Search Publications
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…
INFRA-ICE: An ultra-high vacuum experimental station for laboratory astrochemistry
Santoro, Gonzalo; Sobrado, Jesús. M.; Tajuelo-Castilla, Guillermo +7 more
Laboratory astrochemistry aims at simulating, in the laboratory, some of the chemical and physical processes that operate in different regions of the universe. Amongst the diverse astrochemical problems that can be addressed in the laboratory, the evolution of cosmic dust grains in different regions of the interstellar medium (ISM) and its role in…
Far-infrared star formation rates of six GRB host galaxies with ALMA
Hashimoto, Tetsuya; Goto, Tomotsugu; Kim, Seong Jin +7 more
Gamma-ray bursts (GRBs) can be a promising tracer of cosmic star formation rate history (CSFRH). In order to reveal the CSFRH using GRBs, it is important to understand whether they are biased tracers or not. For this purpose, it is crucial to understand properties of GRB host galaxies, in comparison to field galaxies. In this work, we report ALMA …
Saturn in Lyman α: A comparison of Cassini and Voyager observations
Sandel, B. R.; Quemerais, E.; Yelle, R. V. +2 more
We analyze Saturn Lyman α system scans observed by the Cassini/UVIS instrument probing non-auroral airglow emissions from Saturn's disk, the ring atmosphere and the Saturn hydrogen torus. We constrain variations in disk brightness with latitude and local time, relating them to models of Saturn's upper atmosphere. We compare these results with Voya…
Using cross correlation to estimate Doppler frequency
Li, Fei; Yan, Jianguo; He, Qingbao +2 more
Doppler frequency estimation with high accuracy is very important for precise orbit determination and scientific studies in deep space exploration. In this paper, we propose a new method which implements cross correlation of only received signals from one single station to estimate Doppler frequency. The algorithm is relatively simple and it can a…