[SN, SNR, and Isolated NS -- Oral ]

Discovering X-ray Bright Neutron Stars for Current and Next-Generation Observatories

Derek Fox, Pennsylvania State University
R. E. Rutledge (McGill University), A. S. H. Shevchuk (U. Arizona), R. E. Letcavage (U.C. Irvine)

I will discuss our ongoing program of Swift, Chandra, and XMM-Newton observations aimed at discovering new X-ray bright neutron stars suitable for detailed study with current and next-generation X-ray observatories. This program recently yielded the eighth known isolated neutron star (INS), the first to be discovered in six years,and the highest-temperature INS known: 1RXS~J141256.0+792204 or ``Calvera.'' Our program begins by using statistical techniques of cross-correlation to select objects from the ROSAT Bright Source Catalog that are unlikely to have off-band counterparts. Short Swift observations provide arcsecond X-ray positions and simultaneous UV/optical imaging to confirm the absence of bright counterparts. In this way, we have filtered an initial target list of almost 200 bright X-ray sources down to 36 candidate neutron stars now requiring sub-arcsecond X-ray positions and deep optical imaging for final confirmation; completion of our current programs with Chandra and the Gemini telescopes has the potential to double or triple the number of INSs known. As a demonstration of the interesting science that can result from study of these objects, I will present the results of our recent extended 30 ksec Chandra + ACIS (1/8 subarray)observation of Calvera.