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J/ApJ/719/550      Deep NIR imaging of ρ Oph cloud core       (Marsh+, 2010)

Deep near-infrared imaging of the ρ Oph cloud core: clues to the origin of the lowest-mass brown dwarfs. Marsh K.A., Plavchan P., Kirkpatrick J.D., Lowrance P.J., Cutri R.M., Velusamy T. <Astrophys. J., 719, 550-560 (2010)> =2010ApJ...719..550M
ADC_Keywords: Photometry, infrared ; Stars, late-type ; Effective temperatures ; Stars, masses ; YSOs Keywords: brown dwarfs - infrared: stars - stars: low-mass - stars: pre-main sequence Abstract: A search for young substellar objects in the ρ Oph cloud core region has been made with the aid of multiband profile-fitting point-source photometry of the deep-integration Combined Calibration Scan images of the 2MASS extended mission in the J, H, and Ks bands, and Spitzer IRAC images at 3.6, 4.5, 5.8, and 8.0um. The field of view of the combined observations was 1°x9.3', and the 5σ limiting magnitude at J was 20.5. Comparison of the observed spectral energy distributions with the predictions of the COND and DUSTY models, for an assumed age of 1Myr, supports the identification of many of the sources with brown dwarfs and enables the estimation of effective temperature, Teff. The cluster members are then readily distinguishable from background stars by their locations on a plot of flux density versus Teff. The range of estimated Teff values extends down to ∼750K which, based on the COND model, would suggest the presence of objects of sub-Jupiter mass. The results also suggest that the mass function for the ρ Oph cloud resembles that of the σ Orionis cluster based on a recent study, with both rising steadily toward lower masses. The other main result from our study is the apparent presence of a progressive blueward skew in the distribution of J-H and H-Ks colors, such that the blue end of the range becomes increasingly bluer with increasing magnitude. We suggest that this behavior might be understood in terms of the "ejected stellar embryo" hypothesis, whereby some of the lowest-mass brown dwarfs could escape to locations close to the front edge of the cloud, and thereby be seen with less extinction. Description: Our data set includes the deep J, H, and Ks images from the ρ Oph calibration field of the Two Micron All Sky Survey (2MASS) Extended Mission (Cutri et al. 2006, Explanatory Supplement to the 2MASS All Sky Data Release) that were produced by combining 1582 observations made between 1997 and 2000 during the course of the main survey (Skrutskie et al. 2006, Cat. VII/233). We supplement these images with archival data at 3.6, 4.5, 5.8, and 8.0um from IRAC on the Spitzer Space Telescope, based on observations made in 2004 April 27-May 7 as part of the c2d legacy project (Evans et al. 2003PASP..115..965E). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 119 165 Photometry and estimated effective temperatures, visual absorption, and masses of candidate cluster members in the ρ Ophiuchi cloud core
See also: II/311 : WISE All-Sky Data Release (Cutri+ 2012) VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006) II/281 : 2MASS 6X Point Source Working Database / Catalog (Cutri+ 2006) II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) J/A+A/515/A75 : Low-mass population in ρ Oph cloud (Alves de Oliveira+, 2010) J/A+A/519/A34 : YSOs in DROXO (Deep rho Oph XMM obs.) (Pillitteri+, 2010) J/A+A/485/155 : HK photometry of rho Oph PMS stars (Alves de Oliveira+, 2008) J/ApJ/671/1800 : SCUBA observations of ρ Oph cloud (Andrews+, 2007) J/A+A/452/245 : Near-IR photometry of PMS stars in rho Oph (Natta+, 2006) J/AJ/130/1733 : Optical spectroscopy of ρ Oph stars (Wilking+, 2005) J/ApJ/630/381 : Mid-IR imaging in ρ Oph (Barsony+, 2005) J/A+A/429/963 : XMM-Newton observation of the rho Oph cloud (Ozawa+, 2005) : c2d Spitzer home page : Explanatory supplement to the 2MASS all sky data release Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 I5 --- Seq [10/14819] Object index number <[MPK2010b] NNNNN> in Simbad 7- 8 I2 h RAh Hour of Right Ascension (J2000) 10- 11 I2 min RAm Minute of Right Ascension (J2000) 13- 17 F5.2 s RAs Second of Right Ascension (J2000) 19 A1 --- DE- Sign of the Declination (J2000) 20- 21 I2 deg DEd Degree of Declination (J2000) 23- 24 I2 arcmin DEm Arcminute of Declination (J2000) 26- 29 F4.1 arcsec DEs Arcsecond of Declination (J2000) 31- 36 F6.3 mag Jmag ? 2MASS deep J band magnitude 38- 42 F5.3 mag e_Jmag ? Uncertainty in Jmag 44- 49 F6.3 mag Hmag ? 2MASS deep H band magnitude 51- 55 F5.3 mag e_Hmag ? Uncertainty in Hmag 57- 62 F6.3 mag Ksmag ? 2MASS deep Ks band magnitude 64- 68 F5.3 mag e_Ksmag ? Uncertainty in Ksmag 70- 75 F6.3 mag [3.6] ? Spitzer/IRAC 3.6 micron band magnitude 77- 81 F5.3 mag e_[3.6] ? Uncertainty in [3.6] 83- 88 F6.3 mag [4.5] ? Spitzer/IRAC 4.5 micron band magnitude 90- 94 F5.3 mag e_[4.5] ? Uncertainty in [4.5] 96- 99 I4 K Teff Effective temperature 101-104 I4 K e_Teff Uncertainty in Teff 106-109 F4.1 mag AV Visual absorption 111-113 F3.1 mag e_AV Uncertainty in AV 115-119 F5.3 Msun Mass Mass
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 08-Jun-2012
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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