Sasmirala Individual Information for III Zw 35N
Description
III Zw 35 is a close pair of galaxies (10arcsec separation, PA~ 20∘). The northern galaxy, III Zw 35N, is an infrared-luminous galaxy at a redshift of z = 0.0277 (D ~ 121 Mpc) hosting an AGN, and a OH mega-maser [chapman_oh_1986, chapman_combined_1990]. The AGN is optically classified either as Sy 2 [veron-cetty_catalogue_2010] or LINER [veilleux_optical_1995] or as borderline Sy 2/H II [yuan_role_2010]. Intense star formation appears to be present in III Zw 35N [pihlstrom_evn_2001, hattori_study_2004], and thus we treat this object as AGN/starburst composite. III Zw 35 was observed with Spitzer/IRAC, IRS and MIPS and a marginally resolved nucleus was detected in all images. The southern component is weakly visible as elongated emission in the IRAC 5.8 and 8.0 μm images (nuclear separation~ 8.5arcsec ~ 4.8 kpc, PA~ 200∘). Our IRAC and MIPS photometry for the northern nucleus matches the values published in [u_spectral_2012]. The IRS LR staring-mode spectrum shows deep silicate 10 μm and weak silicate 18 μm absorption, strong PAH emission and a red spectral slope in νFν-space. The MIR SED indicates a highly obscured nucleus with significant star formation on arcsecond scales (see also [willett_mid-infrared_2011]) as already suggested by [chapman_combined_1990] based on different data. III Zw 35 was observed with VISIR in the PAH1 filter in 2009 (unpublished, to our knowledge). A compact MIR nucleus was detected which appears elongated with an orientation roughly coinciding with the optical major axis (FWHM(major axis) ~ 0.61arcsec ~ 340 pc; PA~ 30∘). However, at least a second epoch of subarcsecond observations are needed to verify this extension. The southern component remains undetected in the image. The measured nuclear PAH1 flux is 44% lower than the Spitzer spectrophotometry and indicates that the PAH emission might be significantly lower in the inner ~ 300 pc.
- [chapman_combined_1990] J. M. Chapman, L. Staveley-Smith, D. J. Axon, S. W. Unger, R. J. Cohen, A. Pedlar, and R. D. Davies. A combined optical, infrared and radio study of the megamaser galaxy III ZW 35 . MNRAS , 244 pp. 281–290, May 1990.
- [chapman_oh_1986] J. M. Chapman, R. J. Cohen, L. Pointon, L. Staveley-Smith, and S. W. Unger. OH megamaser in III zwicky 35 . International Astronomical Union Circular , 4180 pp. 2, February 1986.
- [hattori_study_2004] T. Hattori, M. Yoshida, H. Ohtani, H. Sugai, T. Ishigaki, M. Sasaki, T. Hayashi, S. Ozaki, M. Ishii, and A. Kawai. A study of the distribution of star-forming regions in luminous infrared galaxies by means of hα imaging observations . AJ , 127 pp. 736–757, February 2004.
- [pihlstrom_evn_2001] Y. M. Pihlström, J. E. Conway, R. S. Booth, P. J. Diamond, and A. G. Polatidis. EVN and MERLIN observations of III zw 35 . a starburst continuum and an OH maser ring . A&A , 377 pp. 413–424, October 2001.
- [u_spectral_2012] Vivian U, D. B. Sanders, J. M. Mazzarella, A. S. Evans, J. H. Howell, J. A. Surace, L. Armus, K. Iwasawa, D.-C. Kim, C. M. Casey, T. Vavilkin, M. Dufault, K. L. Larson, J. E. Barnes, B. H. P. Chan, D. T. Frayer, S. Haan, H. Inami, C. M. Ishida, J. S. Kartaltepe, J. L. Melbourne, and A. O. Petric. Spectral energy distributions of local luminous and ultraluminous infrared galaxies . ApJS , 203 pp. 9, November 2012.
- [veilleux_optical_1995] S. Veilleux, D.-C. Kim, D. B. Sanders, J. M. Mazzarella, and B. T. Soifer. Optical spectroscopy of luminous infrared galaxies. II. analysis of the nuclear and long-slit data . ApJS , 98 pp. 171, May 1995.
- [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.
- [willett_mid-infrared_2011] Kyle W. Willett, Jeremy Darling, Henrik W. W. Spoon, Vassilis Charmandaris, and Lee Armus. Mid-infrared properties of OH megamaser host galaxies. i. spitzer IRS low- and high-resolution spectroscopy . ApJS , 193 pp. 18, March 2011.
- [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.