Search Publications
Analysis of X-Ray Emission from OB Stars. IV. About X-Ray Emission from Inhomogeneous Winds of OB Stars
Ryspaeva, Elizaveta; Kholtygin, Alexander
We study the origin of X-ray emission from OB stars due to collisions of stellar winds and/or inhomogeneities in the winds. The low-resolution X-ray spectra of a big sample of OB stars were fitted by both the stationary APEC/MEKAL models and by this model with an additional PSHOCK component describing the nonstationary X-ray emission. These spectr…
A joint measurement of galaxy luminosity functions and large-scale field densities during the Epoch of Reionization
Furlanetto, Steven R.; Trapp, A. C.
One of the most exciting advances of the current generation of telescopes has been the detection of galaxies during the epoch of reionization, using deep fields that have pushed these instruments to their limits. It is essential to optimize our analyses of these fields in order to extract as much information as possible from them. In particular, s…
Solar Energetic-Particle-Associated Coronal Mass Ejections Observed by the Mauna Loa Solar Observatory Mk3 and Mk4 Coronameters
St. Cyr, O. C.; Thompson, B. J.; Burkepile, J. T. +2 more
We report on the first comprehensive study of the coronal mass ejections (CMEs) associated with ∼25 MeV solar energetic-proton (SEP) events in 1980 - 2013 observed in the low/inner corona by the Mauna Loa Solar Observatory (MLSO) Mk3 and Mk4 coronameters. Where possible, these observations are combined with space-based observations from the Solar …
The Digitized First Byurakan Survey Data Base. Late-Type Stars Candidates. New Confirmations. I
Gigoyan, K. K.; Gigoyan, K. S.; Kostandyan, G. R. +3 more
The Digitized First Byurakan Survey (DFBS) is the digitized version of the First Byurakan Survey (FBS, or Markarian survey). The FBS was the first systematic survey of the extragalactic sky. This objective-prism survey was carried out in 1965-1980 by B.E.Markarian and his colleagues using the 1 m Schmidt telescope of the Byurakan Astrophysical Obs…
First detailed study of two eccentric eclipsing binaries: TYC 5378-1590-1 and TYC 8378-252-1
Zasche, P.; Marang, F.; Erdem, A. +2 more
Aims: The analysis of combined photometry and spectroscopy of eccentric eclipsing binary systems facilitates the derivation of very precise values for a large ensemble of physical parameters of the component stars and their orbits, thereby providing stringent tests of theories of stellar structure and evolution. In this paper two eccentric ec…
GD 99: Re-investigation of an old ZZ Ceti companion
Sódor, Á.; Bognár, Zs.; Mező, Gy.
Context. Thanks to photometric space missions, we have access to more and more information on the properties of white dwarf stars, especially pulsating ones. In the case of pulsators, we have the opportunity to get an insight into their otherwise hidden interiors by the means of asteroseismology. In addition to space-based observations, we also ta…
Evolution of the truncation radius in GX 339-4 from XMM-Newton spectral timing
Chainakun, P.; Young, A. J.; O'Mathúna, B. +1 more
We investigate the changing geometry of the accretion disc in the X-ray binary GX 339-4 using a combination of spectral and timing models to fit six XMM-Newton observations taken during the end of the 2015 X-ray outburst. We use progressively more complex models of the X-ray reflection spectra, from simple disc lines to full relativistic reflectio…
Analysis of the B-stars in field of the solar neighborhood young open cluster IC 2391 using UVES spectra and Gaia DR3
Hendy, Y. H. M.; El-Depsey, M. H.; Shokry, Ahmed +2 more
In this paper, we present the stellar parameters of individual B-type stars in the IC 2391 young open cluster, using the Barbier-Chalonge-Divan (BCD) Spectrophotometry System, to obtain stellar fundamental parameters from direct measurements of the Balmer discontinuity. This method is optimally suited for late B-stars to determine stellar fundamen…
Solar-like oscillations in γ Cephei A as seen through SONG and TESS. A seismic study of γ Cephei A
Grundahl, F.; Knudstrup, E.; Lund, M. N. +11 more
Context. Fundamental stellar parameters such as mass and radius are some of the most important building blocks in astronomy, both when it comes to understanding the star itself and when deriving the properties of any exoplanet(s) they may host. Asteroseismology of solar-like oscillations allows us to determine these parameters with high precision.…
Interaction of a high-mass X-ray binary with the interstellar medium through stellar wind. The case of GX 301-2
Chaty, S.; Marchioro, J.; Coleiro, A. +2 more
Context. GX 301-2 is a high-mass X-ray binary (HMXB) with strong stellar outflows. The evolution of these binaries can be closely related with the interstellar environment due to strong wind interactions.
Aims: We try to constrain the energy injected in the interstellar medium by GX 301-2 through stellar wind using HAWK-I and Herschel data. <…