EDP Sciences
Free access
Volume 423, Number 3, September I 2004
Page(s) 1045 - 1050
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:20047192

A&A 423, 1045-1050 (2004)
DOI: 10.1051/0004-6361:20047192

Spectral and timing properties of the X-ray emission from the millisecond pulsar PSR B1821-24

T. Mineo1, G. Cusumano1, E. Massaro2, 3, W. Becker4 and L. Nicastro1

1  Istituto di Astrofisica Spaziale e Fisica Cosmica, INAF-CNR, Sezione di Palermo, via Ugo La Malfa 153, 90146 Palermo, Italy
    e-mail: mineo@pa.iasf.cnr.it
2  Dipartimento di Fisica, Universitá La Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
3  Istituto di Astrofisica Spaziale e Fisica Cosmica, INAF-CNR, Sezione di Roma, via Fosso del Cavaliere, 00113 Roma, Italy
4  Max-Planck-Institut für Extraterrestrische Physik, 85740 Garching-bei-München, Germany

(Received 4 February 2004 / Accepted 27 April 2004 )

We report results on the timing and spectral analysis of observations of the millisecond pulsar PSR B1821-24 with RXTE, BeppoSAX and Chandra. The X-ray light curve is characterized by two narrow peaks at a phase distance of $0.452\pm0.002$. The average pulsed emission, over the range 1.6-20 keV, is well represented by a single power law with a photon index $\alpha=1.30_{+0.05}^{-0.02}$ and unabsorbed (2-10 keV) pulsed X-ray flux of $3.9\times10^{-13}$ erg cm -2 s -1. We searched for a possible bunching of X-ray photons to verify if the X ray emission has a time structure similar to that of giant pulses and found a negative result.

Key words: stars: neutron -- stars: pulsars: general -- stars: pulsars: individual: PSR B1821-24 -- X-rays: stars

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© ESO 2004