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Science with ASKAP - the Australian Square Kilometre Array Pathfinder
S. Johnston, R. Taylor, M. Bailes +47
[ABRIDGED VERSION] The future of cm and m-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries. The SKA will be…
The Micro-Arcsecond Scintillation-Induced Variability (MASIV) Survey II: The First Four Epochs
J. E. J. Lovell, B. J. Rickett, J-P. Macquart +8
We report on the variability of 443 flat spectrum, compact radio sources monitored using the VLA for 3 days in 4 epochs at ~ 4 month intervals at 5 GHz as part of the Micro-Arcseco…
A comprehensive study of GRB 070125, a most energetic gamma ray burst
Poonam Chandra, S. Bradley Cenko, Dale Frail +21
We present a comprehensive multiwavelength analysis of the bright, long duration gamma-ray burst GRB 070125, comprised of observations in -ray, X-ray, optical, millimeter and ce…
A Compact Extreme Scattering Event Cloud Towards AO 0235+164
C. E. Senkbeil, S. P. Ellingsen, J. E. J. Lovell +3
We present observations of a rare, rapid, high amplitude Extreme Scattering Event toward the compact BL-Lac AO 0235+164 at 6.65 GHz. The ESE cloud is compact; we estimate its diame…
Limits on the Detection of Transients Imposed by Scattering
Jean-Pierre Macquart
The author has recognized an error in the section of the text regarding induced Compton scattering. The paper has been withdrawn pending a revision to this section.
Observations of Intrahour Variable Quasars: Scattering in our Galactic Neighbourhood
H. E. Bignall, D. L. Jauncey, J. E. J. Lovell +3
Interstellar scintillation (ISS) has been established as the cause of the random variations seen at centimetre wavelengths in many compact radio sources on timescales of a day or l…
Emergence and disappearance of micro-arcsecond structure in the scintillating quasar J1819+3845
Jean-Pierre Macquart, Ger de Bruyn
The 4.8 GHz lightcurves of the scintillating intra-day variable quasar J1819+3845 during 2004-5 exhibit sharp structure, down to a time scale of 15 minutes, that was absent from li…
On the Detectability of Prompt Coherent GRB Radio Emission
J. -P. Macquart
Both induced Compton scattering and induced Raman scattering strongly limit the observability of the extremely bright (<< 10^21K), prompt coherent radio emission recently predicted…
Properties of the Scattering Screen in Front of Scintillating Quasar PKS 1257-326
H. E. Bignall, D. L. Jauncey, J. E. J. Lovell +3
PKS 1257-326 is a quasar showing extremely unusual, rapid interstellar scintillation (ISS), which has persisted for at least a decade. Simultaneous observations with the VLA and AT…
MASIV:The Microarcsecond Scintillation-Induced Variability Survey
J. E. J. Lovell, D. L. Jauncey, C. Senkbeil +8
We are undertaking a large-scale 5 GHz VLA survey of the northern sky to search for rapid intra-day variability (IDV). Over four observing epochs we found that 56% of the sources s…
Scattering of Gravitational Radiation: Intensity Fluctuations
Jean-Pierre Macquart
The effect of gravitational microlensing on the intensity of gravitational radiation as it propagates through an inhomogeneous medium containing small-scale structure is considered…
International Colloquium "Scattering and Scintillation in Radio Astronomy" was held on June 19-23, 2006 in Pushchino, Moscow region, Russia
V. I. Shishov, W. A. Coles, B. J. Rickett +52
Topics of the Colloquium: a) Interplanetary scintillation b) Interstellar scintillation c) Modeling and physical origin of the interplanetary and the interstellar plasma turbulence…
Rapid interstellar scintillation of PKS B1257-326: two-station pattern time delays and constraints on scattering and microarcsecond source structure
H. E. Bignall, J. -P. Macquart, D. L. Jauncey +3
We report measurements of time delays of up to 8 minutes in the centimeter wavelength variability patterns of the intra-hour scintillating quasar PKS 1257-326 as observed between t…
The Rotation Measure and 3.5mm Polarization of Sgr A*
Jean-Pierre Macquart, Geoffrey C. Bower, Melvyn C. H. Wright +2
We report the detection of variable linear polarization from Sgr A* at a wavelength of 3.5mm, the longest wavelength yet at which a detection has been made. The mean polarization i…
Understanding the Radio Variability of Sgr A*
Jean-Pierre Macquart, Geoff Bower
We determine the characteristics of the 7mm to 20cm wavelength radio variability in Sgr A* on time scales from days to three decades. The amplitude of the intensity modulation is b…
Diffractive Interstellar Scintillation of the Quasar J1819+3845 at 21cm
Jean-Pierre Macquart, Ger de Bruyn
We report the discovery of fast, frequency-dependent intensity variations from the scintillating intra-day variable quasar J1819+3845 at a wavelength of 21cm which resemble diffrac…
Scintillation-induced Variability in Radio Absorption Spectra against Extragalactic Sources
Jean-Pierre Macquart
Spectral features absorbed against some radio quasars exhibit ~50mJy variations, with the lines varying both relative to the continuum and, when several lines are present, even rel…
Scattering of gravitational radiation: second order moments of the wave amplitude
J-P Macquart
Gravitational radiation that propagates through an inhomogeneous mass distribution is subject to random gravitational lensing, or scattering, causing variations in the wave amplitu…
Outburst and Post-Outburst Active Phase of the Black Hole X-ray Binary V4641 Sgr in 2002
M. Uemura, T. Kato, R. Ishioka +19
The black hole X-ray binary V4641 Sgr experienced an outburst in 2002 May which was detected at X-ray, optical, and radio wavelengths. The outburst lasted for only 6 days, but the…
First Results from MASIV: The Micro-Arcsecond Scintillation-Induced Variability Survey
J. Lovell, D. Jauncey, H. Bignall +4
We are undertaking a large-scale, Micro-Arcsecond Scintillation-Induced Variability (MASIV) survey of the northern sky, Dec > 0 deg, at 4.9 GHz with the VLA. Our objective is to co…
On the Search for Coherent Radiation from Radio Pulsars
J. M. Smits, B. W. Stappers, J-P. Macquart +2
We have examined data from pulsars B0950+08 and B0329+54 for evidence of temporally coherent radiation using the modified coherence function (MCF) technique of Jenet et al. (2001).…
Rapid Variability and Annual Cycles in the Characteristic Time-scale of the Scintillating Source PKS 1257-326
H. E. Bignall, D. L. Jauncey, J. E. J. Lovell +6
Rapid radio intra-day variability (IDV) has been discovered in the southern quasar PKS 1257-326. Flux density changes of up to 40% in as little as 45 minutes have been observed in…
Rapidly Evolving Circularly Polarized Emission during the 1994 Outburst of GRO J1665-40
J-P Macquart, K. Wu, R. J. Sault +1
We report the detection of circular polarization during the 1994 outburst of the Galactic microquasar GRO J1655-40. The circular polarization is clearly detected at 1.4 and 2.4GHz,…
Microarcsecond Radio Imaging using Earth Orbit Synthesis
J-P Macquart, D. L. Jauncey
The observed interstellar scintillation pattern of an intra-day variable radio source is influenced by its source structure. If the velocity of the interstellar medium responsible…