- 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.
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Search Results
- 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/A+A/561/A8
- Title:
- Binary central stars of SMC PNe
- Short Name:
- J/A+A/561/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Optical Gravitational Lensing Experiment (OGLE), originally designed to search for microlensing events, provides a rich and uniform data set suitable for studying the variability of certain types of objects. We used the OGLE data to study the photometry of central stars of planetary nebulae (PNe) in the Small Magellanic Cloud (SMC). In particular, we searched for close binary central stars with the aim to constrain the binary fraction and period distribution in the SMC. We also searched for PNe mimics and removed them from the PNe sample. We identified 52 counterparts of PNe in the SMC in the I-band images from the OGLE-II and OGLE-III surveys. We analysed the time-series photometry of the PNe. Spectra of the photometric variables were obtained to constrain the nature of the objects or search for additional evidence for binarity. Eight variables were found. Of these, seven objects are PNe mimics, including one symbiotic star candidate. One close binary central star of PN with a period of 1.15 or 2.31 day was discovered. The obtained binary fraction for the SMC PNe and the observational biases are discussed in terms of the OGLE observations.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A119
- Title:
- Black-hole masses of type-1 AGNs
- Short Name:
- J/A+A/549/A119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive masses of the central supermassive black hole (SMBH) and accretion rates for 154 type 1 AGN belonging to a well-defined X-ray-selected sample, the XMM-Newton serendipitous sample (XBS). We used the most recent "single-epoch" relations, based on H{beta] and MgII {lambda}2798{AA} emission lines, to derive the SMBH masses. We then used the bolometric luminosities, computed on the basis of an SED-fitting procedure, to calculate the accretion rates, both absolute and normalized to the Eddington luminosity (Eddington ratio).
- ID:
- ivo://CDS.VizieR/J/ApJ/761/143
- Title:
- Black hole masses of z~1.4 AGNs from SXDS
- Short Name:
- J/ApJ/761/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to investigate the growth of supermassive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line active galactic nuclei (AGNs) at z~1.4 in the Subaru XMM-Newton Deep Survey (SXDS) field. A significant part of the accretion growth of SMBHs is thought to take place in this redshift range. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad MgII line and 3000{AA} monochromatic luminosity. We supplement the MgII FWHM values with the H{alpha} FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMFs and ERDFs are calculated using the V_max_ method. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMFs and ERDFs by applying the maximum likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local universe, then the corrected BHMF at z=1.4 has a higher number density above 10^8^M_{sun}_ but a lower number density below that mass range. The evolution may be indicative of a downsizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDFs from z=1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rates close to the Eddington limit is higher at higher redshifts.
- 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.
