Structure of the suprrnova remnant 3C 58 and its neighborhood

Institute of Radio Physics and Electronics, Armenian Academy of Sciences; Scientific Research Institute of Radio Physics and Physics of the Ionosphere, Gor'kii. Translated from Astrofizika, Vol. 30, No. 3, pp. 470–475, May–June, 1989.     

Properties of OH megamaser galaxies in the radio continuum. I. Observational data

Radio observations with the VLA-A radio telescope of 30 OH megamaser galaxies at a frequency of 1.49 GHz are discussed. Radio emission was detected from all 30 of these galaxies. Radio emission was detected from 5 of the 30 objects for the first time. Important results were obtained for 12 galaxies that had previously been little studied in the radio continuum. Additional data at 1.49 GHz were obtained for the remaining 13 objects. The core component of the continuum radio emission predominates in the OH megamaser galaxies.Translated from Astrofizika, Vol. 48, No. 1, pp. 125–138 (February 2005).     

Rfi Mitigation And The Ska

Radio frequency interference (RFI) has plagued radio astronomy from its inception. The Workshop on the Mitigation of Radio Frequency Interference in Radio Astronomy (RFI2004) was held in Penticton, BC, Canada in July 2004 in order to consider the prognosis for the RFI problem, in particular as it impacts the planned Square Kilometre Array (SKA). This paper concludes that RFI is unlikely to be a “showstopper” in achieving SKA science goals, but that improved RFI mitigation technology may nevertheless be essential in order to take advantage of the vastly improved sensitivity, bandwidth, and field of view. Reported results provide some optimism that the desired improvements in RFI mitigation technology are possible, but indicate that much more work is required.     

The Soviet CETI program

In March 1974 the Board of the Scientific Council on the Radio Astronomy Problem Area, Academy of Sciences of the USSR, considered and approved a Research Program on the Problem of Communication with Extraterrestrial Civilizations. The Program was developed by the Search for Cosmic Signals of Artificial Origin section of the Council on Radio Astronomy, on the basis of recommendations made at the Soviet National Conference on the Problem of Comunication with Extraterrestrial Civilizations held at the Byurakan Astrophysical Observatory in Armenia in May 1964, and the Soviet-American CETI conference held at Byurakan in September 1971. The projected program was reported to the 7th Soviet National Conference on Radio Astronomy, which convened at Gor'kii in 1972.     

Initial results from the Madurai solar radio spectrograph

A new digital radio spectrograph, the Madurai Solar Radio Spectrograph (MSRS), has been constructed at Madurai Kamaraj University, Madurai, India, and is being operated at the Radio Astronomy Centre, Ooty in southern India to observe solar bursts in the frequency range 30–80 MHz. The operation of the new instrument is briefly described. Observations of solar bursts by this instrument and the results from the preliminary analysis are presented.     

Study of Flare Energy Release Using Events with Numerous Type III-like Bursts in Microwaves

The analysis of narrowband drifting of type III-like structures in radio bursts dynamic spectra allows one to obtain unique information about the primary energy release mechanisms in solar flares. The SSRT (Siberian Solar Radio Telescope) spatially resolved images and its high spectral and temporal resolution allow for direct determination not only of the source positions but also of the exciter velocities along the flare loop. Practically, such measurements are possible during some special time intervals when SSRT is observing the flare region in two high-order fringes near 5.7?GHz; thus, two 1D brightness distributions are recorded simultaneously at two frequency bands. The analysis of type III-like bursts recorded during the flare 14?April 2002 is presented. Using multiwavelength radio observations recorded by the SSRT, the Huairou Solar Broadband Radio Spectrometer (SBRS), the Nobeyama Radio Polarimeters (NoRP), and the Radio Solar Telescope Network (RSTN), we study an event with series of several tens of drifting microwave pulses with drift rates in the range from ?7 to 13?GHz?s^?1. The sources of the fast-drifting bursts were located near the top of a flare loop in a volume of a few Mm in size. The slow drift of the exciters along the flare loop suggests a high pitch anisotropy of the emitting electrons.     

BL Lac objects and acceleration model

In this paper, the acceleration model is applied to data from RBLs (Radio Selected BL Lac objects). The corrected data from RBLs are found to be nearly the same as those from XBLs (X-Ray Selected BL Lac objects), the expected result, that points ofU - B, B - V of XBLs and RBLs occupy the same region in the (B - V)-(U - B) diagram has been obtained, and the Radio Doppler factors obtained by us are highly consistent with those found by others.     

Observations of bright coronal points at wavelengths of 5.2 and 1.76 cm

Based on two-dimensional solar images obtained with the Siberian Solar Radio Telescope and the Nobeyama Radio Heliograph and using YOHKOH soft X-ray images, we investigate bright coronal points. The principal microwave emission mechanism of these points is shown to be the thermal bremsstrahlung of an optically thin plasma. The fact that, in several cases, bright coronal points do not coincide at two wavelengths can be explained by imaging peculiarities of the Nobeyama Radio Heliograph rather than by physical factors.     

Observations of the quiet Sun at meter and decameter wavelengths

The new TeePee Tee array of the Clark Lake Radio Observatory has been used to observe the quiet Sun at 121.5, 73.8 and 26.3 MHz. The equatorial brightness distributions at all three frequencies, and the polar brightness distributions at the two higher ones have been measured. From the observed total fluxes and half-power diameters we have derived the peak brightness temperatures of the solar disk as well as of some sources of the slowly varying component.On leave of absence from Instituto Argentino de Radioastronomía, Argentina.     

Gauribidanur Low-Frequency Solar Spectrograph

A new radio spectrograph, dedicated to observe the Sun, has been recently commissioned by the Indian Institute of Astrophysics (IIA) at the Gauribidanur Radio Observatory, about 100 km North of Bangalore. The instrument, called the Gauribidanur Low-frequency Solar Spectrograph (GLOSS), operates in the frequency range≈40?–?440 MHz. Radio emission in this frequency range originates close to the Sun, typically in the radial distance range r≈1.1?–?2.0 R_⊙. This article describes the characteristics of the GLOSS and the first results.     

Development of an Automatic Echo-counting Program for HROFFT Spectrograms

Radio meteor observations by Ham-band beacon or FM radio broadcasts using “Ham-band Radio meteor Observation Fast Fourier Transform” (HROFFT) an automatic operating software have been performed widely in recent days. Previously, counting of meteor echoes on the spectrograms of radio meteor observation was performed manually by observers. In the present paper, we introduce an automatic meteor echo counting software application. Although output images of the HROFFT contain both the features of meteor echoes and those of various types of noises, a newly developed image processing technique has been applied, resulting in software that enables a useful auto-counting tool. There exists a slight error in the processing on spectrograms when the observation site is affected by many disturbing noises. Nevertheless, comparison between software and manual counting revealed an agreement of almost 90%. Therefore, we can easily obtain a dataset of detection time, duration time, signal strength, and Doppler shift of each meteor echo from the HROFFT spectrograms. Using this software, statistical analyses of meteor activities is based on the results obtained at many Ham-band Radio meteor Observation (HRO) sites throughout the world, resulting in a very useful “standard” for monitoring meteor stream activities in real time.     

HI absorption observations of two radio sources near the supernova remnant G 127.1 + 0.5

The compact source 0125 + 628 in the centre of the galactic supernova remnant G 127.1 + 0.5 has been re-observed in HI absorption using the Westerbork Synthesis Radio Telescope (WSRT). The outer arm HI absorption atV = -95km s^-1 has been confirmed. The absorption spectrum is similar to that of the nearby extragalactic source 0123 + 633. We discuss the arguments concerning an extragalactic origin of 0125 + 628 and conclude that it is most likely extragalactic and not an SS 433 type object. The National Radio Astronomy Observatory is operated by Associated Universities Inc. under contract with the National Science Foundation.     

Deep low-frequency observations with the Giant Metrewave Radio Telescope: a search for relic radio emission

We present deep multifrequency observations using the Giant Metrewave Radio Telescope (GMRT) at 153, 244, 610 and 1260 MHz of a field centred on J0916+6348, to search for evidence of fossil radio lobes which could be due to an earlier cycle of episodic activity of the parent galaxy, as well as haloes and relics in clusters of galaxies. We do not find any unambiguous evidence of episodic activity in a list of 374 sources, suggesting that such activity is rare even in relatively deep low-frequency observations. We examine the spectra of all the sources by combining our observations with those from the Westerbork Northern Sky Survey (WENSS), NRAO (National Radio Astronomy Observatories) VLA (Very Large Array) Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty-Centimeters Survey (FIRST). Considering only those which have measurements at a minimum of three different frequencies, we find that almost all sources are consistent with a straight spectrum with a median spectral index,  α∼ 0.8 [S(ν) ∝ν^−α  ], which appears steeper than theoretical expectations of the injection spectral index. We identify 14 very steep-spectrum sources with  α≥ 1.3  . We examine their optical fields and discuss the nature of some of these sources.     

Absolute calibration of solar radio flux density in the microwave region

The absolute calibration of solar radio flux density in the microwave region, which showed considerable discrepancies until 1966, has become completely uniform through international cooperative work. A complete history is described to avoid confusion, and correction factors are derived to convert the published values into absolute values for long series of routine observations. It is also shown that the most reliable calibration can be made by using a large pyramidal horn and by using sky and room temperature as calibration standards.Abbreviation of Stations for Table II, Figures 2 and 3 BERL Heinrich-Hertz-Institut, Berlin Adlershof - BORD The Observatory, the University of Bordeaux - GORK Radiophysical Research Institute, Gorky - HIRA Hiraiso Radio Observatory - HUAN Geophysical Institute of Peru, Huancayo - IRKU Irkutsk Radioastronomical Observatory - KIEL Radio Observatory, Kiel University - Radio Observatory, Kiel University - KSLV Kislovodsk Radioastronomical Observatory - MANI Manila Observatory - ONDR Ondejov Observatory - OTTA National Research Council, Ottawa - PENT Dominion Radioastronomical Observatory, Penticton - SANM Observatory of Cosmic Physics, San Miguel - SAOP Mackenzie University, Sao Paulo - SGMR Sagamore Hill Radio Observatory - SYDN University of Sydney - TOKO Tokyo Astronomical Observatory - TYKW Toyokawa Observatory, Nagoya University - UCCL Belgian Royal Observatory, Uccle     

Optical and infrared variability of the object AFGL 2881 and its neighboring red star

Radio Astrophysical Observatory, Latvian Academy of Sciences; Leningrad State University. Translated from Astrofizika, Vol. 28, No. 3, pp. 586–594, May–June, 1988.     

Deep 610-MHz Giant Metrewave Radio Telescope observations of the Spitzer extragalactic First Look Survey field – I. Observations, data analysis and source catalogue

Observations of the Spitzer extragalactic First Look Survey field taken at 610 MHz with the Giant Metrewave Radio Telescope are presented. Seven individual pointings were observed, covering a total area of ∼4 deg² with a resolution of 5.8 × 4.7 arcsec², PA 60°. The rms noise at the centre of the pointings is between 27 and 30 μJy before correction for the Giant Metrewave Radio Telescope (GMRT) primary beam. The techniques used for data reduction and production of a mosaicked image of the region are described, and the final mosaic, along with a catalogue of 3944 sources detected above ∼5σ, are presented. The survey complements existing radio and infrared data available for this region.     

L-band RFI Measurement and Mitigation at the NSRT Site

近些年,南山台址内部各类电子设备不断引入,此过程忽视了有效的设备管理及电磁防护,且台址周边无线电业务增多,以致电波环境恶化。为改善台址电波环境,采用一种准实时电波环境测量方法测量分析了台址周边瞬态信号的影响;另外,为提高微弱信号检测能力,采用便携式电磁干扰测量系统和26m射电望远镜对台址主要干扰信号特征及来源进行测量分析。依据测量和分析结果,采用屏蔽及滤波技术对望远镜观测室内部主要干扰源进行电磁防护,并针对屏蔽工程的有效性进行测量评估,结果表明,采用的电磁屏蔽措施有效。另外,提出了初步南山无线电宁静区保护办法缓解台址外部电磁干扰。     

The polarization-redshift relation in radio galaxies

We analyze the properties of a sample of optically polarized radio galaxies with a wide range of redshifts. The galaxies were selected both from our survey and from the literature. The aim of this work is checking whether high linear polarization is a general property of high redshift radio galaxies and how it depends on redshift. This provides a critical test on the suggestion that a considerable fraction of rest frame UV light in high redshift radio galaxies is scattered nuclear radiation. Our results show that radio galaxies withz > 0.7 are strongly polarized and that there is a strong dependence of the degree of linear polarization on the redshift. We discuss the possible origin of this correlation. Our results provide support to the validity of the Radio Quasar and Radio Galaxies unifying schemes.     

Results of a long-term monitoring of the 1.35-cm water-vapor maser source ON 1 (1981–2013)

We present the results of our long-term monitoring of the 1.35-cm water-vapor maser source ON 1 performed at the 22-m radio telescope of the Pushchino Radio Astronomy Observatory from 1981 to 2013. Maser emissionwas observed in a wide range of radial velocities, from ?60 to +60 km s^?1. Variability of the integrated flux with a period of ～9 years was detected. We show that the stable emission at radial velocities of 10.3, 14.7, and 16.5 km s^?1 belongs to compact structures that are composed of maser spots with close radial velocities and that are members of two water-maser clusters, WMC 1 and WMC 2. The detected short-lived emission features in the velocity ranges from ?30 to 0 and from 35 to 40 km s^?1 as well as the high-velocity ones are most likely associated with a bipolar molecular outflow observed in the CO line.