Frequency-dependent time-delays for strong outbursts in selected blazars from the Metsähovi and the University of Michigan Radio Astronomy Observatory monitoring databases – I.

AbstractUsing three radio databases of the university of Michigan Radio Astronomy Observatory (UMRAO), the National Radio Astronomy Observatory (NRAO), and the Metsähovi Observatory, we analyzed the radio light curves by the power spectral analysis and CLEANest method in search for possible periodicity. Multiple periods are found in some sources at multi-frequencies. We adopted the wavelets for period analysis of unevenly sampled time series to search for the evolution of the parameters (period, amplitude) of possible periodicities. Some possible variation of these parameters are found.

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Brightness temperature for radio sources

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308017791 ◽

2007 ◽

Vol 3 (S245) ◽

pp. 245-246

Author(s):

J. H. Fan ◽

Y. Huang ◽

Y. Liu ◽

Y. Gao ◽

T. X. Hua ◽

...

Keyword(s):

Brightness Temperature ◽

Radio Astronomy ◽

Radio Sources ◽

University Of Michigan ◽

Astronomy Observatory ◽

Radio Astronomy Observatory ◽

Brightness Temperatures ◽

The University

AbstractIn this work, using the database of the university of Michigan Radio Astronomy Observatory (UMRAO), we determined the brightness temperatures, TB for a sample of 167 radio sources. The value of TB is in a range of log TB(K) = 10.46 to 20.08, which suggested that the boosting factors are in a range of δ = 0.41 to 41.26.

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The early technical development of the VLA

International Astronomical Union Colloquium ◽

10.1017/s0252921100013233 ◽

1991 ◽

Vol 131 ◽

pp. 160-164 ◽

Cited By ~ 2

Author(s):

George W. Swenson

Keyword(s):

Radio Astronomy ◽

Technical Development ◽

Large Array ◽

Astronomy Observatory ◽

University Of Illinois ◽

Very Large Array ◽

Radio Astronomy Observatory ◽

Leave Of Absence ◽

The University ◽

Academic Year

In the spring of 1964, having qualified for a sabbattical leave from the University of Illinois and having recently completed two years as Chairman of the Visiting Committee of the National Radio Astronomy Observatory, I inquired of the NRAO staff as to whether a desk and possibly some augmentation of my University half-salary might be available at Green Bank for the following academic year. Instead I was invited to join the staff as a fulltime employee and to take a coordinating role in the development of the “very large array” as Chairman of the Design Committee. The University granted me a year’s leave of absence which eventually stretched to four years.

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Observations of Some Radio Sources Previously Identified with Clusters of Galaxies

Australian Journal of Physics ◽

10.1071/ph670725 ◽

1967 ◽

Vol 20 (6) ◽

pp. 725

Author(s):

HM Tovmassian ◽

IG Moiseev

Keyword(s):

Radio Telescope ◽

Radio Astronomy ◽

Astronomical Observatory ◽

Radio Sources ◽

Clusters Of Galaxies ◽

Astronomy Observatory ◽

Radio Astronomy Observatory ◽

The University ◽

East West

The positions of 33 radio sources previously identified with distant clusters of galaxies were remeasured more accurately to check the identifications. Observations were made at 1410 and 2650 MHz with the 210 ft radio telescope of the Australian National Radio Astronomy Observatory at Parkes, and at 408 MHz with the east-west arm of the Mills Cross at the Molonglo Radio Astronomical Observatory of the University of Sydney. It was found that 21 sources are situated within 5 min of arc of the centres of the corresponding clusters.

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Design, environmental and sustainability constraints of new African observatories: The example of the Mozambique Radio Astronomy Observatory

2013 Africon ◽

10.1109/afrcon.2013.6757829 ◽

2013 ◽

Author(s):

Domingos Barbosa ◽

Miguel Bergano ◽

Valerio A. R. M. Ribeiro ◽

Anita Loots ◽

Venkatasubramani L. Thondikulam ◽

...

Keyword(s):

Radio Astronomy ◽

Astronomy Observatory ◽

Radio Astronomy Observatory

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On the peculiarities in the spin-down of isolated radio pulsars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312023666 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 208-208

Author(s):

Augustine Chukwude

Keyword(s):

Radio Astronomy ◽

Time Resolution ◽

Local Phase ◽

Astronomy Observatory ◽

Radio Pulsars ◽

Short Term ◽

Radio Astronomy Observatory ◽

Long Term Changes ◽

Timing Data

AbstractWe investigate the spin-down behaviour of a sample of 25 radio pulsars on decadal timescales (~ 18 years) using a continuous timing data obtained over a period of at Hartebeesthoek Radio Astronomy Observatory (HartRAO). Particular attention is placed on achieving a better time resolution of both the short-term and long-term changes in pulsar spin-down using local phase-coherent measurements of the spin-down rates (). We demonstrate that the spin-down of radio pulsars is generally complicated by a superposition of processes that may or may not be related. Specifically, our results show that (i) for 7 pulsars, the observed spin-down variation is largely stochastic, characterized by random and sustained jumps in of varying amplitudes, (ii) for 9 objects, the spin-down evolution shows dominant monotonic variations in superimposed on short-term stochastic jumps in the parameter, and (iii) for the remaining 9 pulsars, the long-term spin-down evolution is non-monotonic, dominated by some systematic excursion in the measured spin-down rates.

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