AAS 198th Meeting, June 2001
Session 27. Neutron Stars, Pulsars Gamma ray Bursts
Oral, Monday, June 4, 2001, 2:00-3:30pm, C107

## [27.03] The X-ray Spectrum of the Rapid Burster using the Chandra HETGS

H.L. Marshall (MIT CSR), R. Rutledge (Caltech SRL), D.W. Fox, J.M. Miller (MIT CSR), R. Guerriero (US Military Academy), E. Morgan (MIT CSR), M. van der Klis (U. Amsterdam), L. Bildsten (ITP UCSB), T. Dotani (ISAS, Japan), W.H.G. Lewin (MIT CSR)

We present observations of the Rapid Burster (RB, also known as MXB 1730-335) using the Chandra High Energy Transmission Grating Spectrometer. The average interval between type II (accretion) bursts was about 40 s. There was one type I (thermonuclear flash) burst and about 20 mini-bursts'' which are probably type II bursts whose peak flux is 10-40% of the average peak flux of the other type II bursts. The time averaged spectra of the type II bursts are well fit by a blackbody with a temperature of kT = 1.6 keV, a radius of 8.9 km for a distance of 8.6 kpc, and an interstellar column density of 1.7 \times 1022 cm-2. No narrow emission or absorption lines were clearly detected. The 3 \sigma upper limits to the equivalent widths of any features are < 10 eV in the 1.1-7.0 keV band and as small as 1.5 eV near 1.7 keV. We suggest that Comptonization destroys absorption features such as the resonance line of Fe {\sc XXVI}.

The author(s) of this abstract have provided an email address for comments about the abstract: mailto:hermanm@space.mit.edu