Search Publications
Seismic Detection of Solar Mesogranular-Scale Flow
Woodard, M. F.
Helioseismic correlation data computed from the Solar and Heliospheric Observatory/Michelson Doppler Imager high-resolution Doppler images were inverted for solar flows of horizontal scale between 5 and 45 Mm. The photospheric Doppler velocity inferred from the inversions was compared with the original Doppler images at each scale. For horizontal …
Gradual Solar Energetic Particle Event Associated with a Decelerating Shock Wave
Laitinen, T.; Valtonen, E.; Kocharov, L. +3 more
On 2000 April 4-6 the Energetic and Relativistic Nuclei and Electron particle telescope on the Solar and Heliospheric Observatory spacecraft observed a major solar energetic particle (SEP) event associated with two coronal mass ejections (CMEs) separated by approximately 8 hr. The first CME was accompanied by a low-frequency type II radio burst ob…
Analysis of Kinetic Process of Energetic Electron During a Flare on 2004 December 1
Yan, Yihua; Huang, Jing
We analyze the M1.1 flare event peaked at 07:20:00 UT on 2004 December 1 mainly from radio and hard X-ray (HXR) observations. By eliminating the thermal component from the observed total radio emission flux, the non-thermal part of the radio and HXR burst process is investigated in a self-consistent way. The spectral index of energetic electrons d…
Search for a Redshifted 2.2 MeV Neutron Capture Line from A0535+262 in Outburst
Kretschmar, Peter; Çalişkan, Şirin; Kalemci, Emrah +2 more
The Be/X-ray binary system A0535+262 underwent a giant outburst in 2005 May-June, followed by a dimmer outburst in 2005 August-September. This increased intensity provided an opportunity to search for redshifted neutron capture lines from the surface of the neutron star. If discovered, such lines would constrain the neutron star equation of state,…
A Deep XMM-Newton Observation of the Quasar 3C 287
Miller, J. M.; Siemiginowska, A.; Cackett, E. +1 more
We report on an XMM-Newton observation of the z = 1.055 quasar and Gigahertz Peaked Spectrum (GPS) source 3C 287. Our 62.3 ks observation provides an exceptional X-ray view of a prominent member of this important subclass of active galactic nuclei (AGNs). The X-ray spectra of 3C 287 are consistent with a simple absorbed power law with a spectral i…
Hard X-Ray Flux Upper Limits of Central Compact Objects in Supernova Remnants
Kalemci, E.; Erdeve, I.; Alpar, M. A.
We searched for hard X-ray (20-300 keV) emission from nine central compact objects (CCOs) 1E 1207.4-5209, 1WGA J1713-3949, J082157.5-430017, J085201.4-461753, J160103.1-513353, J1613483-5055, J181852.0-150213, J185238.6+004020, and J232327.9+584843 with the International Gamma-Ray Astrophysics Laboratory observatory. We applied spectral imaging an…
A Possible Supernova Remnant High Above the Galactic Disk
Henley, David B.; Shelton, Robin L.
We present the analysis of three Suzaku observations of a bright arc in the ROSAT All-Sky Survey 1/4 keV maps at l ≈ 247°, b ≈ -64°. In particular, we have tested the hypothesis that the arc is the edge of a bubble blown by an extraplanar supernova. One pointing direction is near the brightest part of the arc, one is toward the interior of the hyp…
Comparison of High-Degree Solar Acoustic Frequencies and Asymmetry Between Velocity and Intensity Data
Hill, F.; Antia, H. M.; Jain, K. +1 more
Using the local helioseismic technique of ring diagram we analyze the frequencies of high-degree f- and p-modes derived from both velocity and continuum intensity data observed by Michelson Doppler Imager. Fitting the spectra with asymmetric peak profiles, we find that the asymmetry associated with velocity line profiles is negative for all freque…
Subwavelength Resolution Imaging of the Solar Deep Interior
Duvall, Thomas L., Jr.; Hanasoge, Shravan M.
We derive expectations for signatures in the measured travel times of waves that interact with thermal anomalies and jets. A series of numerical experiments that involve the dynamic linear evolution of an acoustic wave field in a solarlike stratified spherical shell in the presence of fully three-dimensional time-stationary perturbations are perfo…
Evidence for Nonlinear Growth of Structure from an X-Ray-Selected Cluster Survey using a Novel Joint Analysis of the Chandra and XMM-Newton Archives
Kahn, S. M.; Peterson, J. R.; Gupta, R. R. +2 more
We present a large X-ray-selected serendipitous cluster survey based on a novel joint analysis of archival Chandra and XMM-Newton data. The survey provides enough depth to reach clusters of flux of ≈10-14ergcm-2s-1 near z≈ 1 and simultaneously a large-enough sample to find evidence for the strong evolution of clust…