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SPORIABYSO - Spitzer Survey of Orion A and B Molecular Clouds YSOs Catalog

HEASARC
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Overview

This table contains results from a survey of the Orion A and B molecular clouds undertaken with the IRAC and MIPS instruments on board Spitzer. In total, five distinct fields were mapped, covering 9 deg2 in five mid-IR bands spanning 3 - 24 microns (um). The survey includes the Orion Nebula Cluster, the Lynds 1641, 1630, and 1622 dark clouds, and the NGC 2023, 2024, 2068, and 2071 nebulae. These data are merged with the Two Micron All Sky Survey point source catalog to generate a catalog of eight-band photometry. The authors identify 3479 dusty young stellar objects (YSOs) in the Orion molecular clouds by searching for point sources with mid-IR colors indicative of reprocessed light from dusty disks or in-falling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. The authors classify 2991 of the YSOs as pre-main-sequence stars with disks and 488 as likely protostars. Most of the sources were observed with IRAC in two to three epochs over six months; the authors search for variability between the epochs by looking for correlated variability in the 3.6 and 4.5 um bands. They find that 50% of the dusty YSOs show variability. The variations are typically small (~ 0.2 mag) with the protostars showing a higher incidence of variability and larger variations. The observed correlations between the 3.6, 4.5, 5.8, and 8 um variability suggests that we are observing variations in the heating of the inner disk due to changes in the accretion luminosity or rotating accretion hot spots.

Catalog Bibcode

2012AJ....144..192M

References

The Spitzer Space Telescope Survey of the Orion A and B Molecular Clouds.
I. A Census of Dusty Young Stellar Objects and a Study of Their Mid-infrared
Variability

    Megeath S.T., Gutermuth R., Muzerolle J., Kryukova E., Flaherty K.,
    Hora J.L., Allen L.E., Hartmann L., Myers P.C., Pipher J.L.,
    Stauffer J., Young E.T., Fazio G.G.
   <Astronomical Journal, Volume 144, Issue 6, article id. 192, 27 pp. (2012)>
   =2012AJ....144..192M

Provenance

This table was created by the HEASARC in January 2013 based on an electronic version of Table 4 from the reference paper which was obtained from the AJ web site.

Parameters

Source_Number
A unique sequential identification number for each Spitzer source in this catalog.

Name
The name for the young stellar object. This was created by the HEASARC using the '[MGM2012] SSTORI' prefix (for Megeath, Gutermuth, Muzerolle 2012, Spitzer Space Telescope, Orion) and the J2000.0 equatorial coordinates, in the style based on that recommended by the Dictionary of Nomenclature of Celestial Objects for other Spitzer catalogs.

RA
The Right Ascension of the young stellar object in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.01 seconds of time in the original reference.

Dec
The Declination of the young stellar object in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in the original reference.

LII
The Galactic Longitude of the young stellar object.

BII
The Galactic Latitude of the young stellar object.

Jmag
The 2MASS J-band magnitude of the young stellar object.

Jmag_Error
The uncertainty in the 2MASS J-band magnitude of the young stellar object. The uncertainties given are the formal uncertainties from the extraction of the photometry.

Hmag
The 2MASS H-band magnitude of the young stellar object.

Hmag_Error
The uncertainty in the 2MASS H-band magnitude of the young stellar object. The uncertainties given are the formal uncertainties from the extraction of the photometry.

Kmag
The 2MASS Ks-band magnitude of the young stellar object.

Kmag_Error
The uncertainty in the 2MASS Ks--band magnitude of the young stellar object. The uncertainties given are the formal uncertainties from the extraction of the photometry.

IRAC_3p6_um_Mag
The Spitzer/IRAC 3.6-micron band magnitude of the YSO.

IRAC_3p6_um_Mag_Error
The uncertainty in the Spitzer/IRAC 3.6-micron band magnitude of the YSO. The uncertainties given are the formal uncertainties from the extraction of the photometry. In addition to these formal uncertainties, the IRAC and MIPS instruments have absolute calibration uncertainties of 0.05 magnitudes. Since the absolute uncertainties affect all the sources equally, the authors tabulate only the formal uncertainties which varies from source to source.

IRAC_4p5_um_Mag
The Spitzer/IRAC 4.5-micron band magnitude of the YSO.

IRAC_4p5_um_Mag_Error
The uncertainty in the Spitzer/IRAC 4.5-micron band magnitude of the YSO. The uncertainties given are the formal uncertainties from the extraction of the photometry. In addition to these formal uncertainties, the IRAC and MIPS instruments have absolute calibration uncertainties of 0.05 magnitudes. Since the absolute uncertainties affect all the sources equally, the authors tabulate only the formal uncertainties which varies from source to source.

IRAC_5p8_um_Mag
The Spitzer/IRAC 5.8-micron band magnitude of the YSO.

IRAC_5p8_um_Mag_Error
The uncertainty in the Spitzer/IRAC 5.8-micron band magnitude of the YSO. The uncertainties given are the formal uncertainties from the extraction of the photometry. In addition to these formal uncertainties, the IRAC and MIPS instruments have absolute calibration uncertainties of 0.05 magnitudes. Since the absolute uncertainties affect all the sources equally, the authors tabulate only the formal uncertainties which varies from source to source.

IRAC_8p0_um_Mag
The Spitzer/IRAC 8.0-micron band magnitude of the YSO.

IRAC_8p0_um_Mag_Error
The uncertainty in the Spitzer/IRAC 8.0-micron band magnitude of the YSO. The uncertainties given are the formal uncertainties from the extraction of the photometry. In addition to these formal uncertainties, the IRAC and MIPS instruments have absolute calibration uncertainties of 0.05 magnitudes. Since the absolute uncertainties affect all the sources equally, the authors tabulate only the formal uncertainties which varies from source to source.

MIPS_24_um_Mag
The Spitzer/MIPS 24-micron band magnitude of the YSO.

MIPS_24_um_Mag_Error
The uncertainty in the Spitzer/MIPS 24-micron band magnitude of the YSO. The uncertainties given are the formal uncertainties from the extraction of the photometry. In addition to these formal uncertainties, the IRAC and MIPS instruments have absolute calibration uncertainties of 0.05 magnitudes. Since the absolute uncertainties affect all the sources equally, the authors tabulate only the formal uncertainties which varies from source to source.

Kmag_Extinction
The Ks band extinction towards the YSO, in magnitudes. This is only provided for sources with valid JHKS or HK[3.6][4.5] photometry. The determination of these values is described in Gutermuth et al. (2009, ApJS, 184, 18).

IRAC_Spectral_Index
The spectral index of the source over the four IRAC bands. Extinction is not accounted for in these values. High extinction can bias the IRAC spectral index to higher values. The determination of these values is described in Gutermuth et al. (2009, ApJS, 184, 18).

Broad_Type
The YSO classification:

      D = disk;
      P = protostar;
     FP = faint candidate protostar;
     RP = red candidate protostar (24-micron detection without 4.5, 5.8
          or 8.0 micron detection).
  

Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 8-Jan-2013