- ID:
- ivo://nasa.heasarc/saxhellasr
- Title:
- BeppoSAX High-Energy Large Area Survey (HELLAS) Radio Source Catalog
- Short Name:
- SAXHELLASR
- Date:
- 14 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains 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 (Fiore et al. 2001, MNRAS, 327, 771). The authors found 53 X-ray/radio likely associations, corresponding to about one-third of the X-ray sample. Using the two-point spectral index alpha<sub>ro</sub> = 0.35 they divided all the HELLAS X-ray sources into radio-quiet and radio-loud. They 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<sub>5-10keV</sub> >~ 10<sup>44</sup> erg/s, while all the identified Type 2 AGNs and emission-line galaxies are radio-quiet objects with L<sub>5-10keV</sub> <~ 10<sup>44</sup> erg/s. The 20 HELLAS sources with Declinations south of -40<sup>o</sup> were observed with the ATCA, while the 127 sources with more northerly Declinations were observed with the VLA. For these latter sources a complete covering at 20 cm down to the 5-sigma flux limit of 2.5 mJy is already available with the NRAO/VLA Sky Survey (NVSS) while the FIRST survey (Faint Images of the Radio Sky at Twenty centimeters) is available only for 27 HELLAS sources (5-sigma limit of ~ 1 mJy).In order to obtain information also on the radio spectral properties of the HELLAS sources the authors adopted the following strategy. All the 147 HELLAS sources were observed at 6 cm down to a 1 -sigma flux limit of ~ 0.10 - 0.25 mJy. For the 20 HELLAS sources observed with the ATCA, they took advantage of the fact that the 6 and 3 cm receivers of the ATCA share a common feed-horn and they observed simultaneously also at 3 cm, obtaining a 3-cm flux limit of ~ 0.22 mJy (1-sigma level). Starting from the radio position of the 53 X-ray/radio associations, the authors searched for optical counterparts within 5 arcseconds from the radio position using the optical positions of the 61 HELLAS sources identified by La Franca et al. (2002, ApJ, 570, 100 = LF02), the USNO-A2.0 1 optical catalog, the APM 2 optical catalog and the NASA Extragalactic Database (NED). 24 X-ray/radio associations have been identified with sources in LF02 (10 Type 1 AGN, 4 Type 2 AGN, 2 BL Lacs, 3 Clusters, 4 ELGs and 1 Radio galaxy), 1 has been identified with a z = 0.708 Radio galaxy in the Lockman Hole using NED (see Table 2 source 116 in Lehmann et al. 2000, A&A, 354, 35 for a description of this source), 13 have an optical (R-band) identification in the USNO and/or APM catalogue while 15 X-ray/radio associations do not have an optical identification brighter than R=20. This table was created by the HEASARC in July 2014 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/342/575">CDS Catalog J/MNRAS/342/575</a> file table1.dat. There was a minor update to the HEASARC's implementation in June 2022 to make the two probability parameters into unitless quantities for improved clarity. This is a service provided by NASA HEASARC .
Number of results to display per page
Search Results
- ID:
- ivo://nasa.heasarc/saxhellas
- Title:
- BeppoSAX High-Energy Large Area Survey (HELLAS) X-Ray Source Catalog
- Short Name:
- SAXHELLAS
- Date:
- 14 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The BeppoSAX High Energy Large Area Survey (HELLAS) has surveyed about 85 deg<sup>2</sup> of sky in the 4.5 - 10 keV band down to a flux of 4 - 5 x 10<sup>-14</sup> erg/cm<sup>2</sup>/s using 142 high Galactic latitude (|b| > 20<sup>o</sup>) observations made by the BeppoSAX Medium Energy Concentrator Spectrometer (MECS). The source surface density of 16.9 +/- 6.4 deg<sup>2</sup> at the survey limit corresponds to a resolved fraction of the 5 - 10 keV 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<sub>E</sub> = 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. There is no overlap among the 142 fields used and, wherever possible, multiple observations of the same field have been merged in one single pointing to increase the sensitivity. Fields were selected among public data (such as that of March 1999) and the authors' proprietary data. Fields centered on bright extended sources and bright Galactic sources were excluded from the survey, as were fields close to the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC) and M 33. Most of the fields have exposures between 30 and 100 ks, and 20 fields have an exposure higher than 80 ks (see Fig. 1 of reference paper). Sources were detected in images accumulated between 4.5 and 10 keV. Source count rates in four bands (1.3 - 10 keV, total or T; 1.3 - 2.5 keV, low band or L; 2.5 - 4.5 keV, middle band or M; 4.5 - 10 keV, high band or H) were extracted and corrected for the energy-dependent vignetting and for the MECS PSF. The count rates were converted to fluxes using a conversion factor of 7.8 x 10<sup>-11</sup> erg cm<sup>-2</sup> s<sup>-1</sup> (5 - 10 keV flux) per one '3 ECS count' (4.5 - 10 keV) appropriate for a power-law spectrum with alpha<sub>E</sub> = 0:6. The factor is not strongly sensitive to the spectral shape, owing to the narrow band: thus, for alpha<sub>E</sub> = 0.4 and 0.8 it is 8.1 and 7.6 x 10<sup>-11</sup> erg cm<sup>-2</sup> s<sup>-1</sup>, respectively. A conversion factor of 9:9 x 10<sup>-11</sup> erg cm<sup>-2</sup> s<sup>-1</sup> per one '3 MECS count' has been used for sources under the 550 micron (µm) beryllium strongback supporting the MECS window to account for the reduced detector sensitivity. This table was created by the HEASARC in July 2014 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/327/771">CDS Catalog J/MNRAS/327/771</a> file table2.dat. This is a service provided by NASA HEASARC .
1733. BeppoSAX 2-10 keV Survey
- ID:
- ivo://nasa.heasarc/sax2to10
- Title:
- BeppoSAX 2-10 keV Survey
- Short Name:
- SAX2-10keV
- Date:
- 14 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog presents the results of a 2 - 10 keV BeppoSAX survey based on 140 high galactic latitude Medium Energy Concentrator Spectrometers (MECS) fields, 12 of which are deep exposures of ``blank'' parts of the sky. The limiting sensitivity is 5 x 10<sup>-14</sup> erg/cm<sup>2</sup>/s (or mW/m<sup>2</sup>) where about 25% of the Cosmic X-ray Background (CXB) is resolved into discrete sources. The log N - log S function, built with a statistically complete sample of 177 sources, is steep and in good agreement with the counts derived from ASCA surveys. This database was created by the HEASARC in December 2000 based upon <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/362/799">CDS Catalog J/A+A/362/799</a>. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/saxnfilog
- Title:
- BeppoSAX NFI Archive and Observation Log
- Short Name:
- SAXNFI
- Date:
- 14 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The SAXNFILOG database contains the SAX Narrow Field Instruments (NFI) approved pointings, but it also served as an observations log. It includes data taken during AO1, AO2, AO3, A04 and AO5 cycles and the Science Verification Phase (SVP). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/saxwfclog
- Title:
- BeppoSAX WFC Observation Log
- Short Name:
- SAXWFC
- Date:
- 14 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The SAXWFCLOG database contains the SAX WFCs observations log for the AO cycles and the Science Verification Phase (SVP). The two WFCs are located at 90 degrees from the NFI and set 180 degrees apart. The field of view is 40 deg X 40 deg and the coordinates given in this databases are the pointing positions. The database is updated regularly to include the most recent timeline, and updates are provided by the SAX-Science Data Center in Rome. This is a service provided by NASA HEASARC .
- 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://nasa.heasarc/saxwfccat2
- Title:
- BeppoSAX Wide Field Camera Unbiased X-Ray Source Catalog
- Short Name:
- SAXWFCCAT2
- Date:
- 14 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- 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 the analyses performed on BeppoSAX WFC data concentrated on the detection of transient sources, the authors have now applied the same techniques developed for the INTEGRAL/IBIS survey so as to produce a similar analysis of the BeppoSAX WFC data. This work represents the first unbiased source list compilation produced from the overall WFC data set which is optimized for faint persistent source detection. This approach recovered 182 more sources compared to the previous WFC catalog reported in Verrecchia et al. (2007, A&A, 472, 705; the HEASARC SAXWFCCAT table). The present catalog contains 404 sources detected between 3 and 17 keV, 10 of which are yet to be seen by the new generation of telescopes. This table was created by the HEASARC in July 2011 based on an electronic version of Table 3 from the reference paper which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/saxwfccat
- Title:
- BeppoSAX Wide Field Camera X-Ray Source Catalog
- Short Name:
- SAXWFCCAT
- Date:
- 14 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the catalog 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, i.e., between April 1996 and April 2002. The BeppoSAX WFCs were coded mask instruments sensitive in the 2 - 28 keV energy band with a 40 x 40 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. The WFCs observed thus the entire sky several times with a typical sensitivity of 2 to 10 mCrab. 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 catalog includes 253 distinct sources, obtained from a total sample of 8253 WFC detections. This table was created by the HEASARC in November 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/472/705">CDS catalog J/A+A/472/705</a> file table3.dat. This is a service provided by NASA HEASARC .
- 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.
