Substellar Objects in Nearby Young Clusters (SONYC) II: The Brown Dwarf Population of Rho Ophiuchi

Abstract

SONYC - Substellar Objects in Nearby Young Clusters - is a survey program to investigate the frequency and properties of brown dwarfs down to masses below the Deuterium burning limit in nearby star forming regions. In this second paper, we present results on the ~1 Myr old cluster Rho Ophiuchi, combining our own deep optical and near-infrared imaging using Subaru with photometry from the 2-Micron All Sky Survey and the Spitzer Space Telescope. Of the candidates selected from iJKs photometry, we have confirmed three -- including a new brown dwarf with a mass close to the Deuterium limit -- as likely cluster members through low-resolution infrared spectroscopy. We also identify 27 sub-stellar candidates with mid-infrared excess consistent with disk emission, of which 16 are new and 11 are previously spectroscopically confirmed brown dwarfs. The high and variable extinction makes it difficult to obtain the complete sub-stellar population in this region. However, current data suggest that its ratio of low-mass stars to brown dwarfs in similar to those reported for several other clusters, though higher than what was found for NGC 1333 in Scholz et al. 2009.

32 pages, 9 figures, accepted for publication in ApJ

References in corpus (12)

• Empirical Color Transformations Between SDSS Photometry and Other Photometric Systems
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• Accretion in the Rho-Oph pre-main sequence stars
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• Characterizing Young Brown Dwarfs using Low Resolution Near-IR Spectra
• Evidence for a Turnover in the IMF of Low Mass Stars and Sub-stellar Objects: Analysis from an Ensemble of Young Clusters
• Substellar Objects in Nearby Young Clusters (SONYC): The bottom of the Initial Mass Function in NGC1333
• Deep near-IR variability survey of pre-main-sequence stars in Rho Ophiuchi
• The low-mass population of the Rho Ophiuchi molecular cloud
• New members in the Upper Sco association from the UKIDSS Early Data Release
• A Young Planetary-Mass Object in the rho Oph Cloud Core
• Spectroscopy of Young Planetary Mass Candidates with Disks

Cited by in corpus (26)

• Brown dwarf disks with ALMA: evidence for truncated dust disks in Ophiuchus
• Spectroscopy of new brown dwarf members of rho Ophiuchi and an updated initial mass function
• Substellar Objects in Nearby Young Clusters (SONYC) IV: A census of very low mass objects in NGC1333
• The Initial Mass Function and Disk Frequency of the Rho Ophiuchi Cloud: An Extinction-Limited Sample
• Surface Gravities for 228 M, L, and T Dwarfs in the NIRSPEC Brown Dwarf Spectroscopic Survey
• Substellar Objects in Nearby Young Clusters (SONYC) V: New brown dwarfs in rho Ophiuchi
• Testing the universality of the IMF with Bayesian statistics: young clusters
• The optical+infrared L dwarf spectral sequence of young planetary-mass objects in the Upper Scorpius association
• A Survey for New Stars and Brown Dwarfs in the Ophiuchus Star-forming Complex
• Constraining the Frequency of Free-Floating Planets from a Synthesis of Microlensing, Radial Velocity, and Direct Imaging Survey Results
• Substellar Objects in Nearby Young Clusters (SONYC) VIII: Substellar population in Lupus 3
• Substellar Objects in Nearby Young Clusters (SONYC) III: Chamaeleon-I
• Herschel survey of brown dwarf disks in Rho Ophiuchi
• A Novel Survey for Young Substellar Objects with the W-band Filter. I. Filter Design and New Discoveries in Ophiuchus and Perseus
• A search for mass segregation of stars and brown dwarfs in ρ Ophiuchi
• Brown dwarf disks with Herschel: Linking far-infrared and (sub)-mm fluxes
• Testing the fragmentation limit in the Upper Sco association
• A Significant Population of Candidate New Members of the Rho Ophiuchi Cluster
• Characterization of the known T type dwarfs towards the Sigma Orionis cluster
• On the origin of planetary-mass objects in NGC1333
• Proper motions of Upper Sco T-type candidates
• Spectroscopy of Candidate Members of the Sco-Cen Complex
• Discovery of Young Methane Dwarfs in the Rho Ophiuchi L 1688 Dark Cloud
• The young low-mass star ISO-Oph-50: Extreme variability induced by a clumpy, evolving circumstellar disk
• Multi-Object and Long-Slit Spectroscopy of Very Low Mass Brown Dwarfs in Orion Nebular Cluster
• Keck Observations in the INfrared of Taurus and $\rho$ Oph Exoplanets And Ultracool dwarfs (KOINTREAU) II: Two Young Bound Companions to Ophiuchus Stars