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WMAPPTSRC - WMAP Nine-Year Five-Band Point Source Catalog

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Overview

The Wilkinson Microwave Anisotropy Probe (WMAP) is designed to produce all-sky maps of the cosmic microwave background (CMB) anisotropy. The WMAP 9-Year Point Source Catalog contained herein has information on point sources in five frequency bands from 23 to 94 GHz, based on data from the entire 9 years of the WMAP sky survey from 10 Aug 2001 0:00 UT to 10 Aug 2010 0:00 UT, inclusive. The 5-band search technique used in the first-year, 3-year, 5-year and 7-year analyses now finds 501 point sources, compared to 471 point sources found in the 7-year analysis and 390 sources found in the 5-year analysis.

The 5-band search method is largely unchanged from the 7-year analysis (Gold et al. 2011, ApJS, 192, 15). This method searches for point sources in each of the five WMAP wavelength bands. The nine-year signal-to-noise ratio map in each band is filtered in harmonic space by bl/[(bl)2 Cl(cmb) + Cl(noise)], where bl is the transfer function of the WMAP beam response, Cl(cmb) is the CMB angular power spectrum, and Cl(noise) is the noise power. The filtering suppresses CMB and Galactic foreground fluctuations relative to point sources. For each peak in the filtered maps that is > 5 sigma in any band, the unfiltered temperature map in each band is fit with the sum of a planar base level and a beam template formed by convolving an azimuthally symmetrized beam profile with a skymap pixel. (This method was previously used by Weiland et al. (2011, ApJS, 192, 19) for selected celestial calibration sources and is more accurate than the Gaussian fitting that was used for the seven-year and earlier point source analyses). The peak temperature from each beam template fit is converted to a source flux density using the conversion factor Gamma given in Table 3 of the reference paper. The flux density uncertainty is calculated from the 1-sigma uncertainty in the peak temperature, and does not include any additional uncertainty due to Eddington bias. Flux density values are entered into the catalog for bands where they exceed 2 sigma and where the source width from an initial Gaussian fit is within a factor of two of the beam width. A point source catalog mask is used to exclude sources in the Galactic plane and Magellanic cloud regions. This mask has changed from the seven-year analysis in accordance with changes in the KQ85 temperature analysis mask. A map pixel is outside of the nine-year point source catalog mask if it is either outside of the diffuse component of the nine-year KQ85 temperature analysis mask or outside of the seven-year point source catalog mask. The present mask admits 83% of the sky, compared to 82% and 78% for the previous 7-year and 5-year versions, respectively.

The authors identify possible 5-GHz counterparts to the WMAP sources found by cross-correlating with the GB6 (Gregory et al. 1996, ApJS, 103, 427), PMN (Griffith et al. 1994, ApJS, 90, 179; Griffith et al. 1995, ApJS, 97, 347; Wright et al. 1994, ApJS, 94, 111; Wright et al. 1996, ApJS, 103, 145), Kuehr et al. (1981, A&AS, 45, 367), and Healey et al. (2009, AJ, 138, 1032) catalogs. A 5-GHz source is identified as a counterpart if it lies within 11 arcminutes of the WMAP source position (the mean WMAP source position uncertainty is 4 arcminutes). When two or more 5 GHz sources are within 11 arcminutes, the brightest is assumed to be the counterpart and a multiple identification flag is entered in the catalog.

A separate 9-year CMB-free Point Source Catalog (available in Browse as the WMAPCMBFPS table) has information on point sources in three frequency bands from 41 to 94 GHz: the CMB-free method identified 502 point sources in a linear combination map formed from 41, 61 and 94 GHz band maps using weights such that CMB fluctuations are removed and flat-spectrum point sources are retained. The two catalogs have 387 sources in common. As noted by Gold et al. (2011, ApJS, 192, 15), differences in the source populations detected by the two search methods are largely caused by Eddington bias in the five-band source detections due to CMB fluctuations and noise. At low flux levels, the five-band method tends to detect point sources located on positive CMB fluctuations and to overestimate their fluxes, and it tends to miss sources located in negative CMB fluctuations. Other point source detection methods have been applied to WMAP data and have identified sources not found by our methods (e.g., Scodeller et al. (2012, ApJ, 753, 27); Lanz (2012, ADASS 7); Ramos et al. (2011, A&A, 528, A75), and references therein).

For more details of how the point source catalogs were constructed, see Section 5.2.2 of the reference paper.


Catalog Bibcode

2012arXiv1212.5225B

References

Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations:Final
Maps and Results

     Bennett C.L., Larson D., Weiland J.L., Jarosik N., Hinshaw G., Odegard N.,
     Smith K.M., Hill R.S., Gold B., Halpern M., Komatsu E., Nolta M.R.,
     Page L., Spergel D.N., Wollack E., Dunkley J., Kogut A., Limon M.,
     Meyer S.S., Tucker G.S., Wright, E.L.
  <Astrophys. J. Suppl., submitted)>
  =2012arXiv1212.5225B

Provenance

This table was last updated by the HEASARC in January 2012 based on an electronic version of Table 18 from the 2012 (ApJS, submitted) paper which was obtained from the LAMBDA web site, the file http://lambda.gsfc.nasa.gov/data/map/dr5/dfp/ptsrc/wmap_ptsrc_catalog_9yr_v5.txt. The source_flag values were modified from those given in this file to reflect the values that were given in the printed version of the table.

HEASARC Implementation

The HEASARC has converted all flux densities from the Jy units given in the original table into the mJy units which it uses in its tables for radio- and mm-band flux densities. The source_flags values were edited by the HEASARC to reflect the values that were given in the published version of the table, viz., values of 'M' were changed to 'a', and the three individual values of 'b', 'c', and 'd'. added to the appropriate entries.

Parameters

Name
The name of the point source using the IAU-style position-based source designation, e.g., 'WMAP JHHMM+DDMM'.

RA
The Right Ascension of the WMAP source in the selected equinox. The RA was given in J2000.0 coordinates to a precision of 0.1 seconds of time in the original table. The WMAP source position uncertainty is 4 arcminutes.

Dec
The Declination of the WMAP source in the selected equinox. The Dec was given in J2000.0 coordinates to a precision of 1 arcsecond in the original table. The WMAP source position uncertainty is 4 arcminutes.

LII
The Galactic Longitude of the WMAP source.

BII
The Galactic Latitude of the WMAP source.

Flux_23_GHz
The K-band (22.5 GHz) flux density of the WMAP source, in mJy. The flux densities were specified to a precision of 0.1 Jy (100 mJy) in the original table. Flux density values are entered into the catalog where they exceed 2 sigma and where the source width from an initial Gaussian fit is within a factor of two of the beam width. A null value is entered for the flux and for the flux uncertainty in a band if the source was not detected in that band.

Flux_23_GHz_Error
The uncertainty in the K-band (22.5 GHz) flux density, in mJy, calculated from the 1-sigma uncertainty in the peak temperature, and does not include any additional uncertainty due to Eddington bias.

Flux_33_GHz
The Ka-band (32.8 GHz) flux density of the WMAP source, in mJy. The flux densities were specified to a precision of 0.1 Jy (100 mJy) in the original table. Flux density values are entered into the catalog where they exceed 2 sigma and where the source width from an initial Gaussian fit is within a factor of two of the beam width. A null value is entered for the flux and for the flux uncertainty in a band if the source was not detected in that band.

Flux_33_GHz_Error
The uncertainty in the Ka-band (32.8 GHz) flux density, in mJy, calculated from the 1-sigma uncertainty in the peak temperature, and does not include any additional uncertainty due to Eddington bias.

Flux_41_GHz
The Q-band (40.4 GHz) flux density of the WMAP source, in mJy. The flux densities were specified to a precision of 0.1 Jy (100 mJy) in the original table. Flux density values are entered into the catalog where they exceed 2 sigma and where the source width from an initial Gaussian fit is within a factor of two of the beam width. A null value is entered for the flux and for the flux uncertainty in a band if the source was not detected in that band.

Flux_41_GHz_Error
The uncertainty in the Q-band (40.4 GHz) flux density, in mJy, calculated from the 1-sigma uncertainty in the peak temperature, and does not include any additional uncertainty due to Eddington bias.

Flux_61_GHz
The V-band (60.2 GHz) flux density of the WMAP source, in mJy. The flux densities were specified to a precision of 0.1 Jy (100 mJy) in the original table. Flux density values are entered into the catalog where they exceed 2 sigma and where the source width from an initial Gaussian fit is within a factor of two of the beam width. A null value is entered for the flux and for the flux uncertainty in a band if the source was not detected in that band.

Flux_61_GHz_Error
The uncertainty in the V-band (60.2 GHz) flux density, in mJy, calculated from the 1-sigma uncertainty in the peak temperature, and does not include any additional uncertainty due to Eddington bias.

Flux_94_GHz
The W-band (93.0 GHz) flux density of the WMAP source, in mJy. The flux densities were specified to a precision of 0.1 Jy (100 mJy) in the original table. Flux density values are entered into the catalog where they exceed 2 sigma and where the source width from an initial Gaussian fit is within a factor of two of the beam width. A null value is entered for the flux and for the flux uncertainty in a band if the source was not detected in that band.

Flux_94_GHz_Error
The uncertainty in the W-band (93.0 GHz) flux density, in mJy, calculated from the 1-sigma uncertainty in the peak temperature, and does not include any additional uncertainty due to Eddington bias.

Alt_Name_5_GHz
The 5-GHz counterpart source identification. The authors have cross-correlated detected sources with the GB6, PMN, Kuehr et al. (1981, A&AS, 45, 367) and Healey et al. (2009, ApJ, 138, 1032) catalogs in order to identify 5-GHz counterparts. If a 5-GHz source was within 11 arcminutes of the WMAP source position (the mean WMAP source position uncertainty is 4 arcminutes), the authors tagged the WMAP source. When more than one source lies within this cutoff radius, the brightest one was assumed to be the WMAP counterpart and a multiple identification flag (source_flag = 'a') was entered for that particular WMAP source.

Source_Flag
This flag parameter contains the following coded source notes:

   a = indicates WMAP sources with multiple 5-GHz IDs,
   b = WMAP J0322-3711 (Fornax A) is extended, and the fluxes listed were
       obtained by aperture photometry,
   c = WMAP J1356+7644 is outside of the declination range of the GB6 and PMN
       catalogs. It was identified as QSO NVSS J135755+764320 by Trushkin
       (2006, private communication),
   d = WMAP J1632+8227 is outside of the declination range of the GB6 and PMN
       catalogs. It was identified as NGC 6251 by Trushkin
       (2003, BSAONC, 55, 90).
  

YR1_Source_Number
The First Year Catalog source identification number. In the first-year catalog, source ID numbers were assigned on the basis of position (sorted by galactic longitude). Now, rather than assigning new numbers to the newly detected sources, the authors recommend that WMAP sources be referred to by their position-based names (see above), but, for reference, the first-year source ID is given in this parameter.

Spectral_Index
The spectral index of the source in the WMAP bands.

Spectral_Index_Error
The uncertainty in the spectral index of the source in the WMAP bands.

Band_Det
A bitmask that indicates in which bands the source was detected above 5 sigma in the filtered map. For example, for a source that was detected above 5 sigma in the K, Ka, and Q bands, the bitmask is set to 20 + 21 + 22 = 7, and for a source detected in W band only the bitmask is set to 24 = 16.


Contact Person

Questions regarding the WMAPPTSRC database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 3-Jan-2013