BeppoSAX observations of the nearby archetypical starburst galaxies NGC253 and M82 are presented. Spectral analysis shows that the 2-10 keV spectra of both galaxies, extracted from the central 4' regions, are best fitted by a thermal emission model with kT similar to 6-9 keV and metal abundances 0.1-0.3 solar. The spatial analysis yields clear evidence that this emission is extended in NGC 253, and possibly also in M82. These results clearly rule out a LLAGN as the main origin of the X-ray emission in NGC 253. For M82, the presence of an Fe-K line at similar to 6.7 keV, and the convex profile of its 2-10 keV continuum, indicate a significant thermal component. Contributions from point sources (e.g. X-ray binaries, supernova remnants, and/or a LLAGN) and Compton emission are also likely. Altogether, BeppoSAX results provide compelling evidence for the existence of a hot interstellar plasma in both galaxies, possibly in the form of superwind outflows from the disks of these galaxies. Order-of-magnitude estimates and some implications, such as the expelled mass and the energetics of the outflowing gas of this superwind scenario, are discussed. These new results also suggest some similarity between the X-ray emission from these galaxies and that from the Galactic Ridge.

Diffuse thermal emission from very hot gas in starburst galaxies / Cappi, M; Persic, M; Bassani, L; Franceschini, A; Hunt, Lk; Molendi, S; Palazzi, E; Palumbo, Ggc; Rephaeli, Y; Salucci, Paolo. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 350:3(1999), pp. 777-790.

Diffuse thermal emission from very hot gas in starburst galaxies

Salucci, Paolo
1999-01-01

Abstract

BeppoSAX observations of the nearby archetypical starburst galaxies NGC253 and M82 are presented. Spectral analysis shows that the 2-10 keV spectra of both galaxies, extracted from the central 4' regions, are best fitted by a thermal emission model with kT similar to 6-9 keV and metal abundances 0.1-0.3 solar. The spatial analysis yields clear evidence that this emission is extended in NGC 253, and possibly also in M82. These results clearly rule out a LLAGN as the main origin of the X-ray emission in NGC 253. For M82, the presence of an Fe-K line at similar to 6.7 keV, and the convex profile of its 2-10 keV continuum, indicate a significant thermal component. Contributions from point sources (e.g. X-ray binaries, supernova remnants, and/or a LLAGN) and Compton emission are also likely. Altogether, BeppoSAX results provide compelling evidence for the existence of a hot interstellar plasma in both galaxies, possibly in the form of superwind outflows from the disks of these galaxies. Order-of-magnitude estimates and some implications, such as the expelled mass and the energetics of the outflowing gas of this superwind scenario, are discussed. These new results also suggest some similarity between the X-ray emission from these galaxies and that from the Galactic Ridge.
1999
350
3
777
790
https://ui.adsabs.harvard.edu/abs/1999A&A...350..777C/abstract
Cappi, M; Persic, M; Bassani, L; Franceschini, A; Hunt, Lk; Molendi, S; Palazzi, E; Palumbo, Ggc; Rephaeli, Y; Salucci, Paolo
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/17026
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 57
  • ???jsp.display-item.citation.isi??? 66
social impact