- ID:
- ivo://CDS.VizieR/J/ApJ/519/533
- Title:
- ROSAT observations of ACO clusters
- Short Name:
- J/ApJ/519/533
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled an X-ray catalog of optically selected rich clusters of galaxies observed by the Position Sensitive Proportional Counter (PSPC) during the pointed GO phase of the ROSAT mission. This paper contains a systematic X-ray analysis of 150 clusters with an optical richness classification of R>=2 from the Abell, Corwin, & Olowin (1989; ACO) catalog. All clusters were observed within 45' of the optical axis of the telescope during pointed PSPC observations. For each cluster, we calculate: the net 0.5-2.0keV PSPC count rate (or 4{sigma} upper limit) in a 1Mpc radius aperture, 0.5-2.0keV flux and luminosity, bolometric luminosity, and X-ray centroid. The cluster sample is then used to examine correlations between the X-ray and optical properties of clusters, derive the X-ray luminosity function of clusters with different optical classifications, and obtain a quantitative estimate of contamination (i.e., the fraction of clusters with an optical richness significantly overestimated due to interloping galaxies) in the ACO catalog.
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- ID:
- ivo://CDS.VizieR/J/A+A/311/384
- Title:
- ROSAT observations of BL Lacertae objects
- Short Name:
- J/A+A/311/384
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present soft X-ray spectra of 74 BL Lacertae objects observed with the PSPC detector on board of the ROSAT satellite. The sample contains all BL Lac objects detected during the pointed observation phase as a target or serendipitously. We have investigated the soft X-ray and broad band spectral properties and discuss the consequences for the X-ray emission processes. For the first time a clear dependence of the X-ray spectral steepness on the radio to X-ray spectral energy distribution is found: {alpha}_rx_ and {alpha}_x_ are correlated in the X-ray selected (XBL) subsample and anticorrelated in the radio selected (RBL) subsample. The objects with intermediate {alpha}_rx_ values thus do have the steepest soft X-ray spectra. Simulated PSPC spectra based on a set of simple two component multifrequency spectra are in good agreement with the measurements and suggest a broad range of synchrotron cutoff energies. We have calculated synchrotron self-Compton beaming factors for a subsample of radio bright objects and find a correlation of the beaming factors {delta}_IC_ with {alpha}_rx_ and {alpha}_x_. The most extreme RBL objects are very similar to flat spectrum radio quasars in all their broad band and X-ray properties.
- ID:
- ivo://CDS.VizieR/J/A+A/353/1044
- Title:
- ROSAT obs. of T Tauri stars in MBM 12
- Short Name:
- J/A+A/353/1044
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the ROSAT PSPC pointed and ROSAT All-Sky Survey (RASS, Cat. <IX/10>) observations and the results of our low and high spectral resolution optical follow-up observations of the T Tauri stars (TTS) and X-ray selected T Tauri star candidates in the region of the high galactic latitude dark cloud MBM 12 (L1453-L1454, L1457, L1458). Table 4 lists all of the X-ray detected sources in the direction of the molecular cloud MBM12 along with relevant X-ray and optical data.
- ID:
- ivo://CDS.VizieR/J/A+A/317/328
- Title:
- ROSAT PSPC survey of M 31
- Short Name:
- J/A+A/317/328
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports on results of the analysis of the first M 31 survey with the ROSAT PSPC performed in July 1991. Within the =~ 6.3deg^2^ field of view we detected 396 individual X-ray sources with (0.1keV-2.4keV) fluxes ranging from =~ 5x10^-15^erg/cm^2^/s^ to =~ 4x10^-12^erg/cm^2^/s. Of these 396 sources, 43 have be en tentatively identified with foreground stars, 29 with globular clusters, 17 with supernova remnants, 3 with other galaxies (including M 32), and 3 with radio sources. A detailed analysis of the integral flux distribution of the sources shows that approximately one fifth are likely to be background objects. By comparison with the results of the Einstein M 31 survey, we find 327 newly detected sources, 15 moderately variable sources, 3 bright and 6 faint possible transient sources. For those sources in M 31, the observed luminosities range from =~ 3x10^35^erg/s to =~ 2x10^38^erg/s (at 690kpc). The total (0.1keV-2.4keV) luminosity of M 31 is (2.9+/-0.3)x10^39^erg/s, roughly one third of which is from the bulge and two thirds of which are from the disk. The luminosity of a diffuse component within the bulge region is estimated to be less than 3.2x10^38^erg/s. An explanation in terms of hot gaseous emission leads to a maximum total gas mass of 1.7x10^6^M_{sun}_. We find that the integral luminosity distribution of sources associated with globular clusters is similar to that of the Milky Way. Finally, the results of spectral fits to 56 of the brightest sources are discussed; we classify 15 objects as "supersoft sources" according to their spectral characteristics.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/87
- Title:
- ROSAT RASS II observations of IRAS galaxies
- Short Name:
- J/A+AS/129/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 120000 X-ray sources detected in the RASS II processing of the ROSAT All-Sky Survey are correlated with the 14315 IRAS galaxies selected from the IRAS Point Source Catalogue: 372 IRAS galaxies show X-ray emission within a distance of 100 arcsec from the infrared position. By inspecting the structure of the X-ray emission in overlays on optical images we quantify the likelihood that the X-rays originate from the IRAS galaxy. For 197 objects the soft X-ray emission is very likely associated with the IRAS galaxy. Their soft X-ray properties are determined and compared with their far-infrared emission.
- ID:
- ivo://nasa.heasarc/roshri
- Title:
- ROSAT Results Archive Sources for the HRI
- Short Name:
- ROSAT/HRI
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The ROSHRI data table contains a list of sources detected by the Standard Analysis Software System (SASS) in reprocessed, public 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 table quickly judge the reliability of a given source. The ROSHRI table excludes sources that meet the following parameter criteria: false_det = 'T' or deferred = 'T' or not_checked = 'T' or un_unique ='T'. See the documentation below for descriptions of these parameters. 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. The RRA contains extracted source and associated products with an indication of reliability for the primary parameters. This database table was last updated in August 2001. More information about the ROSAT Results Archive for HRI sources can be obtained at the following web pages: <pre> <a href="http://heasarc.gsfc.nasa.gov/docs/rosat/rra/RRA.html">http://heasarc.gsfc.nasa.gov/docs/rosat/rra/RRA.html</a> <a href="http://hea-www.harvard.edu/rosat/rra.html">http://hea-www.harvard.edu/rosat/rra.html</a> <a href="http://www.aip.de/groups/xray/rosat/rra.html">http://www.aip.de/groups/xray/rosat/rra.html</a> <a href="http://ledas-www.star.le.ac.uk/rra">http://ledas-www.star.le.ac.uk/rra</a> </pre> This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rospspc
- Title:
- ROSAT Results Archive Sources for the PSPC
- Short Name:
- ROSAT/PSPC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The ROSPSPC database table contains a list of sources detected by the Standard Analysis Software System (SASS) in public, unfiltered, pointed PSPC datasets. In addition to the parameters returned by SASS (like position, count rate, likelihood, 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 ROSPSPC database table quickly judge the reliability of a given source. The ROSPSPC table excludes sources that meet the following parameter criteria: false_det = 'T' or deferred = 'T' or not_checked = 'T'. See the documentation below for descriptions of these parameters. The catalog consists of all primary source parameters from the automated detection algorithm employed by the SASS. In addition each observation has been quality checked, both by automatic algorithms and by detailed visual inspection. The results of this quality checking are contained as a set of logical-value flags for a set of principal source parameters. If a source parameter is suspect, the associated flag is set to "TRUE"; parameters with no obvious problems maintain the default, "FALSE", value. This database table was last updated in August 2001. More information about the ROSAT Results Archive for PSPC sources can be obtained at the following web pages: <pre> <a href="http://heasarc.gsfc.nasa.gov/docs/rosat/rra/RRA.html">http://heasarc.gsfc.nasa.gov/docs/rosat/rra/RRA.html</a> <a href="http://hea-www.harvard.edu/rosat/rra.html">http://hea-www.harvard.edu/rosat/rra.html</a> <a href="http://www.aip.de/groups/xray/rosat/rra.html">http://www.aip.de/groups/xray/rosat/rra.html</a> <a href="http://ledas-www.star.le.ac.uk/rra">http://ledas-www.star.le.ac.uk/rra</a> </pre> This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/IX/11
- Title:
- ROSAT Source Catalog
- Short Name:
- IX/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains sources from PSPC-ROSAT (Position-sensitive Proportional Counter aboard the Roentgen Satellite), as provided by Max-Planck Institut fuer extraterrestrische Physik (MPE) in December 1994. The WGACAT version of the ROSAT PSPC Catalogue (IX/12) is a similar catalogue with slightly different reduction procedures For a description of the ROSAT Mission, see Truemper (1983)
- ID:
- ivo://CDS.VizieR/J/ApJ/514/148
- Title:
- ROSAT survey of bright galaxies clusters
- Short Name:
- J/ApJ/514/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the selection of an X-ray flux-limited sample of bright clusters of galaxies in the southern hemisphere, based on the first analysis of the ROSAT All-Sky Survey data (RASS1). The sample is constructed starting from an identification of candidate clusters in RASS1, after which their X-ray fluxes are remeasured using the steepness-ratio technique. This method is better suited than the RASS1 standard algorithm to measuring flux from extended sources. The final sample is count-rate-limited in the ROSAT hard band (0.5-2.0 keV), so that as a result of the distribution of N_H_, its effective flux limit varies between {~}3 and 4x10^-12^ ergs cm^-2^ s^-1^ over the selected area. This covers the {delta} < 2.5{deg} part of the south Galactic cap region (b < -20{deg}), excluding patches of low RASS1 exposure time and of the Magellanic Clouds area, for a total of 8235 deg^2^. One hundred and thirty candidate sources fulfill our selection criteria for bona fide clusters of galaxies in this area. Of these, 101 are Abell/ACO clusters, while 29 do not have a counterpart in these catalogs. Of these clusters, 126 (97%) have a redshift, and for these we compute an X-ray luminosity. 20% of the cluster redshifts come from new observations, as part of the ESO Key Program survey of RASS clusters that is currently under completion. Considering the intrinsic biases and incompletenesses introduced by the flux selection and source identification processes, we estimate the overall completeness to be better than 90%. The observed number count distribution, log Nlog S, is well fitted by a power law with slope {alpha} =1.34{+/-}0.15 and normalization A=11.87{+/-}1.04 sr^-1^ (10^-11^ ergs cm^-2^ s^-1^)^{alpha}^, in good agreement with other measurements.
- ID:
- ivo://CDS.VizieR/J/ApJ/445/280
- Title:
- ROSAT survey of the Orion nebula region
- Short Name:
- J/ApJ/445/280
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from three deep ROSAT high-resolution imager observations of the Orion Nebula star-forming region. The X-ray images contain over 1500 catalogued stars in a roughly 0.8deg^2^ region centered on the Trapezium. In all, 389 distinct X-ray sources have been detected, at least two-thirds of which are associated with a single proper-motion cluster member. X-ray emission is 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 this paper, we focus 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 have been detected; we have derived X-ray luminosity upper limits for the remaining stars. We found coronal X-ray emission turns on around spectral type F6, with the upper envelope of activity increasing with decreasing effective temperature.
