Coronagraphic Imaging of 3C 273 with the Advanced Camera for Surveys
The nearby and luminous QSO 3C 273 was imaged in 2002 July with the HighResolution Channel (HRC) of the Advanced Camera for Surveys (ACS) incoronagraphic mode in F475W (g), F606W (V), and F814W (I) as part of theEarly Release Observations (ERO) program. After subtraction of theremaining PSF of the QSO, these images offer the most detailed view yetof the morphology and colors of the host galaxy of this QSO. We findthat the central light distribution is elongated along the jet axis andits outer edge is delineated by an arc, centered on the jet at a radiusof ~2.6" from the QSO and bluer than the surrounding galaxy. This systemis embedded in an extended galactic halo. Compared with early-typegalaxies of similar redshifts and luminosities, the light distributionof 3C 273 is flatter in the core, likely from suppression by dust, butsimilar in the outer halo. The QSO is displaced from the isophotalcenter of the galaxy by ~1.4". Previously known emission-line extensionsare confirmed and new morphological features are identified, including adramatic spiral-shaped plume, two faint filaments, a dust lane, and aknot along the jet axis. Part of the inner jet is unambiguously detectedin all three bandpasses, and its morphology matches that of a MERLINradio map. Different mechanisms that could explain the morphology of 3C273 are considered, such as scattered QSO radiation, a face-on disk, anda merger event.Based on observations made with the NASA/ESA Hubble Space Telescope,obtained at the Space Telescope Science Institute, which is operated bythe Association of Universities for Research in Astronomy, Inc., underNASA contract NAS 5-26555.
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