Search Publications
Ortho-to-para Ratio Studies of Shocked H2 Gas in the Two Supernova Remnants IC 443 and HB 21
Lee, Ho-Gyu; Moon, Dae-Sik; Shinn, Jong-Ho
We present near-infrared (2.5-5.0 µm) spectral studies of shocked H2 gas in two supernova remnants, IC 443 and HB 21, which are well known for their interactions with nearby molecular clouds. The observations were performed with the Infrared Camera aboard the AKARI satellite. At the energy range 7000 K lsim E(\upsilon,J) lsim 20,0…
A Weak-lensing and Near-infrared Study of A3192: Disassembling a Richness Class 3 Abell Cluster
Smith, Graham P.; Egami, E.; Marshall, P. J. +5 more
We present a joint gravitational lensing and near-infrared study of the galaxy cluster Abell 3192 (A3192) that has been associated both with galaxies at z = 0.168 and with the X-ray luminous cluster RXC J0358.8-2955 (RXC J0358) at z = 0.425. Weak-lensing analysis of our Hubble Space Telescope snapshot observation with the Advanced Camera for Surve…
Dramatic Infrared Variability of WISE J1810-3305: Catching Early-time Dust Ejection During the Thermal Pulse of an Asymptotic Giant Branch Star?
Gandhi, Poshak; Yamamura, Issei; Takita, Satoshi
We present the discovery of a source with broadband infrared photometric characteristics similar to Sakurai's object. WISE J180956.27-330500.2 (hereafter J1810-3305) shows very red WISE colors, but a very blue 2MASS [K] versus WISE [W1 (3.4 µm)] color. It was not visible during the IRAS era, but now has a 12 µm flux well above the IRAS…
Non-thermal Response of the Corona to the Magnetic Flux Dispersal in the Photosphere of a Decaying Active Region
Abramenko, V. I.; Harra, L. K.
We analyzed Solar Dynamics Observatory line-of-sight magnetograms for a decaying NOAA active region (AR) 11451 along with co-temporal Extreme-Ultraviolet Imaging Spectrometer (EIS) data from the Hinode spacecraft. The photosphere was studied via time variations of the turbulent magnetic diffusivity coefficient, η(t), and the magnetic power spectru…
Remnant Gas in Evolved Circumstellar Disks: Herschel PACS Observations of 10-100 Myr Old Disk Systems
Gorti, Uma; Mamajek, Eric; Meyer, Michael R. +3 more
We present Herschel PACS spectroscopy of the [O I] 63 µm gas line for three circumstellar disk systems showing signs of significant disk evolution and/or planet formation: HR 8799, HD 377, and RX J1852.3-3700. [O I] is undetected toward HR 8799 and HD 377 with 3σ upper limits of 6.8 × 10-18 W m-2 and 9.9 × 10-18
A Transient Sub-Eddington Black Hole X-Ray Binary Candidate in the Dust Lanes of Centaurus A
Sarazin, Craig L.; Jordán, Andrés; Kainulainen, Jouni +18 more
We report the discovery of a bright X-ray transient CXOU J132527.6-430023 in the nearby early-type galaxy NGC 5128. The source was first detected over the course of five Chandra observations in 2007, reaching an unabsorbed outburst luminosity of (1-2) × 1038 erg s-1 in the 0.5-7.0 keV band before returning to quiescence. Such…
The Morphologic Properties of Magnetic Networks over the Solar Cycle 23
Li, Gang; Tan, Baolin; Zhang, Yin +2 more
The morphologic properties of the magnetic networks during Carrington Rotations (CRs) 1955-2091 (from 1999 to 2010) have been analyzed by applying the watershed algorithm to magnetograms observed by the Michelson Doppler Interferometer on board the Solar and Heliospheric Observatory spacecraft. We find that the average area of magnetic cells on th…
Maximizing Magnetic Energy Storage in the Solar Corona
Wolfson, Richard; Drake, Christina; Kennedy, Max
The energy that drives solar eruptive events such as coronal mass ejections (CMEs) almost certainly originates in coronal magnetic fields. Such energy may build up gradually on timescales of days or longer before its sudden release in an eruptive event, and the presence of free magnetic energy capable of rapid release requires nonpotential magneti…
Proper Motions and Internal Dynamics in the Core of the Globular Cluster M71
Richer, Harvey B.; Thanjavur, Karun; Goldsbury, Ryan +4 more
We have used Gemini North together with the NIRI-ALTAIR adaptive optics imager in the H and K bands to explore the core of the Galactic globular cluster M71 (NGC 6838). We obtained proper motions for 217 stars and have resolved its internal proper motion dispersion. Using a 3.8 year baseline, the proper motion dispersion in the core is found to be…
Are Decaying Magnetic Fields Above Active Regions Related to Coronal Mass Ejection Onset?
Li, Y.; Welsch, B. T.; Suzuki, J.
Coronal mass ejections (CMEs) are powered by magnetic energy stored in non-potential (current-carrying) coronal magnetic fields, with the pre-CME field in balance between outward magnetic pressure of the proto-ejecta and inward magnetic tension from overlying fields that confine the proto-ejecta. In studies of global potential (current-free) model…