SCUBAFEMOC - SCUBA Legacy Fundamental and Extended Map Object Catalogs

Overview

This table contains the SCUBA Legacy Catalogs, two comprehensive sets of source catalogs using data at 850 and 450um of the various astronomical objects obtained with the Submillimetre Common User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). The Fundamental Map Data Set contains data only where superior atmospheric opacity calibration data were available. The Extended Map Data Set contains data regardless of the quality of the opacity calibration. Each data set contains 1.2 degrees x 1.2 degrees maps at locations where data existed in the JCMT archive, imaged using the matrix inversion method. The Fundamental Data Set is composed of 1423 maps at 850um and 1357 maps at 450um. The Extended Data Set is composed of 1547 maps at 850um. Neither data set includes high sensitivity, single-chop SCUBA maps of "cosmological fields" nor solar system objects. Each data set was used to determine a respective object catalog, consisting of objects identified within the respective 850um maps using an automated identification algorithm.

The Fundamental and Extended Map Object Catalogs contain 5061 and 6118 objects, respectively. Objects are named based on their respective J2000.0 position of peak 850um intensity. The catalogs provide for each object the respective maximum 850um intensity, estimates of total 850um flux and size, and tentative identifications from the SIMBAD Database. Where possible, the catalogs also provide for each object its maximum 450um intensity and total 450um flux and flux ratios.

Since the goal of this project was to make maps and then catalog objects therein, all raw jiggle and scan data from SCUBA available in the JCMT archive were downloaded from the CADC in 2006 May. (Photometry and polarimetry data were ignored.) A full description of the instrumental characteristics of SCUBA was made by Holland et al. (1999MNRAS.303..659H). All maps are available at http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/scubalegacy/

Catalog Bibcode

2008ApJS..175..277D

References

The SCUBA legacy catalogues: submillimeter-continuum objects detected by SCUBA.
    Di Francesco J., Johnstone D., Kirk H., MacKenzie T., Ledwosinska E.
   <Astrophys. J. Suppl. Ser., 175, 277-295 (2008)>
   =2008ApJS..175..277D

Provenance

This table was created by the HEASARC in December 2010 based on CDS catalog J/ApJS/175/277 files table2.dat and table3.dat.

Parameters

Name
The JCMT-SCUBA source designation. e.g., 'JCMTSn JHHMMSS.s+DDMMSS'. This is based on the position of its pixel of maximum brightness at 850 microns in J2000 coordinates. The convention used is 'JCMTSn_JHHMMSS.S{+/-}DDMMSS' where 'JCMTS' is short for JCMT/SCUBA and 'n' is either 'F' or 'E' depending on whether the object is in the Fundamental or Extended Catalogs respectively.

RA
The Right Ascension of the pixel of maximum brightness for the source in the selected equinox. This was given in J2000 coordinates to a precision of 0.1 seconds of time in the original table.

Dec
The Declination of the pixel of maximum brightness for the source in the selected equinox. This was given in J2000 coordinates to a precision of 1 arcsecond in the original table

LII
The Galactic Longitude of the pixel of maximum brightness for the source.

BII
The Galactic Latitude of the pixel of maximum brightness for the source.

Map_File_Name
The name of the FITS file containing the 850-micron square degree map in which the object was identified. All maps are available at http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/scubalegacy/

Flux_850_um
The maximum 850-micron intensity of the source, in Jy/beam.

Eff_Radius_850_um
The 850-Micron effective radius of the source, in arcseconds. This is determined from the square root of the area of the object found by CLUMPFIND divided by pi. (Note that this is not the FWHM of a given object.)

RMS_850_um
The median 850-micron noise in Jy/beam of all of pixels associated with the object.

SNR_850_um
The signal-to-noise ratio of the 850-micron detection, i.e., the ratio of the 850-um intensity (flux_850_um) to the 850-um median noise (rms_850_um).

Int_Flux_850_um
The 850-micron flux of the source in Jy. This is derived as the flux of the object over its area as defined by CLUMPFIND, i.e., down to a level equal to 3 times the minimum noise of the map of origin. To determine 850 micron fluxes, a Gaussian beam of 22.9 arcseconds FWHM was assumed (see Section 4 of the reference paper).

Alt_Int_Flux_850_um
An alternative 850-micron flux of the object, in Jy. derived as the flux within an alternative area, i.e. that defined by a contour of 3 x 30 mJy/beam = 90 mJy/beam for all possible objects. Determining fluxes for all objects within a common intensity threshold allows fluxes between objects to be compared more easily. The common threshold of 30 mJy/beam was chosen to be representative of typical noise levels of the 850-micron maps, as seen in Figure 8 of the reference paper.

Alt_Eff_Radius_850_um
The effective radius of an alternative area for the source, in arcseconds. This area is defined as that over which the pixels had 850-um intensities >- 90 mJy/beam.

Flux_850_um_Flag
This parameter can contain a flag (value = 'c') which is set for sources for which the maximum 850 micron intensity is < 5 x 30 mJy/beam, or < 150mJy/beam. For stronger sources, this field is left blank.

Min_RMS_850_um
The minimum noise value at 850-um in the square degree map in which the source was identified.

Median_RMS_850_um
The median noise value at 850-um in the square degree map in which the source was identified.

RMS_450_um
The median 450-micron noise in Jy/beam over the alternative area of the source. CLUMPFIND was not used on the 450-um maps to define objects: instead, 450-um characteristics for each source were determined using the alternative area described above, i.e., the angular extent over which the 850-um intensities >= 90 mJy/beam.

Flux_450_um_Limit
This parameter contains an upper limit flag '<' for the maximum 450-micron intensity in the source if the latter is less than 3 times the median 450-um noise: in such cases. the listed 450-um maximum intensity is set to 3 times the median 450-um noise.

Flux_450_um
The maximum 450-micron intensity, in Jy/beam, within the alternative area of the source, or, if flux_450_um_limit = '<', 3 times the median 450-um noise over the source.

Int_Flux_450_um_Limit
This parameter contains an upper limit flag '<' for the 450-micron flux of the source if the maximum 450-um intensity is less than 3 times the median 450-um noise: in such cases, the listed 450-um flux is an upper limit derived by assuming that each pixel within the alternative area of the source has a value equal to to 3 rimes the median 450-um noise.

Int_Flux_450_um
The 450-micron flux of the source, in Jy, assuming a Gaussian beam of 17.3 arcseconds (see Section 4 of the reference paper). If int_flux_450_um_limit is '<', the quoted value is an upper limit calculated by assuming that each pixel within the alternative area of the source has a value equal to to 3 rimes the median 450-um noise.

Flux_Ratio_Limit
This parameter contains an upper limit flag '<' for the ratio of the maximum intensity at 450 um to that at 850 um if the maximum 450-um intensity is an upper limit, i.e., is less than 3 times the median 450-um noise.

Flux_Ratio
The ratio of the maximum 450-um to 850-um intensities of the object. For this ratio the 850-um and 450-um maps were convolved with beams from the other respective wavelength, to produce maps at each wavelength with a common beam size. (After this convolution, both maps are at the same resolution and have common "error beams"). If the flux_ratio_limit = '<' then the quoted value is an upper limit to the intensity ratio where the maximum 450-um intensity upper limit is equal to 3 times the median 450-um noise, corrected to take into account the larger beam size of the convolved 450-um map.

Int_Flux_Ratio_Limit
This parameter contains an upper limit flag '<' for the ratio of the flux at 450 um to that at 850 um if the maximum 450-um intensity is an upper limit, i.e., is less than 3 times the median 450-um noise.

Int_Flux_Ratio
The ratio of the 450-um to 850-um fluxes of the object determined over the alternative area described. If the flux_ratio_limit = '<' then the quoted value is an upper limit to the flux ratio where the 450-um flux upper limit is equal to that determined assuming each pixel in the convolved map within the alternative area contains a value equal to 3 times the beam-corrected median 450-um noise. Note that the large uncertainties of the 850-um and 450-um fluxes make the uncertainties in their ratios accordingly large, i.e., >= 60%.

Flux_Ratio_Flag
This parameter can contain further flags for the 450-um data, as follows:

  c = the maximum 850-micron intensity is not >= 5 X 30mJy/beam = 150 mJy/beam.
  M = no 450-micron data are present in the Fundamental Map Dataset at the
      location of the 850 micron object.
  n = actual median 450 micron noise of object exceeds 999 Jy/beam.

Proximity_State
This parameter contains information on the object proximity to the edge of its respective mapped area, as follows:

      clear = object was defined without any pixel extending to an area of the
              sky not mapped by SCUBA.
       edge = object extends to a map edge, and the determined fluxes should be
              considered as lower limits.

The maximum intensities and fluxes of identified objects can be considered accurate only if it has been sampled in its entirety over the sky.

Alt_Name
This field contains potential identifications of the objects from other catalogs. These were obtained from the SIMBAD astronomical database for objects in the literature that were located within 11.5 arcseconds (i.e., half the effective FWHM of the 850-um beam) of the position of maximum brightness of the object. The SIMBAD object chosen was the one closest to the position of maximum 850-um intensity. Given that many astronomical objects have several names, the authors prioritized the identification of objects based on their name, or if not named, identification within the NGC, IC, 3C, HD, SAO, BD, or IRAS catalogs. (In cases of identification in several of these catalogs, the selection was decided in the order in which the catalogs were just listed.) Many objects, however, are not found within these specific catalogs but were identified in various other studies. Following the nomenclature of the SIMBAD database, the bibliographic abbreviation of these studies, along with the identification in that study, are used for such identifications. If the SIMBAD database did not contain an identified object within an 11.5 arcsecond radius, this field is left blank. Note that extended objects can have very poorly defined positions (e.g., dark nebulae with positions determined from extinction maps), and in some cases these have been left blank when their SIMBAD positions are separated from the SCUBA 850-um positions by > 11.5 arcseconds.

Source_Sample
This parameter (introduced by the HEASARC to allow users to more easily select only objects from a specified SCUBA catalog) is set to 'F' for objects in the Fundamental Catalog, or to 'E' for objects in the Extended Catalog.

Contact Person

Questions regarding the SCUBAFEMOC database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:34:33 EDT