J/A+A/425/99 VLBI and VLA obs. of Seyfert galaxies (Lal+, 2004)
Milliarcsec-scale radio structure of a matched sample of
Seyfert 1 and Seyfert 2 galaxies.
Lal D.V., Shastri P., Gabuzda D.C.
<Astron. Astrophys. 425, 99 (2004)>
=2004A&A...425...99L 2004A&A...425...99L
ADC_Keywords: Galaxies, Seyfert ; VLBI ; Radio continuum
Keywords: galaxies: Seyfert - radio continuum: galaxies
Abstract:
We have obtained mas-scale resolution very long baseline
interferometry (VLBI) images of a sample of Seyfert 1 and Seyfert 2
galaxies at 5GHz (wavelength, λ=6cm). The Seyferts of the two
types were chosen to be matched in several orientation-independent
properties, primarily in order to rigorously test predictions of the
unified scheme. We detected all the 15 objects that we observed. In
this paper we describe the observations and data reduction procedures,
and present the VLBI radio images as well as simultaneous Very Large
Array images that we obtained for these 15 Seyferts.
Description:
We obtained global VLBI observations of the 15 Seyfert galaxies in our
sample that did not have prior VLBI observations published in the
literature during a single 24 hour run on February 18, 1998. Since the
phased VLA was one of our VLBI stations, we also obtained simultaneous
VLA aperture-synthesis data for all these 15 sources.
The global VLBI array consisted of a total of 14 stations: three
stations of the European VLBI Network (EVN), viz., Effelsberg
(Germany), Torun (Poland) and Noto (Italy), all 10 stations of the
Very Long Baseline Array (VLAB) and the phased VLA.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 72 34 The VLBI results for Seyfert galaxies
table6.dat 71 17 VLA observational results
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See also:
VII/173 : Catalogue of Seyfert Galaxies (Lipovetsky+, 1988)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Source name
13- 14 I2 h RAh Right ascension (J2000.0) (1)
16- 17 I2 min RAm Right ascension (J2000.0) (1)
19- 23 F5.2 s RAs Right ascension (J2000.0) (1)
25 A1 --- DE- Declination sign (J2000.0) (1)
26- 27 I2 deg DEd Declination (J2000.0) (1)
29- 30 I2 arcmin DEm Declination (J2000.0) (1)
32- 35 F4.1 arcsec DEs Declination (J2000.0) (1)
37- 40 F4.1 mJy SBPeak ? Peak surface brightness (in mJy/beam)
42- 46 F5.1 mas alpha ? Position relative to phase centre (2)
48- 51 F4.1 mas delta Position relative to phase centre (2)
53- 55 F3.1 mas FWHM ? FWHM (2)
56 A1 --- n_FWHM [p] p: point source
59- 62 F4.1 mJy S5GHz Flux density at 5GHz (2)
64- 67 F4.1 mJy S5GHztot ? Total flux density at 5GHz (2) (3)
69- 72 F4.1 mJy S5GHztoti ? Total flux density at 5GHz from the image
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Note (1): A priori position used for the correlation
Note (2): Model-fit components
Note (3): For Ark 564, see description of the Seyfert in Sect. 4.2
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Source name
13- 14 I2 h RAh Right Ascension (J2000.0) (1)
16- 17 I2 min RAm Right Ascension (J2000.0) (1)
19- 24 F6.3 s RAs Right Ascension (J2000.0) (1)
26 A1 --- DE- Declination sign (J2000.0) (1)
27- 28 I2 deg DEd Declination (J2000.0) (1)
30- 31 I2 arcmin DEm Declination (J2000.0) (1)
33- 37 F5.2 arcsec DEs Declination (J2000.0) (1)
39- 43 F5.2 arcsec oRA ? Optical-radio offset in right ascension (3)
45- 49 F5.2 arcsec oDE ? Optical-radio offset in declination (3)
51- 55 F5.2 mJy SBPeak Peak surface brightness (in mJy/beam) (2)
57- 60 F4.1 mJy Scomp ? Component flux density
62- 65 F4.1 mJy Stot ? Total flux density
67 A1 --- l_LAS Limit flag on LAS
68- 71 F4.2 arcsec LAS ? Largest angular size
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Note (1): Position of radio peak
Note (2): The peak surface brightness of NGC 5929 coincides with one of the
hotspots and not the nucleus
Note (3): Optical-radio offsets
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Acknowledgements: Dharam Vir Lal
(End) Patricia Vannier [CDS] 21-Jun-2004