Zobrazeno 1 - 10
of 37
pro vyhledávání: '"Marchev, V."'
Autor:
Zamanov, R. K., Stoyanov, K. A., Marchev, V., Minev, M., Marchev, D., Moyseev, M., Marti, J., Bode, M. F., Konstantinova-Antova, R., Stefanov, S.
We present high resolution (0.06 A/px) spectroscopic observations of the recurrent nova T Coronae Borealis obtained during the last 1.5 years (September 2022 -- January 2024), with the 2.0m RCC telecope of the Rozhen National Astronomical Observatory
Externí odkaz:
http://arxiv.org/abs/2405.11506
Autor:
Zamanov, R., Stoyanov, K. A., Latev, G., Marti, J., Takey, A., Elhosseiny, E. G., Christova, M. D., Minev, M., Vujcic, V., Moyseev, M., Marchev, V.
We performed optical photometry and spectral observations of the symbiotic stars 4U1954+319 and ZZ CMi. For 4U1954+319 using high-resolution spectra we measure the equivalent widths of diffuse interstellar bands and estimate the interstellar reddenin
Externí odkaz:
http://arxiv.org/abs/2402.14378
Autor:
Marchev, V., Zamanov, R.
We analyze photometric observations of the symbiotic star MWC 560 in B and V bands obtained during the period 1990-2023. We estimate the luminosity and the mass accretion rate of the hot component. We find that the luminosity varies in the range from
Externí odkaz:
http://arxiv.org/abs/2312.04208
Autor:
Zamanov, R., Boeva, S., Latev, G. Y., Semkov, E., Minev, M., Kostov, A., Bode, M. F., Marchev, V., Marchev, D.
Context: T CrB (NOVA CrB 1946) is a famous recurrent nova with a recurrence timescale of 80 years. Aims: We aim to estimate the colours, luminosity, and mass-accretion rate for T CrB (NOVA CrB 1946) during and after the superactive state. Methods and
Externí odkaz:
http://arxiv.org/abs/2312.04342
Publikováno v:
Bulgarian Journal of Physics, vol. 51 (2024) 263-267 (2024)
Pre-outburst signal (a decrease of the optical brightness) just before the outburst is clearly detected in the observations of the T CrB obtained before and during the 1946 outburst. A similar decrease is also visible in the light curve of RS Oph dur
Externí odkaz:
http://arxiv.org/abs/2308.04104
Autor:
Zamanov, R. K., Kostov, A., Moyseev, M., Petrov, N., Nikolov, Y. M., Latev, G. Y., Marchev, D., Boeva, S., Stoyanov, K. A., Minev, M. S., Marti, J., Radeva, V., Sanchez-Ayaso, E., Bode, M. F., Ilkiewicz, K., Nikolov, G., Luque-Escamilla, P. L., Spassov, B., Borisov, B., Marchev, V. D., Kurtenkov, A.
We report photometric observations of the hidden symbiotic star SU Lyn in the optical bands. In five nights we detect a weak flickering in U band with amplitude of about 0.05 magnitudes. No intranight variations are found in B, V, g' and r' bands. Th
Externí odkaz:
http://arxiv.org/abs/2206.10151
Autor:
Zamanov R., Stoyanov K.A., Latev G., Marti J., Takey A., Elhosseiny E.G., Christova M.D., Minev M., Vujčić V., Moyseev M., Marchev V.
Publikováno v:
Serbian Astronomical Journal, Vol 2024, Iss 208, Pp 41-46 (2024)
We performed optical photometry and spectral observations of the symbiotic stars 4U1954+319 and ZZ CMi. For 4U1954+319, using high-resolution spectra, we, measure the equivalent widths of diffuse interstellar bands (DIBs) and estimate the interstella
Externí odkaz:
https://doaj.org/article/c05d390d79ed4d7f8aadeb1f1b977d9a
Using TESS photometry and Rozhen spectra of the Be/gamma-ray binaries MWC 148 and MWC 656, we estimate the projected rotational velocity ($ {v} \sin i$), the rotational period (P$_{\rm rot}$), radius (R$_{\rm 1}$), and inclination ($i$) of the mass d
Externí odkaz:
http://arxiv.org/abs/2102.01971
Using diffuse interstellar bands (DIBs) at 5780 A, 5797 A and 6613 A, visible in the high resolution spectra, and measuring their equivalent widths, we estimate the interstellar extinction toward seven symbiotic stars. We find $E_{B-V}$= $1.28 \pm 0.
Externí odkaz:
http://arxiv.org/abs/2006.14920
Autor:
Zamanov, R. K., Stoyanov, K. A., Wolter, U., Marchev, D., Tomov, N. A., Bode, M. F., Nikolov, Y. M., Marchev, V., Iliev, L., Stateva, I. K.
We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period December 2017 - January 2020 (MJD~58095 - MJD~58865). In December 2017 the $H\alpha$, $H\beta$, and HeI 6678 emission lines were symmetric with violet-to-re
Externí odkaz:
http://arxiv.org/abs/1906.11587