2001/03/01 by N. Grosso, Nicolas Grosso · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #astro-ph
paper · pdf · doi:10.1051/0004-6361:20010325
4 pages, 2 figures, 2 tables. Accepted for publication in A&A
arxiv created 2001/03/01 · openalex publication_date 2001/04/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
I analyze unpublished or partially published archival ROSAT data of the ρ Ophiuchi dark cloud. This set of seven overlapping ROSAT HRI pointings, composed of eight ~one-hour exposures, detects mainly the X-ray brightest T Tauri stars of this star-forming region. Only two HRI sources are new X-ray sources, and their optical counterparts are proposed as new Weak T Tauri star candidates. Meanwhile the ROSAT HRI caught during just one exposure a weak X-ray source (; for Gaussian statistics) among a group of three embedded young stellar objects including two Class I protostars. Previous ROSAT PSPC, ASCA GIS observations, and as I argue here one Einstein IPC observation, have already detected an X-ray source in this area, but this higher angular resolution data show clearly that X-rays are emitted by the Class I protostar YLW16A. This is the second Class I protostar detected by the ROSAT HRI in this dark cloud. The determination of the intrinsic X-ray luminosity of this event, erg s-1, critically depends on the source absorption estimate. Improvements will be obtained only by the direct determination of this parameter from fitting of Chandra and XMM-Newton spectra.