Query : 2010A&A...519A.100M

2010A&A...519A.100M - Astronomy and Astrophysics, volume 519, A100-100 (2010/9-1)

Annihilation emission from young supernova remnants.


Abstract (from CDS):

A promising source of the positrons that contribute through annihilation to the diffuse Galactic 511keV emission is the β+-decay of unstable nuclei like 56Ni and 44Ti synthesised by massive stars and supernovae. Although a large fraction of these positrons annihilate in the ejecta of SNe/SNRs, no point-source of annihilation radiation appears in the INTEGRAL/SPI map of the 511keV emission. We exploit the absence of detectable annihilation emission from young local SNe/SNRs to derive constraints on the transport of MeV positrons inside SN/SNR ejecta and their escape into the CSM/ISM, both aspects being crucial to the understanding of the observed Galactic 511keV emission. We simulated 511keV lightcurves resulting from the annihilation of the decay positrons of 56Ni and 44Ti in SNe/SNRs and their surroundings using a simple model. We computed specific 511keV lightcurves for Cas A, Tycho, Kepler, SN1006, G1.9+0.3 and SN1987A, and compared these to the upper-limits derived from INTEGRAL/SPI observations.The predicted 511keV signals from positrons annihilating in the ejecta are below the sensitivity of the SPI instrument by several orders of magnitude, but the predicted 511keV signals for positrons escaping the ejecta and annihilating in the surrounding medium allowed to derive upper-limits on the positron escape fraction of ∼13% for Cas A, ∼12% for Tycho, ∼30% for Kepler and ∼33% for SN1006.The transport of ∼MeV positrons inside SNe/SNRs cannot be constrained from current observations of the 511keV emission from these objects, but the limits obtained on their escape fraction are consistent with a nucleosynthesis origin of the positrons that give rise to the diffuse Galactic 511keV emission.

Abstract Copyright:

Journal keyword(s): Gamma rays: general - ISM: supernova remnants - ISM: general - nuclear reactions - nucleosynthesis, abundances - astroparticle physics

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 SN 1572A SN* 00 25 21.5 +64 08 27           B8 1172 1
2 SN 1987A SN* 05 35 28.020 -69 16 11.07           SNIIpec 4862 2
3 SN 1993J SN* 09 55 24.77476 +69 01 13.7026   10.8 12.0     SNIIb 1390 1
4 NAME Lupus SN SNR 15 02 22.1 -42 05 49           ~ 1315 1
5 NAME Kepler SNR Rad 17 30 40.5 -21 29 14           ~ 785 4
6 SNR G001.9+00.3 SNR 17 48 46.0 -27 09 52           ~ 201 1
7 NAME Cas A SNR 23 23 24.000 +58 48 54.00     14.30     ~ 2725 1
8 NAME Galactic Bulge reg ~ ~           ~ 4169 0

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