The microarcsecond quasar J1819+3845
Abstract
We present new WSRT observations of the micro-arcsecond radiosource J1819+3845 (see J. Dennett-Thorpe and A.G. de Bruyn, 2000, ApJL, 529,65), a quasar at a redshift of 0.54. Variations as fast as 10% per minute are seen regularly. All short term variations are attributed to interstellar scintillation of a source which is at most about 20-30 microarcseconds in diameter and has a brightness temperature of almost 1013 K. The screen responsible for the scintillation must be very nearby (about 20-25 pc), possibly associated with the local Hot Bubble. Using observations covering a timespan of one year we detect variations in the scintillation timescale consistent, to first order, with changes in the effective velocity resulting from the earth motion relative to the turbulence screen, allowing us to solve for the transverse velocity of the screen. We will also report on searches for diffractive scintillation and observations of variable linear polarisation. Finally we briefly discuss the problems faced in trying to explain the persistent compactness of the source.
- Publication:
-
Galaxies and their Constituents at the Highest Angular Resolutions
- Pub Date:
- January 2001
- DOI:
- 10.48550/arXiv.astro-ph/0012188
- arXiv:
- arXiv:astro-ph/0012188
- Bibcode:
- 2001IAUS..205...88D
- Keywords:
-
- Astrophysics
- E-Print:
- 3 pages, 1 figure, for IAU Symposium 205: Galaxies and their Constituents at the Highest Angular Resolutions, Manchester UK, August 2000. Proceedings to be published by ASP, edited by R. Schilizzi, S. Vogel, F. Paresce, M. Elvis. Includes figure not found in published version