Sasmirala Individual Information for ESO 420-13
Description
ESO 420-13 is an infrared-luminous early-type galaxy at a redshift of z = 0.0119 (D ~ 48.6 Mpc) hosting an AGN and a strong starburst. The AGN is optically classified either as Sy 2 [veron-cetty_catalogue_2010] of an H II nucleus [yuan_role_2010]. Therefore, we treat this object as AGN/starburst composite. It was observed with Spitzer/IRAC, IRS and MIPS and appears compact without significantly extended host emission in the corresponding images. The nucleus is partly saturated in the IRAC 8.0 μm PBCD image. The IRS LR staring-mode spectrum shows very strong PAH emission, silicate absorption and a red slope in νFν-space. Thus, the Spitzer MIR spectrum seems to be star formation dominated. ESO 420-13 was observed with VISIR in three N band filters during one night in 2006 (unpublished, to our knowledge). A compact MIR nucleus embedded in extended host emission is visible in the images. The extended emission has a spiral shape of ~ 3.8arcsec ~ 880 pc in diameter with one arm reaching out to the north-east and the other to the south-west. These structures become more prominent at longer wavelengths. The PSF photometry of the nucleus yields fluxes that are on average ~ 67% lower than the Spitzer spectrophotometry. The resulting shape of the subarcsecond MIR SED suggests a much lower star formation contribution at scales less than 100 pc in ESO 420-13.
- [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.
- [yuan_role_2010] T.-T. Yuan, L. J. Kewley, and D. B. Sanders. The role of starburst-active galactic nucleus composites in luminous infrared galaxy mergers: Insights from the new optical classification scheme . ApJ , 709 pp. 884–911, February 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.