scholarly journals Search for Extraterrestrial Intelligence at 22 GHz with the Very Large Array

2004 ◽  
Vol 213 ◽  
pp. 423-428
Author(s):  
Toshimichi Shirai ◽  
Tomoaki Oyama ◽  
Hiroshi Imai ◽  
Shinsuke Abe
Keyword(s):  
Flux Density ◽  
Direct Search ◽  
Large Array ◽  
Extraterrestrial Intelligence ◽  
Very Large Array ◽  
Exoplanetary Systems ◽  
Solar Type ◽  
Water Maser ◽  
Rule Out

We have conducted a direct Search for Extraterrestrial Intelligence at the Water Maser frequency, 22.235 GHz, using the Very Large Array. The targets were 13 solar-type stars that were known to host exoplanetary systems. In all cases, the RMS limits of the flux density, 20 mJy (5σ), were sufficient to rule out any omnidirectional transmitters of the same power as terrestrial radars (5 × 1012 W). We discuss the significance of this non-detection.

scholarly journals Radio Emission from WR Stars

1982 ◽  
Vol 99 ◽  
pp. 221-224 ◽  
Author(s):  
David E. Hogg
Keyword(s):  
Simple Model ◽  
Radio Emission ◽  
Mass Loss ◽  
Flux Density ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Large Array ◽  
Radio Observations ◽  
Very Large Array

In principle radio observations of WR stars offer the best possibility of determining the rate of mass loss, since for a simple model of the extended atmosphere the mass loss rate depends primarily on quantities—the flux density, the velocity, and the distance—which are observable (Barlow 1979). Until now, detections of Wolf-Rayet stars have been limited by the sensitivity and resolution of available telescopes. The advent of the Very Large Array makes a search for emission from a large number of these stars feasible.

Water Maser Survey toward Low‐Mass Young Stellar Objects in the Northern Sky with the Nobeyama 45 Meter Telescope and the Very Large Array

2003 ◽  
Vol 144 (1) ◽  
pp. 71-134 ◽  
Author(s):  
Ray S. Furuya ◽  
Yoshimi Kitamura ◽  
Alwyn Wootten ◽  
Mark J. Claussen ◽  
Ryohei Kawabe
Keyword(s):  
Young Stellar Objects ◽  
Large Array ◽  
Stellar Objects ◽  
Very Large Array ◽  
Low Mass ◽  
Water Maser

scholarly journals A VLA Survey of Rich Clusters of Galaxies. I. Whole-cluster Maps, Source List and Source Statistics

1989 ◽  
Vol 42 (6) ◽  
pp. 633 ◽  
Author(s):  
OB Slee ◽  
RA Perley ◽  
Betty C Siegman
Keyword(s):  
Flux Density ◽  
Clusters Of Galaxies ◽  
Large Array ◽  
Spectral Indices ◽  
Cluster Radius ◽  
Very Large Array ◽  
Cluster Membership ◽  
Cluster Centre ◽  
5 Ghz

We have surveyed 58 fields near rich clusters of galaxies with the Very Large Array using scaled arrays in the B/C and/or C/O configurations at 1�5 GHz and 4�9 GHz. The fields were centred on steep spectrum sources in or near clusters that were earlier surveyed with lower resolution telescopes. The whole-field maps at 1�5 GHz are given and a list of 940 sources with 1�5 GHz flux densities down to -1 mJy is presented. Spectral indices of sources within 5' of the field centres are given. Complete flux-limited samples of sources are used to establish a criterion for cluster membership. Sources with total 1�5 GHz flux density >20 mjy and closer to the cluster centre than 0�28 of the cluster radius (a total of 57 sources) are accepted as cluster members.

scholarly journals VLA observations of water maser emission associated with SVS 13

2002 ◽  
Vol 206 ◽  
pp. 59-62
Author(s):  
Luis F. Rodríguez ◽  
Guillem Anglada ◽  
José M. Torrelles ◽  
J. Eduardo Mendoza-Torres ◽  
Aubrey D. Haschick ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Radio Source ◽  
Angular Resolution ◽  
Radio Continuum ◽  
Large Array ◽  
Maser Emission ◽  
Very Large Array ◽  
Water Maser ◽  
East West ◽  
Made In

The young stellar object SVS 13 has been proposed as the powering source of the HH 7-11 objects. Recent observations have revealed that in the radio continuum (3.6-cm) the source is a binary separated by about 0.3 in the east-west direction. We present Very Large Array observations, made in the highest angular resolution A configuration, of H2O maser emission toward this source. Our data show that the H2O spots appear to be segregated in two velocity groups: a group with radial velocity similar to that of the ambient cloud (VLSR ⋍ 8 km s−1) that is associated with the western radio source, and a blueshifted (by ∼20 km s−1) velocity group that is associated with the eastern radio source. We discuss the possible implications of this observation.

scholarly journals Jupiter’s Synchrotron Radiation Throughout the Comet P/Shoemaker-Levy 9 Impact Period

1995 ◽  
Vol 10 ◽  
pp. 637-638
Author(s):  
I. de Pater ◽  
C. Heiles ◽  
M. Wong ◽  
R.J. Maddalena ◽  
M.K. Bird ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Flux Density ◽  
Radio Spectrum ◽  
Brightness Distribution ◽  
Microwave Emission ◽  
Central Meridian ◽  
Large Array ◽  
Very Large Array ◽  
Particle Population

Jupiter’s microwave emission was observed throughout the SL9 impact period by many different telescopes, among which the NRAO 140-foot telescope in Green Bank (21 cm), Westerbork (92 cm), Effelsberg (6, 11 cm), Parkes (21 cm), NASA DSN (13 cm), and the Very Large Array (22, 90 cm). We determined the “average” total nonthermal flux density from the planet after having subtracted the thermal contribution, following the formulation by de Pater and Klein, (1989) and Klein et al., (1989). The flux density increased typically by 40-50% at 6 cm wavelength, 27% at 11-13 cm, 22%at 21 cm and 10-15% at 90 cm. Thus the radio spectrum hardened considerably during the week of cometary impacts. Following the week of cometary impacts, the flux density began to subside at all wavelength.VLA images show the brightness distribution of the planet; a comparison of images taken before and during the week of impacts show marked changes in the brightness distribution. At a central meridian longitude λIII≈ 110°, the left side of the belts increased considerably and moved inwards by ~ 0.2 RJ. This suggests that the increase in flux density is caused by energization of the resident particle population.

scholarly journals FIRST DETECTION OF THERMAL RADIO EMISSION FROM SOLAR-TYPE STARS WITH THE KARL G. JANSKY VERY LARGE ARRAY

2014 ◽  
Vol 788 (2) ◽  
pp. 112 ◽  
Author(s):  
Jackie Villadsen ◽  
Gregg Hallinan ◽  
Stephen Bourke ◽  
Manuel Güdel ◽  
Michael Rupen
Keyword(s):  
Radio Emission ◽  
Large Array ◽  
Very Large Array ◽  
Thermal Radio ◽  
Thermal Radio Emission ◽  
Solar Type
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