2017MNRAS.465.1336J


Query : 2017MNRAS.465.1336J

2017MNRAS.465.1336J - Mon. Not. R. Astron. Soc., 465, 1336-1347 (2017/February-3)

A comprehensive long-term study of the radio and X-ray variability of NGC 4051 Paper II.

JONES S., McHARDY I. and MACCARONE T.J.

Abstract (from CDS):

The origin of the low-luminosity radio emission in radio-quiet active galactic nucleus, is unknown. The detection of a positive correlation between the radio and X-ray emission would imply a jet-like origin, similar to that seen in 'hard-state' X-ray binary systems. In our previous work, we found no believable radio variability in the well-known X-ray bright Seyfert 1 galaxy NGC 4051, despite large amplitude X-ray variability. In this study, we have carefully re-analysed radio and X-ray observations using the same methods as our previous work; we again find no evidence for core radio variability. In direct contrast to our findings, another study claim significant radio variability and a distinctive anticorrelation between radio and X-ray data for the same source. The other study report only integral flux values and do not consider the effect of the changing array on the synthesized beam. In both our studies of NGC 4051, we have taken great care to account for the effect that the changing beam size has on the measured radio flux and as a result we are confident that our method gives more accurate values for the intrinsic core radio flux. However, the lack of radio variability we find is hard to reconcile because radio images of NGC 4051 do show jet-like structure. We suggest that the radio structures observed are likely the result of a previous period of higher radio activity and that the current level of radio emission from a compact nuclear jet is low.

Abstract Copyright: © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): galaxies: active - radio continuum: galaxies - X rays: galaxies - X rays: galaxies

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 SDSS J114915.30+393325.4 QSO 11 49 15.3044629056 +39 33 25.448443524   19.85 19.55     ~ 27 0
2 Ton 599 Bla 11 59 31.83391383 +29 14 43.8268224   14.80 14.41 17.652 13.39 ~ 989 1
3 NGC 4051 Sy1 12 03 09.6101337312 +44 31 52.682601288   11.08 12.92 9.94   ~ 2270 1
4 7C 121858.79+442808.00 Bla 12 21 27.04465208 +44 11 29.6721704   19.28 18.85 17.75   ~ 72 1
5 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4558 2
6 HD 226868 HXB 19 58 21.6757355952 +35 12 05.784512688 9.38 9.72 8.91 8.42   O9.7Iabpvar 4590 0
7 NGC 7213 Bla 22 09 16.2100443720 -47 10 00.115999716   10.97 12.08 10.50 10.6 ~ 700 1

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