Publications (37) View all
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Article: The ASTRO-H X-ray Observatory
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ABSTRACT: The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.10/2012; -
Article: The Chandra Carina Complex Project: Deciphering the Enigma of Carina's Diffuse X-ray Emission
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ABSTRACT: We present a 1.42 deg2 mosaic of diffuse X-ray emission in the Great Nebula in Carina from the Chandra X-ray Observatory Advanced CCD Imaging Spectrometer camera. After removing >14,000 X-ray point sources from the field, we smooth the remaining unresolved emission, tessellate it into segments of similar apparent surface brightness, and perform X-ray spectral fitting on those tessellates to infer the intrinsic properties of the X-ray-emitting plasma. By modeling faint resolved point sources, we estimate the contribution to the extended X-ray emission from unresolved point sources and show that the vast majority of Carina's unresolved X-ray emission is truly diffuse. Line-like correlated residuals in the X-ray spectral fits suggest that substantial X-ray emission is generated by charge exchange at the interfaces between Carina's hot, rarefied plasma and its many cold neutral pillars, ridges, and clumps.The Astrophysical Journal Supplement Series 04/2011; 194(1):15. · 13.46 Impact Factor -
Article: An Introduction to the Chandra Carina Complex Project
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ABSTRACT: The Great Nebula in Carina provides an exceptional view into the violent massive star formation and feedback that typifies giant HII regions and starburst galaxies. We have mapped the Carina star-forming complex in X-rays, using archival Chandra data and a mosaic of 20 new 60ks pointings using the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer, as a testbed for understanding recent and ongoing star formation and to probe Carina's regions of bright diffuse X-ray emission. This study has yielded a catalog of properties of >14,000 X-ray point sources; >9800 of them have multiwavelength counterparts. Using Chandra's unsurpassed X-ray spatial resolution, we have separated these point sources from the extensive, spatially-complex diffuse emission that pervades the region; X-ray properties of this diffuse emission suggest that it traces feedback from Carina's massive stars. In this introductory paper, we motivate the survey design, describe the Chandra observations, and present some simple results, providing a foundation for the 15 papers that follow in this Special Issue and that present detailed catalogs, methods, and science results.02/2011; -
Article: The ASTRO-H Mission
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ABSTRACT: The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV) . The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of Delta E ~7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued. Comment: 18 pages, 12 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray"10/2010; -
Article: High energy emission from massive stars: the precocious X-Ray recovery of Eta Carinae after January 2009 minimum
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ABSTRACT: We observed the massive binary stellar system of Eta Carinae in the 0.3-10 keV energy range with the X-ray Telescope onboard the Swift satellite during the period 15 December 2008 - 11 March 2009, i.e. 1 month before to 2 months after the X-ray drop from maximum to minimum, thought to be associated with the periastron encounter of the primary star by the hot companion. Beginning a few months before eclipse, the interaction between the winds of the two stars intensifies and the X-ray flux reaches maximum. The flux drops dramatically thereafter, subsiding in about 20 days to a level that is at least a factor 10 lower than the 'high state', i.e. the X-ray emission state of the system during the largest fraction of its 5.52 yr orbit (~e-11 erg/s/cm2). Unlike in previous cycles, when the low state lasted about 2.5 months, observations with RXTE showed that the X-ray flux started its recovery to normal level about 1.5 months after the minimum. We suggest that this early recovery may be due to the fact that the companion wind reaches terminal velocity before encountering the shock. Comment: 4 pages, 1 figure, to be published in the proceedings of Conf. "Neutron Stars and Gamma-Ray Bursts" - Cairo and Alexandria, Egypt, 30 Mar-4 Apr 2009, Eds. A. Ibrahim and J. Grindlay08/2009;
