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Emergence and disappearance of microarcsecond structure in the scintillating quasar J1819+3845

Macquart, J.-P. and de Bruyn, A. G. (2007) Emergence and disappearance of microarcsecond structure in the scintillating quasar J1819+3845. Monthly Notices of the Royal Astronomical Society, 380 (1). L20-L24. ISSN 0035-8711.

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The 4.8-GHz light curves of the scintillating intraday variable quasar J1819+3845 during 2004–2005 exhibit sharp structure, down to a time-scale of 15 min, that was absent from light curves taken prior to this period and from the 2006 light curves. Analysis of the light curve power spectra show that the variations must be due to the emergence of new structure in the source. The power spectra yield a scattering screen distance of 3.8 ± 0.3 pc for a best-fitting vISS= 59 ± 0.5 km s^−1 or 2.0 ± 0.3 pc for the scintillation velocity reported by Dennett-Thorpe & de Bruyn. The scattering medium is required to be exceptionally turbulent, with C2N≳ 0.7 ΔL^−1pc m^(−20/3) for scattering material of thickness ΔLpc pc along the ray path. The 2004 power spectrum can be explained in terms of a double source with a component separation 240 ± 15 μas in 2004.

Item Type:Article
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Macquart, J.-P.0000-0001-6763-8234
Additional Information:© 2007 The Authors. Journal compilation © 2007 RAS. Accepted 2007 May 23. Received 2007 May 23; in original form 2006 December 3. The WSRT is operated by the Netherlands Foundation for Research in Astronomy (NFRA/ASTRON) with financial support by the Netherlands Organization for Scientific Research (NWO). JPM thanks Mike Ireland and Barney Rickett for suggestions regarding power spectra. The Virginia Tech Spectral-Line Survey (VTSS) is supported by the National Science Foundation. [JPM was an] NRAO Jansky Fellow.
Funding AgencyGrant Number
Netherlands Foundation for Radio Astronomy (ASTRON)UNSPECIFIED
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)UNSPECIFIED
National Radio Astronomy ObservatoryUNSPECIFIED
Subject Keywords:high angular resolution techniques; scattering; active galaxies; quasars; J1819+3845
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Record Number:CaltechAUTHORS:MACmnras07
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11221
Deposited By: Tony Diaz
Deposited On:06 Aug 2008 05:02
Last Modified:03 Oct 2019 00:17

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