Sasmirala Individual Information for ESO 5-4
Description
ESO 5-4 is an edge-on spiral galaxy at a distance of D = 22.4 Mpc [tully_nearby_1988] hosting a Sy 2 nucleus [veron-cetty_catalogue_2010]. It is a member of the nine-month BAT AGN sample and has only recently been discovered as an AGN [landi_agn_2007], which is presumably related to the high nuclear obscuration in this X-ray “buried” AGN [ueda_suzaku_2007]. After first being detected in the MIR with IRAS, ESO 5-4 was also observed with Spitzer/IRAC and IRS. Edge-on host galaxy emission and a compact nucleus are visible in the IRAC (5.8 and 8.0 μm) images. Their nuclear photometry agrees with the IRS LR staring-mode spectrum well, which shows deep silicate 10 μm absorption and strong PAH emission lines. The IRS spectrum resembles a typical star formation MIR SED. ESO 5-4 was observed by us with VLT/VISIR in 2007 and 2011 in narrow N- and Q-band filters. The first N-band photometry (NEII_2) has already been published in [gandhi_resolving_2009] with a lower flux than in our low-S/N optimized analyses presented. Owing to the deep silicate absorption feature, the MIR nucleus has only been detected shortwards of 9 μm and longwards of 11 μm, where the average flux level is ~ 62% lower than the Spitzer spectrophotometry. The extension of this nuclear source remains uncertain because of the low detection significance, in particular at short wavelengths. The high flux in the NEII_2 filter indicates strong [Ne II] λ12.8 μm emission from the nuclear region. However, note that the photometric sensitivity of this (and the SIV_2) observation was 20% worse than expected from the median sensitivity as measured from the corresponding standard star. Because of the uncertain nuclear MIR SED, we do not attempt to correct our 12 μm continuum flux estimate for the silicate feature.
- [gandhi_resolving_2009] P. Gandhi, H. Horst, A. Smette, S. Hönig, A. Comastri, R. Gilli, C. Vignali, and W. Duschl. Resolving the mid-infrared cores of local seyferts . A&A , 502 pp. 457–472, August 2009.
- [landi_agn_2007] R. Landi, N. Masetti, L. Morelli, E. Palazzi, L. Bassani, A. Malizia, A. Bazzano, A. J. Bird, A. J. Dean, G. Galaz, D. Minniti, and P. Ubertini. The AGN nature of 11 out of 12 Swift/RXTE unidentified sources through optical and x-ray spectroscopy . ApJ , 669 pp. 109–125, November 2007.
- [tully_nearby_1988] R. Brent Tully. Nearby galaxies catalog . Cambridge University Press, 1988.
- [ueda_suzaku_2007] Yoshihiro Ueda, Satoshi Eguchi, Yuichi Terashima, Richard Mushotzky, Jack Tueller, Craig Markwardt, Neil Gehrels, Yasuhiro Hashimoto, and Stephen Potter. Suzaku observations of active galactic nuclei detected in the swift BAT survey: Discovery of a ``New type'' of buried supermassive black holes . ApJ , 664 pp. L79–L82, August 2007.
- [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.