Investigating the nuclear activity of barred spiral galaxies: The case of NGC1672

The Astrophysical Journal (Impact Factor: 5.99). 04/2011; 734(1). DOI: 10.1088/0004-637X/734/1/33
Source: arXiv


We have performed an X-ray study of the nearby barred spiral galaxy NGC1672,
primarily to ascertain the effect of the bar on its nuclear activity. We use
both Chandra and XMM-Newton observations to investigate its X-ray properties,
together with supporting high-resolution optical imaging data from the Hubble
Space Telescope (HST), infrared imaging from the Spitzer Space Telescope, and
ATCA ground-based radio data. We detect 28 X-ray sources within the D25 area of
the galaxy, many of which correlate spatially with star-formation in the bar
and spiral arms, while two are identified as background galaxies in the HST
images. Nine of the X-ray sources are ULXs, with the three brightest (LX > 5E39
erg/s) located at the ends of the bar. With the spatial resolution of Chandra,
we are able to show for the first time that NGC1672 possesses a hard
(Gamma~1.5) nuclear X-ray source with a 2-10 keV luminosity of 4E38 erg/s. This
is surrounded by an X-ray bright circumnuclear star-forming ring, comprised of
point sources and hot gas, which dominates the 2-10 keV emission in the central
region of the galaxy. The spatially resolved multiwavelength photometry
indicates that the nuclear source is a low-luminosity AGN (LLAGN), but with
star formation activity close to the central black hole. A high-resolution
multiwavelength survey is required to fully assess the impact of both
large-scale bars and smaller-scale phenomena such as nuclear bars, rings and
nuclear spirals on the fueling of LLAGN.

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