Search Publications
The First Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
Ozaki, M.; Caraveo, P. A.; D'Elia, V. +205 more
We present the first catalog of active galactic nuclei (AGNs) detected by the Large Area Telescope (LAT), corresponding to 11 months of data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 γ-ray sources located at high Galactic latitudes (|b|>10°) that are detected with a test statistic greater than 25 and …
Fading Hard X-ray Emission from the Galactic Center Molecular Cloud Sgr B2
Ponti, G.; Decourchelle, A.; Morris, M. R. +6 more
The center of our Galaxy harbors a four million solar mass black hole that is unusually quiet: its present X-ray luminosity is more than 10 orders of magnitude less than its Eddington luminosity. The observation of iron fluorescence and hard X-ray emission from some of the massive molecular clouds surrounding the Galactic center has been interpret…
Fermi Large Area Telescope Observation of a Gamma-ray Source at the Position of Eta Carinae
Ozaki, M.; Caraveo, P. A.; Frailis, M. +165 more
The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope detected a γ-ray source that is spatially consistent with the location of Eta Carinae. This source has been persistently bright since the beginning of the LAT survey observations (from 2008 August to 2009 July, the time interval considered here). The γ-ray signal is detect…
On the Morphology of the Electron-Positron Annihilation Emission as Seen by Spi/integral
Bouchet, L.; Jourdain, E.; Roques, J. P.
The 511 keV positron annihilation emission remains a mysterious component of the high energy emission of our Galaxy. Its study was one of the key scientific objectives of the SPI spectrometer on board the International Gamma-Ray Astrophysics Laboratory satellite. In fact, a lot of observing time has been dedicated to the Galactic disk with a parti…
Revealing Type Ia Supernova Physics with Cosmic Rates and Nuclear Gamma Rays
Beacom, John F.; Horiuchi, Shunsaku
Type Ia supernovae (SNe Ia) remain mysterious despite their central importance in cosmology and their rapidly increasing discovery rate. The progenitors of SNe Ia can be probed by the delay time between progenitor birth and explosion as SNe Ia. The explosions and progenitors of SNe Ia can be probed by MeV nuclear gamma rays emitted in the decays o…
The 2009 December Gamma-ray Flare of 3C 454.3: The Multifrequency Campaign
Sakamoto, T.; Pian, E.; Fugazza, D. +81 more
During the month of 2009 December, the blazar 3C 454.3 became the brightest gamma-ray source in the sky, reaching a peak flux F ~ 2000 × 10-8 photons cm-2 s-1 for E > 100 MeV. Starting in 2009 November intensive multifrequency campaigns monitored the 3C 454 gamma-ray outburst. Here, we report on the results of a…
Search for Gamma-ray Emission from Magnetars with the Fermi Large Area Telescope
Ozaki, M.; Troja, E.; Caraveo, P. A. +136 more
We report on the search for 0.1-10 GeV emission from magnetars in 17 months of Fermi Large Area Telescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently known magnetars is found. The most stringent upper limits to date on their persistent emission in the Fermi energy range are estimated between ~10
The Evolution and Eddington Ratio Distribution of Compton Thick Active Galactic Nuclei
Ballantyne, D. R.; Draper, A. R.
Previous studies of the active galactic nuclei (AGNs) contribution to the cosmic X-ray background (CXB) consider only observable parameters such as luminosity and absorbing column. Here, for the first time, we extend the study of the CXB to physical parameters including the Eddington ratio of the sources and the black hole mass. In order to calcul…
X-Ray Emission from HESS J1731-347/SNR G353.6-0.7 and Central Compact Source XMMS J173203-344518
Leahy, D. A.; Li, Z.; Tian, W. W. +4 more
We present new results of the HESS J1731-347/SNR G353.6-0.7 system from XMM-Newton and Suzaku X-ray observations and Delinha CO observations. We discover extended hard X-rays coincident with the bright, extended TeV source HESS J1731-347 and the shell of the radio supernova remnant (SNR). We find that spatially resolved X-ray spectra can generally…
Analysis of a Global Moreton Wave Observed on 2003 October 28
Magdalenić, J.; Temmer, M.; Veronig, A. M. +2 more
We study the well-pronounced Moreton wave that occurred in association with the X17.2 flare/CME event of 2003 October 28. This Moreton wave is striking for its global propagation and two separate wave centers, which implies that two waves were launched simultaneously. The mean velocity of the Moreton wave, tracked within different sectors of propa…