Sasmirala Individual Information for NGC 235A
Description
NGC 235A is an early-type spiral galaxy in an interacting pair at a redshift of z = 0.0222 (D ~ 88.7 Mpc) with an AGN controversially classified either as Sy 1.0 [maia_new_1987, veron-cetty_catalogue_2010] or Sy 2 (e.g., [keel_seyfert_1996, tueller_swift_2008]), see the discussion in [kondratko_discovery_2006]. The fact that the nucleus is highly obscured in X-rays favours the Sy 2 classification also adopted [winter_x-ray_2009]. It features extended [O III] emission in east-west direction (~ 9arcsec ~ 3.7 kpc; PA~ 80∘; [mulchaey_emission-line_1996]) with a slightly different radio extension (PA~ 43∘; [nagar_radio_1999]). In addition, a nuclear water maser was detected [kondratko_discovery_2006]. NGC 235A belongs to the nine-month BAT AGN sample. It was observed with Spitzer/IRS in LR staring mode, and the corresponding spectrum shows strong PAH emission, weak silicate 10 μm absorption and a red spectral slope in νFν-space, i.e., is star formation dominated. The interacting system is resolved only in the short wavelength bands of WISE with NGC 235A dominating the MIR emission in all bands. We observed NGC 235A with VISIR in three narrow N-band filters in 2009. In all images, a compact MIR nucleus is weakly detected, which appears marginally resolved in the PAH2 and NEII filters consistent with the [O III] emission orientation (FWHM ~ 0.5arcsec ~ 210 pc; PA ~ 80∘). However, at least a second epoch of deeper subarcsecond-resolution MIR images is required to confirm this extension. The VISIR photometry is on average ~ 41% lower than the IRS spectrum flux levels. Therefore, we estimate that star formation contributes significantly to the projected central ~ 150 pc MIR emission in NGC 235A.
- [keel_seyfert_1996] William C. Keel. Seyfert galaxies with companions: Orbital and kinematic clues to AGN triggering . AJ , 111 pp. 696, February 1996.
- [kondratko_discovery_2006] P. T. Kondratko, L. J. Greenhill, J. M. Moran, J. E. J. Lovell, T. B. H. Kuiper, D. L. Jauncey, L. B. Cameron, J. F. Gómez, C. García-Miró, E. Moll, I. de Gregorio-Monsalvo, and E. Jiménez-Bailón. Discovery of water maser emission in eight AGNs with 70 m antennas of NASA's deep space network . ApJ , 638 pp. 100–105, February 2006.
- [maia_new_1987] M. A. G. Maia, L. N. da Costa, C. Willmer, P. S. Pellegrini, and C. Rite. New southern galaxies with active nuclei . AJ , 93 pp. 546–556, March 1987.
- [mulchaey_emission-line_1996] John S. Mulchaey, Andrew S. Wilson, and Zlatan Tsvetanov. An emission-line imaging survey of early-type seyfert galaxies. i. the observations . ApJS , 102 pp. 309, February 1996.
- [nagar_radio_1999] Neil M. Nagar, Andrew S. Wilson, John S. Mulchaey, and Jack F. Gallimore. Radio structures of seyfert galaxies. VIII. a distance- and magnitude-limited sample of early-type galaxies . ApJS , 120 pp. 209–245, February 1999.
- [tueller_swift_2008] J. Tueller, R. F. Mushotzky, S. Barthelmy, J. K. Cannizzo, N. Gehrels, C. B. Markwardt, G. K. Skinner, and L. M. Winter. Swift BAT survey of AGNs . ApJ , 681 pp. 113–127, July 2008.
- [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.
- [winter_x-ray_2009] Lisa M. Winter, Richard F. Mushotzky, Christopher S. Reynolds, and Jack Tueller. X-ray spectral properties of the BAT AGN sample . ApJ , 690 pp. 1322–1349, January 2009.
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.
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.