects and to reliably find as many groups as possible. To determine the scaling of the linking length we calibrated group sizes and mean galaxy number densities within groups by shifting nearby groups to larger distances. Our final sample contains 17143 groups in the equatorial (E), and 33219 groups in the northern (N) part of the DR5 survey. The mean sizes and velocity dispersions of our groups practically do not change with their distance. This means that the selection effects have been properly taken into account when generating the group catalogue.
2362. Groups of stars in NGC 1893
ID:
ivo://CDS.VizieR/J/other/Ap/50.194
Title:
Groups of stars in NGC 1893
Short Name:
J/other/Ap/50.19
Date:
21 Oct 2021
Publisher:
CDS
Description:
The distribution of 255 O-B9-A2, K-G stars and interstellar dust in the direction of the stellar cluster NGC 1893 is studied using V, B-V, and U-B photometric data. Sixteen groups of stars (associations) are discovered at various distances. The first group includes 9 stars of different spectral classes of later types in the Sun's neighborhood lying at a distance of 110pc. The next 3 groups, at distances of 420, 890, and 14300pc, are type B associations and the remaining twelve groups are OB associations. They are designated as Aur 0.11, Aur B 0.43, Aur B 0.89, Aur OB 1.4, Aur OB 2.6, AurOB 3.8, Aur OB 4.6, Aur OB 5.4, Aur OB 6.1, Aur OB 7.4, Aur OB 9.3, Aur OB11.6, Aur OB14.3, Aur OB 17.9, Aur OB 25.9, and Aur OB 31.3. For most of these stars the absorption lies within the range from 0.45m to 5.41m. Such high absorption may be caused by circumstellar absorption as well as by the diffuse nebula IC 410. The dusty matter is distributed non-uniformly in the Aur 0.11, Aur B 0.43, and Aur B 0.89 associations. There is no dust in the space between the associations. There is essentially no dust within the groups (associations) at distances greater than 0.9kpc (see Table 2).
2363. gr photometry of NGC 5053 blue stragglers
ID:
ivo://CDS.VizieR/J/ApJ/336/780
Title:
gr photometry of NGC 5053 blue stragglers
Short Name:
J/ApJ/336/780
Date:
21 Oct 2021
Publisher:
CDS
Description:
Twenty-four blue straggler stars have been identified in the low central concentration globular cluster NGC 5053. New deep color-magnitude (C-M) diagrams to 23mag, constructed from photometry of over 6000 stars on 4-shooter CCD frames, show that they form a well-defined sequence in the C-M diagram, extending up to ~2.2mag brighter than the main-sequence turnoff point. The 12 most luminous blue stragglers are found to be significantly more centrally concentrated than the cluster subgiants with magnitudes in the same interval (a similar result is known for the blue stragglers in the globular cluster NGC 5466). Furthermore, they are also found to be more centrally concentrated than the 12 lower luminosity blue stragglers. Comparisons of the projected radial distributions of the bright and faint blue stragglers, with the radial distributions that are expected for stars of mass 0.8, 1.6, and 2.4M_{sun}_, (calculated using multimass King models) suggests that the brightest blue stragglers have an average mass of <M>=1.3+/0.3M_{sun}_, which is less than or comparable to twice the mean mass of a main-sequence turnoff star, and the lower luminosity blue stragglers have a mean mass similar to that of the main-sequence turnoff stars (i.e., M~0.8M_{sun}_). By fitting theoretical isochrones computed by Bell and VandenBerg to the observed main-sequence turnoff and subgiant branch regions of NGC 5053, a distance modulus of (m-M)_0_=16.05+/-0.14mag, and an age of 18+/-3Gyr are derived for NGC 5053. The main-sequence luminosity function shows no sign of "turning over" for stars brighter than M_g_~5mag. For a description of the uvgr photometric system, see e.g. <GCPD/38>
2364. gr photometry of Sextans A and Sextans B
ID:
ivo://CDS.VizieR/J/A+A/566/A44
Title:
gr photometry of Sextans A and Sextans B
Short Name:
J/A+A/566/A44
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed study of the stellar and HI structure of the dwarf irregular galaxies Sextans A and Sextans B, members of the NGC3109 association. We use newly obtained deep (r~26.5) and wide field g,r photometry to extend the Surface Brightness (SB) profiles of the two galaxies down to mu_V_~31.0mag/arcsec^2^. We find that both galaxies are significantly more extended than what previously traced with surface photometry, out to ~4kpc from their centers along their major axis. Older stars are found to have more extended distribution with respect to younger populations. We obtain the first estimate of the mean metallicity for the old stars in Sex B, from the color distribution of the Red Giant Branch, <[Fe/H]>=-1.6. The SB profiles show significant changes of slope and cannot be fitted with a single Sersic model. Both galaxies have HI discs as massive as their respective stellar components. In both cases the HI discs display solid-body rotation with maximum amplitude of ~50km/s (albeit with significant uncertainty due to the poorly constrained inclination), implying a dynamical mass ~10^9^~M_{sun}_, a mass-to-light ratio M/L_V_~25 and a dark to-barionic mass ratio of ~10. The distribution of the stellar components is more extended than the gaseous disc in both galaxies. We find that the main, approximately round-shaped, stellar body of Sex A is surrounded by an elongated low-SB stellar halo that can be interpreted as a tidal tail, similar to that found in another member of the same association (Antlia). We discuss these, as well as other evidences of tidal disturbance, in the framework of a past passage of the NGC3109 association close to the Milky Way, that has been hypothesized by several authors and is also supported by the recently discovered filamentary configuration of the association itself
2365. gr photometry of stars in Kim 2
ID:
ivo://CDS.VizieR/J/ApJ/803/63
Title:
gr photometry of stars in Kim 2
Short Name:
J/ApJ/803/63
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of a new, low-luminosity star cluster in the outer halo of the Milky Way. High-quality gr photometry is presented, from which a color-magnitude diagram is constructed, and estimates of age, [Fe/H], [{alpha}/Fe], and distance are derived. The star cluster, which we designate as Kim 2, lies at a heliocentric distance of ~105kpc. With a half-light radius of ~12.8pc and ellipticity of {epsilon}~0.12, it shares the properties of outer halo globular clusters, except for at higher metallicity ([Fe/H]~-1.0) and lower luminosity (M_v_~-1.5). These parameters are similar to those for the globular cluster AM 4, which is considered to be associated with the Sagittarius dwarf spheroidal galaxy. We find evidence of dynamical mass segregation and the presence of extra-tidal stars that suggests that Kim 2 is most likely a star cluster. Spectroscopic observations for radial-velocity membership and chemical abundance measurements are needed to further understand the nature of the object.
2366. GR Tau BV light curves
ID:
ivo://CDS.VizieR/J/A+A/395/587
Title:
GR Tau BV light curves
Short Name:
J/A+A/395/587
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present photometric observations of the eclipsing binary GR Tau made in 1985, 1993, 1998, 2000 and 2001.
2367. GSC 3355-0394 BVRI differential photometry
ID:
ivo://CDS.VizieR/J/AJ/140/1150
Title:
GSC 3355-0394 BVRI differential photometry
Short Name:
J/AJ/140/1150
Date:
21 Oct 2021
Publisher:
CDS
Description:
GSC 3355 0394 has an EB-type light curve, which is dominated by hot and cool spot activities. It displays night-to-night variations in light-curve shapes. The period study yields six new times of minimum light and the first precision ephemeris, HJD TminI=2454408.9547+/-0.0017+0.4621603+/-.0000008d*E. VRcIc standard magnitudes are presented. BVRI Wilson synthetic light-curve solutions are calculated for both a Mode 4 (V1010 Oph-type, semidetached, more massive component filling its Roche lobe) configuration and a Mode 3, contact configuration (fill-out 100% or critical contact). The critical contact is the lowest residual solution. Four major spot regions are needed to model this binary, at least one is evidently a stream spot.
2368. GSC04778-00152 photometry and spectroscopy
ID:
ivo://CDS.VizieR/J/other/JAD/14.1
Title:
GSC04778-00152 photometry and spectroscopy
Short Name:
J/other/JAD/14.1
Date:
21 Oct 2021
Publisher:
CDS
Description:
Photometric and spectroscopic data of the southern contact binary GSC 04778-00152 are presented. Six new times of minimum are listed. For modelling purposes, we provide UBVRI phase diagrams of the contact binary with the contribution of the nearby companion removed.
2369. GSC 8613-2122 UBVRI and uvby light curves
ID:
ivo://CDS.VizieR/J/other/JAD/16.1
Title:
GSC 8613-2122 UBVRI and uvby light curves
Short Name:
J/other/JAD/16.1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a collection of more than 4000 UBVRI and uvby differential photometric measurements of the newly-discovered 12th-magnitude southern Delta Scuti star GSC 08613-02122. The star has a main pulsation period of about 4 hours with an amplitude of 0.05m in the V band. The pulsation amplitude is variable, and the O-C diagram reveals the existence of a long P~29.5-day cycle, which possibly results from the beating of the main pulsation frequency with a nearby frequency.
2370. Guide Star Catalog II
ID:
ivo://archive.stsci.edu/gsc23skynode
Title:
Guide Star Catalog II
Short Name:
GSC2
Date:
17 Feb 2014 21:41:36
Publisher:
STScI
Description:
The Guide Star Catalog 2 (GSC2) is an all sky multi-wavelength, multi-epoch object catalog based on 1 arcsec resolution scans of photographic sky survey plates from the Palomar and UK Schmidt Telescopes.