scholarly journals Interim Report on the Texas Survey

1977 ◽  
Vol 74 ◽  
pp. 15-24
Author(s):  
James N. Douglas ◽  
Frank N. Bash
Keyword(s):  
Radio Astronomy ◽  
Time Scale ◽  
Astronomy Observatory ◽  
Interim Report ◽  
Optical Identification ◽  
University Of Texas ◽  
Optical Position ◽  
Reliable Source ◽  
The University

The University of Texas Radio Astronomy Observatory (UTRAO) is engaged in a survey of the entire sky north of −35° declination at various frequencies in the range 335-380 MHz. Primary goals are (i) determination of accurate (∼1″) positions for about 50,000 sources, followed by (ii) optical identification of the sources on the basis of exact radio-optical position coincidence; (iii) provision of rough structure models for all listed sources; and (iv) monitor the sky for variable sources on the time scale of 1 to 2 years. The survey is not expected to be a reliable source of absolute flux density information except for those sources known to be unresolved from other work.

scholarly journals Mm CO observation of the old nova NQ Vul

1990 ◽  
Vol 122 ◽  
pp. 199-199
Author(s):  
J. S. Albinson ◽  
A. Evans
Keyword(s):  
Interstellar Medium ◽  
Rotational Transition ◽  
Millimetre Wave ◽  
University Of Texas ◽  
Evolutionary Phase ◽  
Mass Estimate ◽  
The University ◽  
Nova Outbursts ◽  
Broad Feature

AbstractWe have observed the old nova NQ Vul in the J = 2 → 1 rotational transition of 12CO at 230.5 GHz at the University of Texas Millimetre Wave Observatory. The spectrum shows narrow features which clearly arise in the local interstellar medium. However these local features are superimposed on a broad feature which peaks at ~ 63 mK. This feature is centred on velocity VLSR ≃ 26 ± 9 km s−1–consistent with that expected for NQ Vul–and has FWHM 80 ± 20 km s−1. The peak antenna temperature corresponds to an integrated flux of 3.2 × 10−15 erg s−1 cm−2.Assuming LTE and a distance of 1.2 kpc the mass of CO is ~ 10−6M⊙ if the line is optically thin. The CO mass is comparable with the total mass ejected in 1976 (4) so the CO we detect at millimetre wavelengths has nothing to do with the 1976 outburst. If the CO/H ratio in the emitting material is similar to that in the interstellar medium (2), the total mass is ~ 0.6 M⊙.The CO mass rules out an origin both in the 1976 outburst and in the post-outburst phase: the CO must have originated in material ejected by the NQ Vul system prior to the 1976 outburst. There are two possibilities. First, the CO may have formed in material accumulated following a large number of nova outbursts. Second, the CO may have been present, or formed, in material ejected by the NQ Vul system during a previous evolutionary phase. The deduced mass is comparable to the mass of CO seen around planetary nebulae (3); the outflow velocity (~ 40 km s−1) would also be in line with this interpretation.In either case, the above mass estimate of 0.6 M⊙ (based on the interstellar CO/H ratio) is likely to be an upper limit as we would expect an enhancement of heavy elements in any ejected material. A determination of 12C/13C and other isotopic ratios would be valuable to pin down the origin of the CO.

scholarly journals The early technical development of the VLA

1991 ◽  
Vol 131 ◽  
pp. 160-164 ◽  
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.

scholarly journals Radio variability properties for sources at multi-frequencies

2007 ◽  
Vol 3 (S245) ◽  
pp. 251-252
Author(s):  
Y. Liu ◽  
J. H. Fan ◽  
H. G. Wang
Keyword(s):  
Time Series ◽  
Radio Astronomy ◽  
Power Spectral Analysis ◽  
Light Curves ◽  
University Of Michigan ◽  
Astronomy Observatory ◽  
Period Analysis ◽  
Radio Astronomy Observatory ◽  
Power Spectral ◽  
The University

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.

scholarly journals Brightness temperature for radio sources

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.

scholarly journals Some Recent Observations of Occultations by the Moon

1971 ◽  
Vol 2 ◽  
pp. 688-691
Author(s):  
Nathaniel M. White
Keyword(s):  
The Moon ◽  
University Of Texas ◽  
Double Stars ◽  
Stellar Diameters ◽  
Accurate Position ◽  
Diffraction Patterns ◽  
The University

A program for the measurement of diffraction patterns resulting from the lunar occultations of stars was begun at the Lowell Observatory by Rakos (1964), resumed by him in 1967 and continued by Pettauer through the summer of 1969. The expected results were accurate timing of occultations and hence accurate position measurements, the discovery of close double stars, and the determination of stellar diameters. The author is continuing the program using new equipment designed by R. E. Nather of the University of Texas.The equipment was built at the Lowell Observatory and put into operation on its new 42-in. reflector in March, 1970.

scholarly journals 30. Commission des Vitesses Radiales Stellaires

1936 ◽  
Vol 5 ◽  
pp. 188-196
Author(s):  
M. J. S. Plaskett ◽  
MM. Adams ◽  
Campbell ◽  
Frost ◽  
Guthnick ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Pacific Coast ◽  
Radial Velocities ◽  
University Of Michigan ◽  
University Of Texas ◽  
University Of Toronto ◽  
Visual Magnitude ◽  
Under Construction ◽  
The University

The three years that have elapsed since the Harvard meeting of the Union have witnessed steady progress in the determination of radial velocities. While the three large Pacific Coast Observatories have naturally been able to make the greatest additions to radial velocity work, the Yerkes Observatory, the Simeiz Observatory and the Observatory of the University of Michigan have also made valuable contributions. It is a pleasure to report that there will soon be three major accessions to the list of observatories capable of determining radial velocities. The David Dunlap Observatory of the University of Toronto with its 74-inch telescope, which should be in operation soon after the meeting, will have radial velocities as a prominent feature of its programme. The McDonald Observatory of the University of Texas with an 80-inch telescope now under construction should be ready to commence operations in 1936 and will undertake an extensive radial velocity programme. The Radcliffe Observatory at Oxford has now been granted permission by the Courts to remove to Pretoria, South Africa, and will establish there a 74-inch reflecting telescope, which will also be largely employed in the determination of the urgently needed radial velocities of the southern stars fainter than 5.5 visual magnitude. The Commission may, I believe, congratulate itself that substantial assistance in the preliminary steps leading to this permission of removal was provided by our action at the last meeting in presenting a resolution to the Union, duly passed by the General Assembly, pointing out the urgent need for additional radial velocities in the southern sky, and strongly supporting the project of the Radcliffe Observatory to establish a large telescope at Pretoria.

Observations at the Mullard Radio Astronomy Observatory, Cambridge

1958 ◽  
Vol 248 (1252) ◽  
pp. 3-9 ◽  
Keyword(s):  
Radio Astronomy ◽  
Doppler Shift ◽  
Second Harmonic ◽  
Astronomy Observatory ◽  
Cavendish Laboratory ◽  
Radio Astronomy Observatory ◽  
Satellite Transmission ◽  
To Receive ◽  
Radio Stars

When the news of the launching of the first satellite was received at Cambridge, we were not aware of any plans for radio observations in this country. Such observa­tions seemed likely to be important: ( a ) In order to provide approximate information on the orbit so that accurate visual and radar observations might be made. ( b ) Because the presence of a transmitter at varying heights and zenith angles offered possibilities for ionospheric investigation. We therefore planned a series of observations which eventually engaged most of the radio astronomy group, and a large part of the ionosphere group of the Cavendish Laboratory. The first observations were aimed at the determination of an approximate orbit, and an interferometer normally used for observing radio stars at a frequency of 38 Mc/s was modified to receive the 40 Mc/s satellite transmission. This instrument was in operation on the night of 5 to 6 October, and a 40 Mc/s receiver for measuring the Doppler shift was installed the following day. A 20 Mc/s interferometer was added for ionospheric investigation, and receivers for measuring the apparent changes of intensity were later installed for 20, 40 and 80 Mc/s, the last being used on the second harmonic of the 40 Mc/s transmitter.

scholarly journals ΙΣΤΟΡΙΑ, ΦΙΛΟΣΟΦΙΑ ΚΑΙ ΕΦΑΡΜΟΓΗ ΤΩΝ ΠΑΓΚΟΣΜΙΩΝ ΣΤΡΩΜΑΤΟΤΥΠΩΝ ΚΑΙ ΤΩΝ ΑΠΟΛΥΤΩΝ ΟΡΙΩΝ. ΠΡΟΣΦΑΤΕΣ ΑΝΑΟΕΩΡΗΣΕΙΣ ΤΗΣ ΓΕΩΛΟΓΙΚΗΣ ΧΡΟΝΙΚΗΣ ΚΛΙΜΑΚΑΣ

2006 ◽  
Vol 39 (1) ◽  
pp. 28
Author(s):  
Μ. Δ. Δερμιτζάκης
Keyword(s):  
Time Scale ◽  
Global Scale ◽  
Quality Of Data ◽  
Geological Time ◽  
Geological Time Scale ◽  
New Methods ◽  
Science Community ◽  
University Of Oslo ◽  
The University

In the last 150 years, the limits of the so called "formal" geochronological/ chronostratigraphical units were determined by several rock researchers using geohistorical events in several ways. The lack of standardisation made them useless for a global scale correlation. During the last two decades, the development of the field and laboratories techniques, the studies of radiogenic and stable isotopes, the improved evaluation of fossil files, the evaluation of paleomagnetic data and the application of cyclostratigraphy, improved the quality of data and contributed to the creation of the most upto-date International Chronostratigraphic Scale, including new subdivisions and determination of the boundaries of geological periods. The compiled New Geological Time Scale GTS 2004 integrates the most recent results of these new methods and was constructed by the International Union of Stratigraphy (ICS), in 2004, presiding F.M. Gradstein, from the University of Oslo, along with 38 other specialists. The new revised Geological Scale encompasses selected new methods that provide the most reliable information. The last Geological Time Scale incorporates important changes and is based on the application of the Global boundary Stratotype Section and Point (GSSP). Almost 50 GSSP have been defined up to now. Despite the enormous efforts for the construction of the most complete Geological Time Scale, a modified version needs the support and consent of the entire geological science community.

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