Constraints on the non-thermal emission from Eta Carinae's blast wave of 1843

Abstract

Non-thermal hard X-ray and high-energy (HE; 1 MeV < E < 100 GeV) gamma-ray emission in the direction of Eta Carinae has been recently detected using the INTEGRAL, AGILE and Fermi satellites. This emission has been interpreted either in the framework of particle acceleration in the colliding wind region between the two massive stars or in the very fast moving blast wave which originates in the historical 1843 "Great Eruption". Archival Chandra data has been reanalysed to search for signatures of particle acceleration in Eta Carinae's blast wave. No shell-like structure could be detected in hard X-rays and a limit has been placed on the non-thermal X-ray emission from the shell. The time dependence of the target radiation field of the Homunculus is used to develop a single zone model for the blast wave. Attempting to reconcile the X-ray limit with the HE -ray emission using this model leads to a very hard electron injection spectrum dN/dE ~ E^-Gamma with Gamma < 1.8, harder than the canonical value expected from diffusive shock acceleration.

5 pages, 3 figures. Accepted for publication in A&A

References in corpus (8)

• Fermi Large Area Telescope Bright Gamma-ray Source List
• Detection of Gamma-ray Emission from the Eta-Carinae Region
• A Blast Wave from the 1843 Eruption of Eta Carinae
• Inverse Compton Scenarios for the TeV Gamma-Ray Emission of the Galactic Centre
• Hard X-ray emission from Eta Carinae
• High-energy radiation from the massive binary system Eta Carinae
• Hard X-ray identification of Eta Carinae and steadiness close to periastron
• Particle acceleration in the expanding blast wave of Eta Carina's Great Eruption of 1843

Cited by in corpus (2)

• H.E.S.S. observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae
• Probing cosmic ray escape from η Carinae