902 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Bulgarian Academy of SciencesBG224 papers
- Centre National de la Recherche ScientifiqueFR67 papers
- Sofia University "St. Kliment Ohridski"BG64 papers
- Shumen UniversityBG62 papers
- Instituto de Astrofísica de CanariasES57 papers
- Instituto de Astrofísica de AndalucíaES55 papers
- National Institute for AstrophysicsIT54 papers
- Universidad de La LagunaES50 papers
- Astronomical ObservatoryRS48 papers
- Evgeni Kharadze Georgian National Astrophysical ObservatoryGE45 papers
- Aryabhatta Research Institute of Observational SciencesIN43 papers
- Osservatorio Astrofisico di TorinoIT43 papers
21 papers · 1 filter
HD 210111: a new lambda Bootis type SB system
E. Paunzen, U. Heiter, L. Fraga +1
The small group of lambda Bootis stars comprises late B to early F-type stars, with moderate to extreme (up to a factor 100) surface underabundances of most Fe-peak elements and so…
Quasi-simultaneous two band optical variability of the blazars 1ES 1959+650 and 1ES 2344+514
Haritma Gaur, Alok C. Gupta, A. Strigachev +8
We report the results of quasi-simultaneous two filter optical monitoring of two high-energy peaked blazars, 1ES 1959+650 and 1ES 2344+514, to search for microvariability and short…
Observatons of NGC 3077 Galaxy in Narrow Band [SII] and H_alpha Filters
M. Andjelic, K. Stavrev, B. Arbutina +2
We present observations of the HI tidal arm near dwarf galaxy NGC 3077 (member of the M81 galaxy group) in narrow band [SII] and H_alpha filters. Observations were carried out in M…
The VLT-FLAMES Tarantula Survey: The fastest rotating O-type star and shortest period LMC pulsar - remnants of a supernova disrupted binary?
P. L. Dufton, P. R. Dunstall, C. J. Evans +12
We present a spectroscopic analysis of an extremely rapidly rotating late O-type star, VFTS102, observed during a spectroscopic survey of 30 Doradus. VFTS102 has a projected rotati…
Bayesian approach to cyclic activity of CF Oct
Ana P. Borisova, Valeri V. Hambaryan, John L. Innis
Bayesian statistical methods of Gregory-Loredo and the Bretthorst generalization of the Lomb-Scargle periodogram have been applied for studying activity cycles of the early K-type…
Spectra probing the number ratio of C- to M-type AGB stars in the NGC 6822 galaxy
Nikolay Kacharov, Marina Rejkuba, Maria-Rosa L. Cioni
Aims: We calibrate spectroscopically the C- versus (vs.) M-type asymptotic giant branch (AGB) star selection made using near-IR photometry, and investigate the spatial distribution…
Optical photometry of GM Cep: evidence for UXor type of variability
E. H. Semkov, S. P. Peneva
Results from optical photometric observations of the pre-main sequence star GM Cep are reported in the paper. The star is located in the field of the young open cluster Trumpler 37…
Abundance analysis of Am binaries and search for tidally driven abundance anomalies - III. HD116657, HD138213, HD155375, HD159560, HD196544 and HD204188
I. Stateva, I. Kh. Iliev, J. Budaj
We continue here the systematic abundance analysis of a sample of Am binaries in order to search for possible abundance anomalies driven by tidal interaction in these binary system…
Magnetic field and convection in the cool supergiant Betelgeuse
P. Petit, M. Aurière, R. Konstantinova-Antova +4
We present the outcome of a highly-sensitive search for magnetic fields on the cool supergiant Betelgeuse. A time-series of six circularly-polarized spectra was obtained using the…
A dominant magnetic dipole for the evolved Ap star candidate EK Eridani
M. Auriere, R. Konstantinova-Antova, P. Petit +8
EK Eri is one of the most slowly rotating active giants known, and has been proposed to be the descendant of a strongly magnetic Ap star. We have performed a spectropolarimetric st…
Direct observation of magnetic cycles in Sun-like stars
A. Morgenthaler, P. Petit, J. Morin +4
A sample of 19 solar-type stars, probing masses between 0.6 and 1.4 solar mass and rotation periods between 3.4 and 43 days, was regularly observed using the NARVAL spectropolarime…
Multi-Wavelength Study of the 2008-2009 Outburst of V1647 Ori
D. Garcia-Alvarez, N. J. Wright, J. J. Drake +11
V1647 Ori is a young eruptive variable star, illuminating a reflection nebula (McNeil's Nebula). It underwent an outburst in 2003 before fading back to its pre-outburst brightness…
Spectral Energy Distribution variation in BL Lacs and FSRQs
Bindu Rani, Alok C. Gupta, R. Bachev +9
We present the results of our study of spectral energy distributions (SEDs) of a sample of ten low- to intermediate-synchrotron-peaked blazars. We investigate some of the physical…
Young Exoplanet Transit Initiative (YETI)
R. Neuhäuser, R. Errmann, A. Berndt +80
We present the Young Exoplanet Transit Initiative (YETI), in which we use several 0.2 to 2.6m telescopes around the world to monitor continuously young (< 100 Myr), nearby (< 1 kpc…
2MASS J01074282+4845188: a new nova-like cataclysmic star with a deep eclipse
Dinko Dimitrov, Diana Kjurkchieva
We present VRI photometry and low-resolution spectroscopy of the object 2MASS J01074282+4845188. The V-shape of the eclipse, the phase variability of the colour indices as well as…
Multi-site, multi-year monitoring of the oscillating Algol-type eclipsing binary CT Her
P. Lampens, A. Strigachev, S. -L. Kim +13
We present the results of a multi-site photometric campaign carried out in 2004-2008 for the Algol-type eclipsing binary system CT Her, the primary component of which shows Delta S…
The VLT-FLAMES Tarantula Survey II: R139 revealed as a massive binary system
W. D. Taylor, C. J. Evans, H. Sana +22
We report the discovery that R139 in 30 Doradus is a massive spectroscopic binary system. Multi-epoch optical spectroscopy of R139 was obtained as part of the VLT-FLAMES Tarantula…
Spectroscopic and physical parameters of Galactic O-type stars. I. Effects of rotation and spectral resolving power in the spectral classification of dwarfs and giants
N. Markova, J. Puls, S. Scuderi +2
The modern-era spectral classification of O-stars relies on either the Walborn or the Conti-Mathys scheme. Since both of these approaches have been developed using low-quality phot…
Intranight variability of 3C 454.3 during its 2010 November outburst
R. Bachev, E. Semkov, A. Strigachev +6
Context. 3C 454.3 is a very active flat spectrum radio quasar (blazar) that has undergone a recent outburst in all observed bands, including the optical. Aims. In this work we expl…
The H-alpha Variations of the Luminous Blue Variable P Cygni: Discrete Absorption Components and the Short S Doradus Phase
Noel D. Richardson, Nancy D. Morrison, Douglas R. Gies +3
P Cygni is a prototype of the Luminous Blue Variables (or S Doradus variables), and the star displays photometric and emission line variability on a timescale of years (known as th…
BBN with Late Electron-Sterile Neutrino Oscillations - The Finest Leptometer
D. Kirilova
A relic lepton asymmetry orders of magnitude bigger than the baryon one may hide in the relic neutrino background. No direct theoretical or experimental limitations on its magnitud…