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DIRBEPSC - COBE DIRBE Point Source Catalog |
HEASARC Archive |
Overview
This table contains the Cosmic Background Explorer (COBE) Diffuse Infrared Background Experiment (DIRBE) Point Source Catalog, an all-sky catalog containing infrared photometry in 10 bands from 1.25 microns to 240 microns for 11,788 of the brightest near and mid-infrared point sources in the sky. Since DIRBE had excellent temporal coverage (100-1900 independent measurements per object during the 10 month cryogenic mission in 1989 to 1990), the catalog also contains information about variability at each wavelength, including amplitudes of variation observed during the mission. Since the DIRBE spatial resolution is relatively poor (0.7 degrees), the authors carefully investigated the question of confusion, and flagged sources with infrared-bright companions within the DIRBE beam. In addition, they filtered the DIRBE light curves for data points affected by companions outside of the main DIRBE beam but within the `sky' portion of the scan. At high Galactic latitudes (|b| > 5 degrees), the catalog contains essentially all of the unconfused sources with flux densities greater than 90, 60, 60, 50, 90, and 165 Jy at 1.25, 2.2, 3.5, 4.9, 12, and 25 microns, respectively, corresponding to magnitude limits of approximately 3.1, 2.6, 1.7, 1.3, -1.3, and -3.5. At longer wavelengths and in the Galactic Plane, the completeness is less certain because of the large DIRBE beam and possible contributions from extended emission. For each source, for comparison, the names of the sources in other catalogs, their spectral types, variability types, IRAS and 2MASS photometry, SIMBAD spectral types and published variability types, and whether or not the sources are known OH/IR stars are also included.Unlike the IRAS and 2MASS Catalogs, the DIRBE Point Source Catalog was not constructed by searching the DIRBE database with a point source template and extracting sources based on S/N and confirmation criteria. The DIRBE Catalog was constructed using a target sample list obtained from other infrared catalogs. Since DIRBE is much less sensitive per scan than IRAS or 2MASS, essentially all of the point sources with high S/N light curves in the DIRBE database are already contained in IRAS, 2MASS, and/or MSX. Thus, for simplicity, the authors used these previous catalogs to select a sample for the DIRBE Point Source Catalog.
Their initial sample included a total of 21,335 sources; the final catalog contains 11,788 sources. The initial sample was selected from the IRAS Point Source Catalog (1988), the 2MASS Point Source Catalog (Cutri 2003), and/or the MSX Point Source Catalog Version 1.2 (Egan et al. 1999, A&A, 349, 236) that satisfied at least one of the following criteria: (a) 2MASS J magnitude <= 4.51 (F1.25 >= 25 Jy), (b) 2MASS K magnitude <= 3.81 (F2.2 >= 20 Jy), (c) IRAS or MSX F12 >= 15 Jy, or (d) IRAS or MSX F25 >= 27.5 Jy. The 1.25 and 2.2 micron limits are equal to the average 1-sigma sensitivity per scan in the raw DIRBE light curves of Smith et al. (2002, AJ, 123, 948), while the 12 and 25 micron limits are 0.5 times the average noise levels per scan in that study. These low limits were selected in order to avoid missing variable stars that may have been faint during the 2MASS, IRAS, or MSX mission and to improve the completeness at 3.5 and 4.9 micron. Since the filtering process improves the average per measurement uncertainty, a sensitive selection criterion is warranted to include as many sources as possible.
There were 7872 sources with 2MASS J <= 4.51, 20,492 sources with 2MASS K <= 3.81, 4969 sources with IRAS F12 >= 15 Jy, 40 sources in the MSX IRAS Gaps survey with MSX F12 >= 15 Jy, 2753 sources with IRAS F25 >= 27.5 Jy, and 18 sources in the MSX IRAS Gaps survey with MSX F25 >= 27.5 Jy. Thus, the initial list is dominated by stars selected by the 2MASS criteria. These lists were merged together to make a single target list, containing 21,335 sources. To merge the 2MASS and IRAS/MSX lists, the authors used a 60 arcsecond matching radius. If more than one 2MASS source was within 60 arcseconds of the IRAS position, they assumed that the brightest K band source was the match.
Note that the authors did not include sources in their input list based on their 60 and/or 100 micron IRAS flux densities, as extended emission from cirrus becomes more significant at these wavelengths. This means that the DIRBE Point Source Catalog is biased against very cold objects, such as galaxies and molecular clouds. Since the authors only used the point source catalogs of 2MASS, IRAS, and MSX for source selection, their sample is also biased against extended objects. Note also that they are only targeting sources bright enough to detect their possible variability in the DIRBE database (i.e., sources that may be detected in a single DIRBE scan at at least one DIRBE wavelength). By co-adding the full light curves, it may be possible to detect fainter objects in the DIRBE database, but without variability information and with a higher likelihood of confusion.
The COBE DIRBE Point Source Catalog as presented here contains the time-averaged DIRBE flux densities Fnu in the 10 DIRBE bands for all 11,785 sources in the initial list that had a flux at minimum in the weekly averaged light curve in any of the six shortest DIRBE wavelengths greater than 3 times the average noise per data point, plus three additional sources (see Section 6 of the reference paper). These flux densities were calculated after filtering the light curves. The name of the object in the catalog from which it was originally selected from is also given (IRAS/MSX and/or 2MASS).
Catalog Bibcode
2004ApJS..154..673SReferences
The COBE DIRBE Point Source Catalog.
Smith B.J., Price S.D., Baker R.I.
<Astrophys. J. Suppl. Ser., 154, 673 (2004)>
=2004ApJS..154..673S
Provenance
This table was created by the HEASARC in April 2012 based on CDS Catalog J/ApJS/154/673 files table1.dat, table4.dat and table8.dat, and contains the DIRBE data for 11,788 of the brightest near- and mid-infrared point sources in the sky together with supporting data from 2MASS, IRAS, MSX and other catalogs.Parameters
Name
The DIRBE source designation using the naming scheme registered
with the CDS Dictionary of Nomenclature of Celestial Object based
on the infrared source position in J2000.0 equatorial coordinates, viz.,
'DIRBE DHHMMSSssADDMMSSs', where A = P is used for positive declination,
and A = N is used for negative declination.
TwoMASS_Name
The 2MASS designation of the infrared source.
A 2MASS name is not given if there was no 2MASS
counterpart to the IRAS/MSX source with J <= 4.51 and/or K <= 3.81.
Alt_Name
The IRAS or MSX designation of the infrared source.
Note that an IRAS/MSX name is only given if there is an IRAS/MSX
counterpart to the 2MASS source with F12um >= 15 Jy and/or F25um >=
27.5 Jy.
RA
The Right Ascension of the infrared source in the selected equinox.
This is based on the 2MASS position for those sources with 2MASS counterparts,
else on the IRAS or MSX position.
Dec
The Declination of the infrared source in the selected equinox.
This is based on the 2MASS position for those sources with 2MASS counterparts,
else on the IRAS or MSX position.
LII
The Galactic Longitude of the infrared source.
BII
The Galactic Latitude of the infrared source.
Flux_1p25um
The 1.25-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_1p25um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 1.25-um weighted mean flux
density of the object (after filtering), in Jy.
Flux_1p25um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_1p25um_Amp
The total observed amplitude of variation Delta-Mag for the
object in the corresponding band during the DIRBE observations, given by
Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_1p25um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_1p25um
The number of unfiltered data points available in the
corresponding band.
Flux_2p2um
The 2.2-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_2p2um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 2.2-um weighted mean flux
density of the object, in Jy.
Flux_2p2um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_2p2um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_2p2um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_2p2um
The number of unfiltered data points available in the
corresponding band.
Flux_3p5um
The 3.5-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_3p5um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 3.5-um weighted mean flux
density of the infrared source, in Jy.
Flux_3p5um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_3p5um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_3p5um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_3p5um
The number of unfiltered data points available in the
corresponding band.
Flux_4p9um
The 4.9-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_4p9um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 4.9-um weighted mean flux
density of the infrared source, in Jy.
Flux_4p9um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_4p9um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_4p9um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_4p9um
The number of unfiltered data points available in the
corresponding band.
Flux_12um
The 12-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_12um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 12-um weighted mean flux
density of the infrared source, in Jy.
Flux_12um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_12um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_12um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_12um
The number of unfiltered data points available in the
corresponding band.
Flux_25um
The 25-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_25um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 25-um weighted mean flux
density of the infrared source, in Jy.
Flux_25um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_25um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_25um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_25um
The number of unfiltered data points available in the
corresponding band.
Flux_60um
The 60-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_60um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 60-um weighted mean flux
density of the infrared source, in Jy.
Flux_60um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_60um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_60um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_60um
The number of unfiltered data points available in the
corresponding band.
Flux_100um
The 100-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_100um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 100-um weighted mean flux
density of the infrared source, in Jy.
Flux_100um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_100um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_100um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_100um
The number of unfiltered data points available in the
corresponding band.
Flux_140um
The 140-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_140um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 140-um weighted mean flux
density of the infrared source, in Jy.
Flux_140um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_140um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_140um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_140um
The number of unfiltered data points available in the
corresponding band.
Flux_240um
The 240-um weighted mean flux density of the infrared source
as measured by DIRBE, in Jy. A null value means that no such information is
available.
Flux_240um_Sigma
The standard deviation (sigma) of the individual flux
measurements constituting the 240-um weighted mean flux
density of the infrared source, in Jy.
Flux_240um_Error
The average uncertainty per individual measurement (err) of
the corresponding flux density (data point in the light curve) of the object,
in Jy.
Mag_240um_Amp
The total observed amplitude of variation for the
object in the corresponding band during the DIRBE
observations, Delta-Mag = 2.5 log(Fmax/Fmin), where Fmin and Fmax are
the minimum and maximum flux densities after block-averaging over 1-week time
intervals using a running average. Note that the observed changes in
brightness given in the DIRBE
Catalog may not represent the full range of variation for these stars, because
many of the light curves are not complete and may not cover a full pulsation
period. In these cases, the observed variations are a lower limit to the true
amplitudes of variation. If the S/N at minimum in the weekly averaged light
curve was less than 3, then an amplitude and amplitude uncertainty were not
calculated and this parameter has been set to a null value.
Mag_240um_Amp_Error
The uncertainty in the total observed amplitude of
variation Delta-Mag for the object in the corresponding band during the DIRBE
observations, calculated from Sigma(Delta-Mag) = 2.5
Sigma(Fmax/Fmin) /[2.303 (F_max/Fmin)], where
Sigma(Fmax/Fmin)/(F_max/Fmin) = [(Sigma(Fmax)/Fmax)2 +
(Sigma(Fmin)/Fmin)2]0.5, and sigma(Fmax) and sigma(Fmin) are set
equal to the average uncertainty per measurement (err).
Number_Obs_240um
The number of unfiltered data points available in the
corresponding band.
Conf_Flags_1p25um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as follows (values of 0 mean that the flag is not
set):
Flag1 = 1: IRAS/2MASS/MSX/CIO/(Egan & Price, CDS Cat. <V/98>)
companion greater than the DIRBE noise level lies within a 0.5 degree
radius of the target source above 25, 20, 20, 10, 30, 55, 320 and 765 Jy
at 1.25, 2.2, 3.5, 4.9, 12, 25, 60 and 100 um, respectively. This flag
was not set at 140 or 240 um
Flag2 = 1: Greater than 3-sigma discrepancy between the
time-averaged DIRBE flux density and the IRAS or 2MASS flux density.
This flag is not set for the Catalog of Infrared Observation
comparison or the MSX catalog comparison, because of possible large
uncertainties in the photometry. It was also not set at 140 or 240
microns, due to the lack of an all-sky survey at those wavelengths.
This flag may be an indicator of extended emission around a point
source rather than a discrete companion. Alternatively, it may
indicate strong variability.
Flag3 = 1: This flag was set if the rms/err in the light
curve was > 3 for any 2-week period containing at least 10 datapoints.
This is an indication that the light curve may be affected by a nearby
companion that was missed by the filtering process.
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_2p2um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_3p5um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_4p9um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_12um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_25um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_60um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_100um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_140um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Conf_Flags_240um
The DIRBE confusion flags Flag1/Flag2/Flag3 in the
corresponding band, coded as for the 1.25-um band (see above).
If a source has a Flag1 value set to 1, there is information about the
confusing source or sources in the file
http://cdsarc.u-strasbg.fr/ftp/cats/J_ApJS/154/673/table5.dat.
Jmag
The 2MASS J magnitude of the object.
Jmag_Error
The uncertainty in the 2MASS J magnitude of the object.
Hmag
The 2MASS H magnitude of the object.
Hmag_Error
The uncertainty in the 2MASS H magnitude of the object.
Kmag
The 2MASS Ks magnitude of the object.
Kmag_Error
The uncertainty in the 2MASS Ks magnitude of the object.
IRAS_Flux_12um
The IRAS 12-um flux density of the object, in Jy.
IRAS_Flux_25um
The IRAS 25-um flux density of the object, in Jy.
IRAS_Flux_60um
The IRAS 60-um flux density of the object, in Jy.
IRAS_Flux_100um
The IRAS 100-um flux density of the object, in Jy.
IRAS_Qual_Flag_12um
The IRAS 12-um quality flag for the IRAS detection
of the object, where 3 means high-quality, 2 means moderate-quality and 1
means an upper limit.
IRAS_Qual_Flag_25um
The IRAS 25-um quality flag for the IRAS detection
of the object, where 3 means high-quality, 2 means moderate-quality and 1
means an upper limit.
IRAS_Qual_Flag_60um
The IRAS 60-um quality flag for the IRAS detection
of the object, where 3 means high-quality, 2 means moderate-quality and 1
means an upper limit.
IRAS_Qual_Flag_100um
The IRAS 100-um quality flag for the IRAS detection
of the object, where 3 means high-quality, 2 means moderate-quality and 1
means an upper limit.
IRAS_Var_Flag
The IRAS variability parameter VAR for the object,
being the percent variability (0 - 99) that the source is variable based
on an anlysis of the 12- and 25-um flux densities and their uncertainties.
IRAS_Conf_Flag
The IRAS confusion flag CONFUSE for the object,
being the Hex-encoded (0 - F) sum of the individual band binary values, with
bit 0 corresponding to 12 um, 1 to 25 um, 2 to 60 um and 3 to 100 um.
Thus, a source confused at 12 and 25 um would have CONFUSE = 0011 = 3 (Hex),
while a source confused at 25, 60 and 100 um wouyld have CONFUSE = 1110 =
E (Hex).
IRAS_Cirr1_Flag
The IRAS cirrus flag CIRR1 for the object.
The infrared cirrus affects a large portion of the entire sky at 60 and 100
microns. Cirrus can seriously hamper efforts to extract point sources from
the data. Additionally, cirrus can also produce structure on a point
source scale that can masquerade as true point source. The CIRR1 flag gives
the number of 100 micron-only sources in the extraction data base within a
radius of 30 arcminutes from the source. The flag is a
good discriminant that warns a user that cirrus which contains structure on
a point source scale is present in a given region. Values above 2 signify
probable contamination.
IRAS_Cirr2_Flag
The IRAS cirrus flag CIRR2 for the object.
The infrared cirrus affects a large portion of the entire sky at 60 and 100
microns. Cirrus can seriously hamper efforts to extract point sources from
the data. Additionally, cirrus can also produce structure on a point
source scale that can masquerade as true point source. The CIRR2 flag gives
the cirrus indication on a larger scale than the
cirr1 flag and compares a 'cirrus flux' with the source flux at 100
micron. Values larger than ~ 4 - 5 indicate the presence of considerable
structure in the 100 micron emission on a 1/2 degree scale. A value of 0
indicates that no 1/2 degree data was available for the source in
question.
IRAS_Cirr3_Flag
The IRAS cirrus flag CIRR3 for the object.
The infrared cirrus affects a large portion of the entire sky at 60 and 100
microns. Cirrus can seriously hamper efforts to extract point sources from
the data. Additionally, cirrus can also produce structure on a point
source scale that can masquerade as true point source. The CIRR3 flag is the
total surface brightness of the sky surrounding the
source in a 1/2 degree beam at 100 micron, clipped to exclude values
greater than 254 MJy sr-1. Values of the cirr3 flag greater than 30 MJy
sr-1 indicate emission from dust with an appreciable column level. A
value of -1 means that no data were available.
Ctrpart_Name_1
The closest source listed in SIMBAD lieing within 1
arcminute and assumed to be the same source.
Object_Type_1
The CDS SIMBAD object type of the nearest SIMBAD object
to the infrared source. The schema used by CDS is described at
http://simbad.u-strasbg.fr/simbad/sim-display?data=otypes . The HEASARC
has changed SIMBAD object type values beginning with an asterisk to avoid
confusion with wild card values, thus:
CDS value In this table
* Star
** Mult
*iA StrA
*iC StrC
*iN StrN
i StrD
Spect_Type_1
The spectral type of the nearest SIMBAD object
to the infrared source.
Offset_1
The offset in arcseconds between the DIRBE PSC Catalog position
and the position of the nearest SIMBAD object.
Ctrpart_Name_2
SIMBAD sometimes has more than one listing for the same
astrophysical source, if the source appeared in 2 different catalogs with
slightly different positions and different names. If a second SIMBAD source
is listed within 5 arcseconds of the first source,its name is listed
in this parameter.
Object_Type_2
The CDS SIMBAD object type of the second nearest SIMBAD object
to the infrared source. The schema used by CDS is described at
http://simbad.u-strasbg.fr/simbad/sim-display?data=otypes . The HEASARC
has changed SIMBAD object type values beginning with an asterisk to avoid
confusion with wild card values, thus:
CDS value In this table
* Star
** Mult
*iA StrA
*iC StrC
*iN StrN
i StrD
Spect_Type_2
The spectral type of the second nearest SIMBAD object
to the infrared source.
Offset_2
The offset in arcseconds between the DIRBE PSC Catalog position
and the position of the second nearest SIMBAD object.
IRAS_LRS_Type
The IRAS low-resolution spectrometer (LRS) spectral type
of the infrared source,
as defined in Section 2 of Kwok et al. (1997, ApJS, 112, 557).
GCVS_Name
The variable star designation of the object, taken from either
the GCVS (General Catalog of Variable Stars: Kholopov et al. 1985-1988),
the New Catalog of Suspected Variables (NSV: Kukarin et al. 1982), or the
NSV Supplement (NSVS: Kazarovets and Durlevich 1998) and using search radii
of 60, 30 and 5 arcseconds, respectively.
Variability_Type
The GCVS/NSV/NSVS variability type of the object.
The HEASARC has changed variability type values of '*' for objects with
'unique' spectra to 'Unique' to avoid confusion with wild card values.
OHIR_Star_Name
This flag parameter is set to `OH' if there is a counterpart
to the infrared source in the Chen et al. (2001, A&A, 368, 1006)
OH/IR star compilation.
Period_Limit
This flag parameter is set to '>' if the quoted period is
a lower limit.
Period
The period of the variable star counterpart to the infrared source
taken from the GCVS, NSV or NSVS Catalogs, in days.
OH_Exp_Velocity
The OH expansion velocity for the counterpart OH/IR star
outflow associated with the infrared source, in km s-1.
Opt_Catalog_Flag
This 2MASS associated optical catalog flag indicates that
there is a counterpart in either the Tycho-2 Catalog (CDS Cat. I/259) if set
to 'T', or the USNO-A2.0 Catalog (CDS Cat. I/252) if set to 'U', else is 0.
See the 2MASS Explanatory Supplement for more information.
Bmag
The optical B-band magnitude of the counterpart taken from the
2MASS associated optical catalog.
Vmag
The 2MASS optical V-vand magnitude of the counterpart taken from the
2MASS associated optical catalog.
Contact Person
Questions regarding the DIRBEPSC database table can be addressed to the HEASARC Help Desk.Page Author: Browse Software Development Team
Last Modified: Wednesday, 23-Nov-2022 19:34:12 EST
- HEASARC Director: Dr. Andy Ptak
- NASA Official: Dr. Andy Ptak
- Web Curator: J.D. Myers
- Last Modified: 23-Nov-2022