- ID:
- ivo://CDS.VizieR/J/ApJS/127/79
- Title:
- BATSE occultation catalog of Gamma-Ray sources
- Short Name:
- J/ApJS/127/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the powerful Earth-occultation technique, long-term, nearly continuous monitoring of the entire low-energy gamma-ray sky is now possible with the advent of BATSE, the Burst and Transient Source Experiment on board the Compton Gamma Ray Observatory (CGRO). In this paper, we present a catalog of 34 moderately strong gamma-ray sources measured by BATSE. It consists of 0.03 - 1.8 MeV photon spectra averaged over weeks and months, and light curves of the 35 - 200 keV flux, with 1 day resolution, covering the first three phases of the CGRO mission (1991 May through 1994 October). This database contains a complete record of {~}1200 daily source count rates in 14 energy channels along with the corresponding Poisson and systematic errors.
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- ID:
- ivo://CDS.VizieR/J/ApJ/855/101
- Title:
- BATSE TTE GRB pulse catalog
- Short Name:
- J/ApJ/855/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze pulse properties of short gamma-ray bursts (GRBs) from a new catalog containing 434 pulses from 387 BATSE time-tagged event (TTE) GRBs. Short GRB pulses exhibit correlated properties of duration, fluence, hardness, and amplitude, and they evolve hard to soft while undergoing similar triple- peaked light curves similar to those found in long/intermediate bursts. We classify pulse light curves using their temporal complexities, demonstrating that short GRB pulses exhibit a range of complexities from smooth to highly variable. Most of the bright, hard, chaotic emission seen in complex pulses seems to represent a separate highly variable emission component. Unlike long/intermediate bursts, as many as 90% of short GRBs are single-pulsed. However, emission in short multipulsed bursts is coupled such that the first pulse's duration is a predictor of both the interpulse separation and subsequent pulse durations. These results strongly support the idea that external shocks produce the prompt emission seen in short GRBs. The similarities between the triple-peaked structures and spectral evolution of long, short, and intermediate GRBs then suggests that external shocks are responsible for the prompt emission observed in all GRB classes. In addition to these findings, we identify a new type of gamma-ray transient in which peak amplitudes occur at the end of the burst rather than at earlier times. Some of these "crescendo" bursts are preceded by rapid-fire "staccato" pulses, whereas the remaining are preceded by a variable episode that could be unresolved staccato pulses.
1693. BAT X-ray survey. I.
- ID:
- ivo://CDS.VizieR/J/ApJ/678/102
- Title:
- BAT X-ray survey. I.
- Short Name:
- J/ApJ/678/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We applied the maximum likelihood (ML) method, as an image reconstruction algorithm, to the BAT (Burst Alert Telescope) X-Ray Survey (BXS). This method was specifically designed to preserve the full statistical information in the data and to avoid mosaicking of many exposures with different pointing directions, thus reducing systematic errors when co-adding images. We reconstructed, in the 14-170keV energy band, the image of a 90x90deg^2^ sky region, centered on (RA, DE)=(105{deg}, -25{deg}), which BAT surveyed with an exposure time of ~1Ms (in 2005 November). The best sensitivity in our image is ~0.85mCrab or 2.0x10^-11^ergs/cm^2^. We detect 49 hard X-ray sources above the 4.5{sigma} level; of these, only 12 were previously known as hard X-ray sources (>15keV). Swift XRT observations allowed us to firmly identify the counterparts for 15 objects, while 2 objects have Einstein IPC counterparts (Harris et al., 1990, in Imaging X-Ray Astronomy. A Decade of Achievements, ed. M. Elvis (Cambridge: Cambridge Univ. Press), 309); in addition to those, we found a likely counterpart for 13 objects by correlating our sample with the ROSAT All-Sky Survey Bright Source Catalog (Voges et al., 1999, Cat. <IX/10>). Seven objects remain unidentified.
1694. BAT X-ray Survey - III
- ID:
- ivo://CDS.VizieR/J/ApJ/673/96
- Title:
- BAT X-ray Survey - III
- Short Name:
- J/ApJ/673/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this concluding part of the series of three papers dedicated to the Swift BAT hard X-ray survey (BXS), we focus on the X-ray spectral analysis and statistical properties of the source sample. Using a dedicated method to extract time-averaged spectra of BAT sources, we show that Galactic sources have, generally, softer spectra than extragalactic objects and that Seyfert 2 galaxies are harder than Seyfert 1's.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A10
- Title:
- Ba V, Ba VI, and Ba VII oscillator strengths
- Short Name:
- J/A+A/566/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the spectral analysis of high-resolution and high-signal-to-noise (S/N) spectra of hot stars, state-of-the-art non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that is used for their calculation. Reliable Ba V-VII oscillator strengths are used to identify Ba lines in the spectra of the DA-type white dwarf G191-B2B and the DO-type white dwarf RE 0503-289 and to determine their photospheric Ba abundances. We newly calculated Ba V-VII oscillator strengths to consider their radiative and collisional bound-bound transitions in detail in our NLTE stellar-atmosphere models for the analysis of Ba lines exhibited in high-resolution and high-S/N UV observations of G191-B2B and RE 0503-289.
- ID:
- ivo://nasa.heasarc/baxgalclus
- Title:
- BAX X-Ray Galaxy Clusters and Groups Catalog
- Short Name:
- BAXGalClus
- Date:
- 18 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the BAX X-Ray Galaxy Clusters and Groups Catalog. BAX (`Base de Donnees Amas de Galaxies X': see <a href="http://bax.ast.obs-mip.fr/">http://bax.ast.obs-mip.fr/</a> for more details) is a multi-wavelength database dedicated to X-ray clusters and groups of galaxies which allows detailed information retrieval. BAX is designed to support astronomical research by providing access to published measurements of the main physical quantities and to the related bibliographic references: basic data stored in the database are cluster/group identifiers, equatorial coordinates, redshift, flux, X-ray luminosity (in the ROSAT band) and temperature, and (in the online version at <a href="http://bax.ast.obs-mip.fr/">http://bax.ast.obs-mip.fr/</a>) links to additional linked parameters (in X-rays, such as spatial profile parameters, as well as SZ parameters of the hot gas, lensing measurements, and data at other wavelengths, such as the optical and radio bands). The clusters and groups in the online BAX database can be queried by the basic parameters as well as the linked parameters or combinations of these. The authors expect BAX to become an important tool for the astronomical community. BAX will optimize various aspects of the scientific analysis of X-ray clusters and groups of galaxies, from proposal planning to data collection, interpretation and publication, from both ground based facilities like MEGACAM (CFHT), VIRMOS (VLT) and from space missions like XMM-Newton, Chandra and Planck. This table was created by the HEASARC in October 2004 based on CDS table B/bax/bax.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/ApJ/898/27
- Title:
- Bayesian Ages For Field LowEr-mass Stars
- Short Name:
- J/ApJ/898/27
- Date:
- 07 Dec 2021 15:25:13
- Publisher:
- CDS
- Description:
- Age is a fundamental parameter of stars, yet in many cases, ages of individual stars are presented without robust estimates of the uncertainty. We have developed a Bayesian framework, BAFFLES, to produce the age posterior for a star from its calcium emission strength (log(R_HK_^'^)) or lithium abundance (Li EW) and B-V color. We empirically determine the likelihood functions for calcium and lithium as functions of age from literature measurements of stars in benchmark clusters with well-determined ages. We use a uniform prior on age, which reflects a uniform star formation rate. The age posteriors we derive for several test cases are consistent with literature ages found from other methods. BAFFLES represents a robust method to determine the age posterior probability distribution for any field star with 0.45<=B-V0.9 and a measurement of R_HK_^'^ and/or 0.35<=B-V<=1.9 and measured Li EW. We compile colors, R_HK_^'^, and Li EW from over 2630 nearby field stars from the literature, and present the derived BAFFLES age posterior for each star.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2717
- Title:
- Bayesian analysis of resolved stellar spectra
- Short Name:
- J/MNRAS/448/2717
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce a Bayesian method for fitting faint, resolved stellar spectra in order to obtain simultaneous estimates of redshift and stellar-atmospheric parameters. We apply the method to thousands of spectra - covering 5160-5280{AA} at resolution R~20000 - that we have acquired with the MMT/Hectochelle fibre spectrograph for red giant and horizontal branch candidates along the line of sight to the Milky Way's dwarf spheroidal satellite in Draco. The observed stars subtend an area of ~4deg^2^, extending ~3 times beyond Draco's nominal 'tidal' radius. For each spectrum, we tabulate the first four moments - central value, variance, skewness and kurtosis - of posterior probability distribution functions representing estimates of the following physical parameters: line-of-sight velocity (v_los_), effective temperature (T_eff_), surface gravity (logg) and metallicity ([Fe/H]). After rejecting low-quality measurements, we retain a new sample consisting of 2813 independent observations of 1565 unique stars, including 1879 observations for 631 stars with (as many as 13) repeat observations. Parameter estimates have median random errors of v_los_=0.88km/s, T_eff_=162K, {sigma}logg=0.37dex and {sigma}[Fe/H]=0.20dex. Our estimates of physical parameters distinguish ~470 likely Draco members from interlopers in the Galactic foreground.
- ID:
- ivo://CDS.VizieR/J/ApJ/758/11
- Title:
- Bayesian distances to M31 satellites
- Short Name:
- J/ApJ/758/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In "A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part I)," a new technique was introduced for obtaining distances using the tip of the red giant branch (TRGB) standard candle. Here we describe a useful complement to the technique with the potential to further reduce the uncertainty in our distance measurements by incorporating a matched-filter weighting scheme into the model likelihood calculations. In this scheme, stars are weighted according to their probability of being true object members. We then re-test our modified algorithm using random-realization artificial data to verify the validity of the generated posterior probability distributions (PPDs) and proceed to apply the algorithm to the satellite system of M31, culminating in a three-dimensional view of the system. Further to the distributions thus obtained, we apply a satellite-specific prior on the satellite distances to weight the resulting distance posterior distributions, based on the halo density profile. Thus in a single publication, using a single method, a comprehensive coverage of the distances to the companion galaxies of M31 is presented, encompassing the dwarf spheroidals Andromedas I-III, V, IX-XXVII, and XXX along with NGC 147, NGC 185, M33, and M31 itself. Of these, the distances to Andromedas XXIV-XXVII and Andromeda XXX have never before been derived using the TRGB. Object distances are determined from high-resolution tip magnitude posterior distributions generated using the Markov Chain Monte Carlo technique and associated sampling of these distributions to take into account uncertainties in foreground extinction and the absolute magnitude of the TRGB as well as photometric errors. The distance PPDs obtained for each object both with and without the aforementioned prior are made available to the reader in tabular form. The large object coverage takes advantage of the unprecedented size and photometric depth of the Pan-Andromeda Archaeological Survey.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A81
- Title:
- Bayesian group finder applied to the 2MRS data
- Short Name:
- J/A+A/618/A81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We propose a probabilistic galaxy group detection algorithm based on marked point processes with interactions. The pattern of galaxy groups in a catalogue is seen as a random set of interacting objects. The positions and the interactions of these objects are governed by a probability density. The parameters of the probability density are chosen using a priori knowledge. The estimator of the unknown cluster pattern is given by the configuration of objects maximising the proposed probability density. Adopting the Bayesian framework, the proposed probability density is maximised using a simulated annealing (SA) algorithm. At fixed temperature, the SA algorithm is a Monte Carlo sampler of the probability density. Hence, the method provides "for free" additional information such as the probabilities that a point or two points in the observation domain belong to the cluster pattern, respectively. These supplementary tools allow the construction of tests and techniques to validate and to refine the detection result. To test the feasibility of the proposed methodology, we applied it to the well-studied 2MASS Redshift Survey (2MRS) data set. Compared to previously published Friends-of-Friends (FoF) group finders, the proposed Bayesian group finder gives overall similar results. However, for specific applications, like the reconstruction of the local Universe, the details of the grouping algorithms are important.
