- ID:
- ivo://CDS.VizieR/J/MNRAS/473/105
- Title:
- LMC Washington CMT1 photometry of star clusters
- Short Name:
- J/MNRAS/473/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analysed Washington CMT1 photometry of star clusters located along the minor axis of the Large Magellanic Cloud (LMC), from the LMC optical centre up to ~39{deg} outwards to the North-West. The data base was exploited in order to search for new star cluster candidates, to produce cluster CMDs cleaned from field star contamination and to derive age estimates for a statistically complete cluster sample. We confirmed that 146 star cluster candidates are genuine physical systems, and concluded that an overall ~30 per cent of catalogued clusters in the surveyed regions are unlikely to be true physical systems. We did not find any new cluster candidates in the outskirts of the LMC (deprojected distance >~8{deg}). The derived ages of the studied clusters are in the range 7.2<log(t[yr^-1^])<=9.4, with the sole exception of the globular cluster NGC 1786 (log(t[yr^-1^])=10.10). We also calculated the cluster frequency for each region, from which we confirmed previously proposed outside-in formation scenarios. In addition, we found that the outer LMC fields show a sudden episode of cluster formation (log(t[yr^-1^])~7.8-7.9) which continued until log(t[yr^-1^])~7.3 only in the outermost LMC region. We link these features to the first pericentre passage of the LMC to the Milky Way (MW), which could have triggered cluster formation due to ram pressure interaction between the LMC and MW halo.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/690/512
- Title:
- LMXBs and globulars in early-type galaxies. II.
- Short Name:
- J/ApJ/690/512
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an astrometry and photometry catalogue of globular cluster (GC) candidates detected with the Hubble Space Telescope Wide Field Planetary Camera 2 in a sample of 19 early-type galaxies, appropriate for comparison with the low-mass X-ray binary populations observed with Chandra. In a companion paper (Cat. J/ApJ/689/983), we present the Chandra data and investigate the relation between these populations. We demonstrate that, although there is little evidence of a color-magnitude correlation for the GCs, after estimating mass and metallicity from the photometry under the assumption of a single-age simple stellar population, there is a significant positive correlation between mass and metallicity.
- ID:
- ivo://CDS.VizieR/J/ApJ/689/983
- Title:
- LMXBs in early-type galaxies. I. Chandra
- Short Name:
- J/ApJ/689/983
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a Chandra survey of LMXBs in 24 early-type galaxies. Correcting for detection incompleteness, the X-ray luminosity function (XLF) of each galaxy is consistent with a power law with negative logarithmic differential slope, {beta}~2.0. However, {beta} strongly correlates with incompleteness, indicating the XLF flattens at low-L_X_. Although the XLFs are similar, we find evidence of some variation between galaxies. The high-L_X_ XLF slope does not correlate with age, but may correlate with [{alpha}/Fe]. Considering only LMXBs with L_X_>10^37^ergs/s, matching the LMXBs with globular clusters (GCs) identified in HST observations of 19 of the galaxies, we find the probability a GC hosts an LMXB is proportional to L^{alpha}^_GC_Z^{gamma}^_Fe_ where {alpha}=1.01+/-0.19 and {gamma}=0.33+/-0.11. The spatial distribution of LMXBs resembles that of GCs, and the specific frequency of LMXBs is proportional to the GC specific luminosity, consistent with the hypothesis that all LMXBs form in GCs.
- ID:
- ivo://CDS.VizieR/J/AJ/160/49
- Title:
- LOAO BV-bands photometry and BOES RVs of WASP 0131+28
- Short Name:
- J/AJ/160/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first BV light curves and high-resolution spectra of the post-mass transfer binary star WASP0131+28 to study the absolute properties of extremely low-mass white dwarfs. From the observed spectra, the double-lined radial velocities were derived, and the effective temperature and rotational velocity of the brighter, more massive primary were found to be Teff_1_=10000{+/-]200K and v_1_sin_i_=55{+/-}10km/s, respectively. The combined analysis of the Transiting Exoplanet Survey Satellite (TESS) archive data and ours yielded the accurate fundamental parameters of the program target. The masses were derived to about 1.0% accuracy and the radii to 0.6%, or better. The secondary component's parameters of M_2_=0.200{+/-}0.002M_{sun}_, R_2_=0.528{+/-}0.003R_{sun}_, Teff_2_=11186{+/-}235K, and L_2_=3.9{+/-}0.3L_{sun}_ are in excellent agreement with the evolutionary sequence for a helium-core white dwarf of mass 0.203M_{sun}, and indicates that this star is halfway through the constant luminosity phase. The results presented in this article demonstrate that WASP0131+28 is an EL CVn eclipsing binary in a thin disk, which is formed from the stable Roche-lobe overflow channel and composed of a main-sequence dwarf with a spectral type A0 and a pre-He white dwarf.
- ID:
- ivo://CDS.VizieR/J/ApJ/711/361
- Title:
- Local Group dE galaxies. II.
- Short Name:
- J/ApJ/711/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present kinematic and metallicity profiles for the M 31 dwarf elliptical (dE) satellite galaxies NGC 147 and NGC 185. The profiles represent the most extensive spectroscopic radial coverage for any dE galaxy, extending to a projected distance of 8 half-light radii (8r_eff_~14'). We achieve this coverage via Keck/DEIMOS multislit spectroscopic observations of 520 and 442 member red giant branch stars in NGC 147 and NGC 185, respectively. In contrast to previous studies, we find that both dEs have significant internal rotation. We measure a maximum rotational velocity of 17+/-2km/s for NGC 147 and 15+/-5km/s for NGC 185. The velocity dispersions decrease gently with radius with average dispersions of 16+/-1km/s and 24+/-1km/s for NGC 147 and NGC 185, respectively. The average metallicities for NGC 147 and NGC 185 are [Fe/H]=-1.1+/-0.1 and [Fe/H]=-1.3+/-0.1, respectively; both dEs have internal metallicity dispersions of 0.5dex, but show no evidence for a radial metallicity gradient.
- ID:
- ivo://CDS.VizieR/J/AJ/158/122
- Title:
- Local structure & star formation history of the MW
- Short Name:
- J/AJ/158/122
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- Gaia DR2 (Cat. I/345) provides unprecedented precision in measurements of the distance and kinematics of stars in the solar neighborhood. Through applying unsupervised machine learning on DR2's 5D data set (3D position + 2D velocity), we identify a number of clusters, associations, and comoving groups within 1 kpc and |b|<30{deg} (many of which have not been previously known). We estimate their ages with the precision of ~0.15 dex. Many of these groups appear to be filamentary or string-like, oriented in parallel to the Galactic plane, and some span hundreds of parsec in length. Most of these string lack a central cluster, indicating that their filamentary structure is primordial, rather than the result of tidal stripping or dynamical processing. The youngest strings (<100 Myr) are orthogonal to the Local Arm. The older ones appear to be remnants of several other arm-like structures that cannot be presently traced by dust and gas. The velocity dispersion measured from the ensemble of groups and strings increase with age, suggesting a timescale for dynamical heating of ~300 Myr. This timescale is also consistent with the age at which the population of strings begins to decline, while the population in more compact groups continues to increase, suggesting that dynamical processes are disrupting the weakly bound string populations, leaving only individual clusters to be identified at the oldest ages. These data shed a new light on the local galactic structure and a large-scale cloud collapse.
- ID:
- ivo://CDS.VizieR/J/other/RAA/18.137
- Title:
- Long-term BVRI photometry of 15 PMS stars
- Short Name:
- J/other/RAA/18.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports results from the multicolor photometric observations of 15 pre-main sequence stars collected in the period September 2010 - October 2017. The stars from our study are located in the star-forming HII region IC 5070. These objects were previously detected as either emission line stars, flare stars, T Tauri variables or Herbig Ae/Be stars. Photometric observations, especially concerning the long-term behavior of the objects, are missing in the literature. We present the first photometric monitoring for all stars from our study. The analysis of the obtained BVRI photometric data allows us to draw the conclusion that all investigated objects are variable stars. In the case of LkHa 146, we identified previously unknown periodicity in its photometric variability.
- ID:
- ivo://CDS.VizieR/J/other/BAJ/29.10
- Title:
- Long-term BVRI photometry of V1704 Cygni
- Short Name:
- J/other/BAJ/29.1
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Results from BVRI photometric observations of the pre-main sequence star V1704 Cyg collected during the time period from August 2010 to December 2017 are presented. The star is located in the star-forming HII region IC 5070 and it exhibits photometric variability in all optical passbands. After analysing the obtained data, V1704 Cyg is classified as a classical T Tauri star.
- ID:
- ivo://CDS.VizieR/J/other/PASA/35.7
- Title:
- Long-term BVRI photometry of V2492 Cygni
- Short Name:
- J/other/PASA/35.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results from BVRI photometric observations of the young stellar object V2492 Cyg collected during the period from August 2010 to December 2017 are presented. The star is located in the field of the Pelican Nebula and it was discovered in 2010 due to its remarkable increase in the brightness by more than 5mag in R-band. According to the first hypothesis of the variability, V2492 Cyg is an FUor candidate. During subsequent observations, it was reported that the star shows the characteristics inherent to EXor- and UXor-type variables. The optical data show that during the whole time of observations the star exhibits multiple large amplitude increases and drops in the brightness. In the beginning of 2017, we registered a significant increase in the optical brightness of V2492 Cyg, which seriously exceeds the maximal magnitudes registered after 2010.
- ID:
- ivo://CDS.VizieR/J/other/Ser/202.31
- Title:
- Long-term BVRI photometry of V900 Mon
- Short Name:
- J/other/Ser/202.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from photometric monitoring of V900 Mon, one of the newly discovered and still under-studied object from the FU Orionis type. The FUor phenomenon is very rarely observed, but it is essential for stellar evolution. Since we only know about twenty stars of this type, the study of each new object is very important for our knowledge. Our data were obtained in optical spectral region with the BVRI Johnson-Cousins set of filters during the period from September 2011 to April 2021. In order to follow the photometric history of the object, we measured its stellar magnitudes on available plates from the Mikulski Archive for Space Telescopes. The collected archival data suggest that the rise in brightness of V900 Mon began after January 1989 and the outburst goes on so far. In November 2009, when the outburst was registered, the star had already reached the level of brightness close to the current one. Our observations indicate that during the period 2011-2017 the stellar magnitude increased gradually in each pass band. The observed amplitude of the ourburst is about 4 magnitudes (R). During the last three years, the increase in brightness has stopped and there has even been a slight decline. The comparison of light curves of the known FUor objects shows that they are very diverse and are rarely repeated. However, the photometric data we have so far show that V900 Mon's light curve is somewhat similar to those of V1515 Cyg and V733 Cep.
