Gamma-ray Nova V407 Gamma-ray Nova V407 Cyg and Fermi-LAT Cyg and Fermi-LAT Galactic Plane Galactic Plane Transients Transients C.C. Teddy Cheung (NRC Research Associate*) on behalf of the Fermi-LAT Collaboration *resident at Naval Research Lab Heidelberg Galactic Binaries – 2010 Dec 3
12
Embed
Gamma-ray Nova V407 Cyg and Fermi-LAT Galactic Plane Transients Gamma-ray Nova V407 Cyg and Fermi-LAT Galactic Plane Transients C.C. Teddy Cheung (NRC.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Gamma-ray Nova V407 Gamma-ray Nova V407 Cyg and Fermi-LAT Cyg and Fermi-LAT
Evolved Red Giant (M6 III) with: Mira-like pulsations (745
day period) SiO maser emission, D-type
symbiotic (wind-accreting) Anomalous Li abundance
Probable distance ~2.7 kpc
Fast rise and decline of nova indicate massive WD (>1 Msun)
Orbital period uncertain; binary separation ~4 day γ-ray peak
RG wind & nova shell velocities inferred from optical spectral line-width measurements
V407 Cyg Binary SystemV407 Cyg Binary System
.
2010 Dec 3 - Cheung
Asymmetric distribution of material from Red Giant wind
Nova γ-ray and X-ray Evolution Nova γ-ray and X-ray Evolution
White dwarf at center
Credit: S. Razzaque
Nova shell initially freely expands into asymmetric dense medium
Shell toward RG slows down quickly Gamma rays peak early when
efficiency for pion and inverse-Compton processes is favorable
Shell decelerates slowly away from RG Later X-rays peak, flux increasing
with volume of shock-heated gas
2010 Dec 3 - Cheung
γ-ray Spectrum and Energeticsγ-ray Spectrum and Energetics
15-day average
Gamma-ray emission process could be:
pion:pion: accelerated accelerated pp’s ’s collide with ambient collide with ambient material producingmaterial producing 00 with with prompt decayprompt decay• inverse Compton:inverse Compton: accelerated electrons up-accelerated electrons up-scattering infrared photons scattering infrared photons from the red giantfrom the red giant