J/MNRAS/435/1671 SCUBA-2 850um survey in σ Ori cluster (Williams+, 2013)
A SCUBA-2 850-µm survey of protoplanetary discs in the σ Orionis
cluster.
Williams J.P., Cieza L.A., Andrews S.M., Coulson I.M., Barger A.J.,
Casey C.M., Chen C.-C., Cowie L.L., Koss M., Lee N., Sanders D.B.
<Mon. Not. R. Astron. Soc., 435, 1671-1679 (2013)>
=2013MNRAS.435.1671W 2013MNRAS.435.1671W
ADC_Keywords: Associations, stellar ; Photometry, millimetric/submm
Keywords: protoplanetary discs - submillimetre: stars
Abstract:
We present the results from a large 850um survey of the σ
Orionis cluster using the SCUBA-2 camera on the James Clerk Maxwell
Telescope. The 0.5 diameter circular region we surveyed contains 297
young stellar objects with an age estimated at about 3Myr. We detect
nine of these objects, eight of which have infrared excesses from an
inner disc. We also serendipitously detect three non-stellar sources
at >5σ that are likely background submillimetre galaxies. The
nine detected stars have inferred disc masses ranging from 5 to about
17MJup, assuming similar dust properties as Taurus discs and an
interstellar medium gas-to-dust ratio of 100. There is a net positive
signal towards the positions of the individually undetected infrared
excess sources indicating a mean disc mass of 0.5MJup. Stacking the
emission towards those stars without infrared excesses constrains
their mean disc mass to less than 0.3MJup, or an equivalent Earth
mass in dust. The submillimetre luminosity distribution is
significantly different from that in the younger Taurus region,
indicating disc mass evolution as star-forming regions age and the
infrared excess fraction decreases. Submillimetre Array observations
reveal CO emission towards four sources demonstrating that some, but
probably not much, molecular gas remains in these relatively evolved
discs. These observations provide new constraints on the dust and gas
mass of protoplanetary discs during the giant planet building phase
and provide a reference level for future studies of disc evolution.
Description:
We observed a circular region with diameter 0.5° (about the
diameter of the full Moon) towards the sigma Orionis cluster at 850um.
The data were taken in queue mode over numerous observing runs from
2011 October to 2013 January (programme IDs: M11BH02A, M12AH02A and
M12BH47A) in median (JCMT band 3) weather conditions, defined by the
zenith optical depths at 225GHz lying between 0.08 and 0.12. This
corresponds to precipitable water vapour levels ∼2-3mm and zenith
optical depths at 850um ∼0.25-0.35. The total on-source integration
time was 31h.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 37 297 SCUBA-2 flux densities
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See also:
J/ApJ/662/1067 : Spitzer observations of sigma Orionis (Hernandez+, 2007)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- [HHM2007] Identification number (1)
6- 8 A3 --- Class YSO class (1)
10- 17 F8.5 deg RAdeg Right ascension (J2000)
19- 26 F8.5 deg DEdeg Declination (J2000)
28- 32 F5.2 mJy F850 SCUBA flux density at 850um
34- 37 F4.2 mJy e_F850 rms uncertainty on F859
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Note (1): from Hernandez et al., 2007ApJ...662.1067H 2007ApJ...662.1067H, Cat. J/ApJ/662/1067.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 26-Sep-2014