Российский фонд
фундаментальных
исследований

Физический факультет
МГУ им. М.В.Ломоносова
 

I

Isaeva E.A.

 

Isaeva E.A., Lytvynenko O.A., Shepelev V.A. «Software for adapting DSPZ receivers to the URAN interferometer network» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 30, с. 219-221 (2017)

DOI: https://doi.org/10.18524/1810-4215.2017.30.115456 More than 10 years ago, URAN interferometer network (Megn A.V.,1997; Konovalenko A.A., 2014) had been equipped with newly designed receivers with a pass band extended up to 250 kHz and software rejection of interferences (Rashkovskii, 2012). The broadening of bandwidth of received signal increase the sensitivity of the receivers significantly and let us to investigate the angular structure about one hundred radio sources. A software package had been developed that allows: preparing a program of observations, carrying out observations automatically, making data cross-correlation, calculating visibility functions for all pairs of antennae, and fitting models of an angular structure of the sources. Data storage formats were elaborated for each stage of recording or processing. At present, new digital radio astronomy receiver DSPZ have been developed by IRA NASU (Zakharenko, 2016). The receiver allows recording an entire bandwidth of signals of a decameter range from 8 to 32 MHz. It is used at UTR-2 and URAN radio telescopes operated in a single dish mode. Application of the receivers for interferometer observation with the URAN network provides additional advantages in accuracy and sensitivity of studies. In this report we consider the data formats and synchronization methods used in URAN equipment and DSPZ receivers, and discuss algorithms of their transformation. Newly elaborated software is described, that allows selecting a set of frequency bands of signals recorded with DSPZ and converting them to the form used by the URAN software. This approach allows us to carry out the interferometer observations in an the extended frequency range provided by DSPZ and to use as much as possible the software package developed for the URAN network for data reduction.

Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 30, с. 219-221 (2017) | Рубрика: 18

Isaeva E.A., Tsap Yu.T. «Microwave emission of solar flares: coronal mass ejections and shock waves» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 30, с. 222-225 (2017)

DOI: https://doi.org/10.18524/1810-4215.2017.30.114670 Coronal mass ejections (CMEs) mostly affect the geomagnetic field. These structures are observed and studied with coronagraphic images therefore we don’t see the corona in the plane of the sky and the measurements of the propagation speed for solar disk events are not accessible to coronagraphic observations. This suggests that microwave emission of solar flares that can be attributed to the gyrosynchrotron mechanism of mildly relativistic electrons can be used. In turn, the relationship between coronal shock waves and CMEs also remains unclear. The data set that we use in this study is based on microwave (μ) observations of spectral fluxes Fμ at 8.8 GHz obtained with the Radio Solar Telescope Network for the 124 proton solar events . The correlation coefficient r between the CME velocities VCME and integral fluxes of microwave emission ∫Fμdt achieves of about 0.8 while it does not exceed 0.36 between VCME and the shock wave velocities. It has been found the quite strong correlation between the growth rate of microwave emission and the deceleration of frequency drift in the frequency range of 25–180 GHz (r≈0.66). The obtained results suggest that microwave observation can be used to predict VCME and the shock wave generation occurs in the region of flare energy release.

Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 30, с. 222-225 (2017) | Рубрика: 18

Ismailov N.Z.

 

Ismailov N.Z., Adigezalzade A.N., Bashirova U.Z. «Circustellar matter activity in AE/BE Herbig star MWC 614» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 30, с. 78-84 (2017)

DOI: https://doi.org/10.18524/1810-4215.2017.30.117155 The results of spectral observations of the Herbig Ae/Be type star HD 179218 are presented. Two wave-like cycles of variability in the parameters of hydrogen lines Hα and Hβ with a characteristic time of ∼40 days are revealed. The first wave of variations is deeper; the branches of decreasing and increasing the spectral parameters of the lines are more clearly expressed. At the time of the first minimum, in the profile of the emission line Hα the appearance and disappearance of additional blue and red emission components are observed. At the same time, narrow absorption components were discovered in the Hβ line. Possible mechanisms of the observed variability of the star are discussed.

Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 30, с. 78-84 (2017) | Рубрика: 18