The XMM-Newton extended survey of the Taurus molecular cloud (XEST)

June 2007 • 2007A&A...468..353G

Authors • Güdel, M. • Briggs, K. R. • Arzner, K. • Audard, M. • Bouvier, J. • Feigelson, E. D. • Franciosini, E. • Glauser, A. • Grosso, N. • Micela, G. • Monin, J. -L. • Montmerle, T. • Padgett, D. L. • Palla, F. • Pillitteri, I. • Rebull, L. • Scelsi, L. • Silva, B. • Skinner, S. L. • Stelzer, B. • Telleschi, A.

Abstract • Context: The Taurus Molecular Cloud (TMC) is the nearest large star-forming region, prototypical for the distributed mode of low-mass star formation. Pre-main sequence stars are luminous X-ray sources, probably mostly owing to magnetic energy release.
Aims: The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST) presented in this paper surveys the most populated ≈5 square degrees of the TMC, using the XMM-Newton X-ray observatory to study the thermal structure, variability, and long-term evolution of hot plasma, to investigate the magnetic dynamo, and to search for new potential members of the association. Many targets are also studied in the optical, and high-resolution X-ray grating spectroscopy has been obtained for selected bright sources.
Methods: The X-ray spectra have been coherently analyzed with two different thermal models (2-component thermal model, and a continuous emission measure distribution model). We present overall correlations with fundamental stellar parameters that were derived from the previous literature. A few detections from Chandra observations have been added.
Results: The present overview paper introduces the project and provides the basic results from the X-ray analysis of all sources detected in the XEST survey. Comprehensive tables summarize the stellar properties of all targets surveyed. The survey goes deeper than previous X-ray surveys of Taurus by about an order of magnitude and for the first time systematically accesses very faint and strongly absorbed TMC objects. We find a detection rate of 85% and 98% for classical and weak-line T Tau stars (CTTS resp. WTTS), and identify about half of the surveyed protostars and brown dwarfs. Overall, 136 out of 169 surveyed stellar systems are detected. We describe an X-ray luminosity vs. mass correlation, discuss the distribution of X-ray-to-bolometric luminosity ratios, and show evidence for lower X-ray luminosities in CTTS compared to WTTS. Detailed analysis (e.g., variability, rotation-activity relations, influence of accretion on X-rays) will be discussed in a series of accompanying papers.

Table 3, Full Tables 4-11 and Appendices A and B are only available in electronic form at http://www.aanda.org Full Table [see full text] is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/468/353

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• PREPRINT http://arxiv.org/abs/astro-ph/0609160
• POSTSCRIPT https://www.aanda.org/10.1051/0004-6361:20065724/postscript
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• SPIRES http://inspirehep.net/search?p=find+eprint+astro-ph/0609160