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SAXHELLASR - BeppoSAX High-Energy Large Area Survey (HELLAS) Radio Source Catalog |
HEASARC Archive |
The 20 HELLAS sources with Declinations south of -40o were observed with the ATCA, while the 127 sources with more northerly Declinations were observed with the VLA. For these latter sources a complete covering at 20 cm down to the 5-sigma flux limit of 2.5 mJy is already available with the NRAO/VLA Sky Survey (NVSS) while the FIRST survey (Faint Images of the Radio Sky at Twenty centimeters) is available only for 27 HELLAS sources (5-sigma limit of ~ 1 mJy).In order to obtain information also on the radio spectral properties of the HELLAS sources the authors adopted the following strategy. All the 147 HELLAS sources were observed at 6 cm down to a 1 -sigma flux limit of ~ 0.10 - 0.25 mJy. For the 20 HELLAS sources observed with the ATCA, they took advantage of the fact that the 6 and 3 cm receivers of the ATCA share a common feed-horn and they observed simultaneously also at 3 cm, obtaining a 3-cm flux limit of ~ 0.22 mJy (1-sigma level).
Starting from the radio position of the 53 X-ray/radio associations, the authors searched for optical counterparts within 5 arcseconds from the radio position using the optical positions of the 61 HELLAS sources identified by La Franca et al. (2002, ApJ, 570, 100 = LF02), the USNO-A2.0 1 optical catalog, the APM 2 optical catalog and the NASA Extragalactic Database (NED). 24 X-ray/radio associations have been identified with sources in LF02 (10 Type 1 AGN, 4 Type 2 AGN, 2 BL Lacs, 3 Clusters, 4 ELGs and 1 Radio galaxy), 1 has been identified with a z = 0.708 Radio galaxy in the Lockman Hole using NED (see Table 2 source 116 in Lehmann et al. 2000, A&A, 354, 35 for a description of this source), 13 have an optical (R-band) identification in the USNO and/or APM catalogue while 15 X-ray/radio associations do not have an optical identification brighter than R=20.
The BeppoSAX High Energy Large Area Survey (HELLAS). VI. The radio properties. Ciliegi P., Vignali C., Comastri A., Fiore F., La Franca F., Perola G.C. <Mon. Not. R. Astron. Soc. 342, 575 (2003)> =2003MNRAS.342..575C The BeppoSAX High Energy Large Area Survey (HELLAS) V. The nature of the hard X-ray source population and its evolution. La Franca F., Fiore F., Vignali C., Antonelli A., Comastri A., Giommi P., Matt G., Molendi S., Perola G.C., Pompilio F. <Astrophys. J. 570, 100 (2002)> =2002ApJ...570..100L The BeppoSAX High Energy Large Area Survey (HELLAS). II. Number counts and X-ray spectral properties. Fiore F., Giommi P., Vignali C., Comastri A., Matt G., Perola G.C., La Franca F., Molendi S., Tamburelli F., Antonelli L.A. <Mon. Not. R. Astron. Soc. 327, 771 (2001)> =2001MNRAS.327..771F
HELLAS_ID
The unique BeppoSAX HELLAS source designation. This was not given
in the original table but was taken by the
HEASARC from table 2 of Fiore et al. (2001, MNRAS, 327, 771, available at the
HEASARC as the SAXHELLAS table) which lists the same set of 147 X-ray sources.
Name
The BeppoSAX HELLAS source designation as recommended by the CDS
Dictionary of Nomenclature of Celestial Objects, using the 'HELLAS' prefix
(for High Energy Large Area Survey) and the source identification number,
replacing the underscore ('_') character in some of the source numbers with a
period ('.'). This was not given in the original table but was taken by the
HEASARC from table 2 of Fiore et al. (2001, MNRAS, 327, 771, available at the
HEASARC as the SAXHELLAS table) which lists the same set of 147 X-ray sources.
HELLAS Identification Number
RA
The Right Ascension of the X-ray source in the selected equinox. This
was given in J2000.0 sexagesimal coordinates to a precision of 0.1 seconds of
time in the original table.
Dec
The Declination of the X-ray source in the selected equinox. This was
given in J2000.0 sexagesimal coordinates to a precision of 1 arcsecond in the
original table. The HEASARC notes that the HELLAS source #124 has a
J2000.0 Declination of -19o 26' 19" which differs by 12 arcseconds from
the corresponding value given in the SAXHELLAS table of -19o 26' 31".
LII
The Galactic Longitude of the X-ray source.
BII
The Galactic Latitude of the X-ray source.
Off_Axis
The off-axis angle of the X-ray source from the field center, in
arcminutes.
Flux
The flux of the X-ray source in the 5-10 keV band, in erg cm-2s-1.
Rmag_Limit
This flag parameter is set to '>' if the corresponding R
magnitude value is an upper limit in brightness rather than a detection.
Rmag
The R-band magnitude of the optical counterpart to the X-ray source,
taken from La Franca et al. (2002, ApJ, 570, 100) unless otherwise specified
by a non-blank value of the ref_rmag parameter (q.v.).
Ref_Rmag
This flag parameter is set to non-blank values in cases where
the R magnitude is not taken from La Franca et al. (2002, ApJ, 570, 100), as
follows:
a = Magnitude from the APM (CDS Cat. <I/267>) catalog; l = Magnitude from Lehmann et al. 2000, A&A, 354, 35; u = Magnitude from the USNO (CDS Cat. <I/252>) catalog.
Source_Type
The spectroscopic identification of the optical counterpart
for the X-ray source taken from La Franca et al. (2002, ApJ, 570, 100), as
follows:
1 = Type 1 AGN; 2 = Type 2 AGN; 3 = BL Lac; 4 = Cluster of galaxies; 5 = ELG (emission-line galaxy); 6 = Radio galaxy.
Ref_Source_Type
This flag parameter is set to 'l' to indicate that the
source type and redshift information come from Lehmann et al. (2000, A&A, 354,
35).
Redshift
The spectroscopic redshift of the optical counterpart
for the X-ray source taken from La Franca et al. (2002, ApJ, 570, 100).
Flux_8p6_GHz_Limit
This flag parameter is set to '<' if the corresponding
flux density value is an upper limit rather than a detection. For the X-ray
sources without radio counterparts, the authors report the 3-sigma upper limit
of their maps.
Flux_8p6_GHz
The flux density of the radio counterpart to the X-ray source
(or upper limit
thereof if the corresponding limit flag value is <') at 8.6 GHz (3 cm), in mJy.
Flux_8p6_GHz_Error
The rms uncertainty in the 8.6-GHz flux density
of the radio counterpart to the X-ray source, in mJy.
Flux_8p6_GHz_Flag
This flag parameter is set to 'n' if the corresponding
flux density value is taken from NED.
Flux_5_GHz_Limit
This flag parameter is set to '<' if the corresponding
flux density value is an upper limit rather than a detection. For the X-ray
sources without radio counterparts, the authors report the 3-sigma upper limit
of their maps.
Flux_5_GHz
The flux density of the radio counterpart to the X-ray source
(or upper limit
thereof if the corresponding limit flag value is <') at 4.9 GHz (6 cm), in mJy.
Flux_5_GHz_Error
The rms uncertainty in the 4.9-GHz flux density
of the radio counterpart to the X-ray source, in mJy.
Flux_5_GHz_Flag
This flag parameter is set to 'n' if the corresponding
flux density value is taken from NED.
Flux_1p4_GHz_Limit
This flag parameter is set to '<' if the corresponding
flux density value is an upper limit rather than a detection.
Flux_1p4_GHz
The flux density of the radio counterpart to the X-ray source
(or upper limit
thereof if the corresponding limit flag value is <') at 1.4 GHz (20 cm), in mJy.
These data are taken from the NVSS and/or FIRST catalogs as discussed in the
Overview above.
Flux_1p4_GHz_Error
The rms uncertainty in the 1.4-GHz flux density
of the radio counterpart to the X-ray source, in mJy.
Flux_1p4_GHz_Flag
This flag parameter is set to 'n' if the corresponding
flux density value is taken from NED.
Rad_Spectral_Index_Limit
This flag parameter is set to '<' or '>' if the
corresponding spectral index values are upper or lower limits, respectively.
Rad_Spectral_Index
The radio spectral index of the X-ray source counterpart
calculated using the available frequencies (mainly 6 and 20 cm).
Radio_RA
The Right Ascension of the radio counterpart to the X-ray source
in the selected equinox. This was given in the original table in J2000.0
equatorial coordinates to a precision of 0.01 seconds of time. The position of
the radio sources is that obtained from the authors' 6-cm map (except when the
source is detected only at 20 cm). The typical positional error of 6-cm sources
is below 1 arcsecond.
Radio_Dec
The Declination of the radio counterpart to the X-ray source
in the selected equinox. This was given in the original table in J2000.0
equatorial coordinates to a precision of 0.01 arcseconds. The position of
the radio sources is that obtained from the authors' 6-cm map (except when the
source is detected only at 20 cm). The typical positional error of 6-cm sources
is below 1 arcsecond.
Xray_Radio_Offset
The angular distance between the X-ray and radio source
positions, in arcseconds.
XR_Random_Assoc_Prob
The probability of a random association between the
X-ray and radio sources, Pxr, defined in Section 3 of the reference paper
(Ciliegi et al. 2003, MNRAS< 342, 575)..
Radio_Optical_Offset
The angular distance between the radio and optical
source positions, in arcseconds.
RO_Random_Assoc_Prob
The probability of a random association between the
radio and optical sources, Pro,
RO_Spectral_Index_Limit
This flag parameter is set to '<' or '>' if the
corresponding spectral index values are upper or lower limits, respectively.
RO_Spectral_Index
The two-point radio-to-optical spectral index of the
source, alpharo. This is defined as alpharo = log (F5GHz/F2500)/5.38,
where F5GHz is the radio flux at 6 cm obtained from the present observation
or by extrapolating the 20-cm flux density with a power-law slope with alphar
= 0.7, and F2500 is the optical flux at 2500 Angstrom derived from the R
magnitude with an optical slope of 0.5.
OX_Spectral_Index_Limit
This flag parameter is set to '<' or '>' if the
corresponding spectral index values are upper or lower limits, respectively.
OX_Spectral_Index
The two-point radio-to-optical spectral index of the
source, alphaox. This is defined as alphaox = log(F2500/F2keV)/2.605,
where F2500 is the optical flux at 2500 Angstrom derived from the R
magnitude with an optical slope of 0.5, and F_2keV is the monochromatic X-ray
flux at 2 keV derived from the measured BeppoSAX 5-10 keV flux and assuming an
energy spectral index in t X-ray band of 0.6 (Fiore et al. 2001, MNRAS, 327,
771).
Class
The HEASARC Browse object classification of the source, based on the
value of the source_type parameter.