J/A+A/701/A206 Puppis A Fermi-LAT TS and eROSITA images (Giuffrida+, 2025)
Evidence for protons accelerated and escaped from the Puppis A region using
Fermi-LAT observations.
Giuffrida R., Lemoine-Gourmard M., Miceli M., Gabici S., Sano H., Aruga M.,
Mayer M., Becker W., Sasaki M., Fukui Y.
<Astron. Astrophys. 701, A206 (2025)>
=2025A&A...701A.206G 2025A&A...701A.206G (SIMBAD/NED BibCode)
ADC_Keywords: Supernova remnants ; Gamma rays ; Radio sources
Keywords: acceleration of particles - shock waves - cosmic rays -
ISM: supernova remnants
Abstract:
Supernova remnants (SNRs) interacting with molecular clouds are
interesting laboratories to study the acceleration of cosmic rays and
their propagation in the dense ambient medium. We analyze 14 years of
Fermi-LAT observations of the supernova remnant Puppis A to
investigate its asymmetric gamma-ray morphology and spectral
properties. This middle-aged remnant (∼4kyr) is evolving in an
inhomogeneous environment, interacting with a dense molecular cloud in
the northeast and a lower-density medium in the southwest. We find
clear differences in both gamma-ray luminosity and spectral energy
distribution between these two regions. The emission from both sides
is consistent with a hadronic origin. However, while the southwestern
emission can be explained by standard Diffusive Shock Acceleration
(DSA), the northeastern side may involve re-acceleration of
pre-existing cosmic rays or acceleration via reflected shocks in the
dense cloud environment. Additionally, we identify two significant
gamma-ray excesses outside the remnant, including a previously
unreported source to the south. These features are likely produced by
cosmic rays that have escaped Puppis A and are interacting with nearby
dense molecular material. From this extended emission, we estimate the
total energy in escaping cosmic rays to be WCR∼1.5x1049erg,
providing important constraints on cosmic-ray propagation around the
remnant.
Description:
We analyzed 14 years of observations carried out by Fermi-LAT
between August 2008 and September 2022 focusing on the region of
interest (ROI) of 15° 15°, centered on 4FGL J0822.1-4253e
(Puppis A, RA=08:24:06.96, DEC=-42:59:49.2), with spatial bins of
0.03° and 10 energy bins, including all sources from the
Fermi-LAT 14-year Source Catalog (4FGL-DR4, Abdollahi et al.
2022ApJS..260...53A 2022ApJS..260...53A, Cat. IX/67; Ballet et al. 2023, arXiv:2307.12546)
in a region of 25°x25°.
Objects:
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RA (2000) DE Designation(s)
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08 24 06.99 -42 59 48.0 Puppis A = 4FGL J0822.1-4253e
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 242 6 List of fits images
fits/* . 6 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 50 A23 "datime" Obs.date Observation date
52- 55 I4 Kibyte size Size of FITS file
57- 77 A21 --- FileName Name of FITS file, in subdirectory fits
79-242 A164 --- Title Title of the FITS file
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Acknowledgements:
Roberta Giuffrida, Roberta.GIUFFRIDA(at)cea.fr
(End) Patricia Vannier [CDS] 29-Aug-2025