Search Publications
Testing Nonstandard Cosmological Models with SNLS3 Supernova Data and Other Cosmological Probes
Li, Zhengxiang; Wu, Puxun; Yu, Hongwei
We investigate the implications for some nonstandard cosmological models using data from the first three years of the Supernova Legacy Survey (SNLS3), assuming a spatially flat universe. A comparison between the constraints from the SNLS3 and those from other SN Ia samples, such as the ESSENCE, Union2, SDSS-II, and Constitution samples, is given a…
A New Method to Constrain Supernova Fractions Using X-Ray Observations of Clusters of Galaxies
Bulbul, Esra; Loewenstein, Michael; Smith, Randall K.
Supernova (SN) explosions enrich the intracluster medium (ICM) both by creating and dispersing metals. We introduce a method to measure the number of SNe and relative contribution of Type Ia supernovae (SNe Ia) and core-collapse supernovae (SNe cc) by directly fitting X-ray spectral observations. The method has been implemented as an XSPEC model c…
The Clustered Nature of Star Formation. Pre-main-sequence Clusters in the Star-forming Region NGC 602/N90 in the Small Magellanic Cloud
Gouliermis, Dimitrios A.; Gennaro, Mario; Dolphin, Andrew E. +3 more
Located at the tip of the wing of the Small Magellanic Cloud (SMC), the star-forming region NGC 602/N90 is characterized by the H II nebular ring N90 and the young cluster of pre-main-sequence (PMS) and early-type main-sequence stars NGC 602, located in the central area of the ring. We present a thorough cluster analysis of the stellar sample iden…
Post-Coronal Mass Ejection Plasma Observed by Hinode
Raymond, J. C.; Landi, E.; Hara, H. +1 more
In the present work we study the evolution of an active region after the eruption of a coronal mass ejection (CME) using observations from the EIS and XRT instruments on board Hinode. The field of view includes a post-eruption arcade, a current sheet, and a coronal dimming. The goal of this paper is to provide a comprehensive set of measurements f…
Localizing INTEGRAL Sources with Chandra: X-Ray and Multi-wavelength Identifications and Energy Spectra
Rahoui, Farid; Kalemci, Emrah; Bodaghee, Arash +5 more
We report on Chandra observations of 18 hard X-ray (>20 keV) sources discovered with the INTEGRAL satellite near the Galactic plane. For 14 of the INTEGRAL sources, we have uncovered one or two potential Chandra counterparts per source. These provide soft X-ray (0.3-10 keV) spectra and subarcsecond localizations, which we use to identify counte…
X-Raying the Beating Heart of a Newborn Star: Rotational Modulation of High-energy Radiation from V1647 Ori
Hamaguchi, Kenji; Petre, Robert; Kastner, Joel H. +5 more
We report a periodicity of ~1 day in the highly elevated X-ray emission from the protostar V1647 Ori during its two recent multiple-year outbursts of mass accretion. This periodicity is indicative of protostellar rotation at near-break-up speed. Modeling of the phased X-ray light curve indicates that the high-temperature (~50 MK), X-ray-emitting p…
Toward Identifying the Unassociated Gamma-Ray Source 1FGL J1311.7-3429 with X-Ray and Optical Observations
Cheung, C. C.; Kataoka, J.; Kawai, N. +9 more
We present deep optical and X-ray follow-up observations of the bright unassociated Fermi-LAT gamma-ray source 1FGL J1311.7-3429. The source was already known as an unidentified EGRET source (3EG J1314-3431, EGR J1314-3417), hence its nature has remained uncertain for the past two decades. For the putative counterpart, we detected a quasi-sinusoid…
Discovery of a Significant Magnetic Cataclysmic Variable Population in the Limiting Window
van den Berg, Maureen; Grindlay, Jonathan E.; Servillat, Mathieu +2 more
We have discovered 10 periodic X-ray sources from the 1 Ms Chandra ACIS observation of the Limiting Window (LW), a low-extinction region (AV ~ 3.9) at 1fdg4 south of the Galactic center. The observed periods (~1.3-3.4 hr) and the X-ray luminosities (1031.8-32.9 erg s-1 at 8 kpc) of the 10 periodic sources, combined…
X-Ray Binaries in the Ultrahigh Encounter Rate Globular Cluster NGC 6388
Heinke, Craig O.; Bailyn, Charles D.; Cohn, Haldan N. +5 more
We report the results of a joint Chandra Hubble Space Telescope study of the X-ray binary (XRB) population in the massive, high-density globular cluster NGC 6388. NGC 6388 has one of the highest predicted XRB production rates of any Galactic cluster. We detected a large population of 61 Chandra sources within the half-mass radius with LX
Multiscale Dynamics of Solar Magnetic Structures
Davila, Joseph M.; Uritsky, Vadim M.
Multiscale topological complexity of the solar magnetic field is among the primary factors controlling energy release in the corona, including associated processes in the photospheric and chromospheric boundaries. We present a new approach for analyzing multiscale behavior of the photospheric magnetic flux underlying these dynamics as depicted by …