- 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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/533/A33
- Title:
- LMXBs detected in nearby galaxies
- Short Name:
- J/A+A/533/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the archival data from the Chandra observations of nearby galaxies, we study different sub populations of low-mass X-ray binaries (LMXBs) - dynamically formed systems in globular clusters (GCs) and in the nucleus of M 31 and (presumably primordial) X-ray binaries in the fields of galaxies. Our aim is to produce accurate luminosity distributions of X-ray binaries in different environments, suitable for quantitative comparison with each other and with the output of population synthesis calculations. Our sample includes seven nearby galaxies (M 31, Maffei 1, Centaurus A, M 81, NGC 3379, NGC 4697, and NGC 4278) and the Milky Way, which together provide relatively uniform coverage down to the luminosity limit of 10^35^erg/s. In total we have detected 185 LMXBs associated with GCs, 35 X-ray sources in the nucleus of M 31, and 998 field sources of which ~365 are expected to be background AGN. We combine these data, taking special care to accurately account for X-ray and optical incompleteness corrections and the removal of the contamination from the cosmic X-ray background sources, to produce luminosity distributions of X-ray binaries in different environments to far greater accuracy than has been obtained previously.
- ID:
- ivo://CDS.VizieR/J/ApJ/662/525
- Title:
- LMXBs in globular clusters of 5 galaxies
- Short Name:
- J/ApJ/662/525
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of LMXBs and GCs in five early-type galaxies using Chandra X-ray and HST optical data. Of the 186 LMXBs within the optical fields of view, 71 are in GCs, confirming that LMXBs are formed particularly efficiently in clusters due to dynamical interactions.
- ID:
- ivo://CDS.VizieR/J/ApJ/663/1021
- Title:
- Log of {omega} Cen scientific images
- Short Name:
- J/ApJ/663/1021
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric investigation on HB, RGB, and MSTO stars in omega Cen = NGC 5139. The center of the cluster was covered with a mosaic of F435W, F625W, and F658N band data collected with HST ACS. The outer reaches were covered with a mosaic of U-, B-, V-, and I-band data collected with the 2.2 m ESO/MPI telescope. The final catalog includes ~1.7 million stars. We identified more than 3200 likely HB stars, the largest sample ever collected in a globular cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A111
- Title:
- Long period variables in omega Cen
- Short Name:
- J/A+A/585/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent studies have detected multiple populations in globular clusters. The massive globular cluster {omega} Cen hosts at least three populations of different metallicity. The most metal-rich one is thought to show also an overabundance of He. These differences should become visible in the structure, evolution, and pulsation of its stars. We aim to study the effects of the different starting compositions of the three populations in {omega} Cen on the most luminous red giants in this cluster. The long-periodic variability of evolved stars in {omega} Cen opens a comparably easy access window to the structure and composition of these objects. We made a detailed search for long-period variables (LPVs) in {omega} Cen leading to the detection of many new variables and period determinations for a significant number of them. Periods and luminosities were then compared with the most recent pulsation models for these kinds of stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/2173
- Title:
- Long-term photometry of M3 RR Lyrae
- Short Name:
- J/MNRAS/419/2173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The period-change behaviour of 134 RR Lyrae stars in the globular cluster Messier 3 (M3) is investigated on the ~120yr time-base of the photometric observations. The mean period-change rates ({beta}~~0.01d/Myr) of the subsamples of variables exhibiting the most regular behaviour are in good agreement with theoretical expectations based on horizontal branch stellar evolution models. However, a large fraction of variables show period changes that contradict the evolutionary expectations.
- ID:
- ivo://CDS.VizieR/J/ApJ/823/157
- Title:
- LOS velocities & [Fe/H] of Pal 5 tidal stream
- Short Name:
- J/ApJ/823/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Subaru/Faint Object Camera and Spectrograph and Keck/Deep Imaging Multi-Object Spectrometer medium-resolution spectroscopy of a tidally disrupting Milky Way (MW) globular cluster Palomar 5 (Pal 5) and its tidal stream. The observed fields are located to cover an angular extent of ~17{deg} along the stream, providing an opportunity to investigate a trend in line-of-sight velocities (V_los_) along the stream, which is essential to constrain its orbit and underlying gravitational potential of the MW's dark matter halo. A spectral fitting technique is applied to the observed spectra to obtain stellar parameters and metallicities ([Fe/H]) of the target stars. The 19 stars most likely belonging to the central Pal 5 cluster have a mean V_los_ of -58.1+/-0.7km/s and metallicity [Fe/H]=-1.35+/-0.06dex, both of which are in good agreement with those derived in previous high-resolution spectroscopic studies. Assuming that the stream stars have the same [Fe/H] as the progenitor cluster, the derived [Fe/H] and V_los_ values are used to estimate the possible V_los_ range of the member stars at each location along the stream. Because of the heavy contamination of the field MW stars, the estimated V_los_ range depends on prior assumptions about the stream's V_los_, which highlights the importance of more definitely identifying the member stars using proper motion and chemical abundances to obtain unbiased information of V_los_ in the outer part of the Pal 5 stream. The models for the gravitational potential of the MW's dark matter halo that are compatible with the estimated V_los_ range are discussed.
- ID:
- ivo://CDS.VizieR/J/ApJ/612/437
- Title:
- Low-luminosity hard X-ray binaries candidates
- Short Name:
- J/ApJ/612/437
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a search for hard X-ray binaries (HXRBs) among previously unidentified sources from ROSAT PSPC pointed observations, using the automated X-ray source classifier ClassX.
- ID:
- ivo://CDS.VizieR/J/ApJ/542/257
- Title:
- MACHO LMC first-overtone RR Lyrae
- Short Name:
- J/ApJ/542/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- More than 1300 variables classified provisionally as first-overtone RR Lyrae pulsators in the MACHO variable-star database of the Large Magellanic Cloud (LMC) have been subjected to standard frequency analysis. Based on the remnant power in the prewhitened spectra, we found 70% of the total population to be monoperiodic. The remaining 30% (411 stars) are classified as one of nine types according to their frequency spectra. Several types of RR Lyrae pulsational behavior are clearly identified here for the first time. Together with the earlier discovered double-mode (fundamental and first-overtone) variables, this study increased the number of known double-mode stars in the LMC to 181. During the total 6.5yr time span of the data, 10% of the stars showed strong period changes.
- ID:
- ivo://CDS.VizieR/J/ApJS/155/401
- Title:
- Magellanic clouds globular clusters ISOCAM obs.
- Short Name:
- J/ApJS/155/401
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Seventeen globular clusters in the Large and Small Magellanic Clouds were observed in the mid-infrared wavelength region with the ISOCAM instrument on board the Infrared Space Observatory (ISO). Observations were made using the broadband filters LW1, LW2, and LW10, corresponding to the effective wavelengths of 4.5, 6.7, and 12{mu}m, respectively. We present the photometry of point sources in each cluster, as well as their precise positions and finding charts.
