2013A&A...554A..85S


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.05CEST06:43:24

2013A&A...554A..85S - Astronomy and Astrophysics, volume 554A, 85-85 (2013/6-1)

Low-frequency radio observations of Seyfert galaxies: a test of the unification scheme.

SINGH V., SHASTRI P., ISHWARA-CHANDRA C.H. and ATHREYA R.

Abstract (from CDS):

We present low-frequency radio imaging and spectral properties of a well-defined sample of Seyfert galaxies using GMRT 240/610MHz dual frequency observations. Radio spectra of Seyfert galaxies over 240MHz to 5.0GHz are investigated using 240MHz, 610MHz flux densities derived from GMRT, and 1.4GHz and 5.0GHz flux densities mainly from published VLA data. We test the predictions of Seyfert unification scheme by comparing the radio properties of Seyfert type 1s and type 2s. We chose a sample such that the two Seyferts subtypes have matched distributions in parameters that are independent of the orientation of AGN, obscuring torus, and the host galaxy. Our sample selection criteria allowed us to assume that the two Seyfert subtypes are intrinsically similar within the framework of the unification scheme. The new observations at 240/610MHz, together with archival observations at 1.4GHz, 5.0GHz show that types 1s and 2s have statistically similar radio luminosity distributions at 240MHz, 610MHz, 1.4GHz, and 5.0GHz. The spectral indices at selected frequency intervals (α240MHz610MHz, α610MHz1.4GHz, and α1.4GHz5.0GHz), as well as index measured over 240MHz to 5.0GHz (αint) for the two Seyfert subtypes, have similar distributions with median spectral index (α)~-0.7(Sν∝να), consistent with the synchrotron emission from optically thin plasma. In our snapshot 240/610 MHz GMRT observations, most of the Seyfert galaxies primarily show an unresolved central radio component, except for a few sources in which faint kpc-scale extended emission is apparent at 610MHz. Our results on the statistical comparison of the multifrequency radio properties of our sample Seyfert galaxies agree with the predictions of the Seyfert unification scheme.

Abstract Copyright:

Journal keyword(s): galaxies: Seyfert - galaxies: active - radio continuum: galaxies

Simbad objects: 31

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Number of rows : 31

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 262 Sy2 00 48 47.1414900 +31 57 25.083955 14.04 13.90 13.06 8.53   ~ 672 3
2 NGC 449 Sy2 01 16 07.2096682810 +33 05 21.651153340   15.90 14.96     ~ 267 4
3 3C 48 QSO 01 37 41.2995845985 +33 09 35.079126038   16.62 16.20     ~ 2495 2
4 Mrk 1066 Sy2 02 59 58.5970307633 +36 49 13.808979663   14.89 13.96     ~ 318 1
5 ICRF J054236.1+495107 Sy1 05 42 36.13789843 +49 51 07.2337251   18.45 17.80 17.210   ~ 1266 1
6 NGC 2110 Sy2 05 52 11.3760694860 -07 27 22.489931610   14.77 13.51 11.86   ~ 582 1
7 QSO B0605-0834 QSO 06 07 59.69923743 -08 34 49.9781718     18.5 17.70   ~ 394 1
8 8C 0609+607 QSO 06 14 23.86617054 +60 46 21.7559014   20 19.1 18.8   ~ 65 1
9 NGC 2273 Sy2 06 50 08.6724567505 +60 50 44.879789544   14.50 13.54     ~ 458 3
10 IC 450 Sy1 06 52 12.32333 +74 25 37.2376   15.16 14.19     ~ 498 1
11 NGC 3227 GiP 10 23 30.57 +19 51 54.3   12.61 11.79     ~ 1530 2
12 NGC 3516 Sy1 11 06 47.4596406816 +72 34 07.189563769   13.12 12.40     ~ 1417 0
13 ICRF J111120.0+195536 Sy2 11 11 20.06576034 +19 55 36.0002856   18.5 18.5     ~ 46 1
14 NGC 4151 Sy1 12 10 32.5771747733 +39 24 21.057727323   12.18 11.48     ~ 3379 2
15 NGC 4253 Sy1 12 18 26.5155239433 +29 48 46.518670434   14.34 13.57     ~ 930 1
16 EQ J1313+675 ? 13 13 +67.5           ~ 1 0
17 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825108   17.51 17.25     ~ 3715 1
18 NGC 5252 Sy2 13 38 15.8711551761 +04 32 33.525903711   15.21 14.21     ~ 419 0
19 Mrk 279 Sy1 13 53 03.4356451470 +69 18 29.410672989   15.15 14.46     ~ 693 0
20 QSO J1357-1527 QSO 13 57 11.24497976 -15 27 28.7867232   18.13   18.40   ~ 131 1
21 NGC 5548 Sy1 14 17 59.5401093128 +25 08 12.600227883   14.35 13.73     ~ 2391 0
22 NGC 5728 Sy2 14 42 23.928 -17 15 11.41   14.34 13.40     ~ 496 0
23 NGC 7212 Sy2 22 07 01.9866638486 +10 14 00.849716443   15.1       ~ 159 1
24 NGC 7213 Sy1 22 09 16.2106632887 -47 10 00.082166299   10.97 12.08 10.50 10.6 ~ 595 0
25 87GB 221004.9+013803 AGN 22 12 37.9679 +01 52 51.267     21.7     ~ 74 1
26 QSO B2232+282 BLL 22 36 22.4706694778 +28 28 57.412050821   19.1 19.0 17.60   ~ 221 1
27 UGC 12163 Sy1 22 42 39.3364258078 +29 43 31.301194419   14.86 14.16     ~ 614 1
28 NGC 7469 Sy1 23 03 15.674 +08 52 25.28 12.60 13.00 12.34     ~ 1885 3
29 NGC 7603 Sy1 23 18 56.6537061537 +00 14 37.974617713   14.73 14.01     ~ 355 0
30 NGC 7674 Sy2 23 27 56.6974755223 +08 46 44.238278540 13.84 13.92 13.23 12.64   ~ 635 4
31 NGC 7682 Sy2 23 29 03.896 +03 32 00.00   14.3       ~ 203 0

    Equat.    Gal    SGal    Ecl

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2020.07.05-06:43:24

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