Search Publications
Multiparametric infrared Tully-Fisher relation as a tool for mapping cosmic flows
Kashibadze, O. G.
The peculiar velocity field for 907 galaxies with heliocentric radial velocities VH ≤ 3000 km/s is examined. The data are divided into three samples, organized according to the principles behind the method for determining the distance to the galaxies: the luminosity of the tip of the red giant branch (TRGB), fluctuations in the surface …
Tests of Broadband Photometric Consistency for Standard Stars, the Hyades, and M67
Joner, Michael D.; van Wyk, Francois; Taylor, Benjamin J. +1 more
New South African Astronomical Observatory (SAAO) BV(RI)C measurements of 19 Hyades stars and 11 M67 stars are reported. The zero points of the new color indices conform closely to those of SAAO data reported in a previous paper. In addition, the new M67 measurements of (V - R)C and (R - I)C are compared to data pu…
Dispersive MHD waves and alfvenons in charge non-neutral plasmas
Stasiewicz, K.; Ekeberg, J.
Dispersive properties of linear and nonlinear MHD waves, including shear, kinetic, electron inertial Alfvén, and slow and fast magnetosonic waves are analyzed using both analytical expansions and a novel technique of dispersion diagrams. The analysis is extended to explicitly include space charge effects in non-neutral plasmas. Nonlinear soliton s…
Extragalactic archeology in integrated light: A test case with NGC 4030
Peletier, R.; Ocvirk, P.; Lançon, A.
We reconstruct the age-velocity distribution of the central region of the Sbc galaxy NGC4030, by applying STECKMAP to very high quality WHT/ISIS data. We find that the main component is a relatively young (≈ 2 Gyr) bulge with a ≈ 100 km/s velocity dispersion. The best fit solution also shows a superimposed young, kinematically cold (σ_{v}∼ 30 km/s…
Observational appearances of isolated stellar-mass black hole accretion Theory and observations
Karpov, S.; Beskin, G.; Biryukov, A. +2 more
General properties of accretion onto isolated stellar-mass black holes in the Galaxy are discussed. An analysis of plasma internal energy growth during the infall is performed. Adiabatic heating of collisionless accretion flow due to magnetic adiabatic invariant conservation is 25% more efficient than in the standard non-magnetized gas case. It is…
Correlation between solar flare productivity and photospheric vector magnetic fields
Wang, Huaning; Cui, Yanmei
Studying the statistical correlation between the solar flare productivity and photospheric magnetic fields is very important and necessary. It is helpful to set up a practical flare forecast model based on magnetic properties and improve the physical understanding of solar flare eruptions. In the previous study ([Cui, Y.M., Li, R., Zhang, L.Y., He…
EIS/ Hinode Observations of Doppler Flow Seen through the 40-Arcsec Wide-Slit
Madjarska, M. S.; Innes, D. E.; Hara, H. +1 more
The Extreme ultraviolet Imaging Spectrometer (EIS) onboard Hinode is the first solar telescope to obtain wide-slit spectral images that can be used for detecting Doppler flows in transition region and coronal lines on the Sun and to relate them to their surrounding small-scale dynamics. We select EIS lines covering the temperature range 6×104…
The 26 year-long X-ray light curve and the X-ray spectrum of the BL Lacertae object 1E 1207.9+3945 in its brightest state
Tramacere, A.; Giommi, P.; Maselli, A. +4 more
Aims:We studied the temporal and spectral evolution of the synchrotron emission from the high energy peaked BL Lac object 1E 1207.9+3945.
Methods: Two recent observations have been performed by the XMM-Newton and Swift satellites; we carried out X-ray spectral analysis for both of them, and photometry in optical-ultraviolet filters for the Swi…
Origin of Jovian hiss in the extended Io torus
Horne, Richard B.; Thorne, Richard M.; Wang, Kaiti
Plasma wave observations on Voyager, Ulysses, and Galileo have shown that whistler-mode hiss at frequencies below one kHz is continuously present in the extended Io torus of Jupiter. Cyclotron resonant energies at frequencies below 1 kHz are extremely high (typically > MeV), and the Jovian resonant electron flux is too low to cause significant …
UV diagnostics for the energy budget of flares and CMEs
Raymond, J. C.
Solar flares and coronal mass ejections convert large amounts of magnetic free energy into thermal, kinetic and potential energies, and into energy of non-thermal particles. The partitioning among these forms of energy is fundamental to both the physics of the eruptive events and the space weather consequences of the eruptions. This talk describes…