Interstellar scattering as a cosmological probe

2011 ◽  
Author(s):  
J. Y. Koay ◽  
J.-P. Macquart ◽  
B. J. Rickett ◽  
H. E. Bignall ◽  
J. E. J. Lovell ◽  
...  
Keyword(s):  
Interstellar Scattering

Southern Hemisphere Seti Survey: Five Years of Project Meta II

1997 ◽  
Vol 161 ◽  
pp. 611-621
Author(s):  
Guillermo A. Lemarchand ◽  
Fernando R. Colomb ◽  
E. Eduardo Hurrell ◽  
Juan Carlos Olalde
Keyword(s):  
Southern Hemisphere ◽  
Scattering Theory ◽  
Galactic Plane ◽  
Narrow Band ◽  
Neutral Hydrogen ◽  
Sky Survey ◽  
Inertial Frames ◽  
Interstellar Scattering ◽  
Extraterrestrial Origin ◽  
Spectral Channels

AbstractProject META II, a full sky survey for artificial narrow-band signals, has been conducted from one of the two 30-m radiotelescopes of the Instituto Argentino de Radioastronomía (IAR). The search was performed near the 1420 Mhz line of neutral hydrogen, using a 8.4 million channels Fourier spectrometer of 0.05 Hz resolution and 400 kHz instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earths rotation, which provides a characteristic changing signature for narrow-band signals of extraterrestrial origin. Among the 2 × 1013spectral channels analyzed, 29 extra-statistical narrow-band events were found, exceeding the average threshold of 1.7 × 10−23Wm−2. The strongest signals that survive culling for terrestrial interference lie in or near the galactic plane. A description of the project META II observing scheme and results is made as well as the possible interpretation of the results using the Cordes-Lazio-Sagan model based in interstellar scattering theory.

scholarly journals A Search for Very Compact Structure in 17 OH Masers

1988 ◽  
Vol 129 ◽  
pp. 255-256
Author(s):  
A. J. Kemball ◽  
P. J. Diamond ◽  
F. Mantovani
Keyword(s):  
Galactic Disk ◽  
Hii Regions ◽  
Scale Structure ◽  
Small Scale ◽  
Compact Structure ◽  
Small Scale Structure ◽  
Interstellar Scattering

The apparent spot sizes of OH masers appear to be significantly broadened when seen through the inner galaxy or large extents of the galactic disk (Burke 1968). Bowers et al (1980) found evidence of small-scale structure (≲ 50 mas) in OH sources at distances of less than 5 kpc but this was characteristically absent in very distant sources (≳ 8kpc) at galactic longitudes 1 ≲ 40°. This result is typically explained in terms of interstellar scattering (ISS) by intervening diffuse HII regions.

Interstellar Scattering and the Pulse from the Vela Pulsar

1971 ◽  
pp. 217-221
Author(s):  
M. M. Komesaroff ◽  
P. A. Hamilton ◽  
J. G. Ables
Keyword(s):  
Interstellar Scattering ◽  
Vela Pulsar

scholarly journals Space-VLBI observations of OH masers

2002 ◽  
Vol 206 ◽  
pp. 105-111 ◽  
Author(s):  
Vyacheslav I. Slysh ◽  
Maxim A. Voronkov ◽  
Irina E. Val'tts ◽  
Victor Migenes ◽  
K.M. Shibata ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Lower Limit ◽  
Radio Telescope ◽  
Angular Resolution ◽  
Main Line ◽  
Radio Telescopes ◽  
Space Radio Telescope ◽  
Vlbi Observations ◽  
Interstellar Scattering

We report on the first space-VLBI observations of the OH masers in two main-line OH transitions at 1665 and 1667 MHz. The observations involved the space radio telescope on board the Japanese satellite HALCA and an array of ground radio telescopes. The maps of the maser region and images of individual maser spots were produced with an angular resolution of 1 mas, which is several times higher than the angular resolution available on the ground. The maser spots were only partly resolved and a lower limit to the brightness temperature 6 × 1012 K was obtained. The masers seem to be located in the direction of low interstellar scattering.

Time Variability of Interstellar Scattering and Improvements to Pulsar Timing

2008 ◽  
Vol 674 (1) ◽  
pp. L37-L40 ◽  
Author(s):  
Daniel A. Hemberger ◽  
Daniel R. Stinebring
Keyword(s):  
Time Variability ◽  
Pulsar Timing ◽  
Interstellar Scattering

Interstellar scattering of the compact radio source 2005 + 403

1990 ◽  
Vol 349 ◽  
pp. L47 ◽  
Author(s):  
R. L. Mutel ◽  
Jean-Francois Lestrade
Keyword(s):  
Radio Source ◽  
Compact Radio Source ◽  
Interstellar Scattering

scholarly journals The Parkes Multibeam Pulsar Survey and Interstellar Scattering

2001 ◽  
Vol 182 ◽  
pp. 32-38
Author(s):  
R.N. Manchester
Keyword(s):  
International Collaboration ◽  
Electron Density Distribution ◽  
Galactic Plane ◽  
Astronomical Observatory ◽  
Massachusetts Institute ◽  
Massachusetts Institute Of Technology ◽  
Pulse Profile ◽  
Interstellar Scattering ◽  
The Galaxy ◽  
Institute Of Technology

AbstractThe Parkes multibeam pulsar survey is a major survey for pulsars lying within a 10°-wide strip along the southern Galactic plane, using the multibeam receiver on the Parkes 64-m radiotelescope. It is an international collaboration between groups at Jodrell Bank Observatory, Massachusetts Institute of Technology, Bologna Astronomical Observatory and the ATNF. The survey commenced in 1997 August, and has so far succeeded in finding more than 550 previously unknown pulsars. Many of these are distant, with some beyond the centre of the Galaxy according to current models of the interstellar electron density distribution. Interstellar scattering affects the pulse profile of many of the more distant pulsars even at 1374 MHz, the centre frequency of the survey. Preliminary results from the survey are presented.

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