Emission spectra of hot accretion disks characteristic of advection dominated accretion flow (ADAF) models are investigated for comparison with the brightest ultra-luminous source, X-1, in the galaxy M82. If the spectral state of the source is similar to the low luminosity hard state of stellar mass black holes in our Galaxy, a fit to the Chandra X-ray spectrum and constraints from the radio an...

Emission spectra of hot accretion disks characteristic of advection dominated accretion flow (ADAF) models are investigated for comparison with the brightest ultra-luminous source, X-1, in the galaxy M82. If the spectral state of the source is similar to the low luminosity hard state of stellar mass black holes in our Galaxy, a fit to the Chandra X-ray spectrum and constraints from the radio an...

We report the discovery and detailed monitoring of X-ray emission associated with the Type IIb SN2011dh using data from the Swift and Chandra satellites, placing it among the best studied X-ray supernovae to date. We further present millimeter and radio data obtained with the SMA, CARMA, and EVLA during Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA Nationa...

We report on a multiwavelength campaign on the TeV γ-ray blazar Markarian (Mrk) 421 performed during December 2002 and January 2003. These target of opportunity observations were initiated by the detection of X-ray and TeV Department of Physics, Washington University, St. Louis, MO 63130, USA Physics Department, Tanta University, Tanta, Egypt Department of Physics, University of Massachussetts,...

The basic concept and the status of currently operating ground-based array detectors for VHE gamma-ray astronomy will be presented and compared with imaging air Cherenkov telescopes. Also an outlook of future prospects will be given.