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J/A+A/530/A147      Megamaser detection in Seyfert galaxies     (Ramolla+, 2011)

Megamaser detection and nuclear obscuration in Seyfert galaxies. Ramolla M., Haas M., Bennert V.N., Chini R. <Astron. Astrophys. 530, A147 (2011)> =2011A&A...530A.147R
ADC_Keywords: Galaxies, Seyfert ; Masers ; Galaxies, IR ; X-ray sources Keywords: galaxies: Seyfert - galaxies: nuclei - masers - X-rays: galaxies - infrared: galaxies Abstract: We revisit the relation between H2O maser detection rate and nuclear obscuration for a sample of 114 Seyfert galaxies, drawn from the CfA, 12um and IRAS F25/F60 catalogs. These sources have mid-infrared spectra from the Spitzer Space Telescope and they are searched for X-ray and [OIII] (5007Å) fluxes from the literature. We use the strength of the [OIV] (25.9um) emission line as tracer for the intrinsic AGN strength. After normalization by [OIV] the observed X-ray flux provides information about X-ray absorption. The distribution of X-ray/[OIV] flux ratios is significantly different for masers and non-masers: The maser detected Seyfert-2s (Sy 1.8-2.0) populate a distinct X-ray/[OIV] range which is, on average, about a factor four lower than the range of Seyfert-2 non-masers and about a factor of ten lower than the range of Seyfert-1s (Sy 1.0-1.5). Non-masers are almost equally distributed over the entire X-ray/[OIV] range. This provides evidence that high nuclear obscuration plays a crucial role for the probability of maser detection. Furthermore, after normalization with [OIV], we find a similar but weaker trend for the distribution of the maser detection rate with the absorption of the 7um dust continuum. This suggests that the obscuration of the 7um continuum occurs on larger spatial scales than that of the X-rays. Hence, in the AGN unified model, at moderate deviation from edge-on, the 7um dust absorption may occur without proportionate X-ray absorption. The absorption of [OIII] appears unrelated to maser detections. The failure to detect masers in obscured AGN is most likely due to insufficient observational sensitivity. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 49 163 *Master sample table3.dat 75 163 Measured fluxes and literature values for sample and off-sample sources refs.dat 46 71 References
Note on table1.dat: All Seyferts from the three catalogs for which we performed a search in the Spitzer archive: * The magnitude limited complete sample of the CfA Redshift Survey by Huchra & Burg (1992ApJ...393...90H) * the 12um Active Galaxy Sample by Spinoglio & Malkan (1989ApJ...342...83S) * the IRAS F25/F60 flux-ratio selected sample by de Grijp et al. (1992A&AS...96..389D), as refined by Schmitt et al. (2003ApJS..148..327S)
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1 A1 --- n_Name [s] s for sample sources (G1) 3- 16 A14 --- Name Name 18- 27 F10.6 deg RAdeg J2000 right ascension in degrees 29- 38 F10.6 deg DEdeg J2000 declination in degrees 40- 49 A10 --- OName Other name
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1 A1 --- n_Name [sa] a for Additional off-sample data (G1) 3- 16 A14 --- Name Source name 18- 22 A5 --- Ref [abc, ] Catalog references for Name (1) 24- 27 F4.1 [Lsun] logLM ? H2O isotropic maser luminosities obtained from Bennert et al., 2009ApJ...695..276B (- for maser undetected source) 28 A1 --- n_logLM [?*] Flag on maser luminosity (2) 30- 32 F3.1 --- Type Seyfert type 34 A1 --- l_F[OIV] Limit flag on F[OIV] 35- 39 I5 aW/m2 F[OIV] ?=- [OIV] flux measurement from Ramolla (2009, Thesis, Ruhr-Universitat, Bochum) 41- 44 I4 aW/m2 e_F[OIV] ? rms uncertainty on F[OIV] 46- 50 I5 aW/m2 F[OIII] ? [OIII] literature flux 52- 53 I2 --- r_F[OIII] ? Reference for F[OIII], in refs.dat file 55- 59 I5 10aW/m2 Fx ?=- 2-10keV literature flux (in 10-14erg/cm2/s) 61- 62 I2 --- r_Fx ? Reference for F2-10keV, in refs.dat file 64 A1 --- l_F7um Limit flag on F7um 65- 69 I5 10aW/m2 F7um ?=- 7um flux measurement from Ramolla (2009, Thesis, Ruhr-Universitat, Bochum) 71- 75 I5 10aW/m2 e_F7um ? rms uncertainty on F7um
Note (1): Catalog references for Names as follows: a = CfA sample (Huchra & Burg, 1992ApJ...393...90H) b = 12um sample (Spinoglio & Malkan, 1989ApJ...342...83S) c = IRAS F25/F60 sample (de Grijp et al., 1992A&AS...96..389D) Note (2): Flag on maser luminosity as follows: ? = sources unobserved for masers * = MRK938 and NGC1320 are listed as Maser in Zhang et al. (2010ApJ...708.1528Z) but have no luminosity information available
Byte-by-byte Description of file: refs.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Ref Reference number 4- 22 A19 --- BibCode BibCode 24- 46 A23 --- Aut Author's name
Global Notes: Note (G1): 126 sources with [s] (sample) flag are common to tables 1 and 3.
Acknowledgements: Michael Ramolla, Astronomisches Institut, Ruhr-Universitaet Bochum, ramolla(at)
(End) Patricia Vannier [CDS] 11-Feb-2011
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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