AAS 197, January 2001
Session 10. Low Mass Star Formation
Display, Monday, January 8, 2001, 9:30am-7:00pm, Exhibit Hall

## [10.15] Chandra Observations of Flaring YSOs in \rho~Ophiuchus

K. J. Daniel, M. Gagné (West Chester University), S. L. Skinner (JILA)

We present initial results from a deep Chandra X-ray observation of the \rho~Ophiuchus star-forming region. 100 X-ray sources have been detected in a 17\arcmin\times 17\arcmin region centered on cloud core A. 52 Chandra sources are identified with previously known Class I, II, and III protostars, including three candidate brown dwarfs. The remaining 48 X-ray sources have no known counterparts at any other wavelength. Most of these are dominated by emission above 2.5 keV, suggesting that they are newly discovered, deeply embedded YSOs.

The uninterrupted 27-hour stream of ACIS event data was used to generate a time-series of 32 high spatial-resolution images color-coded by energy. Flickering background pixels were removed by applying a spatial filter. The resulting movie shows flaring X-ray sources, with some exhibiting noticeable color changes. The color movie illustrates the X-ray Christmas Tree'' effect in \rho~Oph first described by Montmerle et al. (1983).

Funding for this work was provided by NASA grant GO0-1008A to West Chester University.