A5008300000- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Astro and Planetary Science
- earthquake and tectonic studies
- Earthquake Detection and Analysis
- Adaptive optics and wavefront sensing
- Particle Accelerators and Free-Electron Lasers
- Marine and environmental studies
- Seismology and Earthquake Studies
- Wave and Wind Energy Systems
- Solar and Space Plasma Dynamics
- Regional Development and Management Studies
- Advanced Fiber Laser Technologies
- Magnetic confinement fusion research
- Thermography and Photoacoustic Techniques
- Advanced Numerical Analysis Techniques
- Ocean Waves and Remote Sensing
- Neutrino Physics Research
Institute of Astronomy and National Astronomical Observatory
2015-2021
British Society for Heart Failure
2020-2021
Bulgarian Academy of Sciences
2014-2015
Sofia University "St. Kliment Ohridski"
2010-2011
National and Kapodistrian University of Athens
2010
Technische Universität Braunschweig
1995
Aims. Most hot Jupiters are expected to spiral in toward their host stars because the angular momentum of orbital motion is transferred stellar spin. Their orbits can also precess as a result planet-star interactions. Calculations show that both effects might be detected for very-hot exoplanet WASP-12 b using method precise transit-timing over time span about 10 yr.
We report observations of the flickering variability symbiotic recurrent nova RS Oph at quiescence in five bands (UBVRI). find evidence a correlation between peak-to-peak amplitude (ΔF) and average flux hot component (Fav). The is highly significant, with coefficient 0.85 p-value ∼10−20. Combining data from all wavebands, we dependence type |$\Delta F \propto F_{{\rm av}}^k$|, power-law index k = 1.02 ± 0.04 for UBVRI Oph. Thus, relationship consistent linearity. rms on 8 per cent (±2 cent)...
Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected ESA's mission remain recoverable after their discovery. An observation campaign on potentially hazardous asteroid (99 942) Apophis was conducted during asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, test coordination and evaluate overall performance Gaia-FUN-SSO . The 2732 high quality astrometric...
Context. The SW Sex stars are assumed to represent a distinguished stage in cataclysmic variable (CV) evolution, making it especially important study them.
The main goal of our project is to investigate the spatial distribution different stellar populations in Magellanic Clouds. results from modelling Clouds can be useful, among others, for simulations during Gaia mission preparation. Isodensity contour maps have been used order trace morphology and estimate size these structures. Moreover, star density are constructed through counts projected radial profiles obtained. Fitting exponential disk King law curves allows us derive structural...
We present photometric and spectral observations of the symbiotic star ZZ CMi. detect intranight variability - flickering smooth variations in U band. The amplitude is about 0.10-0.20 mag In B band lower, with less than 0.03 mag. also H-alpha H-beta emission lines, find an indication for outflow velocity 120-150 km/s. results indicate that CMi accretion powered containing M4-M6 III cool component white dwarf resembling recurrent novae jet-ejecting stars. [The data are available on...
In this paper we describe the echelle spectrograph of 2 meter telescope Rozhen National Astronomical Observatory. The is a cross-dispersed, bench-mounted, fiber-fed instrument giving resolution from $\sim$30000 to $\sim$45000. spectral range obtained in one single image 3900 9000 Å. We parameters fiber injection and guiding unit, itself, detector. identified orders resulting resolving power are presented. opportunity increase by using narrower slit discussed corresponding loss flux...
We analyse optical photometric data of short term variability (flickering) the accreting white dwarf in jet-ejecting symbiotic star MWC560. The observations are obtained 17 nights during period November 2011 - October 2019. colour-magnitude diagram shows that hot component system becomes redder as it gets brighter. For flickering source we find has colour 0.14 < B-V 0.40, temperature range 6300 T_fl 11000 K, and radius 1.2 R_fl 18 Rsun. a strong correlation (correlation coefficient 0.76,...
We report simultaneous observations of the flaring behavior cataclysmic variable star AE Aquarii (AE Aqr). The are in Johnson B and V bands. color–magnitude diagrams ( – vs. B) show that becomes more blue as it brighter. In our model, Aqr's can be explained with flares (fireballs) 0.03⩽ ⩽0.30, temperature interval 8000⩽ T ⩽12000.
Here we present quasi-simultaneous observations of the flickering symbiotic binary star CH Cyg in U, B and V bands. We calculate source parameters discuss possible reason for cessation period 2010-2013.
We present results from an original observational campaign comprising five epoch optical photopolarimetrical observations of the BL Lac-type AGN OJ287 in period 2012 November–2013 April. The data are gathered with Focal Reducer Rozhen 2 (FoReRo2) on 2-m RCC telescope at NAO Rozhen, Bulgaria. derive photometry and polarization R band as well position angle (PA). There indications for correlation between brightness band. Furthermore, observed variation PA corresponds to a rotation plane 5.80 deg d−1.
We present photometric observations of transiting exoplanets HATP-53b and XO-5b by the Rozhen 2 m telescope. The modeling HAT-P-53b transit required bigger planet radius than previously published value due to depth newly-observed transit. solution led values fitted parameters within errors results. Based on a time span around 9 years we improved orbital period 4.187751515 d. quality our data does not allow determination temperatures solutions. Our results confirmed Jupiter type two targets....
We report photometric observations of the hidden symbiotic star SU Lyn in optical bands. In five nights we detect a weak flickering U band with amplitude about 0.05 magnitudes. No intranight variations are found B, V, g' and r' This is one more indication that secondary component white dwarf accreting at low accretion rate. also searched for variability dozen related object (RR Boo, RT AM Cyg, AG Peg, BF NQ Gem, StHa190, V627 Cas, XX Oph, FS Cet Y Gem) which no above observational errors detected.
Context: The SW Sex stars are assumed to represent a distinguished stage in CV evolution, making it especially important study them. Aims: We discovered new cataclysmic star and carried out prolonged precise photometric observations, as well medium-resolution spectral observations. Modelling these data allowed us determine the psysical parameters establish its peculiarities. Results: newly vataclysmic variable 2MASSJ22560844+5954299 shows deepest eclipse amongst known nova-like stars. It was...