The X-ray emission from young stellar objects in the ρ Ophiuchi dark cloud as seen by XMM-Newton

We observed the dense core F of the rho Ophiuchi cloud, an active star-forming region located at d similar to 140 pc, using XMM-Newton with an exposure of 33 ks. We detect 87 X-ray sources within the 30' diameter field-of-view of the EPIC spectro-imaging detector array. We show that XMM-Newton and Chandra have comparable sensitivity for point source detection when the exposure time is set to similar to 30 ks for both. We detect X-ray emission from 7 Class I sources, 26 Class II sources, and 17 Class III sources. The X-ray detection rate of Class I sources is very high (64%), which is consistent with previous Chandra observations in this area. We propose that 15 X-ray sources are new class III candidates, which doubles the number of known Class III source, and helps complete the census of YSOs in this area. We detect X-ray emission from two young bona fide brown dwarfs, GY310 and GY141, out of three known in the field-of-view. GY141 appears brighter by nearly two orders of magnitude than in the Chandra observation. e observed an X-ray flare from the bona fide brown dwarf GY310.