Related papers: Gamma Ray Lines from the Orion Complex
We mapped quiescent 807 GHz CO(7-6) emission from Orion along a strip in RA extending from 0.7 pc west to 1.2 pc east of Ori theta 1C. The lines arise in warm gas with T > 40 K. The line brightness temperature is > 160 K in the di- rection…
We have analyzed the two blazars of 3C 454.3 and CTA 102 using all available COMPTEL data from 1991 to 1999. In the 10-30 MeV band, emission from the general direction of the sources is found at the 4$\sigma$-level, being consistent with…
The last measurement of the diffuse emission spectrum of the Milky Way in the megaelectronvolt (MeV) photon energy range was performed by CGRO/COMPTEL more than 20 years ago. We report a new analysis with the spectrometer SPI aboard…
Seyfert galaxies have not been detected by COMPTEL on the Compton Gamma Ray Observatory (CGRO) in the energy range 0.75-3 MeV, placing upper limits on their emission which are more than an order of magnitude below previously reported…
In the colliding wind region of early-type binaries, electrons can be accelerated up to relativistic energies displaying power-law spectra, as demonstrated by the detection of non-thermal radio emission from several WR+OB systems. The…
Diffuse galactic gamma-ray emission is produced by the interaction of cosmic rays (CRs) with the interstellar environment. The study of gamma-ray emission is therefore a powerful tool to investigate the origin of CRs and the processes…
We show that gamma ray line emission at $\sim$0.4 MeV and $\lsim 0.2$ MeV can be produced by Compton scattering of beamed radiation in the jets of Galactic black hole candidates. This mechanism has the novel feature of not invoking the…
Orion KL has served as a benchmark for spectral line searches throughout the (sub)millimeter regime. The main goal is to systematically study spectral characteristics of Orion KL in the 1.3 cm band. We carried out a spectral line survey…
We search for MeV gamma-ray emission between 0.75-30 MeV from five galaxy clusters, viz. Coma, VIRGO, SPT-CL J2012-5649, Bullet, and El Gordo, using archival data from the COMPTEL telescope. For this purpose we use three search templates:…
The recently published precise spectrum of cosmic ray protons from the Alpha Magnetic Spectrometer has been examined in some detail from the standpoint of a search for deviations from a smooth, simple, power law. We find a significant…
We report the COMPTEL detection of pulsed $\gamma$-emission from PSR B1509-58 up to at least 10 MeV using data collected over more than 6 years. The 0.75-10 MeV lightcurve is broad and reaches its maximum near radio-phase 0.38, slightly…
Here we review our current knowledge on diffuse gamma-rays from galactic halos. Estimates of the relative contribution of the various emission processes at low and high latitudes are compared to the data over 6 decades in energy. The…
Inverse Compton scattering appears to play a more important role in the diffuse Galactic continuum emission than previously thought, from MeV to GeV energies. We compare models having a large inverse Compton component with EGRET data, and…
I discuss the spectral features of pi-0 decay gamma-radiation from clouds/targets located in proximity of relatively young proton accelerators, and speculate that such ``accelerator+target'' systems in our Galaxy can be responsible for a…
The results of a submillimetre wavelength spectral line survey between 455.1 -- 507.4 GHz of the Orion-KL hot cloud core are reported. A total of 254 lines were detected to a main beam brightness temperature sensitivity ~ 1 - 3 K. The…
We present a new local interstellar spectrum for cosmic ray electrons over an energy range from 1 MeV to 70 GeV. Below (0.8 plus minus 0.2) GeV it has a power law form, E^-(1.55 plus minus 0.05), with E kinetic energy, which is consistent…
OB associations and young open clusters constitute the most prolific nucleosynthesis sites in our Galaxy. The combined activity of stellar winds and core-collapse supernovae ejects significant amounts of freshly synthesised nuclei into the…
We report on the gamma-ray observations of giant molecular clouds Orion A and B with the Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope. The gamma-ray emission in the energy band between \sim100 MeV and \sim100 GeV…
We obtained new upper limits on the diffuse gamma rays from the inner Galactic (IG) and outer Galactic (OG) planes in 3.10 TeV region, using the Tibet air shower data and new Monte Carlo simulation results. A difference of the effective…
The bulk of the diffuse galactic gamma-ray emission above a few tens of GeV has been conventionally ascribed to the decay of neutral pions produced in cosmic-ray interactions with interstellar matter. Cosmic-ray electrons may, however, make…