3.18 tmass_original_valid

2MASS PSC Catalogue
Reference paper: Skrutskie et al. 2006, AJ 131, 1163
Documentation: http://www.ipac.caltech.edu/2mass/releases/allsky/doc/explsup.html
Original catalogue: ftp://ftp.ipac.caltech.edu/pub/2mass/allsky

Columns description:

ph_qual : JHKs Photometric quality flag (string)

Photometric quality flag. Three character flag, one character per band [JHKs], that provides a summary of the net quality of the default photometry in each band.
The value for ph_qual is set for a band according to the precedence of the table below. For example, a source that is tested and meets the conditions for category ”X” is not tested for subsequent qualities.

  • •

    ”X” - There is a detection at this location, but no valid brightness estimate can be extracted using any algorithm. Default magnitude is null.

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    ”U” - Upper limit on magnitude. Source is not detected in this band, or it is detected, but not resolved in a consistent fashion with other bands. A value of ph_qual=”U” does not necessarily mean that there is no flux detected in this band at the location.

  • •

    ”F” - This category includes sources where a reliable estimate of the photometric error could not be determined. The uncertainties reported for these sources in [jhk]_msigcom are flags and have numeric values >8.0.

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    ”E” - This category includes detections where the goodness-of-fit quality of the profile-fit photometry was very poor, or detections where psf fit photometry did not converge and an aperture magnitude is reported, or detections where the number of frames was too small in relation to the number of frames in which a detection was geometrically possible.

  • •

    ”A” - Detections in any brightness regime where valid measurements were made with [jhk]_snr>10 AND [jhk]_cmsig<0.10857.

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    ”B” - Detections in any brightness regime where valid measurements were made with [jhk]_snr>7 AND [jhk]_cmsig<0.15510.

  • •

    ”C” - Detections in any brightness regime where valid measurements were made with [jhk]_snr>5 AND [jhk]_cmsig<0.21714.

  • •

    ”D” - Detections in any brightness regime where valid measurements were made with no [jhk]_snr or [jhk]_cmsig requirement.

tmass_oid : Unique Numeric Identifier (long)

Incremental unique numeric identifier (increasing with declination). This is the only field which was not in the original 2MASS catalogue, but was added for cross-match purposes.

designation : source Id in original catalog (string)

Sexagesimal, equatorial position-based source name in the form: hmmssss+ddmmsss[ABC…] The prefix ”2MASS J” in not explicitely listed in the designation.

ra : RA, ICRS (double, Angle[deg])

J2000 right ascension with respect to the ICRS

dec : DEC, ICRS (double, Angle[deg])

J2000 declination with respect to the ICRS

err_maj : semi-major axis pos uncertainty (float, Angle[arcsec])

Semi-major axis length of the one sigma position uncertainty ellipse

err_min : semi-minor axis pos uncertainty (float, Angle[arcsec])

Semi-minor axis length of the one sigma position uncertainty ellipse

err_ang : position angle (int, Angle[deg])

Position angle on the sky of the semi-major axis of the position uncertainty ellipse (East of North)

j_m : Band J magnitude (float, Magnitude[mag])

Default J-band magnitude.
In case of a source not detected in the J-band, it is an upper limit and the corresponding total photometric uncertainty is NULL.
In case of a source detected in the J-band and with no useful brightness estimate, it is set to NULL.

j_msigcom : J magnitude uncertainty (float, Magnitude[mag])

Total photometric uncertainty for the default J-band magnitude. This column is NULL if the default magnitude is a 95% confidence upper limit (i.e. the source is not detected, or inconsistently deblended in the J-band).

h_m : Band H magnitude (float, Magnitude[mag])

Default H-band magnitude.
In case of a source not detected in the H-band, it is an upper limit and the corresponding total photometric uncertainty is NULL.
In case of a source detected in the H-band and with no useful brightness estimate, it is set to NULL.

h_msigcom : H magnitude uncertainty (float, Magnitude[mag])

Total photometric uncertainty for the default H-band magnitude. This column is NULL if the default magnitude is a 95% confidence upper limit (i.e. the source is not detected, or inconsistently deblended in the H-band).

ks_m : Band Ks magnitude (float, Magnitude[mag])

Default Ks-band magnitude.
In case of a source not detected in the Ks-band, it is an upper limit and the corresponding total photometric uncertainty is NULL.
In case of a source detected in the Ks-band and with no useful brightness estimate, it is set to NULL.

ks_msigcom : Ks magnitude uncertainty (float, Magnitude[mag])

Total photometric uncertainty for the default Ks-band magnitude. This column is NULL if the default magnitude is a 95% confidence upper limit (i.e. the source is not detected, or inconsistently deblended in the Ks-band.

ext_key : UID of the record in the XSC (long)

Unique identification number of the record in the XSC (2MASS Extended Source Catalogue) that corresponds to this point source. Can be NULL if no corresponding extended source is present in the XSC.

j_date : Julian Date of source measurement (double, Time[Julian Date (day)])

The Julian Date of the source measurement accurate to +30 seconds. This value is extrapolated from the start time of the Survey scan using the difference between the declinations of the source and the first row in the Tile divided by the scanning rate of the telescope (approximately 5sec). The scanning rate of the two 2MASS telescopes was slightly different because of the need to optimize the dithering of images on the arrays.