NVSSlist NVSSlist is a program for listing selected portions of the NRAO/VLA Sky Survey (NVSS) radio source catalog. This survey is being made with the NRAO VLA telescope at a frequency of 1.4 GHz and is producing images that will cover the sky north of declination -40 deg with a resolution of 45". Both total intensity and linear polarization are being imaged. The list of sources found on these images and fitted by elliptical Gaussians is stored as a FITS binary table. NVSSlist provides for selection, display, and interpretation of sources in this catalog. NVSSlist can display selected portions of the catalog with various corrections and computed errors associated with the source model parameters (position, flux density, etc.). All NVSS sources satisfying several input criteria (e.g., minimum flux density, location within a specified distance of a given celestial position) can be displayed. The selection criteria can be entered from the keyboard or from a disk file. NVSSlist is available at ftp://nvss.nrao.edu/pub/NVSS/CATALOG/NVSSlist215.tar.gz. Contact bcotton@nrao.edu about any problems. Unix Installation ---- ------------ NVSSlist consists of a number of Fortran routines that call the fitsio package of Bill Pence et al. at NASA. Before installing NVSSlist the fitsio package must first be installed (obtainable via anonymous ftp://legacy.gsfc.nasa.gov/software/fitsio). The current distribution of fitsio (8/95) is fitsio406.tar. NVSSlist is distributed in the form of a Unix tar archive. The routine config.f must be edited to give the name of the directory in which the master configuration file (NVSSlist.cfg) and the documentation file (NVSSlist.hlp) will be installed. The Makefile may need to be edited to point to the correct directory for the fitsio library (libfitsio.a) and possibly the name and options for the Fortran compiler. After these modifications, NVSSlist can be generated using make; "make clean" will delete the object files. The resulting executable is NVSSlist. The OPEN statment in textfile.f uses the READONLY parameter to allow users to read write-protected configuration files. This is an extension to Fortran and may not be supported on your system. If the compilation fails, remove the READONLY and rerun make. In the latter case users will need to make local copies of the configuration file. Under Sun solaris version SC4.0 and later of f77, the "READONLY" should be replaced by "ACTION='read'" (note, 'read' must be lower case!!!). There are two text files which need to be available at run time: 1) the configuration (NVSSlist.cfg) and 2) documentation (NVSSlist.hlp) files. These should be installed in the directory pointed to by config.f. The master configuration file may need to be modified to give the full path name to the NVSS catalog FITS file. There are also options relating to the maximum number of characters in an output line and the number of lines per page. These are described in the comments in the configuration file. Usage ----- NVSSlist needs a number of pieces of information which come from several places. The name of the FITS file, the table version number, the maximum number of characters in an output line etc. are given in a configuration file (NVSSlist.cfg). If a file by this name is in the current working directory then it is used, else the site master configuration file is used. If the site master configuration file is not found then standard defaults are used. The most important of these is that the NVSS catalog file is assumed to be in the current working directory under the name of CATALOG.FIT. The configuration file can be edited to provide the desired values; comments follow the "!". If there is a problem reading the master configuration file (usually involving write permission) then copy the master configuration file to your current working directory. During the execution of NVSSlist, various selection/display options are solicited interactively. More details about each question can be obtained by responding with a ?. Hitting the enter/return key will enter the default value(s). The output can be either to the current display window or to a disk file. If the display is to the current window, the program pauses occasionally and gives you a chance to quit. Until the NVSS is completed a there are two possible reasons that a source is not found at a given position: 1) there is no source detectable by the NVSS within the search area or 2) the region specified is not yet included in the catalog. To help distinguish between these cases a "verification" search box can be specified. If no source is found within the search area but one is found withing the search box then the distance to this source is given. This determines if there are other sources in the area implying that the NVSS has included this region. NOTE: this is not an absolutely certain test as there are small areas not yet covered because those observations were lost to excessive interference or other problems. A verification search box half width of 5 arcmin (0.0833 degree) should include other source if the area has been cataloged. If many fields are to be searched, you may list their positions in a text file ("... input source list ..."). The text file contains one line per field, and each line has up to 5 logical columns containing, in order: 1. Field center right ascension as hh mm ss.ss 2. Field center declination as +/-dd mm ss.s 3. (Optional) Search radius in arcsec (defaults to 15) 4. (Optional) Verification halfwidth in arcsec (default 0 deg.). 5. (Optional) Field label (defaults to blank) An example of a text file line is: 12 34 56.78 -00 12 34.5 15 720 My Star This will search for NVSS sources within 15". of RA=12 34 56.78, Dec=-00 12 34.5. If no source meeting the selection criteria is found within the 15" but there is a source within 720" (12 arcmin.) then a note to this effect is given. Esoteric notes: -------- ----- Terminal input is read from Fortran unit 5 which is stdin on Unix systems; terminal output is to unit 6 (stdout) and error messages are to unit 0 (stderr). All input lines may contain a trailing comment delimited by a "!".