2003A&A...404..113D


Query : 2003A&A...404..113D

2003A&A...404..113D - Astronomy and Astrophysics, volume 404, 113-132 (2003/6-2)

Annual modulation in the scattering of J1819+3845: Peculiar plasma velocity and anisotropy.

DENNETT-THORPE J. and DE BRUYN A.G.

Abstract (from CDS):

We present two years of monitoring observations of the extremely variable quasar J1819+3845. We observe large yearly changes in the timescale of the variations (from ∼1 hour to ∼10 hours at 5GHz). This annual effect can only be explained if the variations are caused by a propagation effect, and thus affected by the Earth's relative speed through the projected intensity pattern. To account for this effect, the scattering plasma must have a transverse velocity with respect to the local standard of rest. The velocity calculated from these observations is in good agreement with that obtained from a two telescope delay experiment (Dennett-Thorpe & de Bruyn, 2002Natur.415...57D). We also show that either the source itself is elongated, or that the scattering plasma is anisotropic, with an axial ratio of >6:1. As the source is extended on scales relevant to the scattering phenomenon, it seems plausible that the anisotropy is due to the source itself, but this remains to be investigated. From the scintillation characteristics we find that the scattering material is a very strong, thin scatterer within ∼ten parsecs. We determine a source size at 5-GHz of 100 to 900-microarcsecs, and associated brightness temperatures of 1010 to 1012K.

Abstract Copyright:

Journal keyword(s): scattering - ISM: structure - quasars: individual: J1819+3845 - radio continuum: galaxies - techniques: high angular resolution

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 3C 48 QSO 01 37 41.2996631208 +33 09 35.080388820   16.62 16.20     ~ 2720 2
2 QSO B0405-385 QSO 04 06 59.03533781 -38 26 28.0423651   19.55 18.0     ~ 223 2
3 ICRF J054236.1+495107 Sy1 05 42 36.13789710 +49 51 07.2337139   18.45 17.80 17.210   ~ 1425 1
4 6C 091739+622838 QSO 09 21 36.23107643 +62 15 52.1803510   19.76 19.26 18.96   ~ 341 1
5 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4172 2
6 ICRF J160913.3+264129 Sy2 16 09 13.32073953 +26 41 29.0361447   19       ~ 222 0
7 ICRF J181926.5+384501 SyG 18 19 26.54735971 +38 45 01.7860362           ~ 116 0
8 PSR B2016+28 Psr 20 18 03.8999255016 +28 39 54.940329468           ~ 345 0

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2023.02.04-10:28:07

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