Superwind evolution: the young starburst-driven wind galaxy NGC 2782

Abstract

We present results from a 30 ksec Chandra observation of the important starburst galaxy NGC 2782, covering the 0.3-10keV energy band. We find evidence of a superwind of small extent, that is likely in an early stage of development. We find a total of 27 X-ray point sources within a region of radius 2$D_{25}$ of the galaxy centre and which are likely associated with the galaxy. Of these, 13 are ULXs ($L_X\ge 10^{39}erg{s}^{-1}$) and a number have likely counterparts. The X-ray luminosities of the ULX candidates are $1.2-3.9\times 10^{39}erg{s}^{-1}$. NGC2782 seems to have an unusually large number of ULXs. Central diffuse X-ray emission extending to ~ 3kpc from the nuclear region has been detected. We also find an X-ray structure to the south of the nucleus, coincident with Hα filaments and with a 5 GHz radio source. We interpret this as a blow-out region of a forming superwind. This X-ray bubble has a total luminosity (0.3-10 keV) of $5\times 10^{39}erg{s}^{-1}$ (around $15\%$ of the total luminosity of the extended emission), and an inferred wind mass of $1.5\times 10^6$ M${}_{\odot }$. We also discuss the nature of the central X-ray source in NGC2782, and conclude that it is likely a low-luminosity AGN (LLAGN), with a total X-ray luminosity of $L_X=6\times 10^{40}erg{s}^{-1}$ with strong Fe line emission at 6.4 keV.

14 pages, 14 figures, 3 tables. Accepted for publication in MNRAS

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