Search Publications
L* neural networks from different magnetic field models and their applicability
Yu, Yiqun; Zaharia, Sorin; Koller, Josef +1 more
The third adiabatic invariant L* plays an important role in modeling and understanding the radiation belt dynamics. The typical way to numerically calculate the L* value follows the method described by Roederer (1970), which is just a line integration method that is computationally slow and expensive. This work describes the application of an arti…
Herschel-ATLAS: VISTA VIKING near-infrared counterparts in the Phase 1 GAMA 9-h data
Ivison, R. J.; Sutherland, W.; González-Nuevo, J. +38 more
We identify near-infrared Ks-band counterparts to Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) submillimetre (submm) sources, using a preliminary object catalogue from the VISTA Kilo-degree Infrared Galaxy (VIKING) survey. The submm sources are selected from the H-ATLAS Phase 1 catalogue of the Galaxy and Mass Assembly 9…
Frequency drifts of 3-min oscillations in microwave and EUV emission above sunspots
Nakariakov, V. M.; Shibasaki, K.; Yan, Y. +3 more
Aims: We analysed 3-min oscillations of microwave and extreme ultraviolet (EUV) emission generated at different heights of a sunspot atmosphere, studied the amplitude and frequency modulation of the oscillations, and its relationship with the variation of the spatial structure of the oscillations.
Methods: High-resolution data obtained w…
Granular-Scale Elementary Flux Emergence Episodes in a Solar Active Region
van Driel-Gesztelyi, L.; Bellot Rubio, L. R.; Vargas Domínguez, S.
We analyse data from Hinode spacecraft taken over two 54-minute periods during the emergence of AR 11024. We focus on small-scale portions within the observed solar active region and discover the appearance of very distinctive small-scale and short-lived dark features in Ca II H chromospheric filtergrams and Stokes I images. The features appear in…
A Multi-epoch Timing and Spectral Study of the Ultraluminous X-Ray NGC 5408 X-1 with XMM-Newton
Pasham, Dheeraj R.; Strohmayer, Tod E.
We present results of new XMM-Newton observations of the ultraluminous X-ray source (ULX) NGC 5408 X-1, one of the few ULXs to show quasi-periodic oscillations (QPOs). We detect QPOs in each of four new (≈100 ks) pointings, expanding the range of frequencies observed from 10 to 40 mHz. We compare our results with the timing and spectral correlatio…
Thermal structure and CO distribution for the Venus mesosphere/lower thermosphere: 2001-2009 inferior conjunction sub-millimeter CO absorption line observations
Moriarty-Schieven, Gerald; Clancy, R. Todd; Sandor, Brad J.
Sub-millimeter 12CO (346 GHz) and 13CO (330 GHz) line absorptions, formed in the mesosphere and lower thermosphere of Venus (70-120 km), have been mapped across the nightside Venus disk during 2001-2009 inferior conjunctions, employing the James Clerk Maxwell Telescope (JCMT). Radiative transfer analysis of these thermal line…
IC 4663: the first unambiguous [WN] Wolf-Rayet central star of a planetary nebula
Crowther, P. A.; De Marco, O.; Miszalski, B. +4 more
We report on the serendipitous discovery of the first central star of a planetary nebula (PN) that mimics the helium- and nitrogen-rich WN sequence of massive Wolf-Rayet (WR) stars. The central star of IC 4663 (PN G346.2-08.2) is dominated by broad He II and N V emission lines which correspond to a [WN3] spectral type. Unlike previous [WN] candida…
Contribution of the Accretion Disk, Hot Corona, and Obscuring Torus to the Luminosity of Seyfert Galaxies: INTEGRAL and Spitzer Observations
Sunyaev, R.; Krivonos, R.; Revnivtsev, M. +12 more
We estimate the relative contributions of the supermassive black hole (SMBH) accretion disk, corona, and obscuring torus to the bolometric luminosity of Seyfert galaxies, using Spitzer mid-infrared (MIR) observations of a complete sample of 68 nearby active galactic nuclei (AGNs) from the INTEGRAL all-sky hard X-ray (HX) survey. This is the first …
Why is the Solar Constant Not a Constant?
Yang, L. H.; Li, K. J.; Xu, J. C. +4 more
In order to probe the mechanism of variations of the solar constant on the inter-solar-cycle scale, the total solar irradiance (TSI; the so-called solar constant) in the time interval of 1978 November 7 to 2010 September 20 is decomposed into three components through empirical mode decomposition and time-frequency analyses. The first component is …
Characteristics of precipitating energetic ions/electrons associated with the wave-particle interaction in the plasmaspheric plume
Yuan, Zhigang; Deng, Xiaohua; Wang, Dedong +5 more
In this paper, we present characteristics of precipitating energetic ions/electrons associated with the wave-particle interaction in the plasmaspheric plume during the geomagnetic storm on July 18, 2005 with observations of the NOAA15 NOAA16, IMAGE satellites and Finnish network of search coil magnetometers. Conjugate observations of the NOAA15 sa…