- 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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/161/160
- Title:
- BINOCS: NEWFIRM & IRAC IR photometry of clusters
- Short Name:
- J/AJ/161/160
- Date:
- 18 Jan 2022
- Publisher:
- CDS
- Description:
- We introduce a new binary detection technique, Binary INformation from Open Clusters using SEDs (binocs), which we show is able to determine reliable stellar multiplicity and masses over a much larger mass range than current approaches. This new technique determines accurate component masses of binary and single systems of the open clusters' main sequence by comparing observed magnitudes from multiple photometric filters to synthetic star spectral energy distributions (SEDs), allowing us to systematically probe the binary population for low-mass stars in clusters for eight well-studied open clusters. We provide new deep, infrared photometric catalogs (1.2-8.0 {mu}m) for the key open clusters NGC 1960 (M36), NGC 2099 (M37), NGC 2420, and NGC 2682 (M67), using observations from NOAO/NEWFIRM and Spitzer/IRAC. Using these deep multiwavelength catalogs, the binocs method is applied to these clusters to determine accurate component masses for unresolved cluster binaries. We explore binary fractions as a function of cluster age, Galactic location, and metallicity.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/1186
- Title:
- BI photometry of bulgeless galaxies
- Short Name:
- J/MNRAS/435/1186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the magnitude and size evolution of bulgeless (discs with no-bulge or pseudo-bulge) galaxies up to z~0.9 in rest-frame B band. Their evolution is compared to that of normal-discs (or discs with classical bulge). The study is done for luminous sources (M_B_<=-20) in two equal-volume redshift bins (0.4<=z<0.77 and 0.77<=z<1.0) and a local range (0.02<=z<0.05). The mean surface-brightness, mu_B_, from z_mean_=0.89 to z_mean_=0.04, shows a dimming of 0.79mag/arcsec2 for bulgeless galaxies and 1.16mag/arcsec2 for normal-discs. The characteristic magnitude, M_B_, shows an increase of 0.55mag for bulgeless galaxies and 0.95mag for normal-discs. Both dimming and faintness observed since z~0.9 is more pronounced for the normal-discs by ~0.4mag. The size distribution is log-normal and both bulgeless and normal-discs show a slight increase in the mean value, <{Delta}log(R_e_)>~0.11, from z_mean_=0.89 to z_mean_=0.04. The proportion of bulgeless galaxies in the full disc sample undergoes a considerable decline with decrease in redshift. This along with the larger dimming and faintness seen for normal-discs suggests that some fraction of the bulgeless sources switch to the normal-disc morphology with time. To ascertain the validity of studying morphology in the optical, the properties of the galaxies observed in both rest-frame B and I band are compared. The common sample is more luminous in the I band but the sizes are larger in the B band for more than 74 percent of the sources. The variation in the Sersic-index values of the galaxies in the two rest-bands is minor enough to have any effect on the morphological classification.
- 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://jvo/isas/darts/bsgc
- Title:
- Bisei Space Guard Center images
- Short Name:
- BSGC_IMAGE
- Date:
- 05 Feb 2025 04:12:46
- Publisher:
- JVO
- Description:
- Bisei Space Guard Center (BSGC) is an optical telescope facility in Japan, operated by JAXA. It tracks near-Earth asteroids and space debris. DARTS provides data observed by a 25 cm telescope from 2000 to 2002 and data observed by a 1 m telescope from 2007 to 2017.
- ID:
- ivo://CDS.VizieR/J/MNRAS/357/1267
- Title:
- b_j_ur photometry and redshifts of QSOs
- Short Name:
- J/MNRAS/357/1267
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The quasar sample selected by cross-correlating the Faint Images of the Radio Sky at Twenty cm (FIRST, <VIII/71>) survey and the 2-degree Field Quasar Redshift Survey (2QZ, <VII/223>) allows us to explore, for the first time, the faint end of the radio and optical luminosity functions up to z=~2.2. We find indications (~3{sigma}) of a negative evolution for these faint sources at z>~1.8, both in radio and optical bands. This corresponds to a decrement in the space density of faint quasars of approximately a factor 2 at z=2.2 and confirms the presence of a differential evolution for the population of radio-active quasars. The faint end of both luminosity functions flattens and the comparison with the (optical) number density of the whole quasar population supports a dependence of the fraction of radio-detected quasars on the optical luminosity. A progressive decrease in the fraction of quasars in the whole radio source population can be consistently accounted for within the receding torus scenario. The population of low-luminosity quasars, which the FIRST-2dF detects, appears to depart from the classical scheme for radio-loud quasars.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A61
- Title:
- BlackCAT, stellar-mass BH in X-ray trans.
- Short Name:
- J/A+A/587/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- During the last ~50 years, the population of black hole candidates in X-ray binaries has increased considerably, with 59 Galactic objects being detected in transient low-mass X-ray binaries, as well as a few in persistent systems (including ~5 extragalactic binaries). We collect near-infrared, optical, and X-ray information spread over hundreds of references to study the population of black holes in X-ray transients as a whole. We present the most updated catalogue of black hole transients. This contains X-ray, optical, and near-infrared observations, together with their astrometric and dynamical properties. The catalogue provides new and useful information in both statistical and observational parameters and provides a thorough and complete overview of the black hole population in the Milky Way. Analysing the distances and spatial distribution of the observed systems, we estimate a total population of ~1300 Galactic black hole transients. This means that we have only discovered less than ~5% of the total Galactic distribution. The complete version of this catalogue will be continuously updated online and in the Virtual Observatory, including finding charts and data in other wavelengths.
- ID:
- ivo://CDS.VizieR/J/MNRAS/447/2059
- Title:
- Black hole binaries quasi-periodic oscillations
- Short Name:
- J/MNRAS/447/2059
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a systematic study of the orbital inclination effects on black hole transients fast time-variability properties. We have considered all the black hole binaries that have been densely monitored by the Rossi X-ray Timing Explorer satellite. We find that the amplitude of low-frequency quasi-periodic oscillations (QPOs) depends on the orbital inclination. Type-C QPOs are stronger for nearly edge-on systems (high inclination), while type-B QPOs are stronger when the accretion disc is closer to face-on (low inclination). Our results also suggest that the noise associated with type-C QPOs is consistent with being stronger for low-inclination sources, while the noise associated with type-B QPOs seems inclination independent. These results are consistent with a geometric origin of the type-C QPOs - for instance arising from relativistic precession of the inner flow within a truncated disc - while the noise would correspond to intrinsic brightness variability from mass accretion rate fluctuations in the accretion flow. The opposite behaviour of type-B QPOs - stronger in low-inclinations sources - supports the hypothesis that type-B QPOs are related to the jet, the power of which is the most obvious measurable parameter expected to be stronger in nearly face-on sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/614/91
- Title:
- Black hole mass and accretion rate of AGNs
- Short Name:
- J/ApJ/614/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using an empirical relation between the broad-line region size and optical continuum luminosity, we estimated the black hole mass and accretion rate for 135 active galactic nuclei (AGNs) with double-peaked broad emission lines in two samples, one from the Sloan Digital Sky Survey (SDSS, Cat. <J/AJ/126/2579>) and the other from a survey of radio-loud broad emission line AGNs (Eracleous & Halpern, 2003, Cat. <J/ApJ/599/886>).
- ID:
- ivo://CDS.VizieR/J/ApJ/641/L21
- Title:
- Black hole mass and velocity dispersion relation
- Short Name:
- J/ApJ/641/L21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine whether active galaxies obey the same relation between black hole mass and stellar velocity dispersion as inactive systems, using the largest published sample of velocity dispersions for active nuclei to date. The combination of 56 original measurements with objects from the literature not only increases the sample from the 15 considered previously to 88 objects but allows us to cover an unprecedented range in both stellar velocity dispersion (30-268km/s) and black hole mass (10^5^-10^8.6^M_{sun}_).
