- ID:
- ivo://CDS.VizieR/J/MNRAS/442/2216
- Title:
- Redshifts of galaxies in Abell 1351 field
- Short Name:
- J/MNRAS/442/2216
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to review the internal structure and dynamics of the Abell 1351 cluster, shown to host a radio halo with a quite irregular shape. Our analysis is based on radial velocity data for 135 galaxies obtained at the Telescopio Nazionale Galileo. We combine galaxy velocities and positions to select 95 cluster galaxy members and analyse the internal dynamics of the whole cluster. We also examine X-ray data retrieved from Chandra and XMM archives. We measure the cluster redshift, <z>=0.325, the line-of-sight (LOS) velocity dispersion, {sigma}V~1500km/s, and the X-ray temperature, kT~9keV. From both X-ray and optical data independently, we estimate a large cluster mass, in the 1-4x10^15^h_70_^-1^M_{sun}_. We attribute the extremely high value of {sigma}V to the bimodality in the velocity distribution. We find evidence of a significant velocity gradient and optical 3D substructure. The X-ray analysis also shows many features in favour of a complex cluster structure, probably supporting an ongoing merger of substructures in Abell 1351. The observational scenario agrees with the presence of two main subclusters in the northern region, each with its brightest galaxy (BCG1 and BCG2), detected as the two most important X-ray substructures with a rest-frame LOS velocity difference of {Delta}V_rf_~2500km/s and probably being in large part aligned with the LOS. We conclude that Abell 1351 is a massive merging cluster. The details of the cluster structure allow us to interpret the quite asymmetric radio halo as a 'normal' halo plus a southern relic, strongly supporting a previous suggestion based only on inspection of radio and preliminary X-ray data.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/312/540
- Title:
- Redshift survey of intercluster galaxies
- Short Name:
- J/MNRAS/312/540
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a redshift survey of intercluster galaxies in the central region of the Shapley Concentration supercluster, aimed at determining the distribution of galaxies in between obvious overdensities. Our sample is formed by 442 new redshifts, mainly in the b_J_ magnitude range 17-18.8. Adding the data from our redshift surveys on the A3558 and A3528 complexes, which are close to the geometrical centre of this supercluster, we obtain a total sample of ~2000 radial velocities. The average velocity of the observed intercluster galaxies in the Shapley Concentration appears to be a function of their ({alpha}, {delta} position, and it can be fitted by a plane in the three dimensional space ({alpha}, {delta}, v): the distribution of the galaxy distances around the best-fitting plane is described by a Gaussian with dispersion 3.8h^-1^Mpc.
- ID:
- ivo://CDS.VizieR/J/A+A/547/A15
- Title:
- Red supergiants around Stephenson 2
- Short Name:
- J/A+A/547/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Several clusters of red supergiants have been discovered in a small region of the Milky Way close to the base of the Scutum-Crux Arm and the tip of the Long Bar. Population synthesis models indicate that they must be very massive to harbour so many supergiants. Amongst these clusters, Stephenson 2, with a core grouping of 26 red supergiants, is a strong candidate to be the most massive young cluster in the Galaxy. Stephenson 2 is located close to a region where a strong over-density of red supergiants had been found. We explore the actual cluster size and its possible connection to this over-density. Taking advantage of Virtual Observatory tools, we have performed a cross-match between the DENIS, USNO-B1 and 2MASS catalogues to identify candidate obscured luminous red stars around Stephenson 2, and in a control nearby region. More than 600 infrared bright stars fulfill our colour criteria, with the vast majority having a counterpart in the I band and >400 being sufficiently bright in I to allow observation with a 4-m class telescope. We observed a subsample of ~250 stars, using the multi-object, wide-field, fibre spectrograph AF2 on the WHT telescope in La Palma, obtaining intermediate-resolution spectroscopy in the 7500-9000{AA} range. We derived spectral types and luminosity classes for all these objects and measured their radial velocities.
1634. Red supergiants in M31
- ID:
- ivo://CDS.VizieR/J/ApJ/703/420
- Title:
- Red supergiants in M31
- Short Name:
- J/ApJ/703/420
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Red supergiants (RSGs) are a short-lived stage in the evolution of moderately massive stars (10-25M_{sun}_), and as such their location in the H-R diagram provides an exacting test of stellar evolutionary models. Since massive star evolution is strongly affected by the amount of mass loss a star suffers, and since the mass-loss rates depend upon metallicity, it is highly desirable to study the physical properties of these stars in galaxies of various metallicities. Here we identify a sample of RSGs in M31, the most metal-rich of the Local Group galaxies. We determine the physical properties of these stars using both moderate resolution spectroscopy and broadband V-K photometry. We find that on average the RSGs of our sample are variable in V by 0.5mag, smaller but comparable to the 0.9mag found for Magellanic Cloud (MC) RSGs. No such variability is seen at K, also in accord with what we know of Galactic and MC RSGs.
- ID:
- ivo://CDS.VizieR/J/A+A/600/A55
- Title:
- Refined Analysis of T-Cyg1-12664
- Short Name:
- J/A+A/600/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observational mass-radius relation of main sequence stars with masses between ~0.3 and 1.0M_{sun}_ reveals deviations between the stellar radii predicted by models and the observed radii of stars in detached binaries. We generate an accurate physical model of the low-mass eclipsing binary T-Cyg1-12664 in the Kepler mission field to measure the physical parameters of its components and to compare them with the prediction of theoretical stellar evolution models. We analyze the Kepler mission light curve of T-Cyg1-12664 to accurately measure the times and phases of the primary and secondary eclipse. In addition, we measure the rotational period of the primary component by analyzing the out-of-eclipse oscillations that are due to spots. We accurately constrain the effective temperature of the system using ground-based absolute photometry in B, V, R_C_, and I_C_. We also obtain and analyze VR_C_I_C_ differential light curves to measure the eccentricity and the orbital inclination of the system, and a precise Teff ratio. From the joint analysis of new radial velocities and those in the literature we measure the individual masses of the stars. Finally, we use the PHOEBE code to generate a physical model of the system.
- ID:
- ivo://CDS.VizieR/J/A+A/613/A76
- Title:
- Relative radial velocities and K2 fluxes of K2-132
- Short Name:
- J/A+A/613/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although the majority of radial velocity detected planets have been found orbiting solar-type stars, a fraction of them have been discovered around giant stars. These planetary systems have revealed different orbital properties when compared to solar-type star companions. In particular, radial velocity surveys have shown that there is a lack of giant planets in close-in orbits around giant stars, in contrast to the known population of hot Jupiters orbiting solar-type stars. It has been theorized that the reason for this distinctive feature in the semimajor axis distribution is the result of the stellar evolution and/or that it is due to the effect of a different formation/evolution scenario for planets around intermediate-mass stars. However, in the past few years a handful of transiting short-period planets (P<~10-days) have been found around giant stars, thanks to the high-precision photometric data obtained initially by the Kepler mission, and later by its two-wheel extension K2. These new discoveries have allowed us for the first time to study the orbital properties and physical parameters of these intriguing and elusive substellar companions. In this paper we report on an independent discovery of a transiting planet in field 10 of the K2 mission, also reported recently by Grunblatt et al. (2017AJ....154..254G). The host star has recently evolved to the giant phase, and has the following atmospheric parameters: Teff=4878+/-70K, logg=3.289+/-0.004, and [Fe/H]=-0.11+/-0.05dex. The main orbital parameters of K2-132 b, obtained with all the available data for the system are: P=9.1708+/-0.0025d, e=0.290+/-0.049, Mp=0.495+/-0.007M_J_ and Rp=1.089+/-0.006R_J_. This is the fifth known planet orbiting any giant star with a<0.1, and the most eccentric one among them, making K2-132 b a very interesting object.
- ID:
- ivo://CDS.VizieR/J/AJ/141/63
- Title:
- Relative radial velocities of HAT-P-4 and HAT-P-14
- Short Name:
- J/AJ/141/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of the Rossiter-McLaughlin effect for two exoplanetary systems, revealing the orientations of their orbits relative to the rotation axes of their parent stars. HAT-P-4b is prograde, with a sky-projected spin-orbit angle of {lambda}=-4.9+/-11.9{deg}. In contrast, HAT-P-14b is retrograde, with {lambda}=189.1+/-5.1{deg}. These results conform with a previously noted pattern among the stellar hosts of close-in giant planets: hotter stars have a wide range of obliquities and cooler stars have low obliquities. This, in turn, suggests that three-body dynamics and tidal dissipation are responsible for the short-period orbits of many exoplanets. In addition, our data revealed a third body in the HAT-P-4 system, which could be a second planet or a companion star.
- ID:
- ivo://CDS.VizieR/J/AJ/162/150
- Title:
- Resolving circumstellar environment of MWC137 .II.
- Short Name:
- J/AJ/162/150
- Date:
- 14 Mar 2022 06:35:34
- Publisher:
- CDS
- Description:
- The Galactic B[e] supergiant MWC137 is surrounded by a large-scale optical nebula. To shed light on the physical conditions and kinematics of the nebula, we analyze the optical forbidden emission lines [NII] {lambda}{lambda}6548,6583 and [SII] {lambda}{lambda}6716,6731 in long-slit spectra taken with ALFOSC at the Nordic Optical Telescope. The radial velocities display a complex behavior but, in general, the northern nebular features are predominantly approaching while the southern ones are mostly receding. The electron density shows strong variations across the nebula with values spreading from about zero to ~800cm^-3^. Higher densities are found closer to MWC137 and in regions of intense emission, whereas in regions with high radial velocities the density decreases significantly. We also observe the entire nebula in the two [SII] lines with the scanning Fabry-Perot interferometer attached to the 6m telescope of the Special Astrophysical Observatory. These data reveal a new bow-shaped feature at PA=225{deg}-245{deg} and a distance 80" from MWC137. A new H{alpha} image has been taken with the Danish 1.54m telescope on La Silla. No expansion or changes in the nebular morphology appear within 18.1yr. We derive a mass of 37_-5_^+9^M{sun} and an age of 4.7{+/-}0.8Myr for MWC137. Furthermore, we detect a period of 1.93d in the time series photometry collected with the TESS satellite, which could suggest stellar pulsations. Other, low-frequency variability is seen as well. Whether these signals are caused by internal gravity waves in the early-type star or by variability in the wind and circumstellar matter currently cannot be distinguished.
- ID:
- ivo://CDS.VizieR/V/143
- Title:
- Revised Bologna Catalog of M31 clusters, V.5
- Short Name:
- V/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dataset lists all the confirmed globular clusters (GC), all the known candidates GCs, and also all the objects that were identified as candidate GCs in the past and were subsequently recognised not to be genuine clusters, each entry being properly classified (GC, candidate GC, foreground star, background galaxy, HII region, etc.). The latter entries are maintained in the catalogue to avoid re-discoveries of objects that may look like M31 GCs and have been already classified as non-GCs. Please take into account the classification flag(s) when you use the RBC.
- ID:
- ivo://CDS.VizieR/J/A+A/471/127
- Title:
- Revised Bologna Catalog of M31 clusters, V.3
- Short Name:
- J/A+A/471/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of a large spectroscopic survey of candidate globular clusters located in the extreme outskirts of the nearby M 31 galaxy. The survey is aimed at ascertaining the nature of the selected candidates to increase the sample of confirmed M 31 clusters lying more that 2{deg} away from the center of the galaxy. We obtained low resolution spectra ({lambda}/{Delta}{lambda}~800-1300) of 48 targets selected from the Extended Source Catalogue of 2MASS, as in Galleti et al. (2005A&A...436..535G). The observed candidates have been robustly classified according to their radial velocity and by verifying their extended/point-source nature from ground-based optical images. We have also obtained a spectrum and a radial velocity estimate for the remote M 31 globular discovered by Martin et al. (2006MNRAS.371.1983M).
