The Extended Mid-Infrared Structure of the Circinus Galaxy

We present subarcsecond resolution mid-IR images of the Circinus galaxy at 8.74 and 18.33 μm. We resolve extended emission at both wavelengths, extending ~2'' from each side of the nucleus in an approximate east-west direction. These extensions are spatially coincident with previously detected compact (~30 pc) V-shaped [O III] emission extending northwest of the nucleus as well as countercone [Si VI] emission, emission at these wavelengths interpreted as delineating the interface between inflowing material and the ionization cone. We detect no extended mid-IR emission associated with the structure responsible for collimating the ionizing photons (i.e., obscuring torus or disk of material), limiting the flux density of the obscuring structure to ≤0.27 mJy or a diameter of ≤0.″20 (≤4 pc).

[1]  H. Kataza,et al.  Improvements in Operating the Raytheon 320 × 240 Pixel Si:As Impurity Band Conduction Mid‐Infrared Array , 2003 .

[2]  R. Siebenmorgen,et al.  Mid-infrared emission of galactic nuclei. TIMMI2 versus ISO observations and models , 2003, astro-ph/0310546.

[3]  James H. Hough,et al.  Near‐infrared imaging polarimetry and modelling of NGC 4151 , 2003 .

[4]  G. Neugebauer,et al.  High Spatial Resolution Mid-Infrared Observations of Three Seyfert Galaxies , 2003, astro-ph/0304105.

[5]  R. Norris,et al.  A Warped Accretion Disk and Wide-Angle Outflow in the Inner Parsec of the Circinus Galaxy , 2003, astro-ph/0302533.

[6]  Robert K. Pina,et al.  Resolved Mid-Infrared Emission in the Narrow-Line Region of NGC 4151 , 2002, astro-ph/0212307.

[7]  William B. Sparks,et al.  Deep 10 Micron Imaging of M87 , 2001 .

[8]  Robert K. Pina,et al.  High-Resolution Mid-Infrared Morphology of Cygnus A , 2001, astro-ph/0110347.

[9]  J. Hough,et al.  Constraints on the nuclear emission of the Circinus galaxy: the torus , 2001, astro-ph/0102412.

[10]  J. Weingartner,et al.  Dust Grain-Size Distributions and Extinction in the Milky Way, Large Magellanic Cloud, and Small Magellanic Cloud , 2001 .

[11]  R. Maiolino,et al.  N-Band Imaging of Seyfert Nuclei and the Mid-Infrared-X-Ray Correlation , 2000, astro-ph/0010119.

[12]  J. A. Nousek,et al.  X-Ray Imaging of the Seyfert 2 Galaxy Circinus with Chandra , 2000, astro-ph/0010355.

[13]  Chris Simpson,et al.  Hubble Space Telescope Imaging of the Circinus Galaxy , 2000, astro-ph/0006147.

[14]  J. Hough,et al.  Modelling the Infrared continuum of Centaurus A , 2000, astro-ph/0003142.

[15]  J. Hough,et al.  A near-infrared polarized bipolar cone in the Circinus galaxy , 2000, astro-ph/0002223.

[16]  J. Surace,et al.  High Resolution Mid-Infrared Imaging of Ultraluminous Infrared Galaxies* , 1999, astro-ph/9911045.

[17]  G. Rieke,et al.  Discovery of a Nuclear Gas Bar Feeding the Active Nucleus in Circinus , 1999, astro-ph/9910160.

[18]  T. Böker.  O ct 2 00 0 N-band Imaging of Seyfert Nuclei and the MIR-X-ray correlation , 2000 .

[19]  J. Hough,et al.  Observations and a model for the infrared continuum of Centaurus A , 1999 .

[20]  Charles M. Telesco,et al.  GatirCam: Gemini mid-infrared imager , 1998, Astronomical Telescopes and Instrumentation.

[21]  E. Sadler,et al.  RADIO CONTINUUM EVIDENCE FOR NUCLEAR OUTFLOW IN THE CIRCINUS GALAXY , 1998 .

[22]  R. Maiolino,et al.  Seyfert Activity and Nuclear Star Formation in the Circinus Galaxy , 1997, astro-ph/9709091.

[23]  S. Veilleux,et al.  Artillery Shells over Circinus , 1997, astro-ph/9703040.

[24]  Giorgio Matt,et al.  The iron Kα line complex in Compton-thick Seyfert 2 galaxies , 1996 .

[25]  R. Siebenmorgen,et al.  Subarcsecond mid-infrared imaging of warm dust in the narrow-line region of NGC 1068 , 1993 .

[26]  C. Beichman,et al.  High-resolution mid-infrared imaging and astrometry of the nucleus of the Seyfert galaxy NGC 1068 , 1993 .

[27]  Ari Laor,et al.  Spectroscopic constraints on the properties of dust in active galactic nuclei , 1993 .

[28]  G. Voit.  Destruction and survival of polycyclic aromatic hydrocarbons in active galaxies , 1992 .

[29]  P. Roche,et al.  An atlas of mid-infrared spectra of galaxy nuclei , 1991 .

[30]  P. Roche,et al.  An investigation of the interstellar extinction – II. Towards the mid-infrared sources in the Galactic centre , 1985 .

[31]  P. Roche,et al.  8–13 µm spectrophotometry of galaxies – IV. Six more Seyferts and 3C 345 , 1985 .

[32]  H. M. Lee,et al.  Optical properties of interstellar graphite and silicate grains , 1984 .