- ID:
- ivo://CDS.VizieR/J/A+A/625/A151
- Title:
- Galactic Bulge Type II Cepheids NIR data
- Short Name:
- J/A+A/625/A151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform parallel Lomb-Scargle and Generalized Lomb-Scargle periodogram analysis of the Ks-band time series of the VISTA Variables in the Via Lactea Survey, to detect periodicities. We take account of periods, light amplitudes, distances and proper motions to provide a classification of the candidate variables. We provide a catalog which will be the starting point for future spectroscopic surveys in the innermost regions of the Galaxy.
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- ID:
- ivo://CDS.VizieR/J/A+A/534/A91
- Title:
- Galactic Bulge Valinhos Observatory Catalog
- Short Name:
- J/A+A/534/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The definition, construction and realization of a reference system is one of the oldest and most fundamental tasks of astronomy. Currently, the ICRS (International Celestial Reference System), realized by the ICRF (International Celestial Reference Frame) or ICRF2, is the reference system adopted by the IAU. It is based on the very precise VLBI positions of a few hundred compact extragalactic radio sources. Despite its excellent precision, the ICRF is far from providing a reference system that is available for the entire sky and accessible to all observers. The ICRF has to be densified and extended to other wavelengths, mainly to the optical domain where the astronomical activities are more intense. For this reason, the IAU has recommended and encouraged works in this direction over the years. Many of them were developed to give sometimes good positions and proper motions, but they are very limited in magnitude, while others are extremely dense and deep in magnitude but have low accuracy, mainly for the proper motions. Nevertheless, all these contributions are very important because they are complementary. We present a homogeneous and precise optical astrometric catalog that extends the ICRF in the direction of 12 low-extinction windows of the Galactic bulge and provides at the same time a useful database for kinematic studies.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/82
- Title:
- Galactic carbon stars infrared spectroscopy
- Short Name:
- J/ApJ/887/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New infrared spectra of 33 Galactic carbon stars from FORCAST on SOFIA reveal strong connections between stellar pulsations and the dust and molecular chemistry in their circumstellar shells. A sharp boundary in overall dust content, which predominantly measures the amount of amorphous carbon, separates the semiregular and Mira variables, with the semiregulars showing little dust in their spectra and the Miras showing more. In semiregulars, the contribution from SiC dust increases rapidly as the overall dust content grows, but in Miras, the SiC dust feature grows weaker as more dust is added. A similar dichotomy is found with the absorption band from CS at ~7.3{mu}m, which is generally limited to semiregular variables. Observationally, these differences make it straightforward to distinguish semiregular and Mira variables spectroscopically without the need for long-term photometric observations or knowledge of their distances. The rapid onset of strong SiC emission in Galactic carbon stars in semiregular variables points to a different dust-condensation process before strong pulsations take over. The break in the production of amorphous carbon between semiregulars and Miras seen in the Galactic sample is also evident in Magellanic carbon stars, linking strong pulsations in carbon stars to the strong mass-loss rates which will end their lives as stars across a wide range of metallicities.
- ID:
- ivo://CDS.VizieR/J/other/NewA/34.234
- Title:
- Galactic cataclysmic variables distances
- Short Name:
- J/other/NewA/34.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to determine the spatial distribution, Galactic model parameters and luminosity function of cataclysmic variables (CVs), a J-band magnitude limited sample of 263 CVs has been established using a newly constructed period-luminosity-colours (PLCs) relation which includes J,KsJ,Ks and W1W1-band magnitudes in 2MASS and WISE photometries, and the orbital periods of the systems. This CV sample is assumed to be homogeneous regarding to distances as the new PLCs relation is calibrated with new or re-measured trigonometric parallaxes.
- ID:
- ivo://CDS.VizieR/J/ApJS/118/201
- Title:
- Galactic Center 6 and 20cm survey
- Short Name:
- J/ApJS/118/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the VLA to survey 10 fields at 20 cm (1658MHz) and 11 fields at 6 cm (5GHz) that are between 7' and 137' from SgrA*. Our objective was to identify extragalactic sources and measure their scattering diameters so as to constrain the GC-scattering region separation. In order to find sources within these fields, we have employed pdfCLEAN, a source detection algorithm in which sources are identified in an image by comparing the intensity histogram of the image to that expected from a noise-only image. We found over 100 sources, with the faintest sources being approximately 3 mJy. The average number of sources per field is approximately 10, though fields close to SgrA* tend to contain fewer sources. A number of Galactic sources are included in our source catalog. The double-lobed source 1LC 359.872+0.178, potentially an X-ray quiet version of 1E 1740.7-2942, a shell-like structure with a central point source, and a possible radio transient, are discussed in the paper.
- ID:
- ivo://nasa.heasarc/galcencxo
- Title:
- Galactic Center Chandra X-Ray Point Source Catalog
- Short Name:
- GALCENCXO
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 9017 X-ray sources identified in Chandra observations of a 2 degrees by 0.8 degrees field around the Galactic center. This enlarges the number of known X-ray sources in the region by a factor of 2.5. The catalog incorporates all of the ACIS-I observations as of 2007 August, which total 2.25 Ms of exposure. At the distance to the Galactic center (8 kpc), we are sensitive to sources with luminosities of 4 x 10<sup>32</sup> erg s<sup>-1</sup> (0.5-8.0 keV; 90% confidence) over an area of 1 degree<sup>2</sup>, and up to an order of magnitude more sensitive in the deepest exposure (1.0 Ms) around Sgr A*. The positions of 60% of the sources are accurate to <1 arcsecond (95% confidence), and 20% have positions accurate to <0.5 arcsec. The authors search for variable sources, and find that 3% exhibit flux variations within an observation, and 10% exhibit variations from observation-to-observation. They also find one source, CXOUGC J174622.7-285218, with a periodic 1745 s signal (1.4% chance probability), which is probably a magnetically accreting cataclysmic variable. The authors compare the spatial distribution of X-ray sources to a model for the stellar distribution, and find 2.8 sigma evidence for excesses in the numbers of X-ray sources in the region of recent star formation encompassed by the Arches, Quintuplet, and Galactic center star clusters. These excess sources are also seen in the luminosity distribution of the X-ray sources, which is flatter near the Arches and Quintuplet than elsewhere in the field. These excess point sources, along with a similar longitudinal asymmetry in the distribution of diffuse iron emission that has been reported by other authors, probably have their origin in the young stars that are prominent at a galactic lonitude ~ 0.1 degrees. This tables was designed to be inclusive, so sources of questionable quality are included, according to the authors. For instance, 134 sources have net numbers of counts in the 0.5-8.0 keV band that are consistent with 0 at the 90% confidence level. These sources are only detected in a single band and are presumably either very hard or very soft, detected in single observations because they were transients, or detected in stacked observations with wvdecomp at marginal significance. The authors have chosen to include them because they passed the test based on Poisson statistics from Weisskopf et al. (2007, ApJ, 657, 1026). The observations which were used to generate the source list herein tabulated are listed in Table 1 of the reference paper. This HEASARC table GALCENCXO supercedes and replaces the previous HEASARC tables CHANGALCEN and CHANC150PC, which were based on Muno et al. (2003, ApJ, 589, 225) and Muno et al. (2006, ApJS, 165, 173), respectively. This table was created by the HEASARC in March 2009 based on the machine-readable versions of Table 2, 3 and 4 from the paper which were obtained from the electronic ApJ website. The information on short-term variability given in Table 5 of the reference paper was not included in this HEASARC table, notice. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/galccxonid
- Title:
- Galactic Center Chandra X-Ray Source Near-IR Counterparts
- Short Name:
- GALCCXONID
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 5184 candidate infrared counterparts to X-ray sources detected toward the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory during the past decade, including data from a recent deep survey of the central 2 degrees x 0.8 degrees of the Galactic plane. A total of 6760 of these sources have hard X-ray colors, and the majority of them lie near the Galactic center, while most of the remaining 2257 soft X-ray sources lie in the foreground. The authors have cross-correlated the X-ray source positions with the 2MASS and SIRIUS near-infrared catalogs, which collectively contain stars with a 10-sigma limiting flux of K<sub>s</sub> <= 15.6 mag. In order to distinguish absorbed infrared sources near the Galactic center from those in the foreground, they defined red and blue sources as those which have H - K<sub>s</sub> >= 0.9 and < 0.9 mag, respectively. The authors find that 5.8% =/- 1.5% (2 sigma) of the hard X-ray sources have real infrared counterparts, of which 228 +/- 99 are red and 166 +/- 27 are blue. The red counterparts are probably comprised of Wolf-Rayet and O stars, high-mass X-ray binaries, and symbiotic binaries located near the Galactic center. Foreground X-ray binaries suffering intrinsic X-ray absorption could be included in the sample of blue infrared counterparts to hard X-ray sources. The authors also find that 39.4% +/- 1.0% of the soft X-ray sources have blue infrared counterparts; most of these are probably coronally active dwarfs in the foreground. There is a noteworthy collection of ~20 red counterparts to hard X-ray sources near the Sagittarius B H II region, which are probably massive binaries that have formed within the last several Myr. For each of the infrared matches to X-ray sources in their catalog, the authors derived the probability that the association is real, based on the source properties and the results of the cross-correlation analysis. These data are included in this catalog and will serve spectroscopic surveys to identify infrared counterparts to X-ray sources near the Galactic center. This table was created by the HEASARC in October 2009 based on the electronic version of Table 3 from the reference paper which was obtained from the Astrophysical Journal web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/A+A/626/A44
- Title:
- Galactic center CO rot-vib absorption lines
- Short Name:
- J/A+A/626/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the near- to mid-infrared wavelength domain, bright continuum sources in the central parsec of the Galactic center (GC) are subject to foreground absorption. These sources therefore represent ideal probes of the intervening material that is responsible for the absorption along the line of sight. Our aim is to shed light on the location and physics of the absorbing clouds. We try to find out which of the gaseous absorbing materials is intimately associated with the GC and which one is associated with clouds at a much larger distance. We used the capabilities of CRIRES spectrograph located at ESO Very Large Telescope in Chile to obtain absorption spectra of individual lines at a high spectral resolution of R=65000, that is, 5km/s. We observed the 12CO R(0), P(1), P(2), P(3), P(4), P(5), P(6), P(7) and P(9) transition lines, applied standard data reduction, and compared the results with literature data. Results. We present the results of CRIRES observations of 13 infrared sources located in the central parsec of the Galaxy. The data provide direct evidence for a complex structure of the interstellar medium along the line of sight and in the close environment of the central sources. In particular we find four cold foreground clouds at radial velocities vLS R of the order of -145, -85, -60, and -40+\/-15km/s that show absorption in the lower transition lines from R(0) to P(2) and in all the observed spectra.We also find in all sources an absorption in velocity range of 50-60km/s, possibly associated with the so-called 50km/s cloud and suggesting an extension of this cloud in front of the GC. Finally, we detect individual absorption lines that are probably associated with material much closer to the center and with the sources themselves, suggesting the presence of cold gas in the local region.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A141
- Title:
- Galactic center early-type stars catalog
- Short Name:
- J/A+A/585/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is still unclear whether the Sagittarius spiral arm is a major spiral arm in the Galaxy or whether it just outlines a region of enhanced star formation because of the local compression of gas. The best way to separate these scenarios out is to study the kinematics across the arm to determine the velocity perturbation it induces. A survey of early-type stars in the direction of the Galactic center is performed covering an area of 100 sq. deg with the aim of identifying candidates for a radial velocity study. Objective prism plates were obtained with the 4{deg} prism on the ESO Schmidt telescope using IIaO, 4415, and IIIaJ emulsions. The plates were digitized and more than 100k spectra were extracted down to a limiting magnitude of B=15m. The spectra were cross-correlated with a template with Balmer lines, which yielded a candidate list of 12675 early-type stars. Magnitudes and equivalent widths of strong lines were calculated from the spectra, which allowed us to estimate the individual extinctions and distances for 11075 stars.
- ID:
- ivo://nasa.heasarc/gcps
- Title:
- Galactic Center P-Band (330 MHz) Survey
- Short Name:
- GCPS
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Galactic Center P-Band (330 MHz) Survey (GCPS) is based on wide-field, subarcminute-resolution Very Large Array (VLA) imagery of the Galactic center region at 330 MHz. With a resolution of ~7"x12" and an rms noise of 1.6 mJy/beam, this image represented a significant increase in resolution and sensitivity over the previously published VLA image at this frequency. The improved sensitivity more than tripled the census of small-diameter sources in the region, resulted in the detection of two new nonthermal filaments (NTFs), 18 NTF candidates, and 30 pulsar candidates, revealed previously known extended sources in greater detail, and has resulted in the first detection of Sagittarius A* in this frequency range. Two sets of observations were obtained. The first was conducted at 330 MHz in the A configuration of the VLA in 1996 October. The second set of P-band observations were obtained in the A and B configurations of the VLA between 1998 March and 1999 May. This Browse table was created by the HEASARC in May 2005 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/128/1646">CDS Catalog J/AJ/128/1646</a>, tables table2.dat and table3.dat. This is a service provided by NASA HEASARC .