Search Publications
Seasonal Evolution on the Nucleus of Comet C/2013 A1 (Siding Spring)
Samarasinha, Nalin H.; A'Hearn, Michael F.; Bodewits, Dennis +6 more
We observed Comet C/Siding Spring using the Hubble Space Telescope (HST) during its close approach to Mars. The high spatial resolution images obtained through the F689M, F775W, and F845M filters reveal the characteristics of the dust coma. The dust production rate of C/Siding Spring, quantified by Afρ, is 590 ± 30, 640 ± 30, and 670 ± 30 cm in a …
Dipolarization front and current disruption
Lui, A. T. Y.
The modification of current density on the dawn-dusk cross section of the magnetotail with the earthward approach of a dipolarization front (DF) is examined through the recently published results of a three-dimensional (3-D) particle-in-cell (PIC) simulation. It is found that the current density intensifies by 37% abruptly within 1.5 ion gyrotime …
Star Formation in Ultraluminous Infrared Galaxies Probed with AKARI Near-infrared Spectroscopy
Nakagawa, Takao; Isobe, Naoki; Shirahata, Mai +1 more
We conducted systematic observations of the H I Brα line (4.05 µm) and the polycyclic aromatic hydrocarbon (PAH) feature (3.3 µm) in 50 nearby (z\lt 0.3) ultraluminous infrared galaxies (ULIRGs) with AKARI. The Brα line is predicted to be the brightest among the H I lines under conditions of high dust extinction ({A}V\gt 15 …
Accretion disc-corona and jet emission from the radio-loud narrow-line Seyfert 1 galaxy RX J1633.3+4719
Misra, R.; Dewangan, G. C.; Gandhi, P. +2 more
We perform X-ray/ultraviolet (UV) spectral and X-ray variability studies of the radio-loud narrow-line Seyfert 1 (NLS1) galaxy RX J1633.3+4719 using XMM-Newton and Suzaku observations from 2011 and 2012. The 0.3-10 keV spectra consist of an ultrasoft component described by an accretion disc blackbody (kT_in = 39.6^{+11.2}_{-5.5} eV) and a power la…
Emission of hydrogen energetic neutral atoms from the Martian subsolar magnetosheath
Kallio, E.; Barabash, S.; Futaana, Y. +3 more
We have simulated the hydrogen energetic neutral atom (ENA) emissions from the subsolar magnetosheath of Mars using a hybrid model of the proton plasma charge exchanging with the Martian exosphere to study statistical features revealed from the observations of the Neutral Particle Detectors on Mars Express. The simulations reproduce well the obser…
Bayesian Analysis of Two Stellar Populations in Galactic Globular Clusters. II. NGC 5024, NGC 5272, and NGC 6352
Jefferys, W. H.; Stenning, D. C.; Wagner-Kaiser, R. +5 more
We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival Advanced Camera for Surveys Treasury observations of Galactic Globular Clusters to find and characterize two stellar populations in NGC 5024 (M53), NGC 5272 (M3), and NGC 6352. For these three clusters, both single and double-population analyses are used to determine a best…
North/South Hemispheric Periodicities in the {>} 25 MeV Solar Proton Event Rate During the Rising and Peak Phases of Solar Cycle 24
Cane, H. V.; Richardson, I. G.; von Rosenvinge, T. T.
We present evidence that >25 MeV solar proton events show a clustering in time at intervals of about six months that persisted during the rising and peak phases of Solar Cycle 24. This phenomenon is most clearly demonstrated by considering events originating in the northern or southern solar hemispheres separately. We examine how these variatio…
From the LIR-T Relation to the Limited Sizes of Dusty Starbursting Regions at High Redshifts
Yan, Haojing; Ma, Zhiyuan
Using the far-infrared (IR) data obtained by the Herschel Space Observatory, we study the relation between the IR luminosity (LIR) and the dust temperature (T) of dusty starbursting galaxies at high redshifts (high-z). We focus on the total IR luminosity from the cold-dust component ({L}{IR}({cd)}), whose emission …
In-situ observations of flux ropes formed in association with a pair of spiral nulls in magnetotail plasmas
Dunlop, Malcolm; He, Jiansen; Xie, Lun +9 more
Signatures of secondary islands are frequently observed in the magnetic reconnection regions of magnetotail plasmas. In this paper, magnetic structures with the secondary-island signatures observed by Cluster are reassembled by a fitting-reconstruction method. The results show three-dimensionally that a secondary island event can manifest the flux…
Wide Field CO Mapping in the Region of IRAS 19312+1950
Zhang, Yong; Hsia, Chih-Hao; Yung, Bosco H. K. +3 more
We report the results of wide field CO mapping in the region of IRAS 19312+1950. This Infrared Astronomical Satellite (IRAS) object exhibits SiO/H2O/OH maser emission, and is embedded in a chemically rich molecular component, the origin of which is still unknown. In order to reveal the entire structure and gas mass of the surrounding mo…