arXiv subjects

M. A. Kitaeva

Publications and source records attributed to M. A. Kitaeva.

At least 19 recordsLinked to original sources

arXiv2026

Pushchino Multibeam Pulsar Search. X. Observations of pulsars at declinations above $+53^o$

A search for pulsars was carried out using a Large Phased Array (LPA) radio telescope at a frequency of 110.4 MHz with a time resolution of 3.072 ms and a frequency resolution of 19.5 kHz with a 2.5 MHz bandwidth used. The survey was conducted in a site with declinations of $+53^\circ < δ< +87^\circ$. The viewing area is approximately 4100 sq.deg. The search was carried out using Fourier power spectra. To increase sensitivity, multiple observations were made in each direction in the sky, and the resulting power spectra were summarized. This made it possible to increase sensitivity by about 5-10 times, depending on the direction in the sky. A blind search opened 35 known pulsars. Estimates of the flux density for 33 pulsars have been obtained.

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arXiv2025

A nearby pulsar J1951+2837 observed by the LPA and FAST

PSR J1951+2837 is a nearby pulsar with a period of 7.334 s and dispersion measure of DM = 2.9 $\pm$ 0.6 pc cm$^{-3}$, located about 200 or 300 pc from the Sun. It occasionally radiates bright pulses and has been observed by the Large Phased Array (LPA) radio telescope at 110 MHz and by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) at 1250 MHz. We detected only 343 pulses in 228 LPA observation sessions and 5 bright pulses in two FAST sessions. Based on the times of arrival (TOAs) of these bright pulses, we determined the coherent timing solution for this pulsar at a frequency of 110 MHz. Based on flux densities (S) of these bright pulses at two frequencies ($ν$), we found that it is probably one of the known pulsars with the lowest luminosities to date, with a spectral index of about $α$ = (2.5 - 3.2) for S $\sim ν^{-α}$.

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arXiv2025

Search of RRATs on declinations from $+42^{\circ}$ to $+55^{\circ}$ with a neural network

In an area of 3,300 square degrees, a search for pulsed dispersed signals using a neural network has been carried out. During the six-month observation period, pulses were detected from fifteen known pulsars as well as three new rotating radio transients (RRATs). The main characteristics of these new sources were provided. The dispersion measures of the transients and the half-widths of the pulses ranged from 7.2 to 59.9 pc/cm$^3$ and from 20 to 300 ms, respectively. A RRAT search scheme has been developed that allows for the detection of pulses with a signal-to-noise ratio (S/N) below the threshold required for reliable detection.

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arXiv2025

Pushchino Multibeam Pulsar Search. VIII. Pulsar with a period of 40.9~s in observations of the LPA LPI

A search has been carried out for the pulsar J0311+1402, which has a period of $P = 40.9$ s, in the data archive of the Large Phased Array (LPA) radio telescope. When searching using fast folding algorithm (FFA), periodic pulsar radiation at a frequency of 111 MHz was not detected. In 3321 observation sessions lasting 5 minutes, 35 strong pulses were detected with a signal-to-noise ratio (S/N) greater than 10. Some of the pulses have a complex multi-peak structure consisting of narrow details, while some of the pulses are single-component. The peak flux densities of the details of these strong pulses range from 2 to 11 Jy. The peak value ($S_{\rm p} = 2$\,Jy) and the integral ($S_{\rm i} = 7$\,mJy) flux density in the average profile were obtained from the strong pulses. It is shown that pulsar pulses in the meter-wavelength range arrive sporadically, and the pulsar is similar in its properties to a rotating radio transient (RRAT). The pulsar has the minimal dispersion measure, the minimal distance from the Sun, and the minimal pseudo-luminosity of all known pulsars. Pulsar timing made it possible to improve the previously obtained value of the period ($P$) and to estimate the period derivative ($\dot P$). In the dependency of timing residuals (TRs) from the times of arrival (TOA) of pulses discontinuities are visible, when no pulses were observed. The duration of these breaks can be hundreds of days.

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arXiv2024

Search for rotating radio transients in monitoring data for three years

The search for rotating radio transients (RRAT) was done at a frequency of 111 MHz, in daily observations carried out on the radio telescope, a Large Phased Array (LPA) at declinations -9o < decj < +42o. 19 new RRATs were discovered for dispersion measures (DM) from 2.5 to 72.6 pc cm^{-3}. Estimates of the periods were obtained for three RRATs. Two of them (J0408+28; J0440+35) are located at distances of 134 and 136 pc from Sun and are among the closest of all known RRATs.

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arXiv2024

Pushchino multibeams pulsar search. IV. Detection of new pulsars at declinations -9o < δ< +55o

The search for pulsars in monitoring data obtained at the radio telescope Large Phased Array (LPA) at a frequency of 111 MHz was carried out. Daily round-the-clock observations were carried out for about 3,000 days. The duration of the observation session for each direction in the sky was 3.5 minutes per day. The search for pulsars was carried out using power spectra. To search for weak pulsars, power spectra were summed up. The expected increase in sensitivity was 35-40 times compared to observations in one session. In a blind search, 330 pulsars with regular radiation were detected, with periods (P) from 0.0333 to 3.7455 s and dispersion measures (DM) up to 249 pc/cm3. 39 pulsars turned out to be new. Average profiles were obtained for 6 pulsars. The DM for 7 pulsars previously detected on the LPA have been clarified.

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arXiv2024

Pushchino multibeams pulsar search -- III. Drift periods of pulsars from summed power spectra method

The drift periods P2 and P3 were searched for using the summed power spectra of 41 pulsars observed at declinations from -9o to +42o. The power spectra of pulses with a given period, pulse width and drift behavior have been simulated, the applicability of such a method for estimating drift parameters is shown. For most pulsars, the distribution of harmonic amplitudes in the power spectra corresponds to the expected distribution for these pulsars without drift. At the same time, it was found that for a number of sources, the summed power spectra accumulated over a long period of time give the same drift parameters as those determined by other methods. For 11 pulsars we have defined or redefined the drift period P2. For 8 sources the drift period P3 has been determined or redefined. The drift direction of subpulses was redefined for them.

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arXiv2024

Search for rotating radio transients in PUMPS

A search for pulsed radiation at a frequency of 111 MHz in the direction of 116 RRAT candidates was carried out. For the search, archival data obtained on a meridian 128-beam radio telescope, a Large Phased Array (LPA), was used. For each candidate, about six days of observations were accumulated over an interval of eight years. Eleven new RRATs have been discovered. It was possible to estimate periods for six of them, and to construct average profiles for four of them. Some of the candidates turned out to be known pulsars observed in the side lobes of the radio telescope and interference. For the part of the candidates could not find pulses with a signal-to-noise ratio of more than seven, and their nature remains unknown.

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arXiv2023

Interplanetary scintillation and pulsar pulse statistics

The effect of interplanetary plasma on pulsed pulsar radiation passing through is considered. The pulses of two rotating radio transients (J0609+16, J1132+25) and a pulsar (B0320+39) detected on the Large Phased Array (Pushchino observatory) were analyzed. It is shown that in observations at the frequency of 111 MHz, on elongations of 20o-40o, both an increase and a decrease in the number of received pulses are observed. The change in the number of pulses is explained by the distortion of the energy distribution of pulses due to interplanetary scintillation. These changes in the number of observed pulses are in qualitative agreement with the expected dependence of the scintillation index on the observed sources elongation. Analytical expressions are obtained that allow estimating the effective modulation index from observations of individual pulses for the power distribution of pulses by energy.

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arXiv2022

Pushchino multibeams pulsar search. First results

Since the discovery of pulsars, dozens of surveys have already been conducted with their searches. In the course of surveys in the sky, areas from thousands to tens of thousands of square degrees are explored. Despite repeated observations of the same areas, new pulsars are constantly being discovered. We present Pushchino Multibeam Pulsar Search (PUMPS), having a sensitivity that is an order of magnitude higher than the sensitivity of all previously made surveys on pulsar search. In PUMPS daily round-the-clock observations are carried out of the area located on declinations $-9^o < δ< +42^o$. The survey is carried out on 96 beams of a Large Phased Array (LPA) at a frequency of 111 MHz. During the observation period of August 2014 - August 2022, the survey was repeated approximately 3,000 times. The expected sensitivity in the survey reaches up to 0.1 mJy. The paper considers some tasks that can be solved when processing the received data.

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arXiv2022

Study of Bright Compact Radio Sources of the Northern Hemisphere at the frequency of 111 MHz

The search for compact components of strong ($S_{int} \ge 5$ Jy at 102.5 MHz) discrete radio sources from the Pushchino catalogue was carried out using the method of interplanetary scintillation. A total of 3620 sources were examined, and 812 of them were found to compact (scintillating) components. Estimates of fluctuations of the flux density of these compact components were derived from the scintillation index ($m_{max}$) corresponding to an elongation of $25^o$. The angular size and compactness of 178 sources with compact components were estimated. Scintillation indices of sources corresponding to the compact component ($m_{max}$) and flux densities of compact components were determined. It was demonstrated that slow variations of the spatial distribution of interplanetary plasma, which are related to the 11-year cycle of solar activity, may exert a systematic influence on the estimates of angular sizes of sources. Coefficients compensating the deviation from the spherical symmetry of solar wind in the estimates of angular sizes were found using the coefficient of asymmetry of the statistical distribution of intensity fluctuations. The study of correlations between the parameters of sources in the sample revealed that the maximum value of the scintillation index decreases as the integrated flux increases, while the angular size has no marked dependence on the integrated flux.

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arXiv2022

Search and detection of pulsars in the monitoring observations at the frequency 111 MHz

Pulsars with periods more than 0.4 seconds in the declination range -9o < decj < 42o and in the right ascension range 0h < r.a.< 24h were searched in parallel with the program of interplanetary scintillations monitoring of a large number of sources with the radiotelescope LPA LPI. Four-year observations carried out at the central frequency 110.25 MHz in the band 2.5 MHz and in six frequency channels with the time resolution 100 ms were used for the search. Initial detections of candidates for pulsars were based on the Fourier power spectra averaged over the whole observations period. The candidates for pulsars were checked in more details from observations analysis with higher time-frequency resolution: 32 frequency channels with time resolution of 12.5 ms. 18 new pulsars was discovered, their main characteristics are presented.

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arXiv2022

Search for pulsars in the summed power spectra at a frequency of 111 MHz

The search of pulsars in monitoring observations being carried out for 5 years using LPA LPI radio telescope was done in 96 spatial beams covering daily 17,000 square degrees. Five new pulsars were detected. Candidates into pulsars were selected in the summed power spectra. The use of a noise generator allowed to renormalize the data and to perform correct summing up of the power spectra for individual directions in the sky. Herewith, the sensitivity increased more than 20 times in comparison with individual sessions of observations. For pulsars with pulse durations greater than 100 ms at declinations +30o<dec.<+40o it is equal to 1.2 mJy and 0.4 mJy in/out of the Galaxy plane.

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arXiv2022

Search for periodic radio emission of gamma pulsar J0357+3205

The search for radio emission from the gamma pulsar J0357+3205 in the meter wavelength range was carried out. Periodic emission was found in one of the 1,700 observation sessions. The average pulsar profile is single-component with a half-width of 20-25 ms. Estimation of the pulsar flux density is 14 mJy.

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arXiv2022

Search for periodic emission of five gamma-ray pulsars at the frequency of 111 MHz

The search for pulsar (periodic) emission of five gamma-ray pulsars was carried out using the summed power spectra and the summed periodograms. No harmonics corresponding to the known pulsar periods were found. The upper estimations of the integral flux density of the pulsars J0357+3205 (<0.5 mJy), J0554+3107 (<0.5 mJy), J1958+2846 (<0.5 mJy), J2021+4026 (<0.4 mJy), and J2055+2539 (<0.55 mJy) is obtained.

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arXiv2022

Search for Dispersed Pulses at Declinations from +56o to +87o

The survey of northern hemisphere were made at a frequency of 111 MHz. The total accumulation time at each point of the sky was at least one hour. 75 sources of pulse emission were detected. More then 80% of these sources are known pulsars observed in the side lobes of the antenna. From one to several hundreds pulses were detected in twelve known pulsars. For four pulsars (J0157+6212, J1910+5655, J2337+6151, J2354+6155) the narrowness of the strongest pulses and the ratio of peak flux densities in the strongest pulse and in the average profile indicate that they can be pulsars with giant pulses. One new rotating radio transient (RRAT) J0812+8626 with a dispersion measure DM=40.25 pc/cm3 was detected.

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arXiv2022

Revisiting Pushchino RRAT search using neural network

The search for rotating radio transients (RRAT) at declination from -9o to +42o was carried out in the semi-annual monitoring data obtained on the Large Phased Array (LPA) radio telescope at the frequency of 111 MHz. A neural network was used to search for candidates. 4 new RRATs were detected, having dispersion measures (DM) 5-16 pc/cm3. A comparison with an earlier RRAT search conducted using the same data shows that the neural network reduced the amount of interference by 80 times, down to 1.3% of the initial amount of interferences. The loss of real pulsar pulses does not exceed 6% of their total number.

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arXiv2022

Pushchino multibeam pulsar search: I. Targeted search of weak pulsars

The search for pulsars in a sample of pulsar candidates found based on a multi-year survey conducted with low (6 channels; sampling 0.1s) time-frequency resolution on declinations -9^o < δ< +42^o was carried out. A Large Phased Array (LPA) transit telescope operating at 111 MHz in the 2.5 MHz band was used. Search, analysis and evidence of pulsar detection were carried out using a visualization program of summed up power spectra obtained from the survey data with high 32 channels; sampling 12.5ms) time-frequency resolution. 11 new pulsars with periods P0 = 0.41-3.75 s and dispersion measure DM=15-154 pc/cm^3 have been discovered. In total, in the survey with a low time-frequency resolution for the period 2016-2021 in a blind search, 208 pulsars were found, of them 42 new and 166 known pulsars. It is shown that in the search on the data with high time-frequency resolution accumulated over a time interval of 7 years, pulsars with a flux density of 0.1 - 0.2 mJy at the frequency of 111 MHz can be detected. When searching for pulsars with regular (periodic) emission at declinations +21^o < δ< +42^o, all pulsars located outside the galactic plane, having P0 \ge 0.5 s, DM \le 100 pc/cm^3 and the flux density S \ge 0.5 mJy, can be detected

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