XMM-Newton detection of a transient X-ray source in the vicinity of V838 Monocerotis - Astrophysics > Solar and Stellar AstrophysicsReportar como inadecuado




XMM-Newton detection of a transient X-ray source in the vicinity of V838 Monocerotis - Astrophysics > Solar and Stellar Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We report the XMM-Newton-EPIC detection in 2008 March of a luminous L X ~10^32-33 erg-s, variable X-ray source in the vicinity within ~6- of theenigmatic star V838 Mon, which underwent a spectacular outburst in early 2002.Spectral modeling of the XMM-Newton X-ray source indicates the presence of twoplasma components with characteristic temperatures of TX ~ 2x10^6K and~1.5x10^7K, attenuated by an absorbing column N H ~ 4 x 10^21cm^-2 that isconsistent with the visual extinction measured toward V838 Mon A V ~ 2. Nosuch luminous source was detected in the immediate vicinity of V838 Mon inChandra-ACIS-S observations obtained about one year after outburst or, mostrecently, in 2010 January. The two XMM source spectral components appear to bemarginally spatially resolved, with the spatial centroid of the hard componentlying closer to within ~2- of the position of V838 Mon than the broad-bandsource or the soft source component; however, if there are two sources at ornear V838 Mon, the Chandra nondetections would imply that both of them arevariable. An alternative is that there is a single variable source, and thatthe apparent spatial separation may actually be due to photon-countingstatistics or is perhaps instrumental in origin. We consider constraints placedby the X-ray detection and nondetections on a stellar merger model for the 2002V838 Mon outburst, in which the spun-up merger product drives a powerfulmagnetic dynamo. Alternatively, the transient behavior of the X-ray sourcecould indicate that the X-rays arose as a consequence of an interaction betweenV838 Mon-s ejecta and its early-type B3 V companion.



Autor: Fabio Antonini, Rodolfo Jr. Montez, Joel H. Kastner, Howard E. Bond, Noam Soker, Romuald Tylenda, Sumner Starrfield, Ehud Behar

Fuente: https://arxiv.org/



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