Search Publications
Synthetic Spectrum Constraints on a Model of the Cataclysmic Variable QU Carinae
Szkody, Paula; Sion, Edward M.; Godon, Patrick +3 more
Neither standard model SEDs nor truncated standard model SEDs fit observed spectra of QU Carinae with acceptable accuracy over the range 900-3000 Å. Nonstandard model SEDs fit the observation set accurately. The nonstandard accretion disk models have a hot region extending from the white dwarf to R = 1.36RWD, a narrow intermediate-tempe…
An Observation of Low-Level Heating in an Erupting Prominence
Landi, E.; Kucera, T. A.
Here we present multiwavelength observations of low-level heating in an erupting prominence observed in the UV and EUV over a wide range of temperatures and wavelengths by the Solar and Heliospheric Observatory (SOHO) Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument and the Transition Region and Coronal Explorer (TRACE), and …
Trouble for AGN Feedback? The Puzzle of the Core of the Galaxy Cluster AWM 4
Buote, David A.; Brighenti, Fabrizio; Mathews, William G. +1 more
The core of the relaxed cluster AWM 4 is characterized by a unique combination of properties which defy a popular scenario for AGN heating of cluster cores. A flat inner temperature profile is indicative of a past, major heating episode which completely erased the cool core, as testified by the high central cooling time (gtrsim3 Gyr) and by the hi…
Evidence for Iroshnikov-Kraichnan-Type Turbulence in the Solar Wind Upstream of Interplanetary Traveling Shocks
Wurz, P.; Hilchenbach, M.; Smith, C. W. +3 more
We analyze suprathermal ions and plasma wave spectra upstream of interplanetary shocks driven by coronal mass ejection events. In particular, we analyze the competition between two processes: (1) the upstream wave generation by suprathermal protons accelerated at the shock, and (2) the cascading of wave energy in the inertial range of solar wind t…
A New Orbit Determination for Bright Sungrazing Comet of 1843
Sekanina, Zdenek; Chodas, Paul W.
Given the critical role of the bright sungrazer C/1843 D1, also called the Great March Comet of 1843, in hypotheses of the origin and evolution of the Kreutz system, a new orbital investigation of this comet was desirable. Closely inspecting Kreutz's classical work, we conclude that his result of 512 yr for the orbital period, which has been endle…
INTEGRAL and BeppoSAX Observations of the Transient Atoll Source 4U 1608-522: From Quiescent to Hard Spectral State
Ubertini, P.; Bazzano, A.; Tarana, A.
We report on the spectral evolution of 4U 1608-522 using observations performed as part of the long-term Galactic bulge monitoring program with INTEGRAL. The data set includes the 2005 April outburst. BeppoSAX archival data (two observations, from 1998 and 2000) are also analyzed and compared with the INTEGRAL data. Three different spectral states…
The Faint-End Slopes of Galaxy Luminosity Functions in the COSMOS Field
Mobasher, Bahram; Capak, Peter; Rich, R. Michael +5 more
We examine the faint-end slope of the rest-frame V-band luminosity function (LF), with respect to galaxy spectral type, of field galaxies with redshift z < 0.5, using a sample of 80,820 galaxies with photometric redshifts in the 2 deg2 Cosmic Evolution Survey (COSMOS) field. For all galaxy spectral types combined, the LF slope ranges…
Photoevaporation of Protoplanetary Disks
Rieke, George H.; Bally, John; Gáspár, András +4 more
We present HST NICMOS Paschen α (Paα) images and low- and high-resolution IRS spectra of photoevaporating disk-tail systems originally detected at 24 µm near O stars. We find no Paα emission in any of the systems. The resulting upper limits correspond to about (2-3) × 10-6 M⊙ of mass in hydrogen in the tails, suggesting…
Investigation into the Subsurface Magnetic Structure in an Emerging Flux Region on the Sun Based on a Comparison between Hinode's Observations and Numerical Simulations
Magara, T.
In this Letter we report a result of investigating the structure of subsurface magnetic field in an emerging flux region on the Sun, which was observed by Hinode. The data obtained by Hinode captured well the structure end evolution of the emerging flux region, showing the appearance of small magnetic features that lead to a well-developed bipolar…
PSR J0737-3039: Interacting Pulsars in X-Rays
Tiengo, A.; Mereghetti, S.; Esposito, P. +2 more
We present the results of a ~230 ks long X-ray observation of the relativistic double-pulsar system PSR J0737-3039 obtained with the XMM-Newton satellite in 2006 October. We confirm the detection in X-rays of pulsed emission from PSR J0737-3039A (PSR A), mostly ascribed to a soft nonthermal power-law component (Γ ~ 3.3) with a 0.2-3 keV luminosity…