ALMA survey of protoplanetary disks in sigma Ori (Ansdell+, 2017)

Our sample consists of the 92 Young Stellar Objects (YSOs) in {sigma} Orionis with infrared excesses consistent with the presence of a protoplanetary disk. hese sources are identified by cross-matching the Class II and transition disk (TD) candidates from the Spitzer survey of Hernandez et al. 2007 (Cat. J/ApJ/662/1067) with the Mayrit catalog (Caballero 2008, Cat. J/A+A/478/667). Both catalogs are expected to be complete down to the brown dwarf limit. Disk classifications are based on the Spitzer/Infrared Array Camera (IRAC) Spectral Energy Distribution (SED) slope, as described in Hernandez et al. 2007 (Cat. J/ApJ/662/1067). We also include in our sample a Class I disk (source 1153), as it is located near the Spitzer/IRAC color cutoff for Class II disks. Our Band 6 Atacama Large Millimeter/sub-millimeter Array (ALMA) observations were obtained on 2016 July 30 and 31 during Cycle 3 (Project ID: 2015.1.00089.S; PI: Williams). The array configuration used 36 and 37 12m antennas on July 30 and 31, respectively, with baselines of 15-1124m on both runs. The correlator setup included two broadband continuum windows centered on 234.293 and 216.484GHz with bandwidths of 2.000 and 1.875GHz and channel widths of 15.625 and 0.976MHz, respectively. The bandwidth-weighted mean continuum frequency was 225.676GHz (1.33mm). The spectral windows covered the ^12^CO (230.538GHz), ^13^CO (220.399GHz), and C^18^O (219.560GHz) J=2-1 transitions at velocity resolutions of 0.16-0.17km/s. These spectral windows were centered on 230.531, 220.392, and 219.554GHz with bandwidths of 11.719MHz and channel widths of 0.122MHz. On-source integration times were 1.2 minutes per object for an average continuum rms of 0.15mJy/beam (Table1). This sensitivity was based on the James Clerk Maxwell Telescope (JCMT)/Submillimeter Common User Bolometer Array (SCUBA)-2 survey of {sigma} Orionis disks by Williams et al. 2013 (Cat. J/MNRAS/435/1671), who found that stacking their individual non-detections revealed a mean 850{mu}m continuum signal of 1.3mJy at 4{sigma} significance. The sensitivity of our ALMA survey was therefore chosen to provide ~3-4{sigma} detections of such disks at 1.3mm, based on an extrapolation of the 850{mu}m mean signal using a spectral slope of {alpha}=2-3. Table1 presents the 1.33mm continuum flux densities and associated uncertainties (F_1.33mm_). Table2 gives our integrated line fluxes or upper limits.

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Metadata Access
Creator Ansdell M., Williams J.P., Manara C.F., Miotello A., Facchini S., van der Marel N., Testi L., van Dishoeck E.F.
Publisher CDS
Contributor International Virtual Observatory Alliance (IVOA)
Publication Year 2017
Rights public
OpenAccess true
Contact CDS support team <cds-question(at)>
Format text/xml+votable
Version 16-Aug-2017
Discipline Astrophysics and Astronomy