ICRC2015

July 29, 2015 to August 6, 2015
World Forum
Europe/Amsterdam timezone

Analysis of GeV-band gamma-ray emission from SNR RX J1713.7-3946

Jul 30, 2015, 3:30 PM
1h
Mississippi Foyer (World Forum)

Mississippi Foyer

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Board: 129
Poster contribution GA-TH

Speaker

Robert Brose (DESY)

Description

RX J1713-3946 is the brightest shell-type supernova remnant (SNR) of the TeV gamma-ray sky. Earlier Fermi-LAT results on low energy gamma-ray emission suggested that, despite large uncertainties in the background determination, the spectrum is inconsistent with a hadronic origin. We update the GeV-band spectra using improved estimates for the diffuse galactic gamma-ray emission and more than double the volume of data. We further investigate the viability of hadronic emission models for RX J1713-3946. We produced a high-resolution map of the diffuse Galactic gamma-ray background corrected for the HI self-absorption and used it in the analysis of more than five years worth of Fermi-LAT data. We used hydrodynamic scaling relations and a kinetic transport equation to calculate the acceleration and propagation of cosmic rays in SNR. We then determined spectra of hadronic gamma-ray emission from RX J1713-3946, separately for the SNR interior and the cosmic-ray precursor region of the forward shock, and computed flux variations that would allow us to test the model with observations. We find that RX J1713-3946 is now detected by Fermi-LAT with very high statistical significance, and the source morphology is best described by that seen in the TeV band. The measured spectrum of RX J1713-3946 is hard with index $\gamma=1.53\pm0.07$, and the integral flux above 500 MeV is $F = (5.5\pm1.1)\times10^{-9}$ photons cm$^{-2}$ s$^{-1}$. We demonstrate that scenarios based on hadronic emission from the cosmic-ray precursor region are acceptable for RX J1713-3946, and we predict a secular flux increase at a few hundred GeV at the level of around 15% over ten years, which may be detectable with the upcoming Cherenkov Telescope Array (CTA) observatory.
Collaboration -- not specified -- 1092

Co-authors

Alina Wilhelm (DESY) Igor Telezhinsky (Astronomical Observatory of Kiev University) Martin Pohl (DESY) Robert Brose (DESY)

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