Search Publications
The Burst Cluster: Dark Matter in a Cluster Merger Associated with the Short Gamma-Ray Burst, GRB 050509B
Dahle, H.; Kouveliotou, C.; Wijers, R. A. M. J. +11 more
We have identified a merging galaxy cluster with evidence of two distinct subclusters. The X-ray and optical data suggest that the subclusters are presently moving away from each other after closest approach. This cluster merger was discovered from observations of the first well-localized short-duration gamma-ray burst (GRB), GRB 050509B. The Swif…
A Search for Magnesium in Europa's Atmosphere
Brown, M. E.; Hörst, S. M.
Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. W…
On Detecting Transient Phenomena
Bélanger, G.
Transient phenomena are interesting and potentially highly revealing of details about the processes under observation and study that could otherwise go unnoticed. It is therefore important to maximize the sensitivity of the method used to identify such events. In this article, we present a general procedure based on the use of the likelihood funct…
The XMM-Newton Spectrum of a Candidate Recoiling Supermassive Black Hole: An Elusive Inverted P-Cygni Profile
Jahnke, K.; Costantini, E.; Vignali, C. +12 more
We present a detailed spectral analysis of new XMM-Newton data of the source CXOC J100043.1+020637, also known as CID-42, detected in the COSMOS survey at z = 0.359. Previous works suggested that CID-42 is a candidate recoiling supermassive black hole (SMBH) showing also an inverted P-Cygni profile in the X-ray spectra at ~6 keV (rest) with an iro…
Does the Oosterhoff Dichotomy Exist in the Andromeda Galaxy? I. The Case of G11
Kinemuchi, Karen; Marconi, Marcella; Fiorentino, Giuliana +8 more
We present the first evidence that Oosterhoff type II globular clusters exist in the Andromeda galaxy (M31). On the basis of time-series photometry of the moderately metal-poor ([Fe/H] ~-1.6 dex) M31 globular cluster G11, obtained with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope, we detected and derived periods for 14 RR …
Evidence of Hot High Velocity Photoionized Plasma Falling on Actively Accreting T Tauri Stars
Gómez de Castro, Ana Ines
The He II (1640 Å) line and the resonance doublet of N V (UV1) provide a good diagnostic tool to constrain the excitation mechanism of hot (Te > 40,000 K) atmospheric/magnetospheric plasmas in T Tauri stars (TTSs). Making use of the data available in the Hubble Space Telescope archive, this work shows that there are at least two dist…
Impulsive Thermal X-Ray Emission from a Low-lying Coronal Loop
Fletcher, Lyndsay; Li, Youping; Liu, Siming
Understanding the relationship among different emission components plays an essential role in the study of particle acceleration and energy conversion in solar flares. In flares where gradual and impulsive emission components can be readily identified, the impulsive emission has been attributed to non-thermal particles. We carry out detailed analy…
Moving Magnetic Features Around AR 10930 from High-resolution Data Observed by Hinode/SOT
Zhang, Hongqi; Li, Xiaobo
We investigate the origin, configuration, and evolution of moving magnetic features (MMFs) in the moat and penumbra regions of NOAA AR 10930 using Hinode/SOT filtergrams and magnetograms. We differentiate MMFs into four types in terms of the location of first appearance and the source of initial flux. The main results are summed up as follows: (1)…
Spatially Resolved Spectroscopy of a Pulsar Wind Nebula in MSH 15-56
Kawai, Nobuyuki; Nakamori, Takeshi; Yatsu, Yoichi +2 more
We report the study of a pulsar wind nebula (PWN) in the middle-aged supernova remnant (SNR) MSH 15-56. High-resolution X-ray imaging observations using XMM-Newton and Chandra provided clear images of its comet-like structure, as seen in other PWNe moving rapidly through interstellar mediums. At the PWN apex, Chandra detected a point source emitti…
Reinterpretation of Slowdown of Solar Wind Mean Velocity in Nonlinear Structures Observed Upstream of Earth's Bow Shock
Liu, Y.; Dandouras, I.; Rème, H. +10 more
Two of the many features associated with nonlinear upstream structures are (1) the solar wind (SW) mean flow slows down and deviates substantially and (2) the temperature of the plasma increases in the structure. In this Letter, we show that the SW beam can be present throughout the entire upstream event maintaining a nearly constant beam velocity…