- ID:
- ivo://CDS.VizieR/J/AN/321/81
- Title:
- Orion Trapezium area ROSAT PSPC obs. II.
- Short Name:
- J/AN/321/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A deep ROSAT PSPC image centred on the Orion Trapezium has been reduced a second time using an improved version of the PSF to fit the data. The outer rim of the field of view was also included. The new catalogue contains 316 X-ray sources which are easily identified with pre-main sequence stars of the Ori OB1 Ic and Id association. All 316 sources were tested for variability. No variations were found inside the single exposures of about 45 minutes length each. Between the 4 exposures spaced over 5 days about 1/3 of the sources show signs of activities of various forms. As above 25% of these have somewhat regular lights curves (monotonically rising or falling or hill- shaped) we infer that at least some outbursts with time scales longer than a day are present and that past searches for X-ray flares of pre-main sequence stars were biased towards shorter time scales.
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32. RASS AGN sample
- ID:
- ivo://CDS.VizieR/J/A+AS/139/575
- Title:
- RASS AGN sample
- Short Name:
- J/A+AS/139/575
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of a program to identify the unknown bright active galactic nuclei (AGN) in the ROSAT All Sky Survey Bright Source Catalog (RASS-BSC). We have used logC+0.4R as an alternative expression for log(f_X_/f_opt_), where C is X-ray count rate and R stands for R magnitude. Then a high X-ray-to-optical flux ratio criterion has been used to select an AGN sample with 165 unidentified X-ray sources for optical spectroscopy. Those 165 X-ray sources have been identified in the following classes: 115 emission line AGN (QSOs and Seyferts), 2 BL Lac objects and 4 BL Lac candidates, 22 clusters of galaxies, 12 Galactic stars and 10 objects remain unidentified. This represent a success rate of about 73% for detecting AGN using our selection criteria. Plausibility is based upon the optical classification and X-ray characteristics of the sources.
- ID:
- ivo://nasa.heasarc/rassasaseb
- Title:
- RASS/All-Sky Automated Survey Eclipsing Binaries Catalog
- Short Name:
- RASSASASEB
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have combined their catalog of eclipsing binaries from the All-Sky Automated Survey (ASAS) with the ROSAT All-Sky Survey (RASS) Bright and Faint Source Catalogs (RASSBSC and RASSFSC). The combination using a matching radius of 50 arcseconds results in 836 eclipsing binaries that display coronal activity and is the largest sample of active binary stars assembled to the date of publication. By using the (V-I) colors of the ASAS eclipsing binary catalog, the authors are able to determine the distances and thus bolometric luminosities for the majority of eclipsing binaries that display significant stellar activity. A typical value for the ratio of soft X-ray to bolometric luminosity is L<sub>X</sub>/L<sub>bol</sub> ~ a few x 10<sup>-4</sup>, similar to the ratio of soft X-ray to bolometric flux F<sub>X</sub>/F<sub>bol</sub> in the most active regions of the Sun. Unlike rapidly rotating isolated late-type dwarfs - stars with significant outer convection zones - a tight correlation between Rossby number and activity of eclipsing binaries is absent. The authors find evidence for the saturation effect and marginal evidence for the so-called "super-saturation" phenomena. Their work shows that wide-field stellar variability searches can produce a high yield of binary stars with strong coronal activity. The authors expect that only 1.4% (i.e., 12 out of 836) of the matches between the ASAS eclipsing binary and RASS sources will be false given their maximum angular separation criterion of 50 arcseconds. This Browse table excludes 29 contact binaries for which the separate distance estimates made by the authors using the source V-band and I-band magnitudes differed by more than 20%, and hence contains 807 (836 - 29) eclipsing and X-ray emitting binary systems. Complete information on ASAS and its freely accessible data are available at the ASAS web site: <a href="http://www.astrouw.edu.pl/asas/">http://www.astrouw.edu.pl/asas/</a>. This table was created by the HEASARC in July 2010 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AcA/58/405">CDS catalog J/AcA/58/405</a> file catalog.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassgb
- Title:
- RASS/Green Bank Catalog
- Short Name:
- RASS/GBC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 5-GHz high-resolution VLA observations of 2,127 radio and X-ray emitting sources found in both the Green Bank (GB) 5-GHz radio catalog and the ROSAT All-Sky Survey (RASS) are presented. This is referred to as the RASS/Green Bank sample: the HEASARC has abbreviated this to RASSGB to conform with the naming convention that we have used for other RASS catalogs (notice the catalog authors use the rather shorter acronym of RGB. Core flux densities and positions accurate to +/- 0.5" are reported, as well as the GB measurements of the total radio emission, for each source. Because of the radio and X-ray selection criteria adopted, this catalog is believed to almost exclusively contain radio- and X-ray-loud active galaxies. These data are used in the paper by Laurent-Muehleisen et al. (1997) that contains the published version of this catalog to derive the core-to-lobe ratio of objects in this sample, and to discuss their core-dominance relative to samples of radio galaxies and BL Lac objects: the authors conclude that this sample is approximately an order of magnitude more core-dominated than the radio galaxy sample, but is more than an order of magnitude less core-dominated than highly-beamed BL Lac objects. The published version of this catalog comprised two main tables, Table 2 and Table 3. Table 2 gave the 5-GHz high resolution radio source properties for the 1861 ROSAT/Green Bank sources for which subarcsecond positions and core radio flux densities had been obtained, while Table 3 gave the 5-GHz radio source properties for the 436 ROSAT/Green Bank sources for which only low resolution data were obtained. A table of the 83 ROSAT/Green Bank sources for which no radio source greater than 5 sigma was observed in the follow-up VLA observations (Table 4 in the paper) is not included in the present HEASARC RASSGB Catalog but is available in data archive at <pre> <a href="https://heasarc.gsfc.nasa.gov/FTP/heasarc/dbase/misc_files/rassgb/">https://heasarc.gsfc.nasa.gov/FTP/heasarc/dbase/misc_files/rassgb/</a> </pre> This HEASARC version of the ROSAT/Green Bank Catalog was created in November 1998 based on the ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+AS/122/235">CDS Catalog <J/A+AS/122/235></a> (Tables 2 and 3). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassvars
- Title:
- RASS X-Ray Variable Sources Catalog
- Short Name:
- ROSAT/Vars
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The RASS X-Ray Variable Sources Catalog contains the results of a systematic search for variability among the ROSAT All-Sky Survey (RASS) X-ray sources. Lightcurves were generated for about 30,000 X-ray point sources which were detected sufficiently high above the background. For the variability study different search algorithms were developed in order to recognize flares, periods and trends, respectively. The variable X-ray sources were optically identified with counterparts in the SIMBAD, the USNO-A2.0 and NED data bases, but a significant part of the X-ray sources remain without cataloged optical counterparts. A complete list of the 1207 X-ray variable sources that were found is presented in this table. This table was created by the HEASARC in July 2003 based on CDS table J/A+A/403/247/table7.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/A+AS/146/323
- Title:
- RASS young sources around R CrA
- Short Name:
- J/A+AS/146/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the ROSAT All-Sky Survey data in a 126 deg^2^ area in and around the CrA star forming region. With low-resolution spectroscopy of unidentified ROSAT sources we could find 19 new pre-main sequence stars, two of which are classical T Tauri stars, the others being weak-lined. The spectral types of these new T Tauri stars range from F7 to M6. The two new classical T Tauri stars are located towards two small cloud-lets outside of the main CrA cloud. They appear to be ~10 Myrs old, by comparing their location in the H-R diagram with isochrones for an assumed distance of 130 pc, the distance of the main CrA dark cloud. The new off-cloud weak-line T Tauri stars may have formed in similar cloudlets, which have dispersed recently. High-resolution spectra of our new T Tauri stars show that they have significantly more lithium absorption than zero-age main-sequence stars of the same spectral type, so that they are indeed young. From those spectra we also obtained rotational and radial velocities. For some stars we found the proper motion in published catalogs. The direction and velocity of the 3D space motion - south relative to the galactic plane - of the CrA T Tauri stars is consistent with the dark cloud being formed originally by a high-velocity cloud impact onto the galactic plane, which triggered the star formation in CrA. We also present VRIJHK photometry for most of the new T Tauri stars to derive their luminosities, ages, and masses.
- ID:
- ivo://CDS.VizieR/J/MNRAS/311/456
- Title:
- RIXOS source catalogue
- Short Name:
- J/MNRAS/311/456
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the ROSAT International X-ray/Optical Survey (RIXOS), a medium-sensitivity survey and optical identification of X-ray sources discovered in ROSAT high Galactic latitude fields (|b|>280) and observed with the Position Sensitive Proportional Counter (PSPC) detector. We presents a catalogue of the RIXOS sources and their optical identifications.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/235
- Title:
- ROSAT active galaxies identifications
- Short Name:
- J/A+AS/122/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 2 gives the 5 GHz high resolution radio source properties for the 1861 Rosat-GreenBank (RGB) sources for which subarcsecond positions and core radio flux densities were obtained. After submission of this paper, we discovered a possible systematic position error in a very small subset of sources. In particular, the sources RGB J0131+005, RGB J0139+178, RGB J0143+129, RGB J0157+235A, RGB J0232+202, RGB J0233+024A, RGB J0243+171, RGB J0256+035, RGB J0303+059, RGB J0308+104, RGB J0312+243A, RGB J0312+242C, and RGB J0314+063 were all observed in our "c" epoch VLA runs and show large systematic offsets with respect to sources found in the NVSS survey. We re-examined these sources and found the position reported in the tables is accurate given our data, but that the noise on these fields before any CLEANing is abnormally high. We thank Dr. Alastair Edge for pointing out this discrepancy. Table 3 gives the 5 GHz radio source properties for the 436 Rosat-Green Bank (RGB) sources for which only low resolution data were obtained. Table 4 gives the 83 Rosat-Green Bank (RGB) sources for which no radio source greater than 5 sigma was observed in the follow-up VLA observations. These catalogs consist of radio- and X-ray-loud AGN selected from a correlation of the 1987 Green Bank radio catalog and the Rosat All-Sky Survey.
- ID:
- ivo://CDS.VizieR/IX/10A
- Title:
- ROSAT All-Sky Bright Source Catalogue (1RXS)
- Short Name:
- IX/10A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT All-Sky Survey Bright Source Catalogue (RASS-BSC, revision 1RXS) is derived from the all-sky survey performed during the first half year (1990/91) of the ROSAT mission. 18,806 sources are catalogued (five sources were removed compared to the 18,811 sources of the 1996 version), down to a limiting ROSAT PSPC count-rate of 0.05cts/s in the 0.1-2.4keV energy band, with a detection likelihood of at least 15 and with at least 15 source photons. For 94% of the sources visual inspection confirmed the results of the standard processing with respect to existence and position; the remaining 6% were re-analysed and appropriately flagged. At a brightness limit of 0.1cts/s (8,547 sources) the catalogue represents a sky coverage of 92%. Broad band images are available for a subset of the flagged sources from http://www.rosat.mpe-garching.mpg.de/survey/rass-bsc . Questions or comments may be directed to <xray-info(at)mpe.mpg.de>
- ID:
- ivo://nasa.heasarc/rassdwarf
- Title:
- ROSAT All-Sky Survey: A-K Dwarfs/Subgiants
- Short Name:
- RASS/Dwarf
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog presents X-ray data for all the main-sequence and subgiant stars of spectral types A, F, G, and K and luminosity classes IV and V listed in the Bright Star Catalogue (also known as the HR Catalogue) that have been detected as X-ray sources in the ROSAT All-Sky Survey (RASS). A number of stars in the appropriate spectral type range that do not have assigned luminosity classes have also been included. The catalogue contains 980 such HR stars detected as X-ray sources out of a total of 3054 stars in the HR Catalogue that satisfy the selection criteris, implying an average detection rate of 32%. In addition to the measured ROSAT PSPC count rates, source detection parameters, hardness ratios, and X-ray fluxes, X-ray luminosities derived from Hipparcos parallaxes are also listed. This database was created at the HEASARC in February 1999 based on the ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+AS/132/155">CDS Catalog J/A+AS/132/155</a>. This is a service provided by NASA HEASARC .
