- ID:
- ivo://nasa.heasarc/rosathard
- Title:
- ROSAT Hard-Spectrum X-Ray Source Catalog
- Short Name:
- ROSATHARD
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 147 serendipitous X-ray sources selected to have hard spectra (spectral indices Alpha < 0.5) from a survey of 188 ROSAT fields. Such sources must be the dominant contributors to the X-ray background at faint fluxes. The authors have used Monte Carlo simulations to verify that their technique is very efficient at selecting hard sources: the survey has >= 10 times as much effective area for hard sources as it has for soft sources above a 0.5 - 2 keV flux level of 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup>. The distribution of best-fitting spectral slopes of the hard sources suggests that a typical ROSAT hard source in this survey has a spectral slope Alpha ~ 0. The hard sources have a steep number-flux relation (dN/dS ~ _S<sup>-Gamma</sup>, with a best-fitting value of Gamma = 2.72 +/- 0.12), and make up about 15% of all 0.5 - 2 keV sources with S > 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup>. If their N(S) continues to fainter fluxes, the hard sources will comprise ~ 40% of sources with 5 x 10<sup>-15</sup> < S < 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup>. The population of hard sources can therefore account for the harder average spectra of ROSAT sources with S < 10<sup>-14</sup>erg cm<sup>-2</sup> s<sup>-1</sup>. They probably make a strong contribution to the X-ray background at faint fluxes and could be the solution to the X-ray background spectral paradox. This table was created by the HEASARC in March 2012 based on CDS Catalog J/MNRAS/318/1073 file table2.dat, the ROSAT hard X-ray source catalog. This is a service provided by NASA HEASARC .
Number of results to display per page
Search Results
- ID:
- ivo://nasa.heasarc/lmchrixray
- Title:
- ROSAT HRI Catalog of LMC X-Ray Sources (Sasaki et al.)
- Short Name:
- HRI/LMC
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- All 543 pointed observations of the ROSAT High Resolution Imager (HRI) with exposure times higher than 50 seconds, and performed between 1990 and 1998 in a field of 10 by 10 degrees covering the Large Magellanic Cloud were analyzed, and a source catalogue was produced that contains 397 X-ray sources whose properties have been measured with the HRI. The list was cross-correlated with the ROSAT Position Sensitive Proportional Counter (PSPC) LMC source catalogue of Haberl and Pietsch (1999, A&AS, 139, 277; the HEASARC database LMCROSXRAY) in order to obtain the (PSPC) hardness ratios for the X-ray sources detected by both instruments. 138 HRI sources are contained in the PSPC Catalogue, while 259 sources are new detections. The spatial resolution of the HRI being better than that of the PSPC, source positions could be determined with errors smaller than 15 arcsec which are dominated by systematic errors. After cross-correlating the source catalogue with the SIMBAD database and the Tycho Catalogue, 94 HRI sources were identified with known objects based on their positional coincidences and X-ray properties. Whenever more accurate coordinates were given in catalogues or the literature, the X-ray coordinates were corrected and the systematic error of the X-ray position was reduced. For other sources observed simultaneously with an identified source, the positional coordinates were also improved. In total, the X-ray positions of 254 sources were newly determined. The sources identified in this study include 39 foreground stars, 24 supernova remnants (SNR), 5 supersoft sources, 9 X-ray binaries, and 9 active galactic nuclei (AGN) well-known from the literature. Another 8 sources were identified with known candidates for these source classes. An additional 21 HRI sources were suggested by the authors as candidates for SNR, X-ray binaries in the LMC, or background AGN, because of their spatial extents, hardness ratios, X-ray to optical flux ratios, or flux variability. This database was created at the HEASARC in June 2000 based on the ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+AS/143/391">CDS Catalog J/A+AS/143/391</a>, and is derived from Table 4 of the reference. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/A+AS/147/75
- Title:
- ROSAT HRI catalogue of SMC X-ray sources
- Short Name:
- J/A+AS/147/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT HRI SMC source catalogue is based on all 71 pointed observations of the Small Magellanic Cloud by the ROSAT HRI between 1990 and 1998. The data was selected in a 5{deg}x5{deg} field covering the SMC. The catalogue which contains 121 X-ray sources, was cross-correlated with data bases and catalogues like SIMBAD, TYCHO, or USNO as well as other publications in order to classify the X-ray sources and find new candidates for various source classes.
- ID:
- ivo://CDS.VizieR/J/A+A/341/751
- Title:
- ROSAT HRI observations of the Pleiades
- Short Name:
- J/A+A/341/751
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a deep X-ray survey of the Pleiades open cluster, we use the ROSAT High Resolution Imager to explore a region of the cluster formerly surveyed with the PSPC. These new observations substantially improve upon both the sensitivity and the spatial resolution for this region of the Pleiades, allowing us to detect 18 cluster members not detected before and 16 members not included in the catalogs used in previous surveys. The high sensitivity of the present observations permits us to obtain more stringent upper limits for 72 additional members and also provides sufficient numbers of stars to enable us to explore the dependence of L_x_ on stellar rotation for the slow rotators of the Pleiades. Using the new high sensitivity X-ray observations and the recent rotational measurements we discuss the activity-rotation relationship in the Pleiades solar type stars. We also present new photometric observations of optical counterparts of a number of X-ray sources detected in previous surveys but not yet identified.
- ID:
- ivo://nasa.heasarc/orionxstar
- Title:
- ROSAT HRI Orion Group 1 Stars
- Short Name:
- ORIONXST
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog presents some of the results from 3 deep ROSAT High Resolution Imager (HRI) observations of the Orion Nebula star-forming region. The fields covered by the X-ray images contain over 1500 catalogued stars in a roughly 0.8 square degree region centered on the Trapezium. In all, 389 distinct X-ray sources were detected, at least two-thirds of which were associated with a single proper-motion cluster member. X-ray emission was detected from stars of all spectral types, from the massive O- and B-type components of the Trapezium to the coolest, low-mass pre-main-sequence (PMS) stars. In the research paper in which these data were presented (Gagne et al. 1995), the authors focussed primarily on X-ray emission from the late-type PMS stars. Of the ~100 late-type cluster members with measured spectral types, approximately three-fourths were detected; the authors derived X-ray luminosity upper limits for the remaining stars. They found that coronal X-ray emission appeared to turn on at around a spectral type of F6, with the upper envelope of activity increasing with decreasing effective temperature. The current database is a representation of Table 6 from Gagne et al. (1995) (notice that the data given in Tables 2 and 3 of this reference is included in the HEASARC database ORIONXRAY, q.v.) which lists X-ray and other data for 175 Orion stars for which spectral types, spectroscopic rotational velocities, and/or spot-modulated photometric rotational periods are available. The X-ray data (either detections or upper limits) are given in the form of X-ray luminosities log Lx and X-ray to bolometric luminosity ratios (log Lx/Lbol). The conversion factor from HRI counts to log Lx was derived for each star based on (i) an assumed 1 keV Raymond and Smith thermal spectrum, (ii) a distance of 440 pc, and (iii) a column density of 2 x 10^21 cm^(-2) per magnitude of visual extinction A(V), where accurate A(V) values are used when available, or otherwise a moderate absorption of 0.25 magnitudes is assumed. Notice that, for stars not identified as candidate optical counterparts in Tables 2 and 3 of Gagne et al. (the HEASARC database ORIONXRAY), the derived upper limit to the X-ray luminosity usually corresponds to the 3 sigma upper limit to the observed count rate. For a handful of stars in the Trapezium region where a star was eliminated as a candidate optical counterpart, despite being within the source search circle, because a more likely counterpart had a smaller position offset, the upper limit corresponds to either half the observed X-ray source count rate or to 3 sigma, whichever is the highest. Such cases are indicated in this database by the presence of the string "NN" in the parameter 'Note'. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/IX/28A
- Title:
- ROSAT HRI Pointed Observations (1RXH)
- Short Name:
- IX/28A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The hricat.dat table contains a list of sources detected by the Standard Analysis Software System (SASS) in reprocessed, public High Resolution Imager (HRI) datasets. In addition to the parameters returned by SASS (like position, count rate, signal-to-noise, etc.) each source in the table has associated with it a set of source and sequence "flags". These flags are provided by the ROSAT data centers in the US, Germany and the UK to help the user of the ROSHRI database judge the reliability of a given source. These data have been screened by ROSAT data centers in the US, Germany, and the UK as a step in the production of the Rosat Results Archive (RRA). The RRA contains extracted source and associated products with an indication of reliability for the primary parameters.
- ID:
- ivo://nasa.heasarc/rixos
- Title:
- ROSAT International X-Ray/Optical Survey Source Catalog
- Short Name:
- RXOS
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The ROSAT International X-Ray/Optical Survey (RIXOS) is a medium-sensitivity survey and optical identification program for X-ray sources which were discovered in ROSAT high Galactic latitude fields (|b| > 28 degrees) and observed with the Position Sensitive Proportional Counter (PSPC) detector. The survey made use of the central 17 arcmin of each ROSAT field. A flux limit of 3 x 10<sup>-14</sup> erg/s/cm<sup>2</sup> (0.5-2.0 keV) was adopted for this survey, and a minimum exposure time of 8000 seconds was required for qualifying ROSAT observations. X-ray sources in the survey are therefore substantially above the detection threshold of each field used, and many contain enough counts to allow the X-ray spectral slope to be estimated. Spectroscopic observations of potential counterparts were obtained of all sources down to the survey limit in 64 fields, totaling a sky area of 15.77 square degrees. Positive optical identifications are made for 94% of the 296 sources thus examined. A further 18 fields (4.44 sq deg), containing 105 sources above the 3 x 10<sup>-14</sup> erg/s/cm<sup>2</sup> survey limit, are completely optically identified to a higher flux of 8 x 10<sup>-14</sup> erg/s/cm<sup>2</sup> (0.5-2.0 keV). Optical spectroscopic data are supplemented by deep CCD imaging of many sources to reveal the morphology of the optical counterparts, and objects too faint to register on Sky Survey plates. The faintest optical counterparts have R ~ 22. This table contains the catalog of the RIXOS sources and their optical identifications. This table was originally ingested by the HEASARC in June 2005 based on CDS table J/MNRAS/311/456/rixos.dat. It was updated in November 2013 shortly after the CDS released an update with the previously inadvertently omitted source RX J111809.9+212554 (RIXOS 123_84) included. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rosnepoid
- Title:
- ROSAT North Ecliptic Pole Survey Optical Identifications
- Short Name:
- ROSATNEPID
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the ROSAT North Ecliptic Pole (NEP) Survey list of optical identifications. The X-ray data around the NEP from the ROSAT All-Sky Survey (RASS) were used to construct a contiguous area survey which consisted of a sample of 445 individual X-ray sources with fluxes more than ~2x10<sup>-14</sup> erg/cm<sup>2</sup>/s in the 0.5 - 2.0 keV energy band. The NEP survey is centered at RA= 18hr 00min Dec= +66deg 33', and covers a region of 80.7 square degrees at a moderate Galactic latitude b= 29.8 degrees. Hence, the NEP survey is as deep as and covers a comparable solid angle to the ROSAT serendipitous surveys but is also contiguous. The authors identified 99.6% of the sources and determined redshifts for the extragalactic objects. This table contains the optical identifications for the NEP catalog of X-ray sources, including basic X-ray data and properties of the sources. The classification of the optical counterparts to the NEP sources is very similar to that of previous surveys, in particular the Einstein Extended Medium Sensitivity Survey (EMSS). The main constituents of the catalog are active galactic nuclei (AGN) (~49%), either type 1 or type 2 according to the broadness of their permitted emission lines. Stellar counterparts are the second most common identification class (~34%). Clusters and groups of galaxies comprise 14%, and BL Lacertae objects 2%. One non-AGN galaxy and one planetary nebula have also been found. The NEP catalog of X-ray sources is a homogeneous sample of astronomical objects featuring complete optical identification. The data on AGN in this catalog are essentially superceded by the data in the more recent catalog of Mullis et al. (2004, ApJ, 617, 192), available in HEASARC Browse as the ROSNEPOID table (q.v.), in which, inter alia, a corrected count rate to flux conversion and a different cosmology were used. This table was created by the HEASARC in April 2005 based on CDS table J/ApJS/149/29/table3.dat This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rosnepxray
- Title:
- ROSAT North Ecliptic Pole Survey X-Ray Source Catalog
- Short Name:
- ROSATNEP
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the ROSAT North Ecliptic Pole (NEP) Survey X-Ray Source Catalog. The sky around the NEP, at RA (J2000.0) = 18h00m00s, Declination (J2000.0) = +66d33'39", has the deepest exposure of the entire ROSAT All-Sky Survey (RASS). The NEP is an undistinguished region of moderate Galactic latitude, b = 29.8 degrees, and hence it is suitable for compiling statistical samples of both Galactic and extragalactic objects. The authors have made such a compilation in the 80.6 square degrees region surrounding the NEP. Their sample fully exploits the properties of the RASS, since the only criteria for inclusion are source position and significance, and it yields the deepest large solid angle contiguous sample of X-ray sources to date. They find 442 unique sources above a flux limit ~2 x 10<sup>-14</sup> ergs cm<sup>-2</sup> s<sup>-1</sup> in the 0.5-2.0 keV band. In this table, the X-ray properties of these sources as determined from the RASS are presented. These include positions, fluxes, spectral information in the form of hardness ratios, and angular sizes. This table was created by the HEASARC in February 2006 based on a machine-readable version of Table 4 in the above paper which was obtained from the electronic ApJ website. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rosatlog
- Title:
- ROSAT Observation Log
- Short Name:
- ROSATLog
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The ROSATLOG database table has been created for the purpose of providing a complete, accurate, and easily accessible record of ROSAT observations. ROSATLOG is made by cross-correlating ROSAT observation records with the short-term timeline and contains information about all pointings executed by the satellite during the performance verification (PV) and AO phases. For each observation, details are given concerning target name and coordinates, pointing start and stop times, PI name and country, ROSAT Observation Request sequence number, and more. ROSATLOG is based on the short-term timelines and observation records generated at the German ROSAT Science Data Center at the Max Planck Institute for Extraterrestrial Physics (MPE) and sent to the ROSAT Guest Observer Facility at Goddard Space Flight Center (GSFC). Many duplicate entries were removed from the HEASARC implementation of this catalog in June 2019. This is a service provided by NASA HEASARC .