Search Publications
Missions
Journals
Publication Years
A Generalized Fisk-type HMF: Implications of Spatially Dependent Photospheric Differential Rotation
Burger, R. A.; Steyn, P. J.
The existence of a Fisk-type heliospheric magnetic field (HMF) has been debated ever since Fisk proposed an alternative to the traditional view of the HMF first proposed by Parker. Several modifications of the original Fisk field model have been published in the past, for example, the Schwadron field and the Fisk-Parker hybrid HMF model. This stud…
Faint Standards for ZYJHK from the UKIDSS and VISTA Surveys
Leggett, S. K.; Hambly, Nigel C.; Cross, Nicholas J. G.
The currently defined 'United Kingdom Infrared Telescope (UKIRT) Faint Standards' have JHK magnitudes between 10 and 15, with Kmedian = 11.2. These stars will be too bright for the next generation of large telescopes. We have used multi-epoch observations taken as part of the UKIRT Infrared Deep Sky Survey (UKIDSS) and the Visible and I…
Constraints on the Abundance of 0.01 c Stellar Engines in the Milky Way
Lingam, Manasvi; Loeb, Abraham
Stellar engines are hypothesized megastructures that extract energy from the host star, typically with the purpose of generating thrust and accelerating the stellar system. We explore the maximum potential speeds that could be realizable by stellar engines, and determine that speeds up to ∼0.1 c might perhaps be attainable under optimal conditions…
Suzaku and Fermi view of the supernova remnant 3C 396
Kisaka, S.; Sezer, A.; Yamazaki, R. +4 more
3C 396 is a composite supernova remnant (SNR), consisting of a central pulsar wind nebula (PWN) and a bright shell in the west, which is known to be interacting with molecular clouds (MCs). We present a study of X-ray emission from the shell and the PWN of the SNR 3C 396 using archival Suzaku data. The spectrum of the SNR shell is clearly thermal,…
A revision of the vdB 130 cluster stellar content based on Gaia DR2 data: interstellar extinction toward the Cyg OB1 supershell
Rastorguev, A. S.; Egorov, O. V.; Sitnik, T. G. +3 more
Two star-forming regions are studied: the young embedded open cluster vdB 130 and the protocluster neighbourhood observed in the head and tail of the cometary molecular cloud located in the wall of the expanding supershell surrounding the Cyg OB1 association. The Gaia DR2 catalogue is employed to verify the stellar composition of the vdB 130 clust…
Discovery of a transient X-ray source Suzaku J1305-4930 in NGC 4945
Yoneyama, Tomokage; Hayashida, Kiyoshi; Matsumoto, Hironori +3 more
We report the serendipitous discovery of a transient X-ray source, Suzaku J1305-4930, ∼3 kpc southwest of the nucleus of the Seyfert 2 galaxy NGC 4945. Among the seven Suzaku observations of NGC 4945 from 2005 to 2011, Suzaku J1305-4930 was detected four times in July and August in 2010. The X-ray spectra are better approximated with a multi-color…
The Role of Peak Temperatures in Solar X-Ray Flare Associations with CME Speeds and Widths and in Flare Size Distributions
Kahler, S. W.; Ling, A. G.
Recently, we reported that solar X-ray flares with relatively low peak (0.05-0.3 nm)/(0.1-0.8 nm) ratios R, a proxy for peak flare temperature T, were preferentially associated not only with solar energetic (E > 10 MeV) particle (SEP) events, but also with fast (Vcme ≥ 1000 km s-1) coronal mass ejections (CMEs) that produc…
Three new late-type hypervelocity star candidates from Gaia DR2 with refined selection criteria
Kupfer, Thomas; Liu, Chao; Jiang, Deng-Kai +6 more
Several dozen hypervelocity star (HVS) candidates have been reported based on the second data release of Gaia (Gaia DR2). However, it has been proven that the radial velocities of some Gaia HVS candidates are not reliable. In this paper, we employ refined astrometric criteria to re-examine Gaia DR2, arriving at a more reliable sample of HVS and hi…
MUSE observations of comet 67P/Churyumov-Gerasimenko. A reference for future comet observations with MUSE
Snodgrass, C.; Besse, S.; Opitom, C. +2 more
Aims: Observations of comet 67P/Churyumov-Gerasimenko were performed with MUSE at large heliocentric distances post-perihelion between 3 and 7 March 2016. These observations are part of a simultaneous ground-based campaign aimed at providing broad-scale information about comet 67P to complement the ESA/Rosetta mission.
Methods: We obtain…
Electron dynamics near diamagnetic regions of comet 67P/Churyumov- Gerasimenko
Goldstein, R.; Mokashi, P.; Richter, I. +8 more
The Rosetta spacecraft detected transient and sporadic diamagnetic regions around comet 67P/Churyumov-Gerasimenko. In this paper we present a statistical analysis of bulk and suprathermal electron dynamics, as well as a case study of suprathermal electron pitch angle distributions (PADs) near a diamagnetic region. Bulk electron densities are corre…