2010A&A...510A.101F


C.D.S. - SIMBAD4 rel 1.7 - 2020.12.02CET10:07:24

2010A&A...510A.101F - Astronomy and Astrophysics, volume 510, A101-101 (2010/2-1)

On the shape of the spectrum of cosmic rays accelerated inside superbubbles.

FERRAND G. and MARCOWITH A.

Abstract (from CDS):

Supernova remnants are believed to be a major source of energetic particles (cosmic rays) on the Galactic scale. Since their progenitors, namely the most massive stars, are commonly found clustered in OB associations, one has to consider the possibility of collective effects in the acceleration process. We investigate the shape of the spectrum of high-energy protons produced inside the superbubbles blown around clusters of massive stars. We embed simple semi-analytical models of particle acceleration and transport inside Monte Carlo simulations of OB associations timelines. We consider regular acceleration (Fermi 1 process) at the shock front of supernova remnants, as well as stochastic reacceleration (Fermi 2 process) and escape (controlled by magnetic turbulence) occurring between the shocks. In this first attempt, we limit ourselves to linear acceleration by strong shocks and neglect proton energy losses. We observe that particle spectra, although highly variable, have a distinctive shape because of the competition between acceleration and escape: they are harder at the lowest energies (index s<4) and softer at the highest energies (s>4). The momentum at which this spectral break occurs depends on the various bubble parameters, but all their effects can be summarized by a single dimensionless parameter, which we evaluate for a selection of massive star regions in the Galaxy and the LMC. The behaviour of a superbubble in terms of particle acceleration critically depends on the magnetic turbulence: if B is low then the superbubble is simply the host of a collection of individual supernovae shocks, but if B is high enough (and the turbulence index is not too high), then the superbubble acts as a global accelerator, producing distinctive spectra, that are potentially very hard over a wide range of energies, which has important implications on the high-energy emission from these objects.

Abstract Copyright:

Journal keyword(s): acceleration of particles - shock waves - turbulence - cosmic rays - ISM: supernova remnants

Simbad objects: 28

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Number of rows : 28

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 Ass Per OB 2 As* 03 42.2 +33 26           ~ 309 0
2 NGC 1761 As* 04 56 39 -66 29.0     9.94     ~ 96 0
3 LHA 120-N 11 HII 04 56 51.4 -66 24 24           ~ 235 0
4 NGC 1763 As* 04 56 51.5 -66 24 25     9.40     ~ 156 3
5 NGC 1769 As* 04 57 44.5 -66 27 42           ~ 67 2
6 NGC 1773 HII 04 58 12.0 -66 21 36           ~ 50 1
7 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15061 1
8 LHA 120-N 51D HII 05 25 17.3 -67 22 47           ~ 107 0
9 KMHK 879 As* 05 25 26 -67 28.4     11.75     ~ 38 0
10 NGC 1955 As* 05 26 12 -67 29.9   8.95 8.87     ~ 63 0
11 NAME Ori I As* 05 38 -02.8           ~ 563 0
12 NAME 30 Dor Nebula SFR 05 38 36.0 -69 05 11           ~ 1054 2
13 RMC 136 Cl* 05 38 42.396 -69 06 03.36           ~ 1761 1
14 Cl Westerlund 2 OpC 10 23 58.1 -57 45 49   11.59 10.5     ~ 288 0
15 GUM 29 HII 10 24 14.6 -57 46 58           ~ 192 0
16 Cl Trumpler 14 OpC 10 43 56 -59 33.0   5.70 5.5     ~ 435 0
17 NGC 3372 HII 10 44 19.0 -59 53 21           ~ 904 2
18 Cl Trumpler 16 OpC 10 45 10 -59 43.0   5.35 5.0     ~ 432 0
19 Cl Westerlund 1 OpC 16 47 04.00 -45 51 04.9           ~ 482 0
20 PN H 1-44 EB* 17 58 10.65 -31 42 56.0     17.00   18.939 ~ 59 0
21 Ass Cyg OB 3 As* 20 07 +35.9           ~ 169 0
22 Ass Cyg OB 1 As* 20 17.8 +37 38           ~ 249 1
23 MGRO J2019+37 gam 20 20.1 +36 43           ~ 55 0
24 NAME Cyg Complex reg 20 32 +45.0           ~ 528 0
25 TeV J2032+4130 gam 20 32.1 +41 34           ~ 122 0
26 Ass Cyg OB 2 As* 20 33.2 +41 19           ~ 810 0
27 NAME Cyg Superbubble PoC 20 47 +41.2           ~ 73 1
28 NAME Ass ORI OB 1a As* ~ ~           ~ 200 0

    Equat.    Gal    SGal    Ecl

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2020.12.02-10:07:24

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