Sasmirala Individual Information for NGC 7674

Description

NGC 7674 is an infrared-luminous, nearly face-on late-type spiral galaxy at a redshift of z = 0.0289 (D ~ 126 Mpc) hosting a Sy 2 nucleus [veron-cetty_catalogue_2010] with polarized broad emission lines [miller_spectropolarimetry_1990]. It features a compact radio core with kiloparsec-scale, bended jet-like emission to the east and west [unger_radio_1988, momjian_sensitive_2003], which is roughly aligned with the biconical ~ 4.4arcsec ~ 2.5 kpc extended [O III] emission (PA~ 120^∘; [schmitt_hubble_2003]). After first being detected in the MIR with IRAS, NGC 7674 was followed up with ground-based MIR observations [aitken_8-13_1985, edelson_broad-band_1987, carico_iras_1988, roche_atlas_1991, maiolino_new_1995, miles_high-resolution_1996]. The latter presented the first subarcsecond MIR observations of NGC 7674 and detected an unresolved nucleus, while [siebenmorgen_mid-infrared_2004] report an east-west elongation of ~ 0.5arcsec ~ 240 pc in their ESO 3.6 m/TIMMI2 image. [gorjian_10_2004] mention no extension in the comparable Palomar 5 m/MIRLIN N-band image. NGC 7674 was followed up in space with ISO [clavel_2.5-11_2000, ramos_almeida_mid-infrared_2007] and Spitzer/IRAC, IRS and MIPS observations. The corresponding IRAC and MIPS images are dominated by a bright compact nucleus embedded within the much fainter spiral-like host emission. Our nuclear IRAC 5.8 μm photometry agrees with [gallimore_infrared_2010]. On the other hand, our IRAC 8.0 μm flux is significantly lower than the published value, yet in agreement with the IRS LR mapping-mode spectrum. The latter exhibits silicate 10 μm absorption, weak PAH features, and a broad emission peak at ~ 18 μm in νF_ν-space (see also [buchanan_spitzer_2006, wu_spitzer/irs_2009, tommasin_spitzer-irs_2010, gallimore_infrared_2010, stierwalt_mid-infrared_2013]). Thus, the arcsecond-scale MIR SED appears to be AGN-dominated. We observed NGC 7674 with VISIR with three narrow N-band images and one LR N-band spectrum between 2006 and 2009 (partly published in [horst_mid_2008, horst_mid-infrared_2009, honig_dusty_2010-1]). In addition, a Qa filter image was obtained with T-ReCS in 2007 (unpublished, to our knowledge). A compact nucleus without further host emission was detected in all cases. The nucleus is marginally resolved in the sharpest image (ARIII) as well as all remaining images except for the PAH2_2 filter. The nuclear elongation is consistently detected at PA~ 125^∘ with a FWHM ~ 15% larger than the corresponding standard stars. Therefore, we classify the nucleus of NGC 7674 as generally extended in the MIR at subarcsecond resolution. Note that this extension aligns roughly with the ionization cone. The resulting unresolved nuclear fluxes are ~ 20% lower than the Spitzer spectrophotometry, the 0.75arcsec-extracted VISIR spectrum [honig_dusty_2010-1], and the published total nuclear NEII flux measurement [horst_mid_2008]. This flux difference may either be attributed to nuclear star formation as indicated by the weak PAH 11.3 μm feature in the VISIR spectrum or to dust in the NLR as suggested by the elongation.

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• [carico_iras_1988] David P. Carico, D. B. Sanders, B. T. Soifer, J. H. Elias, K. Matthews, and G. Neugebauer. The IRAS bright galaxy sample. III - 1-10 micron observations and coadded IRAS data for galaxies with l(IR) equal to or greater than 10 to the 11th solar luminosities . AJ , 95 pp. 356–373, February 1988.
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• [gallimore_infrared_2010] J. F. Gallimore, A. Yzaguirre, J. Jakoboski, M. J. Stevenosky, D. J. Axon, S. A. Baum, C. L. Buchanan, M. Elitzur, M. Elvis, C. P. O'Dea, and A. Robinson. Infrared spectral energy distributions of seyfert galaxies: Spitzer space telescope observations of the 12 μm sample of active galaxies . ApJS , 187 pp. 172–211, March 2010.
• [gorjian_10_2004] V. Gorjian, M. W. Werner, T. H. Jarrett, D. M. Cole, and M. E. Ressler. 10 micron imaging of seyfert galaxies from the 12 micron sample . ApJ , 605 pp. 156–167, April 2004.
• [honig_dusty_2010-1] S. F. Hönig, M. Kishimoto, P. Gandhi, A. Smette, D. Asmus, W. Duschl, M. Polletta, and G. Weigelt. The dusty heart of nearby active galaxies. i. high-spatial resolution mid-IR spectro-photometry of seyfert galaxies . A&A , 515 pp. 23, June 2010.
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• [miller_spectropolarimetry_1990] J. S. Miller and R. W. Goodrich. Spectropolarimetry of high-polarization seyfert 2 galaxies and unified seyfert theories . ApJ , 355 pp. 456–467, June 1990.
• [momjian_sensitive_2003] Emmanuel Momjian, Jonathan D. Romney, Christopher L. Carilli, and Thomas H. Troland. Sensitive VLBI continuum and h i absorption observations of NGC 7674: First scientific observations with the combined array VLBA, VLA, and arecibo . ApJ , 597 pp. 809–822, November 2003.
• [ramos_almeida_mid-infrared_2007] C. Ramos Almeida, A. M. Pérez García, J. A. Acosta-Pulido, and J. M. Rodríguez Espinosa. The mid-infrared emission of seyfert galaxies: A new analysis of ISOCAM data . AJ , 134 pp. 2006–2019, November 2007.
• [roche_atlas_1991] Patrick F. Roche, David K. Aitken, Craig H. Smith, and Martin J. Ward. An atlas of mid-infrared spectra of galaxy nuclei . MNRAS , 248 pp. 606–629, February 1991.
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• [stierwalt_mid-infrared_2013] S. Stierwalt, L. Armus, J. A. Surace, H. Inami, A. O. Petric, T. Diaz-Santos, S. Haan, V. Charmandaris, J. Howell, D. C. Kim, J. Marshall, J. M. Mazzarella, H. W. W. Spoon, S. Veilleux, A. Evans, D. B. Sanders, P. Appleton, G. Bothun, C. R. Bridge, B. Chan, D. Frayer, K. Iwasawa, L. J. Kewley, S. Lord, B. F. Madore, J. E. Melbourne, E. J. Murphy, J. A. Rich, B. Schulz, E. Sturm, V. U, T. Vavilkin, and K. Xu. Mid-infrared properties of nearby luminous infrared galaxies. i. spitzer infrared spectrograph spectra for the GOALS sample . ApJS , 206 pp. 1, May 2013.
• [tommasin_spitzer-irs_2010] Silvia Tommasin, Luigi Spinoglio, Matthew A. Malkan, and Giovanni Fazio. Spitzer-IRS high-resolution spectroscopy of the 12 μm seyfert galaxies. II. results for the complete data set . ApJ , 709 pp. 1257–1283, February 2010.
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• [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.
• [wu_spitzer/irs_2009] Yanling Wu, Vassilis Charmandaris, Jiasheng Huang, Luigi Spinoglio, and Silvia Tommasin. Spitzer/IRS 5-35 μm low-resolution spectroscopy of the 12 μm seyfert sample . ApJ , 701 pp. 658–676, August 2009.

Images

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.