- ID:
- ivo://CDS.VizieR/J/AJ/160/284
- Title:
- 2590 binary stars in Hipparcos and Gaia DR2
- Short Name:
- J/AJ/160/284
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- The Hipparcos catalog and its Double and Multiple System Annex (DMSA) lists 4099 components with individual proper motions and coordinates on the epoch 1991.25. Many of these long-period binary stars are also present in Gaia Data Release 2 (DR2). Using the available relative positions and proper motions separated by 24.25yr, the equations of relative orbital motion can be solved for the two epoch eccentric anomalies, orbital period, and eccentricity. This method employs elimination of the linear Thiele-Innes unknowns and nonlinear optimization of the remaining condition equations. The quality of these solutions is compromised by the insufficient condition and modest precision of the Hipparcos astrometric data, as revealed by Monte Carlo simulations with artificially perturbed data points. The presence of multiple systems and optical pairs can also perturb the results. Limited experiments with artificial data indicate that useful estimates can be obtained with a 25yr epoch difference for wide binaries with orbital periods up to ~500yr. The prospects of this method dramatically improve with the proposed next-generation space astrometry missions such as Gaia-NIR and Theia, especially when additional conditions are included from astrometric or spectroscopic measurements. An ancillary catalog of cross-identification and astrometric information for 1295 double-star pairs cross-matched in Gaia DR2 and Hipparcos is also published.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/159/15
- Title:
- Binary stars in Upper Scorpius
- Short Name:
- J/AJ/159/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To address the statistics of binary stars in the 8 Myr old Upper Scorpius (USco) star formation region, we conducted a speckle interferometric survey of 614 association members more massive than 0.4 M_{sun}_ (spectral types earlier than M3V) based on the list of Luhman et al. (2018, J/AJ/156/271). We resolved 187 pairs, 55 of which are new discoveries. Also using the published data and the Gaia DR2 (Cat. I/345), a catalog of 250 physical binaries was produced. We carefully estimated detection limits for each target and studied binary statistics in the separation range from 0.06" to 20" (9-2800 au), as well as clustering at larger separations. The frequency of companions with mass ratios q>0.3 in this separation range is 0.33+/-0.04 and 0.35+/-0.04 for early M- and solar-type stars, respectively, larger by 1.62+/-0.22 and 1.39+/-0.18 times compared to field stars of similar masses. The excess is produced mostly by pairs closer than 100 au. At separations from 100 to 10^4^ au, the separation distribution and companion fraction resemble those of solar-type stars in the field. However, unlike in the field, we see a relative deficit of equal-mass binaries at separations of ~500 au, compared to smaller and larger separations. The distribution of q depends on the separation, with a preference of larger q and a larger fraction of twins with q>0.95 at smaller separations. The binary population of USco differs from binaries in the field in several ways and suggests that binary statistics is not universal.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/43
- Title:
- Binary stars parameters from LAMOST & Kepler obs.
- Short Name:
- J/ApJS/244/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The parameter distribution of binaries is a fundamental knowledge of the stellar systems. A statistical study on the binary stars is carried out based on the LAMOST spectral and Kepler photometric database. We presented a catalog of 1320 binary stars with plentiful parameters, including period, binary subtype, atmosphere parameters (Teff, [Fe/H], and logg), and the physical properties, such as mass, radius, and age, for the primary component stars. Based on this catalog, the unbiased distribution, rather than the observed distribution, was obtained after the correction of selection biases by the Monte Carlo method considering comprehensive affecting factors. For the first time, the orbital eccentricity distribution of the detached binaries is presented. The distribution differences between the three subtypes of binaries (detached, semidetached, and contact) are demonstrated, which can be explained by the generally accepted evolutional scenarios. Many characteristics of the binary stars, such as huge mass transfer on semidetached binaries, period cutoff on contact binaries, period-temperature relationship of contact binaries, and the evolved binaries, are reviewed by the new database. This work supports a common evolutionary scenario for all subtypes of binary stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/794/35
- Title:
- Binary white dwarfs atmospheric parameters
- Short Name:
- J/ApJ/794/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed spectroscopic analysis of 61 low-mass white dwarfs and provide precise atmospheric parameters, masses, and updated binary system parameters based on our new model atmosphere grids and the most recent evolutionary model calculations. For the first time, we measure systematic abundances of He, Ca, and Mg for metal-rich, extremely low mass white dwarfs and examine the distribution of these abundances as a function of effective temperature and mass. Based on our preliminary results, we discuss the possibility that shell flashes may be responsible for the presence of the observed He and metals. We compare stellar radii derived from our spectroscopic analysis to model-independent measurements and find good agreement except for white dwarfs with T_eff_<~10000 K. We also calculate the expected gravitational wave strain for each system and discuss their significance to the eLISA space-borne gravitational wave observatory. Finally, we provide an update on the instability strip of extremely low mass white dwarf pulsators.
- ID:
- ivo://CDS.VizieR/J/MNRAS/366/1230
- Title:
- BI photometry of NGC 1407 and NGC 1400 GCs
- Short Name:
- J/MNRAS/366/1230
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wide-field Keck telescope imaging of the globular cluster (GC) systems around NGC 1407 and 1400 in the Eridanus galaxy cloud. This is complemented by Hubble Space Telescope (HST) images from the Advanced Camera for Surveys of NGC 1407 and Wide Field and Planetary Camera 2 images of NGC 1400.
- ID:
- ivo://CDS.VizieR/J/ApJ/881/L24
- Title:
- Black hole masses of SDSS Seyfert 1 galaxies
- Short Name:
- J/ApJ/881/L24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Narrow-line Seyfert 1 galaxies (NLS1s) are believed to be powered by the accretion of matter onto low-mass black holes (BHs) in spiral host galaxies with BH masses M_BH_~10^6^-10^8^M_{sun}_. However, the broadband spectral energy distribution of the {gamma}-ray-emitting NLS1s are found to be similar to flat-spectrum radio quasars. This challenges our current notion of NLS1s having low M_BH_. To resolve this tension of low M_BH_ values in NLS1s, we fitted the observed optical spectrum of a sample of radio-loud NLS1s (RL-NLS1s), radio-quiet NLS1s (RQ-NLS1s), and radio-quiet broad-line Seyfert 1 galaxies (RQ-BLS1s) of ~500 each with the standard Shakura-Sunyaev accretion disk (AD) model. For RL-NLS1s we found a mean log(M_BH_^AD^/M_{sun}_) of 7.98+/-0.54. For RQ-NLS1s and RQ-BLS1s we found mean log(M_BH_^AD^/M_{sun}_) of 8.00+/-0.43 and 7.90+/-0.57, respectively. While the derived M_BH_^AD^ values of RQ-BLS1s are similar to their virial masses, for NLS1s the derived M_BH_^AD^ values are about an order of magnitude larger than their virial estimates. Our analysis thus indicates that NLS1s have M_BH_ similar to RQ-BLS1s and their available virial M_BH_ values are underestimated, influenced by their observed relatively small emission line widths. Considering Eddington ratio as an estimation of the accretion rate and using M_BH_^AD^, we found the mean accretion rate of our RQ-NLS1s, RL-NLS1s, and RQ-BLS1s as 0.06_-0.05_^+0.16^, 0.05_-0.04_^+0.18^ and 0.05_-0.04_^+0.15^, respectively. Our results therefore suggest that NLS1s have BH masses and accretion rates that are similar to BLS1s.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/4068
- Title:
- BLAGNs and NLS1s characteristics.
- Short Name:
- J/MNRAS/478/4068
- Date:
- 10 Dec 2021 00:54:07
- Publisher:
- CDS
- Description:
- investigated narrow-line Seyfert 1 galaxies (NLS1s) at optical, mid-infrared (MIR), and X-ray wavelengths, comparing them to the broad-line active galactic nuclei (BLAGNs). We found that black hole mass, coronal line luminosities, X-ray hardness ratio and X-ray, and optical and MIR luminosities are higher for the BLAGNs than for NLS1s, while policyclic aromatic hydrocarbon (PAH) contribution and the accretion rates are higher for NLS1s. Furthermore, we found some trends among spectral parameters that NLS1s have and BLAGNs do not have. The evolution of FWHM(H{beta}) with the luminosities of MIR and coronal lines, continuum luminosities, PAH contribution, H{beta} broad line luminosity, FWHM[OIII], and EW(H{beta}NLR) are important trends found for NLS1s. That may contribute to the insight that NLS1s are developing AGNs, growing their black holes, while their luminosities and FWHM(H{beta}) consequently grow, and that BLAGNs are mature, larger objects of slower and/or different evolution. Black hole mass is related to PAH contribution only for NLS1s, which may suggest that PAHs are more efficiently destroyed in NLS1s.
- ID:
- ivo://CDS.VizieR/J/ApJS/216/20
- Title:
- Blanco Cosmology Survey (BCS) new reduction
- Short Name:
- J/ApJS/216/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Blanco Cosmology Survey is a four-band (griz) optical-imaging survey of ~80deg^2^ of the southern sky. The survey consists of two fields centered approximately at (RA,DE)=(23h,-55{deg}) and (5h30m,-53{deg}) with imaging sufficient for the detection of L_*_ galaxies at redshift z<=1. In this paper, we present our reduction of the survey data and describe a new technique for the separation of stars and galaxies. We search the calibrated source catalogs for galaxy clusters at z<=0.75 by identifying spatial over-densities of red-sequence galaxies and report the coordinates, redshifts, and optical richnesses, {lambda}, for 764 galaxy clusters at z<=0.75. This sample, >85% of which are new discoveries, has a median redshift of z=0.52 and median richness {lambda}(0.4L_*_)=16.4.
- ID:
- ivo://CDS.VizieR/J/ApJ/742/48
- Title:
- Blanco survey of the lens BCS J2352-5452
- Short Name:
- J/ApJ/742/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the serendipitous discovery in the Blanco Cosmology Survey (BCS) imaging data of a z=0.9057 galaxy that is being strongly lensed by a massive galaxy cluster at a redshift of z=0.3838. The lens (BCS J2352-5452) was discovered while examining i- and z-band images being acquired in 2006 October during a BCS observing run. Follow-up spectroscopic observations with the Gemini Multi-Object Spectrograph instrument on the Gemini-South 8m telescope confirmed the lensing nature of this system. Using weak-plus-strong lensing, velocity dispersion, cluster richness N_200_, and fitting to a Navarro-Frenk-White (NFW) cluster mass density profile, we have made three independent estimates of the mass M_200_ which are all very consistent with each other. The combination of the results from the three methods gives M_200_=(5.1+/-1.3)x10^14^M_{sun}_, which is fully consistent with the individual measurements. The final NFW concentration c_200_ from the combined fit is c_200_=5.4^+1.4^_-1.1_. We have compared our measurements of M_200_ and c_200_ with predictions for (1) clusters from {Lambda}CDM simulations, (2) lensing-selected clusters from simulations, and (3) a real sample of cluster lenses.
- ID:
- ivo://CDS.VizieR/J/ApJ/867/131
- Title:
- Blazar candidates behind the Magellanic Clouds
- Short Name:
- J/ApJ/867/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the identification of blazar candidates behind the Magellanic Clouds. The objects were selected from the Magellanic Quasars Survey (MQS), which targeted the entire Large Magellanic Cloud (LMC) and 70% of the Small Magellanic Cloud (SMC). Among the 758 MQS quasars and 898 of the unidentified (featureless spectra) objects, we identified a sample of 44 blazar candidates, including 27 flat-spectrum radio quasars and 17 BL Lacertae objects, respectively. All the blazar candidates from our sample were identified with respect to their radio, optical, and midinfrared properties. The newly selected blazar candidates possess the long-term, multicolor photometric data from the Optical Gravitational Lensing Experiment, multicolor midinfrared observations, and archival radio data for one frequency at least. In addition, for nine of them, the radio polarization data are available. With such data, these objects can be used to study the physics behind the blazar variability detected in the optical and midinfrared bands, as a tool to investigate magnetic field geometry of the LMC and SMC, and as an exemplary sample of point-like sources most likely detectable in the {gamma}-ray range with the newly emerging Cherenkov Telescope Array.
