Sasmirala Individual Information for ESO 323-77
Description
ESO 323-77 is a spiral galaxy at a redshift of z = 0.0150 (D ~ 66.3 Mpc) with an AGN with optical Sy 1.2 classification [veron-cetty_catalogue_2010] that appears partly obscured [schmid_spectropolarimetry_2003]. It was observed with Spitzer/IRAC, IRS and MIPS and appears compact in all images. The IRS LR staring-mode spectrum exhibits weak silicate 10 μm absorption and strong PAH emission, which indicates significant star formation. The MIR spectral slope is rather flat in νFν-space. We observed ESO 323-77 with VISIR in three different narrow-N filters in 2009 (two images) and 2010 (two images). A compact MIR nucleus was detected in all images without any sign of extended host galaxy emission. Quantitative extension analysis shows that the source is marginally resolved in all images (FWHM ~ 0.39arcsec ~ 120 pc; PA~ 100∘). The VISIR photometry from 2009 together and a VISIR N-band spectrum were published by [honig_dusty_2010-1]. The VISIR spectrum differs significantly from the IRS spectrum in having lower flux levels but no PAH emission and no silicate absorption, which indicates that most of the star-formation related emission is resolved out at subarcsecond resolution. Our new Gaussian flux measurements agree with the previous values well, while the nuclear fluxes using the PSF measurement are significantly lower, in particular at the shortest wavelengths. Compared to the Spitzer spectrophotometry, the nuclear fluxes are on average ~ 52% lower. MIDI interferometric observations of ESO 323-77, however, found a compact source with a size of ~ 2 pc to dominate the nuclear MIR emission [burtscher_diversity_2013].
- [burtscher_diversity_2013] L. Burtscher, K. Meisenheimer, K. R. W. Tristram, W. Jaffe, S. F. Hönig, R. I. Davies, M. Kishimoto, J.-U. Pott, H. Röttgering, M. Schartmann, G. Weigelt, and S. Wolf. A diversity of dusty AGN tori. data release for the VLTI/MIDI AGN large program and first results for 23 galaxies . A&A , 558 pp. 149, October 2013.
- [honig_dusty_2010-1] S. F. Hönig, M. Kishimoto, P. Gandhi, A. Smette, D. Asmus, W. Duschl, M. Polletta, and G. Weigelt. The dusty heart of nearby active galaxies. i. high-spatial resolution mid-IR spectro-photometry of seyfert galaxies . A&A , 515 pp. 23, June 2010.
- [schmid_spectropolarimetry_2003] H. M. Schmid, I. Appenzeller, and U. Burch. Spectropolarimetry of the borderline seyfert 1 galaxy ESO 323-g077 . A&A , 404 pp. 505–511, June 2003.
- [veron-cetty_catalogue_2010] M.-P. Véron-Cetty and P. Véron. A catalogue of quasars and active nuclei: 13th edition . A&A , 518 pp. 10, July 2010.
Images
Optical image (DSS, red filter). Displayed are the central 4 arcmin with North being up and East to the left. The colour scaling is linear with white corresponding to the median background (BG) and black to the 0.01% pixels with the highest intensity.
Spitzer MIR images. Displayed are the inner 40 arcsec with North being up and East to the left. The colour scaling is logarithmic with white corresponding to median BG and black to the 0.1% pixels with the highest intensity. The label in the bottom left states instrument and central wavelength of the filter in micron (I: IRAC, M: MIPS).
Subarcsecond-resolution MIR images sorted by increasing filter central wavelength. Displayed are the inner 4 arcsec with North being up and East to the left. The colour scaling is logarithmic with white corresponding to median BG and black to the 75% of the highest intensity of all images in units of sig_bg. The inset image (where present; either bottom or top right) shows the central arcsecond of the PSF from the calibrator star, scaled to match the science target. The labels in the bottom left state instrument and filter names (C: COMICS, M: Michelle, T: T-ReCS, V: VISIR).
SEDs
MIR SED. The description of the symbols in all the SED plots (where present) is the following: Grey crosses and solid lines mark the Spitzer/IRAC, MIPS and IRS data. The colour coding of the other symbols is as follows: green for COMICS, magenta for Michelle, blue for T-ReCS and red for VISIR data. Darker-coloured solid lines mark spectra of the corresponding instrument. The black filled circles mark the nuclear 12 and 18 micron continuum emission estimate from the data (where present). The ticks on the top axis mark positions of common MIR emission lines, while the light grey horizontal bars mark wavelength ranges affected by the silicate 10 and 18 micron features.