... astro-ph/0003002 We cross-identified the ROSAT Bright Source Catalog (RBSC) and the NRAO VLA Sky Survey (NVSS) to construct the RBSC-NVSS sample of the brightest X-ray sources (~0.1 counts s^{-1} ~= 10^{-12} ergs cm^-2s^-1 in the 0.1--2.4 keV band) that are also radio sources (S ~= 2.5 mJy at 1.4 GHz) in the 7.8 sr of extragalactic sky with |b| > 15deg and DEC > -40deg. ... We used the more accurate radio positions to make reliable X-ray/radio/optical identifications down to the POSS plate limits. ...

True Color Image Gallery: Galactic SNR | Magellanic Cloud SNR . ... 1988 ) . ... Radio Images Page . Link to Green's Catalog page . PDF version of this page : 1 column per page , 2 columns per page . ... Exposure uf . ... Exposure uf Exposure time of unfiltered event file . Exposure f Exposure time of filtered event file . ... Event 2 FITS File . ... AUX file . ... see fit detail page for more about the fit. see chandra spectrum page for region used. ... True Color Image . ... 5.9" . ...

The process of determining the number and characteristics of sources in astronomical images is so fundamental to a large range of astronomical problems that it is perhaps surprising that no standard procedure has ever been defined that has well understood properties with a high degree of statistical rigour on completeness and reliability. ... In this analysis we present results from testing such algorithms as implemented in the SExtractor, Selavy (Duchamp), and sfind tools on simulated data. ...

... This is followed by astrometric columns - ie columns for the Right Ascension, declination, position error, galactic longitude and galactic latitude. There then follows columns for the computed significance (signal-to-noise) of each source for each of the filters present. Columns for the instrumental magnitudes and colours for each filter, follow. ... Columns for the standard magnitudes and errors, for each filter, follow. ... Standard colours and errors then follow. ...

... Full details of the observations, data reduction and calibration of this survey, and the production of the 7C(G) compact source list, are described in Vessey & Green (1998, MNRAS, 294, 607) . ... b |<5њ, with a resolution of about 1.2 ? ... The survey consisted of 24 fields, spaced 3њ.5 in l , and alternating between b = +3њ and -3њ, but with a gap near l = 110њ. ... Please refer to the source list description for details of the entries ; the catalogue itself is available as: . ...

The Texas survey of radio sources covering -35.5{deg} < {delta} < 71.5{deg} at 365MHz . ... We present the Texas Survey of discrete radio sources between -35.5deg and 71.5deg declination (B1950), which was carried out at 365MHz with the Texas Interferometer during 1974-1983. ... The Texas Survey . ... The sources in the simpler model. ... Right Ascension 1950 . ... field separator . ... Some sources came from Version 6 of the Texas Survey ('TS6' in strp field) or Version 7 ('TS7' in strp field) . ...

... The VSOP Survey Continuum Source List . The radio sample for the VSOP continuum survey was defined to include all extragalactic radio sources with: . a total flux density at 5 GHz, S>=1.0 Jy . ... The sample also included all sources in the sky with a 5 GHz flux density S>5 Jy, regardless of spectral index and galactic latitude. ... The source would then be included in the VSOP sample (three of the sources were found with a flux density above 1 Jy and added to the sample). ...

... Next: The PROS Big Up: Software Systems Previous: Data Reduction Software . ... The srcinten task provides PROS users with a tool to compute count rates for point sources in the ROSAT High Resolution Imager (HRI). ... Corrected upper limits are cited at locations where the count rate falls below the source detection threshold. ... Srcinten is a new PROS task that computes and applies the above correction factors to the net counts in a user-specified aperture. ...

... The exact directions of the offsets are parallel to the rows and columns of the CCD on which the aperture is specified. ... It is often useful to explicitly specify the desired rotation of the WFPC2 field-of-view on the sky. ... Figure 7.8 shows the CCD orientation and aperture locations relative to the U3 axis. ... Obtain the Position Angle (PA) of the source axis on the sky, measured in the standard way, North through East. ... desired source angle in field-of-view measured CW from +U3 axis) . ...

... LABORATORY OF RADIO ASTRONOMICAL OBSERVATIONS . Radio sources identification is one of the most important tasks of the current radio astrophysics. ... Optical idetification. ... Optical identifications of subsample of steep spectra radio sources from RC catalog using 6m SAO telescope of SAO RAS: optical observations. ... Astronomy Reports. ... Identification of radio sources with data of various radio catalogs allows one to construct continual spectrum of the object and its radio structure. ...