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- ID:
- ivo://CDS.VizieR/J/MNRAS/431/3608
- Title:
- BeppoSAX/GRBM and Fermi/GBM long GRBs
- Short Name:
- J/MNRAS/431/3608
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From past experiments the average power density spectrum (PDS) of gamma-ray bursts (GRBs) with unknown redshift was found to be modelled from 0.01 to 1Hz with a power law, f^-{alpha}^, with {alpha} broadly consistent with 5/3. Recent analysis of the Swift/Burst Alert Telescope (BAT) catalogue showed analogous results in the 15-150keV band. We carried out the same analysis on the bright GRBs detected by BeppoSAX/Gamma-ray Burst Monitor (GRBM) and Fermi/Gamma-ray Burst Monitor (GBM). The BeppoSAX/GRBM data, in the energy range 40-700keV and with 7.8 and 0.5ms time resolutions, allowed us to explore for the first time the average PDS at very high frequencies (up to 1kHz) and reveal a break around 1-2Hz, previously found in Compton Gamma Ray Observatory/Burst and Transient Source Experiment data. The Fermi/GBM data, in the energy band 8-1000keV, allowed us to explore for the first time the average PDS within a broad energy range. Our results confirm and extend the energy dependence of the PDS slope, according to which harder photons have shallower PDS.
- ID:
- ivo://CDS.VizieR/J/ApJS/180/192
- Title:
- BeppoSAX/GRBM {gamma}-ray Burst Catalog
- Short Name:
- J/ApJS/180/192
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the catalog of Gamma-Ray Bursts (GRBs) detected with the Gamma Ray Burst Monitor aboard the BeppoSAX satellite. It includes 1082 GRBs with 40-700keV fluences in the range from 1.3x10-7 to 4.5x10-4erg/cm^2^, and 40-700keV peak fluxes from 3.7x10-8 to 7.0x10-5erg/cm^2^/s. We report in the catalog some relevant parameters of each GRB.
- ID:
- ivo://CDS.VizieR/J/MNRAS/327/771
- Title:
- BeppoSAX HELLAS survey. II.
- Short Name:
- J/MNRAS/327/771
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The BeppoSAX High Energy Large Area Survey (HELLAS) has surveyed about 85deg^2^ of sky in the 5-10keV band down to a flux of 4-5x10^-14^erg/cm^2^/s. The source surface density of 16.9+/-6.4deg^2^ at the survey limit corresponds to a resolved fraction of the 5-10keV X-ray background (XRB) of the order of 20-30 per cent. Hardness ratio analysis indicates that the spectra of a substantial fraction of the HELLAS sources (at least one-third) are harder than a {alpha}_E_=0.6 power law. This hardness may be caused by large absorbing columns. The hardness ratio analysis also indicates that many HELLAS sources may have a spectrum more complex than a single absorbed power law. A soft component, superimposed on a strongly cut-off power law, is likely to be present in several sources.
- ID:
- ivo://CDS.VizieR/J/A+A/370/900
- Title:
- BeppoSAX HELLAS survey. IV
- Short Name:
- J/A+A/370/900
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive study of the soft X-ray properties of the BeppoSAX High-Energy Large Area Survey (HELLAS) sources. A large fraction (about 2/3) of the hard X-ray selected sources is detected by ROSAT. The soft X-ray colors for many of these objects, along with the 0.5-2keV flux upper limits for those undetected in the ROSAT band, do imply the presence of absorption. The comparison with the ROSAT Deep Survey sources indicates that a larger fraction of absorbed objects among the HELLAS sources is present, in agreement with their hard X-ray selection and the predictions of the X-ray background synthesis models. Another striking result is the presence of a soft (additional) X-ray component in a significant fraction of absorbed objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/570/100
- Title:
- BeppoSAX HELLAS survey. V.
- Short Name:
- J/ApJ/570/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical spectroscopic identifications of hard X-ray (5-10keV) selected sources belonging to the High-Energy Large-Area Survey sample obtained with BeppoSAX down to a 5-10keV flux limit of F(5-10kev)~3x10^-14^erg/cm^2^/s. The sample consists of 118 sources. There are 25 sources that have been identified through correlations with catalogs of known sources. A spectroscopic identification for 49 more has been searched for with the telescope. The results of 13 fields were empty down to R=21. There were 37 sources identified as type 1 active galactic nuclei (AGNs) and nine as type 2 AGNs. The remaining sources are five narrow emission-line galaxies, six clusters, two BL Lac objects, one radio galaxy, and one star.
- ID:
- ivo://CDS.VizieR/J/MNRAS/342/575
- Title:
- BeppoSAX HELLAS survey. VI.
- Short Name:
- J/MNRAS/342/575
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a complete radio follow-up obtained with the VLA and ATCA radio telescopes down to a 6-cm flux limit of about 0.3 mJy (3{sigma}) of all the 147 X-ray sources detected in the BeppoSAX HELLAS survey. We found 53 X-ray/radio likely associations, corresponding to about one-third of the X-ray sample. Using the two-point spectral index {alpha}_ro_=0.35 we divided all the HELLAS X-ray sources into radio-quiet and radio-loud. We have 26 sources classified as radio-loud objects, corresponding to 18 per cent of the HELLAS sample. In agreement with previous results, the identified radio-loud sources are associated mainly with Type 1 active galactic nuclei (AGNs) with L_5-10kev_>~10^44^erg/s, while all the identified Type 2 AGNs and emission-line galaxies are radio-quiet objects with L_5-10kev_<~10^44^erg/s.
- ID:
- ivo://CDS.VizieR/J/ApJS/195/9
- Title:
- BeppoSAX/WFC: source list
- Short Name:
- J/ApJS/195/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- During the operational life of the Italian/Dutch X-ray satellite (1996-2002), BeppoSAX, its two Wide Field Cameras (WFCs) performed observations that covered the full sky at different epochs. Although the majority of analysis performed on BeppoSAX WFC data concentrated on the detection of transient sources, we have now applied the same techniques developed for the INTEGRAL/IBIS survey to produce the same work with the BeppoSAX WFC data. This work represents the first unbiased source list compilation produced from the overall WFC data set optimized for faint persistent source detection. This approach recovered 182 more sources compared to the previous WFC catalog reported in Verrecchia et al. (Cat. J/A+A/472/705). The catalog contains 404 sources detected between 3 and 17keV, 10 of which are yet to be seen by the new generation of telescopes.
- ID:
- ivo://CDS.VizieR/J/A+A/472/705
- Title:
- BeppoSAX WFC X-ray source catalogue (SAXWFC)
- Short Name:
- J/A+A/472/705
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of X-ray sources detected by the two Wide Field Cameras (WFCs) in complete observations on board BeppoSAX during its 6 years of operational lifetime, between April 1996 and April 2002. The BeppoSAX WFCs were coded mask instruments sensitive in the 2-28keV energy band with a 40x40 square degree fields of view, pointing in opposite directions and perpendicularly to the BeppoSAX Narrow Field Instruments (NFI). The WFCs were usually operated simultaneously to NFI observations, each lasting up to several days. WFCs observed thus the entire sky several times with a typical sensitivity of 2 to 10mCrab. A systematic analysis of all WFC observations in the BeppoSAX archive has been carried out using the latest post-mission release of the WFC analysis software and calibrations. The catalogue includes 253 distinct sources, obtained from a total sample of 8253 WFC detections. We describe the basic statistical properties of the sample and present a six-year history of two celestial calibration X-ray sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/429
- Title:
- Berkeley 94 and Berkeley 96 UBVRcIcJHKs
- Short Name:
- J/MNRAS/435/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed multiband UBVRcIcJHKs photometry of two young clusters located at large Galactocentric distances in the direction of the Perseus spiral arm. The obtained distances and colour excesses amount to 3.9+/-0.11kpc, E(B-V)=0.62+/-0.05 for Berkeley 94, and 4.3+/-0.15kpc, E(B-V)=0.58+/-0.06 for Berkeley 96. The respective ages, as measured from the comparison of the upper colour-magnitude diagrams to model isochrones, amount to log10Age(yr)=7.5+/-0.07 and 7.0+/-0.07, respectively. A sequence of optical pre-main-sequence (PMS) members is proposed in both clusters. In addition, samples of objects showing (H-Ks) excess are found. Part of these are suggested to be PMS cluster members of lower mass than the optical candidates. The spatial distribution of these sources, the comparison to Galactic models and to the expected number of contaminating distant red galaxies, and the spectral energy distribution in particular cases support this suggestion. The spatial distributions shown by members in different mass ranges can be interpreted in terms of the results from numerical simulations. According to these, different initial conditions and evolutionary dynamical paths are suggested for the clusters. Berkeley 94 would have formed under supervirial conditions, and followed the so-called warm collapse model in its evolution, whereas Berkeley 96 would have formed with a subvirial structure, and would have evolved following a cold collapse path. Both processes would be able to reproduce the suggested degree of mass segregation and their spatial distribution by mass range. Finally, the mass distributions of the clusters, from the most massive stars down to PMS stars around 1.3M_{sun}_, are calculated. An acceptable general agreement with the Salpeter initial mass function slope is found.
