Search Publications
Suzaku Observation of Strong Solar-Wind Charge-Exchange Emission from the Terrestrial Exosphere during a Geomagnetic Storm
Miyoshi, Yoshizumi; Ezoe, Yuichiro; Ishikawa, Kumi +3 more
We present an analysis of X-ray data exhibiting strong solar-wind charge-exchange emission obtained with the Suzaku satellite during a geomagnetic storm that occurred on 2005 August 31. A temporal variation of diffuse soft X-ray emission, correlating with the solar-wind proton flux, was found. The diffuse emission consisted of exospheric solar-win…
Doppler Shifts in Active Region Moss Using SOHO/SUMER
Del Zanna, Giulio; Tripathi, Durgesh; Mason, Helen E. +1 more
The velocity of the plasma at the footpoint of hot loops in active region cores can be used to discriminate between different heating frequencies. Velocities on the order of a few kilometers per second would indicate low-frequency heating on sub-resolution strands, while velocities close to zero would indicate high-frequency (steady) heating. To d…
The Effect of UV/Soft X-Ray Excess Emission on the Warm Absorber Properties of Active Galactic Nuclei—A Case Study of IRAS 13349+2438
Dewangan, Gulab C.; Laha, Sibasish; Chakravorty, Susmita +1 more
The ultraviolet (UV) to X-ray continuum of active galactic nuclei (AGNs) is important for maintaining the ionization and thermal balance of the warm absorbers (WAs). However, the spectra in the sensitive energy range ~13.6-300 eV are unobservable due to Galactic extinction. Moreover, many AGNs show soft X-ray excess emission of varying strength in…
Mechanisms of Spontaneous Reconnection: From Magnetospheric to Fusion Plasma
Zelenyi, Lev; Artemyev, Anton
Very often space plasma is treated as collisionless. We check the validity of this paradigm considering various regimes of tearing mode (spontaneous reconnection) including effects of particle collisions and shear of magnetic field. We briefly describe Pitaevskii's effect of effective modification of collision frequency due to the finite particle …
Fast Magnetoacoustic Waves in a Fan Structure Above a Coronal Magnetic Null Point
Karlický, M.; Mészárosová, H.; Dudík, J. +2 more
We analyze the 26 November 2005 solar radio event observed interferometrically at frequencies of 244 and 611 MHz by the Giant Metrewave Radio Telescope (GMRT) in Pune, India. These observations are used to make interferometric maps of the event at both frequencies with the time cadence of 1 s from 06:50 to 07:12 UT. These maps reveal several radio…
The NGC 3341 minor merger: a panchromatic view of the active galactic nucleus in a dwarf companion
Fiore, Fabrizio; Mathur, Smita; Bianchi, Stefano +4 more
We present X-ray (Chandra), radio (Expanded Very Large Array and European VLBI Network) and archival optical data of the triple-merging system in NGC 3341. Our panchromatic analysis confirms the presence of a Seyfert 2 active galactic nucleus (AGN) in NGC 3341B, one of the secondary dwarf companions. On the other hand, the nucleus of the primary g…
A 0535+26 in the April 2010 outburst: probing the accretion regime at work
Müller, D.; Klochkov, D.; Santangelo, A. +1 more
Context. A number of accreting X-ray pulsars experience spectral changes, both on the long time scales and on the time scales of the neutron star spin period. The sources seem to form two distinct groups that differ by the type of the spectral variations with flux. Such a bimodality probably reflects two different regimes of accretion that may res…
An External Origin for Carbon Monoxide on Uranus from Herschel/SPIRE?
Irwin, P. G. J.; Teanby, N. A.
Previous studies have demonstrated an external source of CO on Jupiter, Saturn, and Neptune. However, it has not been possible to demonstrate this on Uranus because of its low CO abundance, low upper-tropospheric temperatures, and low stratospheric thermal gradient, which make detection very challenging. Here we use 17 Herschel/SPIRE observation s…
Supernovae and radio transients in M82
Smartt, S. J.; Fraser, M.; Romero-Cañizales, C. +4 more
We present optical and near-infrared (NIR) photometry and NIR spectroscopy of SN 2004am, the only optically detected supernova (SN) in M82. These demonstrate that SN 2004am was a highly reddened Type II-P SN similar to the low-luminosity Type II-P events such as SNe 1997D and 2005cs. We show that SN 2004am was located coincident with the obscured …
Morphology with light profile fitting of confirmed cluster galaxies at z = 0.84
Demarco, R.; Lidman, C.; Rosati, P. +3 more
We perform a morphological study of 124 spectroscopically confirmed cluster galaxies in the redshift (z) = 0.84 galaxy cluster RX J0152.7-1357. Our classification scheme includes color information, visual morphology, and one- and two-component light profile fitting derived from Hubble Space Telescope riz imaging. We adopt a modified version of a d…