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ROSATRLQ - ROSAT Radio-Loud Quasars Catalog

HEASARC
Archive

Overview

Brinkmann et al. (1997) have compiled a sample of all quasars with measured radio emission from the Veron-Cetty - Veron catalog (1993, VERON93, CDS/ADC Cat. VII/166) detected by ROSAT (i) in the ALL-SKY SURVEY (RASS, Voges 1992, in Proc. of the ISY Conference `Space Science', ESA ISY-3, ESA Publications, p.9, ADC/CDS Cat. IX/10), (ii) as targets of pointed observations, or (iii) as serendipitous sources from pointed observations, as publicly available from the ROSAT point source catalog (ROSAT-SRC, Voges et al. 1995, ADC/CDS Cat. IX/11). The total number of ROSAT detected radio quasars from the above three sources is 654 objects. 69 of the objects are classified as radio-quiet using the defining line at a radio-loudness of 1.0, and 10 objects have no classification. The 5GHz data are from the 87GB radio survey, the NED database, or from the Veron-Cetty - Veron catalog. The power law indices and their errors are estimated from the two hardness ratios given by the SASS assuming Galactic absorption. The X-ray flux densities in the ROSAT band (0.1-2.4keV) are calculated from the count rates using the energy to counts conversion factor for power law spectra and Galactic absorption. For the photon index, the authors used the value obtained for a individual source if the estimated 1 sigma error was smaller than 0.5, otherwise they used the mean value of 2.14.

Catalog Bibcode

1997A&A...319..413B

References

Broad-band energy distribution of ROSAT detected quasars. I. Radio-loud objects. Brinkmann W., Yuan W., Siebert J. <Astron. Astrophys. 319, 413 (1997)>=1997A&A...319..413B (SIMBAD/NED BibCode)

Provenance

This database was created by the HEASARC in January 1999, based on CDS/ADC Catalog J/A+A/319/413.

Parameters

IAU_Name
The IAU name or designation of the object, based on its B1950 equatorial co-ordinates.

RA
Right Ascension of the optical object in the selected equinox; this was given to the nearest tenth of a second of time in the original CDS/ADC catalog and in J2000 equinox.

Dec
Declination of the optical object in the selected equinox; this was given to the nearest arcsecond in the original CDS/ADC catalog and in J2000 equinox.

LII
The galactic longitude of the optical object.

BII
The galactic latitude of the optical object.

Type_Flag
A flag for classification and/or additional information about the object; the following values are used:


  type_flag value    Meaning

        S          An object for which radio emission has been detected but which
                   does not qualify as radio-loud according to the flux criterion
                   that log(f(5 GHz)/f(2500 A)) > 1.
        U          An object for which no 5 GHz flux density is available.
        C          An object for which the X-ray flux is probably corrupted
                   by another nearby source.
  

Alt_Name
Alternate name from VERON93.

Redshift
The redshift of the quasar, as taken from the VERON93 Catalog. Notice that a '0' in the third decimal place is mostly an artifact of the machine-readable version of that catalog and that the printed version should be consulted if the user needs to know the actual precision of such a value.

Appmag
The optical magnitude (often but not always in the Johnson V band), as taken from the VERON93 Catalog.

Flux_6_cm
The radio flux density at 5 GHz in milliJanskies, taken from the 87GB radio survey, the NED database, or from VERON93.

Radio_Spect_Index
The radio spectral index. For most objects multifrequency radio data are available from NED which allow a good detemination of their radio spectra. For objects with obvious power-law spectra or objects with large scatter in the measured fluxes, the spectral indices are determined by fitting a power-law slope to the data. For objects showing a distinct non power-law spectral shape or with only a few measured flux density values, the authors calculated two-point indices between 5 and 1.4 GHz, if available.

Fx
The 'unabsorbed' X-ray flux (in the 0.1 - 2.4 keV bandpass), in units of erg/s/cm2 (or mW/m2), assuming a power-law spectrum, i.e., the flux which would have been measured without any interstellar absorption.

Fx_Error
The error in the X-ray flux, based on the 1-sigma statistical error in the count rate only. However, for sources with a small number of total counts (mostly RASS sources), the systematic errors can be of the order of about 30 percent, notice. Also, for strong sources, the assumed simple power-law slope is often an inappropriate representation of the spectrum, so that again there may be a significant systematic error in the quoted X-ray flux. In both of these cases, therefore, the systematic uncertainties can be considerably larger than the purely statistical errors, and the errors given in this catalog should be taken as lower limits.

PI_Gal
The X-ray photon index, obtained under the assumption of a fixed Galactic absorption and from a power law fit of the form C*E**(-pi_gal) in the ROSAT energy band. A missing entry means that no reasonable spectral index could be obtained.

PI_Gal_Poserr
The positive 1-sigma error in the X-ray photon index for the assumed Galactic hydrogen column density. If no error is given, its value is unphysically large.

PI_Gal_Negerr
The negative 1-sigma error in the X-ray photon index for the assumed Galactic hydrogen column density. If no error is given, its value is unphysically large.

Detection
This parameter give information on the X-ray detection: an 'S' indicates that the object was detected in the All-Sky Survey only, a 'P' indicates that the object was detected only in a pointed observation, and 'SP' indicates that the object was detected in both.

Ref_PI
A field that gives a reference code that indicates if other published data were available for an object. The codes and their corresponding references in these cases are as follows:

         BP: Buehler P., et al. (1995A&A...295..309B)
         BH: Brunner H., et al. (1994A&A...287..436B)
         BW: Brinkmann W. & Siebert J. (1995A&A...300L..33B)
         EM: Elvis M., et al. (1994ApJ...422...60E)
         LA: Laor A., et al. (1994ApJ...435..611L)
         NM: Neumann M., et al. <J/A+AS/106/303>
         SN: Schartel N., et al. (1996A&A...307...33)
         SJ: Siebert J., et al., (1996A&A...307....8S)
         ZY: Zhang Y.F. & Marscher A.P., 1994  AIP Conf. Proc. 313, p.406
  

Class
The HEASARC browse classification for the radio source: we have set this to `Radio-Loud Quasar' for all entries in this database, except for those entries with type_flag='S' which we have set to `Radio-Quiet Quasar'.


Contact Person

Questions regarding the ROSATRLQ database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Monday, 08-Nov-2004 11:27:15 EST