Bibcode
DOI
Marconi, Alessandro; Schreier, Ethan J.; Koekemoer, Anton; Capetti, Alessandro; Axon, David; Macchetto, Duccio; Caon, N.
Referencia bibliográfica
The Astrophysical Journal, Volume 528, Issue 1, pp. 276-291.
Fecha de publicación:
1
2000
Revista
Número de citas
82
Número de citas referidas
73
Descripción
We report new Hubble Space Telescope WFPC2 and NICMOS observations of
the center of the nearest radio galaxy Centaurus A (NGC 5128) and
discuss their implications for our understanding of the active nucleus
and jet. We detect the active nucleus in the near-IR (K and H) and, for
the first time, in the optical (I and V), deriving the spectral energy
distribution of the nucleus from the radio to X-rays. The optical and
part of the near-IR emission can be explained by the extrapolation of
the X-ray power law reddened by AV~14, a value consistent
with other independent estimates. The 20 pc scale nuclear disk
discovered by Schreier and colleagues is detected in the [Fe II]
λ1.64 μm line and presents a morphology similar to that
observed in Paα with a [Fe II]/Paα ratio typical of
low-ionization Seyfert galaxies and LINERs. NICMOS 3 Paα
observations in a 50''x50'' circumnuclear region
suggest enhanced star formation (~0.3 Msolar yr-1)
at the edges of the putative bar seen with ISO, perhaps due to shocks
driven into the gas. The light profile, reconstructed from V, H, and K
observations, shows that Centaurus A has a core profile with a resolved
break at ~4" and suggests a black hole mass of ~109
Msolar. A linear blue structure aligned with the radio/X-ray
jet may indicate a channel of relatively low reddening in which dust has
been swept away by the jet.