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A Method to Estimate the Physical Properties of Magnetospheric Generators From Observations of Quiet Discrete Auroral Arcs
Gunell, H.; De Keyser, J.; Lamy, H. +3 more
We discuss a method to estimate the properties of a magnetospheric generator using a quasi-electrostatic magnetosphere-ionosphere coupling model and in situ or remote sensing observations of discrete quiet arcs. We first construct an ensemble of Vlasov equilibrium solutions for generator structures formed at magnetospheric plasma interfaces. For e…
HD 126516: A Triple System Containing a Short-period Eclipsing Binary
Henry, Gregory W.; Fekel, Francis C.; Sowell, James R.
From numerous radial velocities as well as Johnson B and V differential photoelectric photometry, we have determined the orbital elements and other properties of the single-lined triple system HD 126516. This system consists of a narrow-lined F5 V star and an unseen M dwarf companion in a 2.1241 day circular orbit. The small, low-mass secondary pr…
Localized Structures and Turbulent Spectra in the Magnetopause
Sharma, R. P.; Pathak, Neha; Uma, R.
Kinetic Alfvén wave (KAW) and whistler wave play a key role in the framework of turbulence and reconnection. There are lot of observations of these wave in the magnetopause region. The present paper deals with the nonlinear evolution of KAW and a weak whistler wave through the preexisting magnetic reconnection site. For this study the dynamical ev…
AT 2017fvz: a nova in the dwarf irregular galaxy NGC 6822
Zheng, W.; Filippenko, A. V.; Henze, M. +7 more
A transient in the Local Group dwarf irregular galaxy NGC 6822 (Barnard's Galaxy) was discovered on 2017 August 2 and is only the second classical nova discovered in that galaxy. We conducted optical, near-ultraviolet, and X-ray follow-up observations of the eruption, the results of which we present here. This `very fast' nova had a peak V-band ma…
Ionization state of the accretion disc in the neutron star low-mass X-ray binary 4U 1728-34
Méndez, Mariano; Xiang, Fu-Yuan; Lyu, Ming +1 more
We analysed an XMM-Newton plus a simultaneous Rossi X-ray Timing Explorer observation and a separate Suzaku observation of the neutron star low-mass X-ray binary 4U 1728-34. We fitted the X-ray spectra with the self-consistent reflection model RELXILL. We found that the inclination angle of 4U 1728-34 is 49 ± 5 degree, consistent with the upper li…
A search for evolutionary changes in the pulsation period of the classical Cepheid V609 Cygni
Dambis, A. K.; Berdnikov, L. N.; Pastukhova, E. N.
A total of 820 magnitude estimates were made for the long-period classical Cepheid V609 Cyg (
Ion escape from the upper ionosphere of Titan triggered by the solar wind
Lazar, M.; Moslem, W. M.; El-Labany, S. K. +3 more
The observed escape of ions from the ionosphere of Titan suggests a potential role of the solar wind in the interaction with the upper atmospheric layers. We investigate such a plausible scenario using a hydrodynamic fluid approach for the plasma expansion in the upper ionosphere of Titan, combining (Maxwellian) electrons and three different speci…
Swift, NuStar, and XMM-Newton observations of the NLS1 galaxy RX J2317.8-4422 in an extreme X-ray low flux state
Fabian, Andrew C.; Komossa, S.; Miniutti, Giovanni +6 more
We report the discovery of RX J2317.8-4422 in an extremely low X-ray flux state by the Neil Gehrels Swift observatory in 2014 April/May. In total, the low-energy X-ray emission dropped by a factor of 100. We have carried out multiwavelength follow-up observations of this narrow-line Seyfert 1 galaxy. Here we present observations with Swift, XMM-Ne…
Multiwavelength survey of X-ray sources in the Sculptor Dwarf Spheroidal Galaxy
Barmby, P.; Maccarone, T. J.; Bahramian, A. +2 more
We present an unprecedented, deep study of the primordial low-mass X-ray binary population in an isolated, lower metallicity environment. We perform follow-up observations of previously identified X-ray binary candidates in the Sculptor Dwarf Galaxy by combining a second Chandra observation with Spitzer and Gemini photometry, as well as Gemini spe…
Characteristics of solar wind rotation
Li, K. J.; Feng, W.
Over 54 yr of hourly mean value of solar wind velocity from 1963 November 27 to 2017 December 31 are used to investigate characteristics of the rotation period of solar wind through autocorrelation analysis. Solar wind of high velocity is found to rotate faster than low-velocity wind, while its rotation rate increases with increasing velocity, but…