scholarly journals The Sgr B2 Region Seen at 43 GHZ

1987 ◽  
Vol 115 ◽  
pp. 158-160
Author(s):  
Hisashi Hirabayashi ◽  
Kenji Akabane ◽  
Masaki Morimoto ◽  
Yosiaki Sofue ◽  
Makato Inoue ◽  
...  
Keyword(s):  
Flux Density ◽  
Noise Temperature ◽  
Central Frequency ◽  
Radio Observatory ◽  
System Noise ◽  
Ngc 7027 ◽  
Pointing Accuracy ◽  
Half Power ◽  
5 Ghz ◽  
Better Than

The Sgr B2 region was mapped at 43 GHz (λ = 6.9 mm) with the 45m radio telescope of Nobeyama Radio Observatory. The observing parameters were: a) half power beamwidth 38″, b) pointing accuracy better than 10″, c) central frequency 43.0 GHz, d) bandwidth 500 MHz, and e) system noise temperature 400 K; and the observational aspects were: a) mapping with one polarization, b) liquid-nitrogen cooled load switching and c) reduction by NOD-2 programme. The obtained map is shown in Figure 1. Sgr B2 is resolved into several components which correspond to those by Martin and Downes (1972) and Downes et al. (1978). But the component at RA = 17h44m11.8s Dec. = −28°23′55″ at 1950 is not seen in Martin and Downes (1972) nor in the 5 GHz map of Downes et al. (1978), although the feature is seen in the 10.7 GHz map of Downes et al. (1978). The components derived from the map in Figure 1 by a morphological estimate are listed in Table 1. The total flux density of the region is 146J±30 Jy. The intensity calibration was made by observing NGC 7027.

scholarly journals A 10-GHZ Radio Continuum Survey of the Galactic Plane

1987 ◽  
Vol 115 ◽  
pp. 538-539
Author(s):  
T. Handa ◽  
Y. Sofue ◽  
N. Nakai ◽  
H. Hirabayashi ◽  
K. Akabane ◽  
...  
Keyword(s):  
Galactic Plane ◽  
Noise Temperature ◽  
Radio Continuum ◽  
Beam Size ◽  
Calibration Source ◽  
Polarization Component ◽  
Radio Observatory ◽  
System Noise ◽  
Ngc 7027 ◽  
5 Ghz

A radio continuum survey of the galactic plane has been made with the 45-m telescope of the Nobeyama Radio Observatory at 10.55 GHz, which is the highest frequency among such surveys. The sensitivity of the telescope was Tb/S = 0.47 K/Jy and the HPBW was 2!6, which was a great advantage because of the same beam size of the Bonn 5-GHz survey (Altenhoff et al. 1978). The receiver was a cooled parametric amplifier. The instantaneous bandwidth was 500 MHz, and the system noise temperature was about 100 K. The calibration source was NGC 7027, which was assumed to be 6.6 Jy. One circular polarization component was observed. The observational parameters are summarized in Table I.

scholarly journals Radio observations of O-type stars

1981 ◽  
Vol 59 ◽  
pp. 179-180
Author(s):  
M. Felli ◽  
N. Panagia
Keyword(s):  
New Mexico ◽  
Flux Density ◽  
Radio Astronomy ◽  
Noise Level ◽  
National Science Foundation ◽  
Astronomy Observatory ◽  
Upper Limits ◽  
National Science ◽  
5 Ghz ◽  
Better Than

Eight O-type giants and supergiants, selected for being relatively isolated in the sky, have been observed at 5 GHz with 17 antennae of the partially completed VLA (NRAO, Socorro, New Mexico: The National Radio Astronomy Observatory is operated by Associated Universities under contract with the National Science Foundation) on October 7 and 8, 1979. The integration times ranged between 38 and 187 minutes. The results are displayed in Table 1. Most of the stars (6 out of 8) were not detected. The upper limits given in Table 1 for these stars correspond to the 3σ noise level. Possible detection has been achieved for the two supergiants HD 225160 and HD 30614 both with a flux density of 0.15 mJy. Although this flux is equal to the 3a noise level, the detections can be considered to be real because 1) Excellent positional coincidence is found between stars and the radio peaks (better than 1”) 2) The observed source pattern corresponds very well to the expected response to a point-like source.

The New Wuqing 70 m Radio Telescope and Measurements of Main Electronic Properties in X-band

2022 ◽  
Author(s):  
De-Qing Kong ◽  
Chunlai Li ◽  
Hongbo Zhang ◽  
Yan Su ◽  
Jian-Jun Liu ◽  
...  
Keyword(s):  
Flux Density ◽  
Radio Telescope ◽  
Noise Temperature ◽  
Calibration Model ◽  
Space Communications ◽  
Condi Tions ◽  
X Band ◽  
Measurement Results ◽  
Pointing Accuracy ◽  
Exploration Mission

Abstract The new Wuqing 70 m radio telescope is firstly used for the downlink data reception in the first Mars exploration mission of China, and will be used for the other deep space communications and radio astronomical observations in the future. The main specifications and measurement results of some properties in X-band are introduced in this paper, such as pointing calibration, gain and efficiency, system noise temperature, system equivalent flux density, and variations with elevation. The 23 parameters pointing calibration model considering the atmospheric refraction correction in real time is presented in the telescope, and the pointing accuracy is reached 5.70″ in azimuth direction and 6.07″ in elevation direction respectively for different weather condi-tions. More than 62% efficiencies are achieved at full elevation range, and more than 70% in the mid-elevation. The system equivalent flux density of X-band in the mid-elevation is reached 26 Jy.

scholarly journals A Southern Hemisphere Survey of the Galactic Plane at 5 GHz

1978 ◽  
Vol 31 (4) ◽  
pp. 351
Author(s):  
RF Haynes ◽  
JL Caswell ◽  
LWJ Simons
Keyword(s):  
Detection Limit ◽  
Southern Hemisphere ◽  
Galactic Plane ◽  
Point Sources ◽  
Half Power ◽  
5 Ghz ◽  
Better Than

Seventy five maps are presented showing the 5 GHz emission from the galactic plane in the range I = 190� ~ 360� .... 40� for - 2� < b < 2� (an area of approximately 600 square egrees). The method of observing and the computer reduction of the data are discussed. the telescope resolution is 4'�1 arc to half-power points and the detection limit for point sources is better than 0�5 Jy.

22 GHz Observations with the Resurfaced Central 17 m of the Parkes Radio Telescope

1976 ◽  
Vol 3 (1) ◽  
pp. 61-63 ◽  
Author(s):  
J. L. Caswell ◽  
R. A. Batchelor ◽  
W. M. Goss ◽  
R. F. Haynes ◽  
S. H. Knowles ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Radio Telescope ◽  
Noise Temperature ◽  
Parametric Amplifier ◽  
Total System ◽  
High Frequencies ◽  
Second Stage ◽  
System Noise ◽  
Front End ◽  
5 Ghz

At the centre of the Parkes 64—m radio telescope a region of diameter 17 m has recently been resurfaced to improve its efficiency at high frequencies. The first measurements using this section have been made at 22 GHz, in observations of both continuum sources and water tfapour masers. For these observations the receiver front-end used a mixer cooled in liquid nitrogen, followed by a 5 GHz cryogenic parametric amplifier as a second stage. The option of switching against an offset horn was available and the total system noise temperature was ∽ 750 K.

scholarly journals High Spatial Resolution Studies of H13CN, H12CN and HCO+ J = 1-0 Emissions in Orion A

1980 ◽  
Vol 87 ◽  
pp. 39-40 ◽  
Author(s):  
O.E.H. Rydbeck ◽  
Å. Hjalmarson ◽  
G. Rydbeck ◽  
J. Elldér ◽  
A. Sume ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Spatial Resolution ◽  
Molecular Cloud ◽  
Room Temperature ◽  
High Spatial Resolution ◽  
Beam Width ◽  
Main Beam ◽  
Pointing Accuracy ◽  
Half Power ◽  
Better Than

The distributions of the H13CN, H12CN and H12CO+ J =1-0 lines have been mapped with 20″ spacing towards the Orion A molecular cloud using the new Onsala 20 m millimeter wave telescope equipped with a room temperature mixer. The aperture and main beam efficiencies are about 49 and 65% and the half power beam width is ∼ 43″. The absolute pointing accuracy is estimated to be better than 5″ rms in the Orion elevation range.

Time Variation of the Radio Emission from Sco X-1

1969 ◽  
Vol 1 (5) ◽  
pp. 237-240 ◽  
Author(s):  
J. G. Ables
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Time Variation ◽  
Radio Observatory ◽  
Half Power

The radio object associated with Sco X—1 noted by Andrew and Purton has been observed at a wavelength of 6 cm with the 210 ft radio telescope at the Australian National Radio Observatory, Parkes. At this wavelength the half-power antenna beamwidth is 4′ arc.

scholarly journals A New 21-cm Line Survey of the LMC

1984 ◽  
Vol 108 ◽  
pp. 395-396
Author(s):  
K. Rohlfs ◽  
J. Kreitschmann ◽  
J. V. Feitzinger
Keyword(s):  
Noise Temperature ◽  
Beam Width ◽  
Main Beam ◽  
Corrugated Waveguide ◽  
Line Survey ◽  
Single Polarization ◽  
Switching Mode ◽  
Half Power ◽  
Channel Separation ◽  
Made In

The measurements were made in Feb. 1982 with the Parkes 64 m telescope using a corrugated waveguide horn with total half-power beam width of 15′, the first sidelobes being 19 dB down, resulting in an aperture efficiency ηA=0.53±0.007, a main beam efficiency of ηmb=0.80±0.005 and a ratio of source flux to antenna temperature of Γ=0.62±0.1 K/Jy (Murray, priv. comm.). A cooled two channel FET frontend used in the frequency switching mode with Δν = 2 MHz resulted in a system noise temperature at zenith of Tsyst = 40 K for one channel and Tsyst = 50 K for the other. Each frontend channel received a single polarization mode, and this radiation was then further analysed in a 2 × 512 channel autocorrelation spectrometer set at a channel separation of 3.906 KHz corresponding to a velocity resolution of V = 0.824 km s−1. Hanning smoothed this resulted in a σT = 0.05 K for the average of both polarization.

scholarly journals The Evolution and Distance to SCORPIUS X-1

1998 ◽  
Vol 164 ◽  
pp. 339-340
Author(s):  
E. B. Fomalont ◽  
C. F. Bradshaw ◽  
B. J. Geldzahler
Keyword(s):  
Flux Density ◽  
X Ray ◽  
The Third ◽  
Trigonometric Parallax ◽  
Relative Luminosity ◽  
5 Ghz ◽  
Eddington Limit

AbstractFrom three VLBA observations at 5 GHz, spanning 13 months, we have measured the trigonometric parallax of Sco X-1 of 0.23 ± 0.28 mas; hence its distance is > 1300 pc. This supports the hypothesis that the the x-ray luminosity is near the Eddington Limit.All three VLBA observations show a radio core of flux density 0.5 mJy and size < 4 mas. However, the third VLBA observation revealed two additional radio components, separated by 12 mas (≈ 20 au) on opposite sides of the radio core. The evolution of these new components is unknown until additional observations can be made. The relative luminosity and separation of the two radio components are inconsistent with the Doppler beaming of two identical ejecta from the radio core.

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