- ID:
- ivo://CDS.VizieR/J/MNRAS/492/3408
- Title:
- Galactic disc RR Lyrae stars
- Short Name:
- J/MNRAS/492/3408
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a kinematical study of 314 RR Lyrae stars in the solar neighbourhood using the publicly available photometric, spectroscopic, and Gaia DR2 astrometric data to explore their distribution in the Milky Way. We report an overdensity of 22 RR Lyrae stars in the solar neighbourhood at a pericentre distance of between 5 and 9kpc from the Galactic Centre. Their orbital parameters and their chemistry indicate that these 22 variables share the kinematics and the [Fe/H] values of the Galactic disc, with an average metallicity and tangential velocity of [Fe/H]=-0.60dex and v_theta_=241km/s, respectively. From the distribution of the Galactocentric spherical velocity components, we find that these 22 disc-like RR Lyrae variables are not consistent with the Gaia Sausage (Gaia-Enceladus), unlike almost half of the local RR Lyrae stars. Chemical information from the literature shows that the majority of the selected pericentre-peak RR Lyrae variables are alpha-poor, a property shared by typically much younger stars in the thin disc. Using the available photometry, we rule out a possible misclassification with the known classical and anomalous Cepheids. The similar kinematic, chemical, and pulsation properties of these disc RR Lyrae stars suggest they share a common origin. In contrast, we find that the RR Lyrae stars associated with the Gaia- Enceladus based on their kinematics and chemical composition show a considerable metallicity spread in the old population (approximately 1dex).
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- ID:
- ivo://CDS.VizieR/J/A+A/493/785
- Title:
- Galactic disk stellar populations from ISOGAL
- Short Name:
- J/A+A/493/785
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify the stellar populations (mostly red giants and young stars) detected in the ISOGAL survey at 7 and 15um towards a field (LN45) in the direction l=-45, b=0.0. The sources detected in the survey of the Galactic plane by the Infrared Space Observatory were characterised based on colour-colour and colour-magnitude diagrams. We combine the ISOGAL catalogue with the data from surveys such as 2MASS and GLIMPSE. Interstellar extinction and distance were estimated using the red clump stars detected by 2MASS in combination with the isochrones for the AGB/RGB branch. Absolute magnitudes were thus derived and the stellar populations identified from their absolute magnitudes and their infrared excess. A standard approach to analysing the ISOGAL disc observations has been established. We identify several hundred RGB/AGB stars and 22 candidate young stellar objects in the direction of this field in an area of 0.16deg^2^. An overdensity of stellar sources is found at distances corresponding to the distance of the Scutum-Crux spiral arm. In addition, we determined mass-loss rates of AGB-stars using dust radiative transfer models from the literature.
- ID:
- ivo://CDS.VizieR/J/ApJS/235/41
- Title:
- Galactic EB stars with eccentric orbits based on ETDs
- Short Name:
- J/ApJS/235/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A comprehensive catalog of 623 galactic eclipsing binary (EB) systems with eccentric orbits is presented with more than 2830 times of minima determined from the archived photometric data by various sky-survey projects and new photometric measurements. The systems are divided into two groups according to whether the individual system has a GCVS name or not. All the systems in both groups are further classified into three categories (D, A, and A+III) on the basis of their eclipse timing diagrams: 453 D systems showing just constantly displaced secondary minima, 139 A systems displaying only apsidal motion (AM), and 31 A+III systems exhibiting both AM and light-time effects. AM parameters for 170 systems (A and A+III systems) are consistently calculated and cataloged with basic information for all systems. Some important statistics for the AM parameters are discussed and compared with those derived for the eccentric EB systems in the Large and Small Magellanic Clouds.
- ID:
- ivo://CDS.VizieR/J/MNRAS/503/5351
- Title:
- Galactic extinction at low Galactic latitudes
- Short Name:
- J/MNRAS/503/5351
- Date:
- 19 Jan 2022 00:31:53
- Publisher:
- CDS
- Description:
- We use near-infrared (J-K) colours of bright 2MASS galaxies, measured within a 7-arcsec-radius aperture, to calibrate the Schlegel, Finkbeiner & Davis DIRBE/IRAS Galactic extinction map at low Galactic latitudes (|b|<10{deg}). Using 3460 galaxies covering a large range in extinction (up to A_K_=1.15mag or E(B-V)~=3.19mag), we derive a correction factor f=0.83+/-0.01 by fitting a linear regression to the colour-extinction relation, confirming that the Schlegel et al. maps overestimate the extinction. We argue that the use of only a small range in extinction (e.g., A_K_<0.4mag) increases the uncertainty in the correction factor and may overestimate it. Our data confirm the Fitzpatrick extinction law for the J- and K-band. We also tested four all-sky extinction maps based on Planck satellite data. All maps require a correction factor as well. In three cases, the application of the respective extinction correction to the galaxy colours results in a reduced scatter in the colour-extinction relation, indicating a more reliable extinction correction. Finally, the large galaxy sample allows an analysis of the calibration of the extinction maps as a function of Galactic longitude and latitude. For all but one extinction map, we find a marked offset between the Galactic Centre and Anticentre region, but not with the dipole of the cosmic microwave background. Based on our analysis, we recommend the use of the GNILC extinction map by Planck Collaboration XLVIII with a correction factor f=0.86+/-0.01.
- ID:
- ivo://CDS.VizieR/J/A+A/474/121
- Title:
- Galactic globular cluster 2MASS GC02 JKs phot.
- Short Name:
- J/A+A/474/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained deep infrared images and K-band spectra of the Galactic globular cluster 2MASS GC02. A variable star search has also been carried out. Some basic physical properties of the cluster, such as metallicity, reddening, distance modulus and radial velocity, are derived. These measurements are based on an analysis of the J-Ks versus Ks color-magnitude diagram of the cluster. Spectroscopically derived metallicities and radial velocities of 15 stars are presented. In addition, periods and amplitudes are provided for five RR Lyrae stars discovered in the field. The cluster is moderately metal-rich and has a relatively high radial velocity. Its horizontal branch appears to be predominantly red, though our photometry cannot rule out the presence of a blue component as seen in NGC 6388 and NGC 6441. Similar to these two clusters, the detected RR Lyrae stars in GC02 have anomalously long periods for the cluster's moderately high metallicity, which suggests that it too is an Oosterhoff type III cluster. Comparison with the existing kinematic and abundance information for the Galactic globular clusters shows that GC02 most probably belongs to the bulge sub population, although an inner halo association cannot be ruled out.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/1725
- Title:
- Galactic globular clusters SDSS photometry
- Short Name:
- J/MNRAS/437/1725
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present g' and z' aperture photometry for 96 Galactic globular clusters, making this the largest homogeneous catalogue of photometry for these objects in the Sloan Digital Sky Survey (SDSS) filter system. For a subset of 56 clusters, we also provide photometry in r' and i'. We carry out comparisons with previous photometry as well as with the SDSS data set. The data will be useful for a series of applications in Galactic and extragalactic astrophysics. Future papers will analyse the colour-metallicity relation, colour-magnitude diagrams and structural parameters. The compilation of results based on this data set will be collected in the Galactic Globular Cluster Catalog (G2C2).
- ID:
- ivo://CDS.VizieR/J/ApJ/731/4
- Title:
- Galactic halo as seen by the CFHTLS
- Short Name:
- J/ApJ/731/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Canada-France-Hawaii Telescope Legacy Survey data for 170deg^2^, recalibrated and transformed to the Sloan Digital Sky Survey ugri photometric system, to study the distribution of near-turnoff main-sequence stars in the Galactic halo along four lines of sight to heliocentric distances of ~35kpc. We find that the halo stellar number density profile becomes steeper at Galactocentric distances greater than R_gal_~28kpc, with the power-law index changing from n_inner_=-2.62+/-0.04 to n_outer_=-3.8+/-0.1. In particular, we test a series of single power-law models and find them to be strongly disfavored by the data. The parameters for the best-fit Einasto profile are n=2.2+/-0.2 and R_e_=22.2+/-0.4kpc. We measure the oblateness of the halo to be q=c/a=0.70+/-0.01 and detect no evidence of it changing across the range of probed distances. The Sagittarius stream is detected in the l=173{deg} and b=-62{deg} direction as an overdensity of [Fe/H]~-1.5dex stars at R_gal_~32kpc, providing a new constraint for the Sagittarius stream and dark matter halo models. We also detect the Monoceros stream as an overdensity of [Fe/H]>-1.5dex stars in the l=232{deg} and b=26{deg} direction at R_gal_<~25kpc. In the two sight lines where we do not detect significant substructure, the median metallicity is found to be independent of distance within systematic uncertainties ([Fe/H]~-1.5+/-0.1dex).
- ID:
- ivo://CDS.VizieR/J/ApJ/763/32
- Title:
- Galactic halo RRab stars from CSS
- Short Name:
- J/ApJ/763/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present analysis of 12227 type-ab RR Lyraes (RRLs; ~9400 are newly discovered) found among the 200 million public light curves in Catalina Surveys Data Release 1. These stars span the largest volume of the Milky Way ever surveyed with RRLs, covering ~20000deg^2^ of the sky (0{deg}<{alpha}<360{deg}, -22{deg}<{delta}<65{deg}) to heliocentric distances of up to 60kpc. Each of the RRLs is observed between 60 and 419 times over a six-year period. Using period finding and Fourier fitting techniques we determine periods and apparent magnitudes for each source. We find that the periods are generally accurate to {sigma}=0.002% in comparison to 2842 previously known RRLs and 100 RRLs observed in overlapping survey fields. We photometrically calibrate the light curves using 445 Landolt standard stars and show that the resulting magnitudes are accurate to ~0.05mag using Sloan Digital Sky Survey (SDSS) data for ~1000 blue horizontal branch stars and 7788 RRLs. By combining Catalina photometry with SDSS spectroscopy, we analyze the radial velocity and metallicity distributions for >1500 of the RRLs. Using the accurate distances derived for the RRLs, we show the paths of the Sagittarius tidal streams crossing the sky at heliocentric distances from 20 to 60kpc. By selecting samples of Galactic halo RRLs, we compare their velocity, metallicity, and distance with predictions from a recent detailed N-body model of the Sagittarius system. We find that there are some significant differences between the distances and structures predicted and our observations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/447/2307
- Title:
- Galactic HII region IRAS 16148-5011 content
- Short Name:
- J/MNRAS/447/2307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An investigation of the IRAS 16148-5011 region - a cluster at a distance of 3.6kpc - is presented here, carried out using multiwavelength data in near-infrared (NIR) from the 1.4m Infrared Survey Facility telescope, mid-infrared (MIR) from the archival Spitzer GLIMPSE (Galactic Legacy Infrared Midplane Survey Extraordinaire) survey, far-infrared (FIR) from the Herschel archive, and low-frequency radio continuum observations at 1280 and 843MHz from the Giant Metrewave Radio Telescope and Molonglo Survey archive, respectively. A combination of NIR and MIR data is used to identify 7 Class I and 133 Class II sources in the region. Spectral energy distribution (SED) analysis of selected sources reveals a 9.6M_{sun}_ high-mass source embedded in nebulosity. However, Lyman continuum luminosity calculation using radio emission - which shows a compact HII region - indicates the spectral type of the ionizing source to be earlier than B0-O9.5. Free-free emission SED modelling yields the electron density as 138cm^-3^, and thus the mass of the ionized hydrogen as ~16.4M_{sun}_. Thermal dust emission modelling, using the FIR data from Herschel and performing modified blackbody fits, helped us construct the temperature and column density maps of the region, which show peak values of 30K and 3.3x10^22^cm^-2^, respectively. The column density maps reveal an A_V_>20mag extinction associated with the nebular emission, and weak filamentary structures connecting dense clumps. The clump associated with this IRAS object is found to have dimensions of ~1.1pcx0.8pc, and a mass of 10^23^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/PASJ/71/6
- Title:
- Galactic infrared bubbles
- Short Name:
- J/PASJ/71/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galactic infrared (IR) bubbles, which have shell-like structures in the mid-IR wavelengths, are known to contain massive stars near their centers. Infrared bubbles in inner Galactic regions (|l|<=65{deg}, |b|<=1{deg}) have so far been studied well to understand the massive star formation mechanisms. In this study, we expand the research area to the whole Galactic plane (0{deg}<=l<360{deg}, |b|<=5{deg}), using the AKARI all-sky survey data. We limit our study to large bubbles with angular radii of >1' to reliably identify and characterize them. For the 247 IR bubbles in total, we derived the radii and the covering fractions of the shells, based on the method developed by Y. Hattori et al. (2016PASJ...68...37H). We also created their spectral energy distributions, using the AKARI and Herschel photometric data, and decomposed them with a dust model to obtain the total IR luminosity and the luminosity of each dust component, i.e., polycyclic aromatic hydrocarbons (PAHs), warm dust, and cold dust. As a result, we find that there are systematic differences in the IR properties of the bubbles between the inner and outer Galactic regions. The total IR luminosities are lower in outer Galactic regions, while there is no systematic difference in the range of the shell radii between inner and outer Galactic regions. More IR bubbles tend to be observed as broken bubbles rather than closed ones and the fractional luminosities of the PAH emission are significantly higher in outer Galactic regions. We discuss the implications of these results for the massive stars and the interstellar environments associated with the Galactic IR bubbles.
