Sasmirala Individual Information for Mrk 926
Description
Mrk 926 is a low-inclination early-type spiral galaxy at a redshift of z = 0.0469 (D ~ 194 Mpc) with a Sy 1.5 nucleus [veron-cetty_catalogue_2010], belonging to the nine-month BAT AGN sample. It possesses a compact radio core with very weak extension in east-west direction of one arcsecond (~ 0.85 kpc) scale. [mundell_parsec-scale_2000]. Mrk 926 was observed with Spitzer/IRAC, IRS and MIPS and appears point-like in the corresponding images. The IRS LR staring-mode spectrum exhibits silicate 10 and 18 μm emission, a weak PAH 11.3 μm feature, and an emission peak at ~ 18 μm in νFν-space (see also [shi_9.7_2006]). We observed Mrk 926 with VISIR in three narrow N-band filters in 2009 and detected a compact MIR nucleus without any host emission in all images. The nucleus appears marginally extended in all images (FWHM ~ 0.43arcsec ~ 370 pc) with significant but inconsistent elongations. Therefore, it is uncertain, whether this extension is object-intrinsic or caused by an unstable PSF and at least a second epoch of subarcsecond MIR imaging is required to check. The nuclear photometry is on average ~ 35% lower than the Spitzer spectrophotometry. Note that the MIPS 24 μm flux is significantly below the IRS spectrum and thus might indicate contamination of cold dust in the host affecting the latter.
- [mundell_parsec-scale_2000] C. G. Mundell, A. S. Wilson, J. S. Ulvestad, and A. L. Roy. Parsec-scale images of flat-spectrum radio sources in seyfert galaxies . ApJ , 529 pp. 816–831, February 2000.
- [shi_9.7_2006] Y. Shi, G. H. Rieke, D. C. Hines, V. Gorjian, M. W. Werner, K. Cleary, F. J. Low, P. S. Smith, and J. Bouwman. 9.7 μm silicate features in active galactic nuclei: New insights into unification models . ApJ , 653 pp. 127–136, December 2006.
- [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.