Search Publications
Patchy Accretion Disks in Ultra-luminous X-Ray Sources
Harrison, F. A.; Fabian, A. C.; Miller, J. M. +5 more
The X-ray spectra of the most extreme ultra-luminous X-ray sources—those with L >= 1040 erg s-1—remain something of a mystery. Spectral roll-over in the 5-10 keV band was originally detected in the deepest XMM-Newton observations of the brightest sources; this is confirmed in subsequent NuSTAR spectra. This emission can be…
Type II solar radio bursts predicted by 3-D MHD CME and kinetic radio emission simulations
Cairns, Iver H.; Schmidt, J. M.
Impending space weather events at Earth are often signaled by type II solar radio bursts. These bursts are generated upstream of shock waves driven by coronal mass ejections (CMEs) that move away from the Sun. We combine elaborate three-dimensional (3-D) magnetohydrodynamic predictions of realistic CMEs near the Sun with a recent analytic kinetic …
Deep optical observations of the γ-ray pulsar J0357+3205
Zharikov, S.; Shternin, P.; Kirichenko, A. +3 more
Context. A middle-aged radio-quiet pulsar J0357+3205 was discovered in gamma rays with Fermi and later in X-rays with Chandra and XMM-Newton observatories. It produces an unusual thermally emitting pulsar wind nebula that is observed in X-rays.
Aims: Deep optical observations were obtained to search for the pulsar optical counterpart and its …
Planetary companions in K giants β Cancri, µ Leonis, and β Ursae Minoris
Hatzes, A. P.; Lee, B. -C.; Park, M. -G. +3 more
Aims: The aim of our paper is to investigate the low-amplitude and long-period variations in evolved stars with a precise radial velocity survey.
Methods: The high-resolution, the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) was used from 2003 to 2013 for a radial velocity survey of giant stars as part of the exoplanet sea…
The scale height of gas traced by [C ii] in the Galactic plane
Langer, W. D.; Pineda, J. L.; Velusamy, T.
Context. The distribution of various interstellar gas components and the pressure in the interstellar medium (ISM) is a result of the interplay of different dynamical mechanisms and energy sources on the gas in the Milky Way. The scale heights of the different gas tracers, such as H i and CO, are a measure of these processes. The scale height of […
Survey analysis of chorus intensity at Saturn
Gurnett, D. A.; Hospodarsky, G. B.; Woodfield, E. E. +5 more
In order to conduct theoretical studies or modeling of pitch angle scattering of electrons by whistler mode chorus emission at Saturn, a knowledge of chorus occurrence and magnetic intensity levels, PB, as well as the distribution of PB relative to frequency and spatial parameters is essential. In this paper an extensive surv…
Multi-wavelength High-resolution Observations of a Small-scale Emerging Magnetic Flux Event and the Chromospheric and Coronal Response
Yurchyshyn, Vasyl; Vargas Domínguez, Santiago; Kosovichev, Alexander
State-of-the-art solar instrumentation is now revealing magnetic activity of the Sun with unprecedented temporal and spatial resolutions. Observations with the 1.6 m aperture New Solar Telescope (NST) of the Big Bear Solar Observatory are making next steps in our understanding of the solar surface structure. Granular-scale magnetic flux emergence …
Coronal behavior before the large flare onset
Kusano, Kanya; Bamba, Yumi; Imada, Shinsuke
Flares are a major explosive event in our solar system. They are often followed by a coronal mass ejection that has the potential to trigger geomagnetic storms. There are various studies aiming to predict when and where the flares are likely to occur. Most of these studies mainly discuss the photospheric and chromospheric activity before the flare…
Characteristics of polar coronal hole jets
Teriaca, L.; Gupta, G. R.; Bemporad, A. +2 more
Context. High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind.
Aims: We studied the dynamics of two jets seen in a polar coronal hole with a…
Complex Analysis of the Stellar Binary HD25811: A Subgiant System
Al-Wardat, Mashhoor A.; Widyan, Hatem S.; Al-thyabat, Ahmed
The visually close binary system HD25811 is analysed to estimate its physical and geometrical parameters in addition to its spectral type and luminosity class. The method depends on obtaining the best fit between the entire observational spectral energy distribution (SED) of the system and synthetic SEDs created by atmospheric modelling of the ind…