Search Publications
Low-frequency Observations of Polarized Emission from Long-lived Non-thermal Radio Sources in the Solar Corona
Ramesh, R.; Kathiravan, C.; Narayanan, A. Satya
We report observations of circularly polarized emission from the solar corona at 77 MHz during the periods 2006 August 11-18, 2006 August 23-29, and 2007 May 16-22 in the minimum phase between the sunspot cycles 23 and 24. The observations were carried out with the east-west one-dimensional radio polarimeter at the Gauribidanur observatory located…
Evidence for Three Accreting Black Holes in a Galaxy at z ~ 1.35: A Snapshot of Recently Formed Black Hole Seeds?
Schawinski, Kevin; Natarajan, Priyamvada; Treister, Ezequiel +3 more
One of the key open questions in cosmology today pertains to understanding when, where, and how supermassive black holes form. While it is clear that mergers likely play a significant role in the growth cycles of black holes, the issue of how supermassive black holes form, and how galaxies grow around them, still needs to be addressed. Here, we pr…
Suzaku View of X-Ray Spectral Variability of the Radio Galaxy Centaurus A: Partial Covering Absorber, Reflector, and Possible Jet Component
Fukazawa, Yasushi; Ohno, Masanori; Yamazaki, Syoko +6 more
We observed a nearby radio galaxy, Centaurus A (Cen A), three times with Suzaku in 2009 and measured the wide-band X-ray spectral variability more accurately than previous measurements. The Cen A was in an active phase in 2009, and the flux became higher by a factor of 1.5-2.0 and the spectrum became harder than that in 2005. The Fe-K line intensi…
The Suzaku view of 3C 382
Ballo, L.; Reynolds, C. S.; Tombesi, F. +4 more
We present a long (116 ks) Suzaku observation of the broad-line radio galaxy (BLRG) 3C 382 acquired in 2007 April. A Swift BAT spectrum in 15-200 keV from the 58 month survey is also analyzed, together with an archival XMM-Newton EPIC exposure of 20 ks obtained one year after Suzaku. Our main result is the finding with Suzaku of a broad Fe K line …
Suzaku View of the Swift/BAT Active Galactic Nuclei. IV. Nature of Two Narrow-line Radio Galaxies (3C 403 and IC 5063)
Ueda, Yoshihiro; Terashima, Yuichi; Mushotzky, Richard F. +1 more
We report the results of Suzaku broadband X-ray observations of the two narrow-line radio galaxies, 3C 403 and IC 5063. Combined with the Swift/Burst Alert Telescope (BAT) spectra averaged for 58 months, we are able to accurately constrain their spectral properties over the 0.5-200 keV band. The spectra of both nuclei are well represented with an …
Modeling of the HerMES Submillimeter Source Lensed by a Dark Matter Dominated Foreground Group of Galaxies
Pérez-Fournon, I.; Rodighiero, G.; Valtchanov, I. +85 more
We present the results of a gravitational lensing analysis of the bright z s = 2.957 submillimeter galaxy (SMG) HERMES found in the Herschel/SPIRE science demonstration phase data from the Herschel Multi-tiered Extragalactic Survey (HerMES) project. The high-resolution imaging available in optical and near-IR channels, along with CO emi…
A Statistical Model for the γ-ray Variability of the Crab Nebula
Yuan, Qiang; Zhang, Bing; Wu, Xue-Feng +3 more
A statistical scenario is proposed to explain the γ-ray variability and flares of the Crab Nebula, which were observed recently by the Fermi/LAT. In this scenario electrons are accelerated in a series of knots, whose sizes follow a power-law distribution. These knots presumably move outward from the pulsar and have a distribution in the Doppler bo…
Seasonal Changes in Titan's Surface Temperatures
Flasar, F. M.; Coustenis, A.; Jennings, D. E. +9 more
Seasonal changes in Titan's surface brightness temperatures have been observed by Cassini in the thermal infrared. The Composite Infrared Spectrometer measured surface radiances at 19 µm in two time periods: one in late northern winter (LNW; Ls = 335°) and another centered on northern spring equinox (NSE; Ls = 0°). In b…
Ultraviolet Spectroscopy of Circumnuclear Star Clusters in M83
Leitherer, Claus; Chandar, Rupali; Wofford, Aida
We analyze archival HST/STIS/FUV-MAMA imaging and spectroscopy of 13 compact star clusters within the circumnuclear starburst region of M83, the closest such example. We compare the observed spectra with semi-empirical models, which are based on an empirical library of Galactic O and B stars observed with IUE, and with theoretical models, which ar…
Plasmoid Releases in the Heliospheric Current Sheet and Associated Coronal Hole Boundary Layer Evolution
Sauvaud, J. -A.; Luhmann, J. G.; Farrugia, C. J. +10 more
As the heliospheric current sheet (HCS) is corotating past STEREO-B, near-Earth spacecraft ACE, Wind and Cluster, and STEREO-A over more than three days between 2008 January 10 and 14, we observe various sections of (near-pressure-balanced) flux-rope- and magnetic-island-type plasmoids in the associated heliospheric plasma sheet (HPS). The plasmoi…