- 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
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Search Results
- 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.
- 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.
- 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.
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/II/143A
- Title:
- Guide Star Photometric Catalog, Updated Version 1
- Short Name:
- II/143A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Guide Star Photometric Catalog (GSPC) is an all-sky set of 1477 photoelectrically determined BV sequences covering the magnitude range from 9 to 15. The GSPC was created to provide photometric calibrators for the HST Guide Star Catalog (GSC). Each sequence nominally contains (at least) six stars, each with a photometric precision of 0.05 mag. In practice, a small number of sequences contain fewer stars; and the precisions achieved for the faintest stars are more nearly 0.1 mag. For declinations greater than +3 degrees the sequences generally lie near the centers of the original Palomar Observatory - National Geographic Society Sky Atlas. Other sequences lie near the centers of the ESO/SERC Southern Sky Atlas. The catalog also includes a list of suspected variable stars, a bibliography of literature sequences, and additional information which was useful in the data reduction and for quality control of the final catalog. The full catalog is made of 7 FITS files: tables 1 to 5, references (table 6 of the paper) and the actual catalogue (table 7 of the paper). The ascii versions of Tables 1 to 5 are included in this file; the ascii version of the references (refs.dat) and of the actual catalogue (catalog.dat) are described here. The updated version 1 was created by replacing photometric sequences P040, P421, S335 and S742 in GSPC version 1. The updated sequences have improved photometry and/or positions. In addition the sigma's in V and B-V (here e_V and e_B-V) were replaced with the values provided by the authors when we noted a discrepancy with the published values.
- ID:
- ivo://CDS.VizieR/II/272
- Title:
- Guide Star Photometric Catalog V2.4
- Short Name:
- II/272
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We publish 1653 CCD photometric sequences in the Johnson-Kron-Cousins standard system, distributed both in the northern and southern hemispheres, useful for the calibration of photographic photometry of Schmidt survey plates. The collection and reduction of the CCD data presented here are part of a long-term program devoted to the construction of the Second Guide Star Photometric Catalog (GSPC-II). The GSPC-II is an all-sky catalog of photometric stellar sequences with a limiting magnitude of V=19 or fainter, in the (B), V, and R passbands of the Johnson-Kron-Cousins system. Standard photometric errors are at the level of ~ 0.07 for a V ~ 19 magnitude star. These sequences are being used by teams of the Space Telescope Science Institute (STScI) and the Osservatorio Astronomico of Torino (OATo) for the photometric calibration of the Second Guide Star Catalog.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A45
- Title:
- GU Mon BV light curves
- Short Name:
- J/A+A/590/A45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive analysis, including B and V light curves and 11 high-resolution spectra, to verify the orbital period and determine parameters. The spectroscopic and photometric analyses agree on a period of 0.896640+/-0.000007d. We determine a mass of 9.0+/-0.6M_{sun}_ for each component and temperatures of 28000+/-2000K. Both values are consistent with the spectral type B1V. The two stars are overfilling their respective Roche lobes, sharing a common envelope, and therefore the orbit is synchronised and circularised. Thetwo stars are in a very advanced stage of interaction, with their extreme physical similarity likely due to the common envelope. The expected evolution of such a system will very probably lead to a merger while still on the main sequence.
- ID:
- ivo://CDS.VizieR/J/MNRAS/465/2748
- Title:
- Haffner 9 CT1 photometry
- Short Name:
- J/MNRAS/465/2748
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We turn our attention to Haffner 9, a Milky Way open cluster whose previous fundamental parameter estimates are far from being in agreement. In order to provide with accurate estimates, we present high-quality Washington CT_1_ and Johnson BVI photometry of the cluster field. We put particular care in statistically cleaning the colour-magnitude diagrams (CMDs) from field star contamination, which was found a common source in previous works for the discordant fundamental parameter estimates. The resulting cluster CMD fiducial features were confirmed from a proper motion membership analysis. Haffner 9 is a moderately young object (age~350Myr), placed in the Perseus arm - at a heliocentric distance of ~3.2kpc - , with a lower limit for its present mass of ~160M_{sun}_ and of nearly metal solar content. The combination of the cluster structural and fundamental parameters suggest that it is in an advanced stage of internal dynamical evolution, possibly in the phase typical of those with mass segregation in their core regions. However, the cluster still keeps its mass function close to that of the Salpeter's law.
