J/MNRAS/493/3159 Modelling of wind and supernovae shocks (Gupta+, 2020)
Realistic modelling of wind and supernovae shocks in star clusters:
addressing 22Ne/20Ne and other problems in Galactic cosmic rays.
Gupta S., Nath B.B., Sharma P., Eichler D.
<Mon. Not. R. Astron. Soc., 493, 3159-3177 (2020)>
=2020MNRAS.493.3159G 2020MNRAS.493.3159G (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Supernova remnants ; Milky Way ; Positional data ;
X-ray sources ; Radio sources
Keywords: hydrodynamics - shock waves - methods:numerical - cosmic rays
Abstract:
Cosmic ray (CR) sources leave signatures in the isotopic abundances of
CRs. Current models of Galactic CRs that consider supernovae (SNe)
shocks as the main sites of particle acceleration cannot
satisfactorily explain the higher 22Ne/20Ne ratio in CRs compared
to the interstellar medium. Although stellar winds from massive stars
have been invoked, their contribution relative to SNe ejecta has been
taken as a free parameter. Here, we present a theoretical calculation
of the relative contributions of wind termination shocks (WTSs) and
SNe shocks in superbubbles, based on the hydrodynamics of winds in
clusters, the standard stellar mass function, and stellar evolution
theory. We find that the contribution of WTSs towards the total CR
production is at least 25 per cent, which rises to ≳50 per cent for
young (~<10Myr) clusters, and explains the observed 22Ne/20Ne
ratio. We argue that since the progenitors of apparently isolated
supernovae remnants (SNRs) are born in massive star clusters, both WTS
and SNe shocks can be integrated into a combined scenario of CRs being
accelerated in massive clusters. This scenario is consistent with the
observed ratio of SNRs to γ-ray bright
(Lγ≳1035erg/s) star clusters, as predicted by star
cluster mass function. Moreover, WTSs can accelerate CRs to PeV
energies, and solve other long-standing problems of the standard SN
paradigm of CR acceleration.
Description:
Observations show that in Sbc galaxies (Milky-Way-type) the ratio of
thermonuclear to core-collapse SNe is ∼1/3 (Mannucci et al.
2005A&A...433..807M 2005A&A...433..807M). Adding thermonuclear SNRs, this indicates a
ratio of SNRs to WTS γ-ray sources in our Galaxy of order 33-65.
We can check this argument by counting the SNRs and γ-ray bright
clusters in a given volume. The size of the sampling volume is hard to
decide, since γ-ray bright clusters are rare: there are only
three γ-ray bright clusters near us, Cygnus at ∼1.4kpc,
Westerlund 1 at ∼4kpc (Aharonian, Yang & de Ona Wilhelmi
2019NatAs...3..561A 2019NatAs...3..561A), and Westerlund 2 at ∼5kpc (Yang et al.
2018A&A...611A..77Y 2018A&A...611A..77Y). Therefore, it makes sense to use all these three
and use a sphere of radius 5kpc around us. Counting the number of SNRs
from the available catalogue, we find 124 of them within a distance of
5kpc (listed in Table C1).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 32 125 This table provides a list of SNRs which are
located within 5kpc
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See also:
VII/272 : A catalogue of Galactic supernova remnants (Green, 2014)
Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [1/125] Internal SNR identifier
4 A1 --- m_ID [ab] Multiplicity flag (1)
6- 10 F5.1 deg GLON Galactic longitude
12- 17 F6.2 deg GLAT Galactic latitude
19- 20 A2 --- l_Dist [~< ] Limit flag on Dist
22- 30 A9 kpc Dist Distance
32 I1 --- Ref [1/2] Reference (2)
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Note (1): In the original table two sources were labelled 120, we have added a
multiplicity flag (a,b) to distinguish these two sources
Note (2): Reference as follows:
1 = Green (2014BASI...42...47G 2014BASI...42...47G, Cat. VII/272),
https://www.mrao.cam.ac.uk/surveys/snrs/
2 = https://hea-www.cfa.harvard.edu/ChandraSNR/snrcat_gal.html
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 20-Apr-2023