- ID:
- ivo://CDS.VizieR/J/MNRAS/501/1116
- Title:
- GAIA pulsars and where to find them
- Short Name:
- J/MNRAS/501/1116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- While the majority of massive stars have a stellar companion, most pulsars appear to be isolated. Taken at face value, this suggests that most massive binaries break apart due to strong natal kicks received in supernova explosions. However, the observed binary fraction can still be subject to strong selection effects, as monitoring of newly discovered pulsars is rarely carried out for long enough to conclusively rule out multiplicity. Here, we use the second Gaia data release to search for companions to 1534 rotation-powered pulsars with positions known to better than 0.5arcsec. We find 22 matches to known pulsars, including 1 not reported elsewhere, and 8 new possible companions to young pulsars. We examine the photometric and kinematic properties of these systems and provide empirical relations for identifying Gaia sources with potential millisecond pulsar companions. Our results confirm that the observed multiplicity fraction is small. However, we show that the number of binaries below the sensitivity of Gaia and radio timing in our sample could still be significantly higher. We constrain the binary fraction of young pulsars to be f^true^_young_<5.3(8.3) per cent under realistic (conservative) assumptions for the binary properties and current sensitivity thresholds. For massive stars (>10M_{sun}_) in particular, we find f^true^_OB_<3.7 per cent, which sets a firm independent upper limit on the Galactic neutron star merger rate, <=7.2x10^-4^/yr. Ongoing and future projects, such as the CHIME/pulsar program, MeerTime, HIRAX, and ultimately the SKA, will significantly improve these constraints in the future.
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4982. Gaia QSO Table
- ID:
- ivo://irsa.ipac/Gaia/QSO
- Title:
- Gaia QSO Table
- Short Name:
- Gaia-QSO
- Date:
- 01 Oct 2018 20:27:21
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- This table has an entry for all sources in the auxiliary QSO solution matched to the ICRF2 sources and passing all quality filters discussed in the corresponding documentation.
- ID:
- ivo://CDS.VizieR/J/A+A/651/A20
- Title:
- Gaia RVS benchmark stars. I.
- Short Name:
- J/A+A/651/A20
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The Radial Velocity Spectrometer (RVS) on board the Gaia satellite is not provided with a wavelength calibration lamp. It uses its observations of stars with known radial velocity to derive the dispersion relation. To derive an accurate radial velocity calibration, a precise knowledge of the line spread function (LSF) of the RVS is necessary. Good-quality ground-based observations in the wavelength range of the RVS are highly desired to determine the LSF. Several radial velocity standard stars are available to the Gaia community. The highest possible number of calibrators will surely allow us to improve the accuracy of the radial velocity. Because the LSF may vary across the focal plane of the RVS, a large number of high-quality spectra for the LSF calibration may allow us to better sample the properties of the focal plane. We selected a sample of stars to be observed with UVES at the Very Large Telescope, in a setting including the wavelength range of RVS, that are bright enough to allow obtaining high-quality spectra in a short time. We also selected stars that lack chemical investigation in order to increase the sample of bright, close by stars with a complete chemical inventory. We here present the chemical analysis of the first sample of 80 evolved stars. The quality of the spectra is very good, therefore we were able to derive abundances for 20 elements. The metallicity range spanned by the sample is about 1dex, from slightly metal-poor to solar metallicity. We derived the Rb abundance for all stars and investigated departures from local thermodynamical equilibrium (NLTE) in the formation of its lines. The sample of spectra is of good quality, which is useful for a Gaia radial velocity calibration. The Rb NLTE effects in this stellar parameters range are small but sometimes non-negligible, especially for spectra of this good quality.
4984. Gaia-RVS standards
- ID:
- ivo://CDS.VizieR/J/A+A/552/A64
- Title:
- Gaia-RVS standards
- Short Name:
- J/A+A/552/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Radial Velocity Spectrograph (RVS) on board of Gaia needs to be calibrated using stable reference stars known in advance. The catalogue presented here has being built for that purpose. It includes 1420 radial velocity standard star candidates selected on strict criteria in order to fulfill the Gaia-RVS requirements. The radial velocities (RV) presented here have been obtained with the echelle spectrographs ELODIE and SOPHIE on the 1.93-m telescope at Observatoire de Haute-Provence (OHP), NARVAL on the Telescope Bernard Lyot at Observatoire du Pic du Midi and CORALIE on the Euler-Swiss Telescope at La Silla. Data from the OHP and Geneva Observatory archives have also been retrieved as well as HARPS spectra from the ESO archive. The RVs have been measured with the same method : Cross-Correlation Function (CCF) of the echelle spectra with a numerical mask. We provide for each star a mean radial velocity in the SOPHIE scale, derived from the combination of velocities measured with those instruments, after having carefully estimated their differences of zero-points. In total 10214 radial velocity measurements have been obtained for the 1420 stars. With a mean time baseline of 6.35 years, 92.9% of the candidates fulfill a target stability criterion of 300m/s. 343 stars are found to be constant at the level of 100m/s over 10 years. Comparisons with the catalogues of Nidever et al. (2002, Cat. J/ApJS/141/503) and Chubak et al. (2012, arXiv:1207.6212) show an excellent agreement for FGK stars, with zero-point differences lower than 100m/s and a remarkably low RMS scatter of 33m/s in the case of Nidever et al. (2002, Cat. J/ApJS/141/503), suggesting that the precision of the catalogue presented here is better than this value. This catalog will likely be useful for other large-scale spectroscopic surveys such as APOGEE, Gaia-ESO, HERMES and LAMOST.
- ID:
- ivo://CDS.VizieR/J/ApJ/832/L18
- Title:
- Gaia's DR1 parallaxes vs previous measurements
- Short Name:
- J/ApJ/832/L18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 612 single stars with previously published trigonometric parallaxes placing them within 25pc to evaluate parallaxes released in Gaia's first data release (DR1). We find that the Gaia parallaxes are, on average, 0.24+/-0.02mas smaller than the weighted mean trigonometric parallax values for these stars in the solar neighborhood. We also find that the offset changes with distance out to 100pc, in the sense that the closer the star, the larger the offset. We find no systematic trends in the parallax offsets with stellar V magnitude, V-K color, or proper motion. We do find that the offset is roughly twice as large for stars south of the ecliptic compared to those that are north.
- ID:
- ivo://CDS.VizieR/VI/137
- Title:
- GaiaSimu Universe Model Snapshot
- Short Name:
- VI/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Context: This study has been developed in the framework of the computational simulations that are executed for the preparation of the ESA Gaia astrometric mission. Aims: We focus on describing the objects and characteristics that Gaia will potentially observe without taking into consideration instrumental effects (detection efficiency, observing errors). Methods: The theoretical Universe Model prepared for the Gaia simulation has been statistically analysed at a given time. Ingredients of the model are described, with the greatest emphasis on the stellar content, the double and multiple stars, and variability. Results: In this simulation the errors have not yet been included. Hence we estimated the number of objects and their theoretical photometric, astrometric and spectroscopic characteristics if they are perfectly detected.We show that Gaia will be able to potentially observe 1.1 billion of stars (single or part of multiple star systems) of which about 2% are variable stars and 3% have one or two exoplanets. At the extragalactic level, observations will be potentially composed of several millions of galaxies, half a million to 1 million quasars and about 50,000 supernovae that will occur during the five years of the mission.
- ID:
- ivo://irsa.ipac/Gaia/GaiaDR2
- Title:
- Gaia Source Catalogue DR2
- Short Name:
- GaiaDR2
- Date:
- 06 Jan 2020 23:36:06
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Gaia DR2 Source Catalogue contains positions and brightnesses for 1.693 billion stars, including distances and proper motions for more than 1.3 billion stars. For more details, see the Gaia documentation, particularly the Source Catalogue columns description.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/1767
- Title:
- Gaia spectrophotometric standard stars I.
- Short Name:
- J/MNRAS/426/1767
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe two ground-based observing campaigns aimed at building a grid of approximately 200 spectrophotometric standard stars (SPSS), with an internal =~1% precision and tied to Vega within =~3%, for the absolute flux calibration of data gathered by Gaia, the European Space Agency (ESA) astrometric mission. The criteria for the selection and a list of candidates are presented, together with a description of the survey strategy and the adopted data analysis methods. We also discuss a short list of notable rejected SPSS candidates and difficult cases, based on identification problems, literature discordant data, visual companions and variability. In fact, all candidates are also monitored for constancy (within +/-5mmag, approximately). In particular, we report on a CALSPEC standard, 1740346, that we found to be a {delta} Scuti variable during our short-term monitoring (1-2h) campaign.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/3616
- Title:
- Gaia SPSS variability monitoring
- Short Name:
- J/MNRAS/462/3616
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the short-term constancy monitoring of candidate Gaia Spectrophotometric Standard Stars (SPSS). We obtained time series of typically 1.24 hour - with sampling periods from 1-3 min to a few hours, depending on the case - to monitor the constancy of our candidate SPSS down to 10mmag, as required for the calibration of Gaia photometric data. We monitored 162 out of a total of 212 SPSS candidates. The observing campaign started in 2006 and finished in 2015, using 143 observing nights on nine different instruments covering both hemispheres. Using differential photometry techniques, we built light curves with a typical precision of 4 mmag, depending on the data quality. As a result of our constancy assessment, 150 SPSS candidates were validated against short term variability, and only 12 were rejected because of variability including some widely used flux standards such as BD+174708, SA 105-448, 1740346, and HD 37725.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/53.439
- Title:
- Gaia stars with GALEX NUV excess
- Short Name:
- J/other/RMxAA/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate parallaxes from Gaia DR1 (TGAS) are combined with GALEX visual Nuv magnitudes to produce absolute MNUV magnitudes and an ultraviolet HR diagram for a large sample of astrometric stars. A functional fit is derived of the lower envelope main sequence of the nearest 1403 stars (distance <40pc), which should be reddening-free. Using this empirical fit, 50 nearby stars are selected with significant Nuv excess. These are predominantly late K and early M dwarfs, often associated with X-ray sources, and showing other manifestations of magnetic activity. The sample may include systems with hidden white dwarfs, stars younger than the Pleiades, or, most likely, tight interacting binaries of the BY Dra-type. A separate collection of 40 stars with precise trigonometric parallaxes and Nuv-G colors bluer than 2mag is presented. It includes several known novae, white dwarfs, and binaries with hot subdwarf (sdOB) components, but most remain unexplored.