Bibcode
Kotilainen, J. K.; Prieto, M. A.
Referencia bibliográfica
Astronomy and Astrophysics, v.295, p.646
Fecha de publicación:
3
1995
Revista
Número de citas
19
Número de citas referidas
18
Descripción
We present near-infrared (JHK) imaging of the Seyfert 2 galaxy NGC 5252,
taken with the IRAC2 array on the 2.2m telescope at ESO, La Silla. The
unresolved and galactic components to the nuclear emission are separated
by a multicomponent fitting of the light profiles in the optical and
near-infrared bands. The nuclear flux in a 3" aperture is found to be
dominated by the host galaxy with the unresolved component becoming less
evident toward shorter wavelengths, suggesting considerable reddening in
the nuclear region. The continuum energy distribution from the optical
to the radio wavelengths and the near-infrared nonstellar colours
confirm a heavily reddened (A_V_>=6mag) nonstellar/intrinsic source
and the presence of hot dust in the vicinity of the nucleus. On the
other hand, the stellar component shows a progressive reddening toward
the center, consistent with an optical extinction of A_V_~1mag. The
infrared luminosity, computed assuming reradiation by dust of UV/optical
nuclear photons, agrees within an order of magnitude with the observed
infrared luminosity. The near-infrared data are combined with optical
narrow band continuum images to construct colour ratio maps. We find a
band of red material in the optical-infrared ratio maps extending ~3kpc
across the nucleus and perpendicular to the biconical ionised structure
of NGC 5252. If this infrared band is tracing the distribution of a ring
or disk of dust in this galaxy, it may be getting denser in the
proximity of the nucleus, significantly contributing to the obscuration
of the Seyfert 1 nucleus.