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J/A+A/456/953     Narrow-band imaging of 6 Seyfert-2 galaxies   (Bennert+, 2006)

Size and properties of the narrow-line region in Seyfert-2 galaxies from spatially-resolved optical spectroscopy Bennert N., Jungwiert B., Komossa S., Haas M., Chini R. <Astron. Astrophys. 456, 953 (2006)> =2006A&A...456..953B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, Seyfert ; Active gal. nuclei ; Photometry, narrow-band Keywords: galaxies: active - galaxies: nuclei - galaxies: Seyfert Abstract: While [OIII] narrow-band imaging is commonly used to measure the size of the narrow-line regions (NLRs) in active galactic nuclei (AGNs), it can be contaminated by emission from surrounding starbursts. Recently, we have shown that long-slit spectroscopy provides a valuable alternative approach to probe the size in terms of AGN photoionisation. Moreover, several parameters of the NLR can be directly accessed. We here apply the same methods developed and described for the Seyfert-2 galaxy NGC1386 to study the NLR of five other Seyfert-2 galaxies by using high-sensitivity spatially-resolved optical spectroscopy obtained at the VLT and the NTT. We probe the AGN-photoionisation of the NLR and thus, its "real" size using diagnostic line-ratio diagrams. We derive physical properties of the NLR such as reddening, ionisation parameter, electron density, and velocity as a function of distance from the nucleus. For NGC5643, the diagnostic diagrams unveil a similar transition between line ratios falling in the AGN regime and those typical for HII regions as found for NGC1386, thus determining the size of the NLR. For the other four objects, all measured line ratios fall in the AGN regime. In almost all cases, both electron density and ionisation parameter decrease with radius. Deviations from this general behaviour (such as a secondary peak) seen in both the ionisation parameter and electron density can be interpreted as signs of shocks from the interaction of a radio jet and the NLR gas. In several objects, the gaseous velocity distribution is characteristic for rotational motion in an (inclined) emission-line disk in the centre. We compare our results to those of NGC1386 and show that the latter can be considered as prototypical also for this larger sample. We discuss our findings in detail for each object. Description: Observed and reddening-corrected emission-line ratios relative to Hbeta are presented as a function of distance from the nucleus. The uncertainties are in the range of ∼1-15%. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 20 52 02.0 -57 04 09 IC 5063 = ESO 187- 23 22 07 02.1 +10 14 00 NGC 7212 = UGC 11910 05 11 09.0 -34 23 36 ESO 362-8 = IRAS 05093-3427 10 31 52.1 -34 51 13 NGC 3281 = ESO 375- 55 14 32 40.7 -44 10 28 NGC 5643 = ESO 272- 16 03 36 46.4 -36 00 02 NGC 1386 = ESO 358- 35 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 91 99 Observed and reddening-corrected emission-line ratios relative to Hbeta for 6 galaxies
See also: J/A+A/459/55 : Narrow-band imaging of 5 Seyfert-1 galaxies (Bennert+, 2006) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 9 A9 --- Name Galaxy Name 11- 16 F6.2 arcsec r Distance from center (1) 18- 22 F5.2 --- OIIobs ?=- Observed line-ratio [OII] 3727 to Hbeta 24- 28 F5.2 --- OIIcor ?=- Reddening-corrected line-ratio [OIII] 3727 to Hbeta 30- 34 F5.2 --- OIIIobs Observed line-ratio [OIII] 5007 to Hbeta 36- 40 F5.2 --- OIIIcor Reddening-corrected line-ratio [OIII] 5007 to Hbeta 42- 45 F4.2 --- OIobs ?=- Observed line-ratio [OI] 6300 to Hbeta 47- 50 F4.2 --- OIcor ?=- Reddening-corrected line-ratio [OI] 6300 to Hbeta 52- 55 F4.2 --- HAobs Observed line-ratio Halpha to Hbeta 57- 60 F4.2 --- HAcor Reddening-corrected line-ratio Halpha to Hbeta 62- 66 F5.2 --- NIIobs Observed line-ratio [NII] 6583 to Hbeta 68- 71 F4.2 --- NIIcor Reddening-corrected line-ratio [NII] 6583 to Hbeta 73- 76 F4.2 --- SII1obs ?=- Observed line-ratio [SII] 6716 to Hbeta 78- 81 F4.2 --- SII1cor ?=- Reddening-corrected line-ratio [SII] 6716 to Hbeta 83- 86 F4.2 --- SII2obs ?=- Observed line-ratio [SII] 6731 to Hbeta 88- 91 F4.2 --- SII2cor ?=- Reddening-corrected line-ratio [SII] 6731 to Hbeta
Note (1): Negative values correspond to spectra to the northwest of the center, positive values correspond to spectra to the southeast.
Acknowledgements: Nicola Benner, nicola.bennert(at)ucr.edu References: Bennert et al., NGC 1386, 2006A&A...446..919B
(End) Patricia Vannier [CDS] 30-May-2006
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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