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J/MNRAS/470/3071         PAH features of AGN                     (Jensen+, 2017)

PAH features within few hundred parsecs of active galactic nuclei. Jensen J., Hoenig S.F., Rakshit S., Alonso-Herrero A., Asmus D., Gandhi P., Kishimoto M., Smette A., Tristram K.R.W. <Mon. Not. R. Astron. Soc. 470, 3071 (2017)> =2017MNRAS.470.3071J (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Spectra, infrared Keywords: galaxies: active galaxies - galaxies: Seyfert - infrared: galaxies Abstract: Spectral features from polycyclic aromatic hydrocarbon (PAH) molecules observed in the mid-infrared (mid-IR) range are typically used to infer the amount of recent and ongoing star formation on kiloparsec scales around active galactic nuclei (AGN) where more traditional methods fail. This method assumes that the observed PAH features are excited predominantly by star formation. With current ground-based telescopes and the upcoming James Webb Space Telescope, much smaller spatial scales can be probed and we aim at testing if this assumption still holds in the range of few tens to few hundreds of parsecs. For that, we spatially map the emitted 11.3um PAH surface flux as a function of distance from 0.4-4 arcsec from the centre in 28 nearby AGN using ground-based high-angular-resolution mid-IR spectroscopy. We detect and extract the 11.3um PAH feature in 13 AGN. The fluxes within each aperture are scaled to a luminosity-normalized distance from the nucleus to be able to compare intrinsic spatial scales of AGN radiation spanning about two orders of magnitude in luminosity. For this, we establish an empirical relation between the absorption-corrected X-ray luminosity and the sublimation radius in these sources. Once normalized, the radial profiles of the emitted PAH surface flux show similar radial slopes, with a power-law index of approximately -1.1, and similar absolute values, consistent within a factor of a few of each other as expected from the uncertainty in the intrinsic scale estimate. We interpret this as evidence that the profiles are caused by a common compact central physical process, either the AGN itself or circumnuclear star formation linked in strength to the AGN power. A photoionization-based model of an AGN exciting dense clouds in its environment can reproduce the observed radial slope and confirms that the AGN radiation field is strong enough to explain the observed PAH surface fluxes within ∼10-500pc of the nucleus. Our results advice caution in the use of PAH emission as a star formation tracer within a kpc around AGN. Description: We use archival low-resolution 8-13um spectroscopic data from Very Large Telescope Spectrometer and Imager for the mid-InfraRed (VISIR) observations of a sample of local AGN (Hoenig et al. 2010A&A...515A..23H; Burtscher et al. 2013, Cat. J/A+A/558/A149). We supplement these data with new, unpublished observations taken in 2005, 2008 and 2010, which represent VISIR spectra for Circinus, ESO 138-G001, F9, F49 and NGC 1068. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 221 28 Characteristics of our AGN mid-IR spectroscopic sample sp/* 35 250 Individual spectra
See also: J/A+A/418/465 : Mid-infrared and hard X-ray emission in AGN (Lutz+, 2004) J/ApJ/697/506 : Mid-infrared galaxy luminosity function from AGN (Dai+ 2009) J/A+A/558/A149 : VLTI/MIDI AGN Large Program observations (Burtscher+, 2013) J/MNRAS/439/1648 : Subarcsecond mid-infrared atlas of local AGN (Asmus+, 2014) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 12 A12 --- Object Object name 14- 17 A4 --- Type AGN type (1) 20- 21 I2 h RAh Right ascension (J2000) 23- 24 I2 min RAm Right ascension (J2000) 26- 29 F4.1 s RAs RAm Right ascension (J2000) 31 A1 --- DE- Declination sign (J2000) 32- 33 I2 deg DEd Declination (J2000) 35- 36 I2 arcmin DEm Declination (J2000) 38- 39 I2 arcsec DEs Declination (J2000) 41- 46 F6.4 --- z Redshift from NED 48- 52 F5.1 Mpc DL Luminosity distance (2) 54- 56 I3 deg Slit Slit orientation 58- 62 F5.2 [10-7W] logLX Absorption-corrected 2-10keV luminosity from Asmus et al. (2015MNRAS.454..766A) 64- 67 F4.2 [10-7W] e_logLX rms uncertainty on logLX 69- 73 F5.3 pc rsub Dust sublimation radius (3) 75- 79 F5.3 pc e_rsub rms uncertainty on rsub 81 I1 --- Ref [1/3] Reference (4) 83- 85 A3 --- PAH [yes/no ] PAH detected ? 87- 97 A11 --- sp0 Name of spectrum file extracted slit position r=0" in subdirectory sp 99-111 A13 --- sp0.4 Name of spectrum file extracted slit position r=0.4" in subdirectory sp 113-125 A13 --- sp0.8 Name of spectrum file extracted slit position r=0.8" in subdirectory sp 127-139 A13 --- sp1.2 Name of spectrum file extracted slit position r=1.2" in subdirectory sp 141-153 A13 --- sp1.6 Name of spectrum file extracted slit position r=1.6" in subdirectory sp 154-165 A12 --- sp2 Name of spectrum file extracted slit position r=2" in subdirectory sp 167-179 A13 --- sp2.4 Name of spectrum file extracted slit position r=2.4" in subdirectory sp 181-193 A13 --- sp2.8 Name of spectrum file extracted slit position r=2.8" in subdirectory sp 195-207 A13 --- sp3.2 Name of spectrum file extracted slit position r=3.2" in subdirectory sp 209-221 A13 --- sp3.6 Name of spectrum file extracted slit position r=3.6" in subdirectory sp
Note (1): from Veron-Cetty and Veron (2010A&A...518A..10V, Cat. VII/258) Note (2): luminosity distance based on CMB reference frame redshifts from NED and H0 = 73 km s-1 Mpc-1, Ωm = 0.27, and Ωvac = 0.73 Note (3): dust sublimation radius calculated from equation ??? in this work, except for IC4329 A (kishimoto et al., 2011A&A...527A.121K), NGC 3783 (Glass, 1992MNRAS.256p..23G), and Mark 509, NGC 3227, and NGC 4593 (Koshida et al., 2014ApJ...788..159K). Note (4): Reference for the VISIR spectroscopic data as follows: 1 = This work 2 = Honig et al., 2010A&A...515A..23H 3 = Burtscher et al., 2013, Cat. J/A+A/558/A149
Byte-by-byte Description of file: sp/*
Bytes Format Units Label Explanations
1- 8 F8.5 um lambda Wavelength 11- 22 E12.10 Jy S Flux density 25- 35 E11.10 Jy e_S rms uncertainty on S
Acknowledgements: Jens Jual Jensen, juel(at)
(End) Patricia Vannier [CDS] 16-Jun-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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