arXiv subjects

Georgi Latev

Publications and source records attributed to Georgi Latev.

4 recordsLinked to original sources

arXiv2025

A network for solar optical observations in Bulgaria

The report presents a new initiative for the development of a network of ground-based stations for solar observations in the optical range. Three separate locations in Bulgaria have installed instrumentation for solar dedicated observations. The currently used telescopes (type, mounting, guiding systems) and designated filters (white-light, H-alpha) are described in detail. Test images are also included. Future plans for improvements are briefly discussed.

astro-ph.SR↗

arXiv2023

Post-superhumps maximum on intranight time scales of the AM CVn star CR Boo

We present observations of the intranight brightness variability of CR Boo, a member of the AM CVn stars group. The observational data are obtained with the 2m telescope of the Rozhen National Astronomical Observatory and the 60 cm telescope of the Belogradchik Observatory, Bulgaria, in BVR bands. We report the appearance of superhumps, with an amplitude from 0.08 to 0.25 mag, when the maximum brightness reaches the magnitude 14.08 in the V band, and 14.13 in the B band. A secondary maximum of each superhump is detected with the same periodicity as the superhumps: Psh = 24.76 - 24.92 min. In our results, the post maxima are shifted in time from $\approx 7.62$ min to $\approx 16.35$ min in different nights, with an amplitude of $\approx 0.06 - 0.09$ mag and an amplitude difference of $\approx 0.035$ mag towards the superhumps' maximum. We find a correlation of the post maxima with the accretion processes at the outer side of the disc.

astro-ph.SR↗

arXiv2022

Recent humps and superhumps observations and an estimation of outburst parameters of the AM CVn star CR Boo

We present our observational results of AM CVn star CR Boo in the UBVR bands. Our observational campaign includes data obtained over 5 nights with the National Astronomical Observatory Rozhen, Belogradchik and the AS Vidojevica telescopes. During the whole time of our observations the brightness of the system varied between $13.95 - 17.23$ in B band. We report the appearance of humps during the period of quiescence and superhumps during the active state of the object, (where the latter are detected in two nights). We obtain the superhumps periodicity for two nights, $P_{sh}\approx 24.76 - 24.92$ min. The color during maximum brightness is estimated as $ - 0.107 < (B-V)_{0} < 0.257$ and the corresponding temperature is in the range as $7700 [K] < T(B-V)_{0} < 11700 [K]$. We found that CR Boo varies from bluer to redder in the nights with outbursts activity. The star becomes bluer during the times of superhumps.

astro-ph.SR↗

arXiv2016

The Extremes in Intra-Night Blazar Variability: The S4 0954+65 Case

We present results of optical observations of the extremely violently variable blazar S4 0954+65 on intra-night time scales. The object showed flux changes of up to 100% within a few hours. Time delays between optical bands, color changes and "rms-flux" relations are investigated and the results are discussed in terms of existing models of blazar variability.

astro-ph.HE↗