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Survey of Saturn auroral storms observed by the Hubble Space Telescope: Implications for storm time scales
Nichols, J. D.; Cowley, S. W. H.; Meredith, C. J.
We examine the ultraviolet images of Saturn obtained by the Hubble Space Telescope (HST) between 1997 and 2013 for the presence of auroral storm signatures, consisting of 2060 individual images over 74.4 h of exposure time. We find 12 storm intervals in these data, identified by bright high-latitude auroras spanning the dawn sector, which previous…
Origin of Multi-band Emission from the Microquasar Cygnus X-1
Zhang, Jianfu; Xu, Bing; Lu, Jufu
We study the origin of non-thermal emissions from the Galactic black hole X-ray binary Cygnus X-1, which is a confirmed high-mass microquasar. By analogy with the methods used in studies of active galactic nuclei, we propose a two-dimensional, time-dependent radiation model from the microquasar Cygnus X-1. In this model, the evolution equation for…
Near-infrared Detection of WD 0806-661 B with the Hubble Space Telescope
Luhman, K. L.; Morley, C. V.; Burgasser, A. J. +2 more
WD 0806-661 B is one of the coldest known brown dwarfs (T eff = 300-345 K) based on previous mid-infrared photometry from the Spitzer Space Telescope. In addition, it is a benchmark for testing theoretical models of brown dwarfs because its age and distance are well constrained via its primary star (2 ± 0.5 Gyr, 19.2 ± 0.6 pc). We prese…
High-resolution ammonia mapping of the very young protostellar core Chamaeleon-MMS1
Walmsley, C. M.; Harju, J.; Miettinen, O. +4 more
Aims: The aim of this study is to investigate the structure and kinematics of the nearby candidate first hydrostatic core Cha-MMS1.
Methods: Cha-MMS1 was mapped in the NH3(1,1) line and the 1.2 cm continuum using the Australia Telescope Compact Array (ATCA). The angular resolution of the ATCA observations is 7″ (~1000 AU), and…
VLBI observations of H2O maser annual parallax and proper motion in IRAS 20143+3634: Reflection on the Galactic constants
Hayashi, Masahiko; Nakagawa, Akiharu; Omodaka, Toshihiro +8 more
We report the results of very long baseline interferometry (VLBI) observations of H2O masers in the IRAS 20143+3634 star-forming region (SFR) using VERA (VLBI Exploration of Radio Astrometry). By tracking masers for a period of over two years we measured a trigonometric parallax of π = 0.367 ± 0.037 mas, corresponding to a source distan…
Suzaku discovery of Fe K-shell line from the O-rich SNR G292.0+1.8
Katsuda, Satoru; Koyama, Katsuji; Uchida, Hiroyuki +7 more
We report the Suzaku/XIS results of the Galactic oxygen-rich supernova remnant G292.0+1.8, a remnant of a core-collapse supernova. The X-ray spectrum of G292.0+1.8 consists of two types of plasma, one is in collisional ionization equilibrium (CIE) and the other is in non-equilibrium ionization (NEI). The CIE plasma has nearly solar abundances, and…
Extended star clusters in NGC 1023 from HST/ACS mosaic imaging
Spitler, Lee R.; Forbes, Duncan A.; Pota, Vincenzo +1 more
Faint fuzzies (FFs) are a relatively new class of star cluster, first found in the nearby S0 galaxy NGC 1023 by Larsen & Brodie using Wide Field Planetary Camera 2 (WFPC2) images from the Hubble Space Telescope (HST). Here, we investigate the star cluster system of NGC 1023 using an eight pointing mosaic of Advanced Camera for Surveys (ACS) im…
GRB 051008: a long, spectrally hard dust-obscured GRB in a Lyman-break galaxy at z ≈ 2.8
Klose, S.; Stecklum, B.; Kann, D. A. +17 more
We present observations of the dark gamma-ray burst GRB 051008 provided by Swift/BAT, Swift/XRT, Konus-WIND, INTEGRAL/SPI-ACS in the high-energy domain and the Shajn, Swift/UVOT, Tautenburg, NOT, Gemini and Keck I telescopes in the optical and near-infrared bands. The burst was detected only in gamma- and X-rays and neither a prompt optical nor a …
The first source counts at 18 µm from the AKARI NEP Survey
Im, M.; Lee, H. M.; Serjeant, S. +9 more
We present the first galaxy counts at 18 µm using the Japanese AKARI satellite's survey at the North Ecliptic Pole (NEP), produced from the images from the NEP-Deep and NEP-Wide surveys covering 0.6 and 5.8 deg2, respectively. We describe a procedure using a point source filtering algorithm to remove background structure and a min…
Constraints on Two Active Galactic Nuclei in the Merger Remnant COSMOS J100043.15+020637.2
Comerford, J. M.; Wrobel, J. M.; Middelberg, E.
COSMOS J100043.15+020637.2 is a merger remnant at z = 0.36 with two optical nuclei, NW and SE, offset by 500 mas (2.5 kpc). Prior studies suggest two competing scenarios for these nuclei: (1) SE is an active galactic nucleus (AGN) lost from NW due to a gravitational-wave recoil. (2) NW and SE each contain an AGN, signaling a gravitational-slingsho…