Search Publications
X-ray emission from GPS and CSS sources
Siemiginowska, A.
Many X-ray observations of GigaHertz Peaked Spectrum and Compact Steep Spectrum sources have been made with Chandra X-ray Observatory and XMM-Newton Observatory over the last few years. The X-ray spectra contribute the important information to the total energy distribution of the compact radio sources. In addition the spatial resolution of Chandra…
Parameters of the components of visually close binary systems: Hip 11352
Al-Wardat, M. A.
Model atmospheres of the components of the visually close binary system Hip 11352 were constructed using a grid of Kurucz's blanketed models. The entire observational spectral energy distribution of the system was used as a reference for the comparison with synthetic ones created from the model atmospheres. The parameters of the components of the …
New absolute magnitude calibrations for W Ursa Majoris type binaries
Demircan, O.; Eker, Z.; Bilir, S. +2 more
Parallaxes of W UMa stars in the Hipparcos catalogue have been analyzed. 31 W UMa stars, which have the most accurate parallaxes (σπ/π<0.15) which are neither associated with a photometric tertiary nor with evidence of a visual companion, were selected for re-calibrating the Period-Luminosity-Color (PLC) relation of W UMa stars. Usin…
The evolution of cluster early-type galaxies over the past 8 Gyr
Fritz, A.; Jørgensen, I.; Schiavon, R. P. +1 more
We present the Fundamental Plane (FP) of early-type galaxies in the clusters of galaxies RXJ1415.1+3612 at z=1.013. This is the first detailed FP investigation of cluster early-type galaxies at redshift z=1. The distant cluster galaxies follow a steeper FP relation compared to the local FP. The change in the slope of the FP can be interpreted as a…
NGC 1275: Baryonic cycling in the Perseus cluster of galaxies
Gallagher, J. S.
NGC 1275, the central galaxy of the Perseus cluster, contains a remarkable cool ISM. This gas is arrayed in a series of filaments extending over 30 kpc with an extension of 70 kpc to the north. These emit substantial cooling line radiation from H II, a hot H_2 zone, and CO in a cool molecular region which contains most of the gas mass. This contri…
The symbiotic system CH Cygni: An analysis of the shocked nebulae at different epochs
Rafanelli, P.; Angeloni, R.; Contini, M.
We analyse the line and continuum spectra of the symbiotic system CH Cygni. We adopt the colliding-wind model to explain the symbiotic system at different phases. Peculiar observed features such as flickering, radio variation, X-ray emission, as well as the distribution of the nebulae and shells throughout the system are investigated by modelling …
The chromospherically active binary star EI Eridani: I. Absolute dimensions
Strassmeier, K. G.; Weber, M.; Granzer, T. +2 more
We present a detailed determination of the astrophysical parameters of the chromospherically active binary star EI Eridani. Our new radial velocities allow to improve the set of orbital elements and reveal long-term variations of the barycentric velocity. A possible third-body orbit with a period of {≈ 19} years is presented. Absolute parameters a…
Orbits of Comets C/1845 L1 (Great June Comet) and C/1846 D1 (de Vico)
Branham, R. L., Jr.
Orbits are calculated for Comet C/1845 L1 (the Great June Comet) and C/1846 D1 (de Vico), the former based on 157 observations in right ascension and 152 in declination and the latter on 10 and 9, respectively. Both orbits are hyperbolic and statistically distinguishable from parabolas. Statistical tests indicate that the residuals are random and …
Smooth, undisturbed dwarf spheroidal galaxies in the Perseus cluster core: Implications for dark matter content
Held, E. V.; Conselice, C. J.; De Rijcke, S. +1 more
Using deep HST/ACS observations of the core of the Perseus Cluster, we identify a large population of dwarf elliptical galaxies down to MV = -12. All these dwarfs are remarkably smooth in appearance, showing no evidence for internal features that could be the result of tidal processes or star formation induced by the cluster potential. …
High energy emission from AGN cocoons in clusters of galaxies
Nagai, H.; Kawakatu, N.; Kino, M. +1 more
Gamma-ray emission from cocoons of young radio galaxies is predicted. Considering the process of adiabatic injection of the shock dissipation energy and mass of the relativistic jet into the cocoon, we find that the thermal electron temperature of the cocoon is typically predicted to be of the order of ∼MeV, and is determined only by the bulk Lore…