Light curves of the eclipsing binary FL Lyr acquired by the Kepler space telescope are analyzed. Eclipse timing measurements for FL Lyr testify to the presence of a third body in the system. Preliminary estimates of its mass and orbital period are 2MJ and 7 yrs. The times of primary minimum in the light curve of FL Lyr during the operation of the Kepler mission are presented.
A method for searching for new periodic radio sources is described. The method is based on the spectral analysis of data from daily monitoring of the sky on the Large Phased Antenna (LPA) of the Pushchino Radio Astronomy Observatory at 111 MHz in a 2.5-MHz band. The 96-beam directivity pattern of the LPA is used. The signal is received in six 0.42-MHz frequency channels with a sampling rate of 0.1 s. The duration of the processed survey is four months. The particulars of detecting periodic sources with the LPA are considered. In total, 16 such radio sources have been detected, for which equatorial and Galactic coordinates, periods, and dispersion measures are given.
Observations of H2O maser sources at 1.35 cm associated with extended regions of 4.5-μm emission (indicated as “green” on Spitzer survey maps — so-called Extended Green Objects, EGOs) are reported. EGOs are considered as characteristic signposts of regions of formation of massive stars, which host high-velocity outflows, as well as methanol, water, and hydroxyl masers. The observations were carried out in January–May 2015 on the 22-meter radio telescope of the Pushchino Radio Astronomy Observatory. The sample studied includes 24 EGOs north of declination −29◦ taken from the Spitzer GLIMPSE survey, together with one of the brightest Class I methanol masers G6.05−1.45 (M8E) and the Class I methanol maser in an IRDC G359.94+0.17. H2O maser emission was detected toward 11 of the EGOs: G11.94−0.62, G14.33−0.64, G16.59−0.06, G23.01−0.41, G24.943+0.074, G28.83−0.25, G34.3+0.2, G34.403+0.233, G35.20−0.74, G45.47+0.07, and G49.267−0.337. These including the well known H2O maser in the W44 region, G34.3+0.2. H2O emission from G28.83−0.25 was detected for the first time, at 77.6 km/s, with a flux density of 19 Jy in January and 16 Jy in February 2015. The source was probably caught at an early stage of the propagation of a shock wave. The Class I methanol masers G359.94+0.17 and G6.05−1.45 (M8E) and 13 of the EGOs were not detected in the H2O line, with 3σ upper limits of ∼6−7 Jy. Spectra and maser-emission parameters are given for the detected H2O masers, for some of which strong variability of the H2O maser emission was observed. The detected H2O masers, together with the Class I methanol masers and extended 4.5-μm emission, are associated with a very early stage in the development of young stellar objects in the regions of the EGOs. However, this sample of EGOs is not uniform. The presence of 44-GHz Class I methanol masers together with EGOs cannot be considered the only sign of early stages of star formation.
Individual probability-density distributions for the masses of compact objects in 20 X-ray binary systems have been constructed. The mass distributions were modeled using Monte-Carlo simulations. The closeness of the components in systems with massive optical stars was taken into account using K corrections. The parameters of the resulting black-hole mass distributions were obtained using nonparametric statistical methods. The presence of a statistically significant mass gap in the range 3–5M ⊙ is confirmed. The currently observed probability-density distributions of the compact-object masses are stable against small amounts of data contamination.
Observations of the RRAT pulsars J0627+16, J0628+09, J1819−1458, J1826−1419, J1839−01, J1840−1419, J1846−0257, J1848−12, J1850+15, J1854+0306, J1919+06, J1913+1330, J1919+17, J1946+24, and J2033+00 observed earlier on the 64-m Parkes telescope (Australia) and the 300-m Arecibo radio telescope (Puerto Rico) at 1400 MHz were conducted at 111 MHz on the LSA radio telescope of the Pushchino Radio Astronomy observatory in 2010–2012. A characteristic feature of these pulsars is their sporadic radio emission during rare active epochs and the absence of radio emission during long time intervals. No appreciable flare activity of these pulsars was detected in the Pushchino observations. However, processing the observations using the Fast Folding Algorithm taking into account known information about the pulsar dispersion measures and periods shows that, even during quiescent intervals, the majority of the studied pulsars generate weak radio pulses with a period corresponding to that of the radio emission of the sporadic pulses observed at active epochs. The flux of this radio emission does not exceed 100 mJy at the pulse peak, even at the low frequency of 111 MHz. This considerably hinders detection of the radio emission of RRAT pulsars at high frequencies, since the radio fluxes of RRAT pulsars decreases with increasing frequency.
An analysis of monitoring observations for the pulsar PSR B0655+64, which is located in a binary system, at 111 MHz during 2002–2015 are presented. The Keplerian parameters of the pulsar have been refived: the longitude of periastron ω = 276 ◦ .5785 ± 0 ◦ .0005 and the orbital semi-major axis is a p sin i = 4.124976 ± 0.000003 s. The parameters of the perturbed motion have been determined: the motion of periastron ω ̇ = 0 ◦ .315 ± 0 ◦ .005/ year, and the derivative of the period of the binary system P ̇ = (−1.66 ± 0.11) × 10 −14 s/s = (−0.524 ± 0.038) μs/year. The estimated time scale for the decay of the PSR 0655+64 system is (1.7 ± 0.1) × 10 11 yrs.