INTEGRAL Status Report - May 2004
Operations and Archiving
During the first quarter of 2004, INTEGRAL continued making scans of the central radian of the galaxy and along the galactic plane searching for new transients and other interesting phenomena. In addition, many classes of astronomical objects where observed from nearby stellar system such as Algol, to distant active galaxies such as 3C273, Cen A and NGC4945. The X-ray binary systems IGR J16318-484 (jointly with XMM-Newton) and GX 339-4 were studied, as were the likely sites of nucleosynthesis SNR 1987A and Cygnus X and the supernova remnant SN1006. A target of opportunity observation was made of PSR B1259-63, a unique system consisting of a msec radio pulsar and a Be star in an eccentric 3.4 year orbit, and the region containing the unidentified Comptel source GRO J0332-87 was studied. Finally, deep observations of one of INTEGRAL's most important regions - the Galactic centre - were made.
The fourth release of the Integral Science Data Centre (ISDC) public off-line scientific analysis (OSA) software is scheduled for 2004 July. Together with the instrument teams, the ISDC are working hard to ensure that this release will include a number of improved data analysis tools as well as the latest low-energy imager (ISGRI) spectral response matrix. This new matrix includes a significantly improved model of the instrumental response allowing users to better compare their source models with ISGRI data. The ISDC continues to routinely dispatch data products to observers within 6-8 weeks of their observation. Using results obtained with OSA-3, the ISDC and instrument teams are evaluating the in-flight instrument sensitivities in order to verify or update those published in the AO-2 documentation. The first Integral AO-1 will start entering the public domain from 17 July and will be made available to interested users via the on-line ISDC archive.
Science Highlights
The 5th INTEGRAL Workshop was held in Munich in February. Around 230 participants displayed and discussed the latest scientific results obtained from INTEGRAL during the first year of the nominal mission operations. The workshop opened with a session devoted to nucleosynthesis studies. The line at 1809 keV from radioactive 26Al is an important tracer of this process. Studies of the 26Al line profile from the Cygnus region are beginning to provide new information about the kinematics of the emitting material, hinting that there are large scale motions within the star formation region responsible for the line emission. Exciting results from many X-ray binaries such as Vela X-1, where intense flaring was observed, SS 443, and GRS 1915+105 were presented. The first results from the INTEGRAL imager survey of the Galactic center region were presented. These were the result of observations obtained in approximately the first year of the Core Programme and revealed at least 121 sources, of which 31% are unidentified and 14 were previously unknown. Understanding the nature of these new sources is proving to be one of the "hot topics" for the INTEGRAL scientists.