- 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.
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Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/298/461
- Title:
- Main sequence of NGC 6171
- Short Name:
- J/A+A/298/461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep J, K IR-array photometry for individual Main Sequence stars in NGC 6171 reaching K~18, about two magnitudes below the turnoff, is presented. The observations were made during 3 nights on June 1993 at the 2.2m ESO/MPI telescope at ESO (La Silla), equipped with the IR-array camera IRAC2.
- ID:
- ivo://CDS.VizieR/J/AJ/122/3219
- Title:
- M3 and M13 CCD BV photometry
- Short Name:
- J/AJ/122/3219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-precision V, B-V color-magnitude diagrams (CMDs) for the classic second-parameter globular clusters M3 and M13 from wide-field, deep CCD photometry. The data for the two clusters were obtained during the same photometric nights with the same instrument, allowing us to determine accurate relative ages. Based on a differential comparison of the CMDs using the {Delta}(B-V) method, an age difference of 1.7+/-0.7Gyr is obtained between these two clusters. We compare this result with our updated horizontal-branch (HB) population models, which confirm that the observed age difference can produce the difference in HB morphology between the clusters. This provides further evidence that age is the dominant second parameter that influences HB morphology.
- ID:
- ivo://CDS.VizieR/J/AJ/119/1760
- Title:
- M54 and Sgr dSph VI photometry
- Short Name:
- J/AJ/119/1760
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep VI-band photometry of the globular cluster M54, a nearby field in the Sagittarius dwarf galaxy, and a control field. The color-magnitude diagrams reach well below the oldest main-sequence turnoffs, thus enabling an analysis of the galaxy's age-metallicity relation with unprecedented clarity. We also study the variable stars in the direction of M54. From 67 RR Lyrae variables, we confirm and improve on our previous estimates of the cluster horizontal branch magnitude, foreground reddening, and horizontal branch morphology. These values are used in determining the ages of M54 and the Sagittarius field populations. We confirm our previous result that M54 is the same age as Galactic globular clusters of similar metallicity.
- ID:
- ivo://CDS.VizieR/J/ApJ/891/85
- Title:
- Manganese abundances in GC & dSph galaxies
- Short Name:
- J/ApJ/891/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Manganese abundances are sensitive probes of the progenitors of TypeIa supernovae (SNe Ia). In this work, we present a catalog of manganese abundances in dwarf spheroidal satellites of the Milky Way, measured using medium-resolution spectroscopy. Using a simple chemical evolution model, we infer the manganese yield of SNe Ia in the Sculptor dwarf spheroidal galaxy (dSph) and compare to theoretical yields. The sub-solar yield from SNIa ([Mn/Fe]_Ia_=-0.30_-0.03_^+0.03^ at [Fe/H]=-1.5dex, with negligible dependence on metallicity) implies that sub-Chandrasekhar-mass (sub-MCh) white dwarf progenitors are the dominant channel of SNe Ia at early times in this galaxy, although some fraction (>~20%) of M_Ch_ Type Ia or Type Iax SNe are still needed to produce the observed yield. First-order corrections for deviations from local thermodynamic equilibrium increase the inferred [Mn/Fe]_Ia_ by as much as ~0.3dex. However, our results also suggest that the nucleosynthetic source of SNe Ia may depend on environment. In particular, we find that dSphs with extended star formation histories (Leo I, Fornax dSphs) appear to have higher [Mn/Fe] at a given metallicity than galaxies with early bursts of star formation (Sculptor dSph), suggesting that M_Ch_ progenitors may become the dominant channel of SNe Ia at later times in a galaxy's chemical evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/90
- Title:
- Mass segregation effect of X-ray sources in GCs. II.
- Short Name:
- J/ApJ/883/90
- Date:
- 06 Dec 2021 13:23:40
- Publisher:
- CDS
- Description:
- Using archival Chandra observations with a total effective exposure of 734ks, we derive an updated catalog of point sources in the massive globular cluster (GC) Terzan 5. Our catalog covers an area of 58.1arcmin^2^ (R<=4.3') with 489 X-ray sources, and more than 75% of these sources are first detected in this cluster. We find significant dips in the radial distribution profiles of X-ray sources in Terzan 5, with the projected distance and width of the distribution dips for bright (L_X_>~9.5x10^30^erg/s) X-ray sources larger than those of the faint (L_X_<~9.5x10^30^erg/s) sources. By fitting the radial distribution of the X-ray sources with a "generalized King model," we estimated an average mass of 1.48+/-0.11 and 1.27+/-0.13M_{sun}_ for the bright and faint X-ray sources, respectively. These results are in agreement with that observed in 47 Tuc, which may suggest a universal mass segregation effect for X-ray sources in GCs. Compared with 47Tuc, we show that the two-body relaxation timescale of Terzan 5 is much smaller, but its dynamical age is significantly younger than 47 Tuc. These features suggest that the evolution of Terzan 5 is not purely driven by two-body relaxation, and the tidal stripping effect also plays an important role in accelerating the dynamical evolution of this cluster.
