Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2009-12-18
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
2009 Fermi Symposium: eConf Proceedings C091122; 6 pages, 6 figures; fixed typos
Scientific paper
Diffuse gamma-ray emission arising from interactions of cosmic rays with the interstellar gas traces the densities of both of them throughout the Milky Way. We discuss the results obtained from the analysis of Fermi LAT observations in the region of Cassiopeia and Cepheus, towards the Perseus spiral arm. We find that the gamma-ray emissivity of local gas is consistent with expectations based on the cosmic-ray spectra measured at the Earth. The emissivity decreases from the Gould Belt to the Perseus arm, but the measured gradient is flatter than predictions by a propagation model based on a cosmic-ray source distribution peaking in the inner Galaxy as suggested by pulsars. The Xco=N(H2)/W(CO) conversion factor moderately increases by a factor ~2 from the Gould Belt to the Perseus arm. The presence of additional gas not properly traced by HI and CO surveys in the Gould Belt is suggested by the correlation between gamma rays and thermal emission from cold interstellar dust.
Fermi/LAT collaboration for the
Grenier Isabelle A.
Tibaldo Luigi
No associations
LandOfFree
The cosmic-ray puzzle and the census of the interstellar medium: the Fermi LAT view of Cassiopeia, Cepheus and the Perseus arm does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The cosmic-ray puzzle and the census of the interstellar medium: the Fermi LAT view of Cassiopeia, Cepheus and the Perseus arm, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The cosmic-ray puzzle and the census of the interstellar medium: the Fermi LAT view of Cassiopeia, Cepheus and the Perseus arm will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-381414