MITGB6CM - MIT-Green Bank 5-GHz Survey Catalog
00h < RAB < 24h, -00d30'13" < DECB < +19d29'47" for MG1 04h < RAJ < 21h, +17.0d < DECJ < +39d09' for MG2 16h30m < RAB < 05h, +17d < DECB < +39d09' for MG3 15h30m < RAB < 02h30m, +37.00d < DECB < +50d58'48" for MG4where RAB and DECB refer to B1950 coordinates, and RAJ and DECJ refer to J2000 coordinates. The catalog contains 20344 sources detected with a signal-to-noise ratio greater than 5 and 3836 possible detections (MG1) with a signal-to-noise ratio less than 5. Spectral indices are computed for MG1 sources also identified in the Texas 365 MHz survey (Douglas et al. 1980, Univ. Texas Pub. Astr. No. 17), and for MG1-MG4 sources also identified in the NRAO 1400 MHz Survey (Condon and Broderick 1985, AJ, 90, 2540 = 1985AJ.....90.2540C).
The MIT-Green Bank (MG) 5 GHz survey Bennett C.L., Lawrence C.R., Burke B.F., Hewitt J.N., Mahoney J. <Astrophys. J. Suppl. Ser. 61, 1 (1986)> =1986ApJS...61....1B The second MIT-Green Bank 5 GHz survey Langston G.I., Heflin M.B., Conner S.R., Lehar J., Carrilli C.L., Burke B.F. <Astrophys. J. Suppl. Ser. 72, 621 (1990)> =1990ApJS...72..621L The third MIT-Green Bank 5 GHz survey Griffith M., Langston G., Heflin M., Conner S., Lehar J., Burke B. <Astrophys. J. Suppl. Ser. 74, 129 (1990)> =1990ApJS...74..129G The fourth MIT-Green Bank 5 GHz survey Griffith M., Langston G., Heflin M., Conner S., Burke B. <Astrophys. J. Suppl. Ser. 75, 801 (1991)> =1991ApJS...75..801G
The HEASARC has also added a new parameter called survey which identifies in which survey (1, 2, 3 or 4) the source was identified, based on the original name prefix, e.g., survey = 3 for the source used in the example above.
The survey number 1, 2, 3, or 4 from which the source was taken.
A flag 's' that indicates sources with signal-to-noise ratios of less than 5.
The original name of the radio source as listed in the catalog.
The name of the radio source. Notice that the HEASARC has changed the names given in the original CDS table, e.g., MG3_J000335+3747, in order to conform to the naming convention that is recommended by the Dictionary of Nomenclature of Celestial Objects. Thus, the object above is now named MITG J0003+3747. Since some names would be duplicates for objects lying in similar directions, we have appended prefixes, "a", "b", etc., to the names in such cases, in order of increasing right ascension.
The Right Ascension of the radio source. This was given in B1950 equatorial coordinates and to a precision of 0.1 seconds of time in the original table.
The Declination of the radio source. This was given in B1950 equatorial coordinates and to a precision of 1 arcseconds in the original table.
The Galactic Longitude of the radio source.
The Galactic Latitude of the radio source.
This is a flux density limit flag which is left blank if the quoted flux density value is the actual flux density, or is set to '>' if the quoted value is actually a lower limit on the flux density. Notice that MG1 fluxes over 5 Jy (5000 mJy) are listed as "> 5000" due to the receiver saturation.
The flux density in milliJanskies (mJy) measured by the Green Bank 91-m Telescope at either 4.830 or 4.775 GHz, according to the value of the flux_6_cm_flag parameter.
This flag is left blank if the observing frequency is 4.830 GHz (as in the MG2, MG3, and MG4 Surveys), or is set to "1" if the observing frequency is 4.775 GHz (as in the MG1 Survey).
This is a signal-to-noise ratio limit flag which is left blank if the quoted SNR value is the actual signal-to-noise, or is set to '>' if it is a lower limit on the actual signal-to-noise. Notice that MG1 SNR values over 100 are listed as ">99.9".
The signal-to-noise ratio of the radio source detection or, if snr_6_cm_limit = ">", the lower limit to the signal-to-noise ratio.
The "group" in which the source was found. Each source is assigned to one of nine groups depending on the source location and on whether the source was found in both the north moving and south moving scans. Sources with b > +10 deg and detected in the south, north, or both surveys are assigned to groups 0, 1, or 2, respectively. Sources lying in regions observed only once or at low Galactic latitude |b| < 10 deg, and detected in the south, north, or both surveys are assigned to groups 3, 4, or 5, respectively. Sources in the region observed twice but with b < -10 deg and detected in the south, north, or both surveys are assigned to groups 6, 7, or 8, respectively.
The radio spectral index of the source. The frequencies used to create the spectral index are a function of the value of the spectral_index_flag parameter (q.v.).
This parameter is a flag which indicates what frequencies were used to create the quoted spectral index: it is left blank if the spectral index is derived using NRAO 1400 MHz and Green Bank Telescope 4.830 GHz observations (as in the MG2, MG3 and MG4 Surveys), or is set to "1" if it is derived using Texas 365 MHz and Green Bank Telescope 4.775 GHz observations (as in the MG1 Survey).