A study of the X-ray pulsars X1845-024 and XTE J1858+034 based on INTEGRAL observations

We present an analysis of observations of the relatively unstudied X-ray pulsars X1845-024 and XTE J1858+034 carried out from May 2003 through November 2004 using the JEM-X and IBIS telescopes of the INTEGRAL international gamma-ray observatory at energies of 5-70 keV. The X-ray spectra and light curves of the pulsars are constructed. During the observation period, outbursts at 18-70 keV at levels of 13 mCrab and 111 mCrab were detected for X1845-024 and XTE J1858+034, respectively. We refined the rotational period of the neutron star in XTE J1858+034 (220.4 s), measured its acceleration during the outburst, and derived a probable value of the orbital period (≃380 d).