Search Publications
Signature of slow acoustic oscillations in a non-flaring loop observed by EIS/Hinode
Srivastava, A. K.; Dwivedi, B. N.
We study intensity oscillations near the apex of a coronal loop to find the signature of MHD oscillations. We analyse the time series of the strongest Fe XII 195.12 Å image data, observed by 40″ SLOT of the EUV Imaging Spectrometer (EIS) onboard the Hinode spacecraft. Using a standard wavelet tool, we produce power spectra of intensity oscillation…
Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos II. Preliminary orbits for six astrometric binaries
Gontcharov, G. A.; Kiyaeva, O. V.
Based on a direct combination of the Hipparcos data with astrometric ground-based observational catalogues having epochs between 1938 and 1999 the preliminary orbits and component masses are calculated for six binaries with no previous orbit calculation: ι Vir (HIP 69701) with period of 55 years, photocentric semi-major axis of 200 mas, relative s…
New intrinsic-colour calibration for uvby- β photometry
Karataş, Yüksel; Schuster, William J.
A new intrinsic-colour calibration ((b-y)o-β) is presented for the uvby- β photometric system, making use of re-calibrated Hipparcos parallaxes and published reddening maps. This new calibration for (b-y)o-β, our Eq. (1), has been based upon stars with dHip<70pc in the photometric catalogues of Schuster and Niss…
X-ray emission from O-type stars: DH Cep and HD 97434
Pandey, J. C.; Singh, K. P.; Kumar, Brijesh +2 more
We present X-ray emission characteristics of the massive O-type stars DH Cep and HD 97434 using archival XMM-Newton observations. There is no convincing evidence for short-term variability in the X-ray intensity during the observations. However, the analysis of their spectra reveals X-ray structure being consistent with two-temperature plasma mode…
The data mining II: An analysis of 33 eclipsing binary light-curves observed by the INTEGRAL/OMC
Zasche, P.
Thirty-three eclipsing binaries were selected for an analysis from a huge database of observations made by the INTEGRAL/OMC camera. The photometric data were processed and analyzed, resulting in a first light-curve study of these neglected eclipsing binaries. The system CY Lac was discovered to be an eccentric one. In several systems from this sam…
Evidence of wave harmonics in a brightened magnetic network observed from Hinode/EIS
Srivastava, A. K.
We study intensity oscillations in the upper chromosphere to search acoustic wave harmonics in a low-atmospheric solar cavity associated with a brightened magnetic network near the south pole of the Sun. We use a wavelet tool to produce power spectrum of He II 256.32 Å intensity oscillation as observed by EUV Imaging Spectrometer (EIS) onboard Hin…
Absolute parameters of the newly-identified contact binary star IS Canis Major
Özkardeş, B.; Erdem, A.
This paper presents the results of the first high-resolution spectroscopic observations of the Southern W UMa type system IS CMa. Spectroscopic observations of the system were made at Mt. John University Observatory using a HERCULES fibre-fed échelle spectrograph in September 2007. The first radial velocities of the component stars of the system w…
Is NP Aqr a new near-contact binary?
Çakırlı, Ö.; İbanoǧlu, C.; Dervişoǧlu, A.
We present radial velocities of the double-lined spectroscopic binary NP Aqr. The radial velocities and the optical light curves obtained by Hipparcos and ASAS-3 are analyzed separately. The masses of the primary and secondary components have been found to be 1.65±0.09 and 0.99±0.05M⊙, respectively. The cross-correlation functions indic…
The gravitationally lensed, luminous infrared galaxy IRAS F10214+4724 observed with XMM-Newton
Sanders, D. B.; Vignali, C.; Iwasawa, K. +2 more
We report on a short XMM-Newton observation of the gravitationally lensed, luminous infrared galaxy IRAS F10214+4724 at z = 2.3 . A faint X-ray source is detected at 4 σ . The observed 0.5-2 keV (1.7-6.6 keV in the rest-frame) flux is 1.3 ×10-15erg cm - 2s-1 and the spectral slope in the rest-frame 1-10 keV band is…
Spectroscopic analysis of the candidate β Cephei star σ Cas: Atmospheric characterization and line-profile variability
Catanzaro, G.; Ventura, R.; Ferrara, F. +1 more
This study is an exploratory search to ascertain for the first time the detailed properties of σ Cas as a candidate pulsator of β Cephei type in view of future observing campaigns. This search is devoted to a precise characterization of the parameters of the star for verifying its location with respect to the β Cephei instability region and to a p…