Gamma Rays from the Distant BL Lac 1ES 0347-121
October 2007 To disentangle the processes at work in gamma-ray sources, multi-wavelength observations over a wide range of frequencies are required. In the investigation of the active galaxy 1ES 0347-121, contemporaneous observations with the …
A novel type of source? Gamma rays from the vicinity of the Wolf-Rayet binary WR 20a
December 2006 Infrared/optical image of the RCW 49 HII region – a massive star formation region about 300-400 light years across – and the Westerlund 2 stellar cluster. Westerlund 2 contains a number of…
TeV gamma rays from the core of M87
November 2006 The radio galaxy M87 viewed at radio wavelengths at different scales, successively zooming into smaller structures in the jet emerging from the supermassive black hole at the core of the galaxy. The…
A different type of “source” – Iron nuclei among cosmic rays
October 2006 Cherenkov light generated in the atmosphere by heavy nuclei among cosmic rays: while traversing the atmosphere, the nucleus radiates “direct” Cherenkov light. Then, it interacts and generates a cascade of secondary particles,…
HESS J1804-216 – Supernova remnant or pulsar wind nebula?
September 2006 Radio map of the W30 region fromBrogan et al. (2006), showing the roughly circular large supernova remnant W30 (or G8.7-0.1), the compact remnant G8.31-0.09, and a number of additional structures identified as…
One Year Later – LS 5039 Revisited
August 2006 Orbital geometry of LS 5039, where a compact object – presumable a black hole – is in a tight orbit around a massive star (Casares et al. 2005). The system is viewed…
HESS J1702-420 – Mystery Source or Pulsar Wind?
July 2006 Pulsar wind nebulae seen by H.E.S.S.; in all cases, the gamma-ray emission is significantly displaced from the pulsar considered as the energy source for the nebula The H.E.S.S. survey of the Galactic…
HESS J1834-087 – Another Supernova Remnant?
VLA images of the Galactic Plane around 23.3 degr. longitude, showing the supernova remnants G23.3-0.3 (center) and G22.7-0.2 (left on the 90 cm image). The 90 cm image shows a 2 by 2 degree…
Vela X – a Cosmic Accelerator
May 2006 Three views of the Vela region: the ROSAT image in the 0.1-2.4 keV range (left) shows the huge Vela supernova remnant, with the smaller Puppis supernova remnant in the upper corner. An…
The Wings of the Kookaburra
April 2006 adio image at 20 cm wavelength (Roberts et al. 1999) of a region near the Galactic Plane around 313o longitude, showing a complex of radio sources extending over a square degree. The…