Sasmirala Individual Information for NGC 3166
Description
NGC 3166 is an inclined spiral galaxy at a redshift of z = 0.0045 (D ~ 25.3 Mpc), forming a possibly interacting group with NGC 3165 and NGC 3169. It hosts a little-studied LINER nucleus [ho_search_1997-1], which remained undetected at radio wavelengths [nagar_radio_2005] but is supported by the detection of [Ne V] in the MIR [dudik_spitzer_2009]. After IRAS, it was observed with IRTF [devereux_infrared_1987], and with Spitzer/IRAC, IRS and MIPS. NGC 3166 shows an elliptical extended nucleus embedded in spiral-like host emission in the corresponding IRAC and MIPS images. The IRS HR staring-mode spectrum exhibits prominent a PAH 11.3 μm feature on-top of silicate 10 μm emission and a flat spectral slope in νFν-space. Note however that no background subtraction was performed for this spectrum. The nuclear region of NGC 3166 was observed with T-ReCS in the Si2 filter in 2007 [mason_nuclear_2012] and a weak, compact MIR nucleus was detected. The low S/N prevents us to perform a quantitative extension analysis. Our re-measurement of the nuclear flux is consistent with the value by [mason_nuclear_2012] and an order of magnitude lower than the Spitzer spectrophotometry. We conclude that the AGN is very weak and completely dominated by host emission even on arcsecond scales (~ 0.4 kpc).
- [devereux_infrared_1987] Nicholas A. Devereux, E. E. Becklin, and Nick Scoville. Infrared characteristics of the nuclei of normal galaxies . ApJ , 312 pp. 529–541, January 1987.
- [dudik_spitzer_2009] R. P. Dudik, S. Satyapal, and D. Marcu. A spitzer spectroscopic survey of low-ionization nuclear emission-line regions: Characterization of the central source . ApJ , 691 pp. 1501–1524, February 2009.
- [ho_search_1997-1] Luis C. Ho, Alexei V. Filippenko, and Wallace L. W. Sargent. A search for ``Dwarf'' seyfert nuclei. III. spectroscopic parameters and properties of the host galaxies . ApJS , 112 pp. 315, October 1997.
- [mason_nuclear_2012] R. E. Mason, E. Lopez-Rodriguez, C. Packham, A. Alonso-Herrero, N. A. Levenson, J. Radomski, C. Ramos Almeida, L. Colina, M. Elitzur, I. Aretxaga, P. F. Roche, and N. Oi. The nuclear infrared emission of low-luminosity active galactic nuclei. AJ , 144 pp. 11, July 2012.
- [nagar_radio_2005] N. M. Nagar, H. Falcke, and A. S. Wilson. Radio sources in low-luminosity active galactic nuclei. IV. radio luminosity function, importance of jet power, and radio properties of the complete palomar sample . A&A , 435 pp. 521–543, May 2005.
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.