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First observations of the Phoebe ring in optical light
Hedman, Matthew M.; Burns, Joseph A.; Tamayo, Daniel
The Phoebe ring, Saturn’s largest and faintest ring, lies far beyond the planet’s well-known main rings. It is primarily sourced by collisions with Saturn’s largest irregular satellite Phoebe, perhaps through stochastic macroscopic collisions, or through more steady micrometeoroid bombardment. The ring was discovered with the Spitzer Space Telesco…
Density Diagnostics of Coronal Mass Ejection Cores with the Solar Dynamics Observatory/Atmospheric Imaging Assembly
Landi, E.; Miralles, M. P.
In this Letter, we investigate the application of the intensity ratio from pairs of narrow-band images from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory, the Extreme Ultraviolet (EUV) Imager (EUVI) on board the Sun Earth Connection Coronal and Heliospheric Investigation, and the EUV Imaging Telescope (EIT) on board the …
Reverse-current effect in present-day models of solar flares: Theory and high-accuracy observations
Gritsyk, P. A.; Somov, B. V.
We propose an accurate analytical model for the source of hard X-ray emission from a flare in the form of a "thick target" with a reverse current to explain the results of present-day observations of solar flares onboard the GOES, Hinode, RHESSI, and TRACE satellites. The model, one-dimensional in coordinate space and two-dimensional in velocity s…
Effective absorbing column density in the gamma-ray burst afterglow X-ray spectra
D'Avanzo, P.; Campana, S.; Tagliaferri, G. +9 more
We investigate the scaling relation between the observed amount of absorption in the X-ray spectra of gamma-ray burst afterglows and the absorber redshift. Through dedicated numerical simulations of an ideal instrument, we establish that this dependence has a power-law shape with index 2.4. However, for real instruments, this value depends on thei…
Young Star Clusters in the Circumnuclear Region of NGC 2110
Durré, Mark; Mould, Jeremy
High-resolution observations in the near infrared show star clusters around the active galactic nucleus (AGN) of the Seyfert 1 NGC 2110, along with a 90 × 35 pc bar of shocked gas material around its nucleus. These are seen for the first time in our imaging and gas kinematics of the central 100 pc with the Keck OSIRIS instrument with adaptive opti…
Influence of Martian crustal magnetic anomalies on the emission of energetic neutral hydrogen atoms
Barabash, S.; Futaana, Y.; Grigoriev, A. +2 more
We analyze the data on hydrogen energetic neutral atoms (ENAs) emissions from the dayside of Mars, recorded by a Neutral Particle Detector of the Analyzer of Space Plasmas and Energetic Atoms aboard Mars Express from 14 March to 9 July 2004. We first identify and analyze events of the ENA flux enhancement coinciding with the presence of the crusta…
The counterpart/s of IGR J20159+3713/SWIFT J2015.9+3715: dissecting a complex region with emission from keV to TeV
Bird, A. J.; Ubertini, P.; Landi, R. +4 more
We report on the identification of a new soft gamma-ray source, namely IGR J20159+3713/SWIFT J2015.9+3715, first detected by INTEGRAL/IBIS and then confirmed by Swift/BAT. The source, which has an observed 20-100 keV flux in the range (0.7-1.4) × 10-11 erg cm-2 s-1, encloses a Fermi variable source (2FGL J2015.6+37…
Binary pulsars studies with multiwavelength sky surveys - I. Companion star identification
Page, M. J.; Possenti, A.; Corongiu, A. +7 more
The identification of the stellar companions to binary pulsars is key to studying the evolution of the binary system and how this is influenced by the interactions between the two stars. For only a fraction of the known binary pulsars, the stellar companions have been identified. Here, we used 11 source catalogues available from multiwavelength (u…
The Panchromatic Hubble Andromeda Treasury. VI. The Reliability of Far-ultraviolet Flux as a Star Formation Tracer on Subkiloparsec Scales
Bell, Eric F.; Dolphin, Andrew E.; Skillman, Evan D. +6 more
We have used optical observations of resolved stars from the Panchromatic Hubble Andromeda Treasury to measure the recent (<500 Myr) star formation histories (SFHs) of 33 far-UV (FUV)-bright regions in M31. The region areas ranged from ~104 to 106 pc2, which allowed us to test the reliability of FUV flux as a tr…
Detection of a strongly negative surface potential at Saturn's moon Hyperion
Coates, A. J.; Krupp, N.; Dougherty, M. K. +7 more
On 26 September 2005, Cassini conducted its only close targeted flyby of Saturn's small, irregularly shaped moon Hyperion. Approximately 6 min before the closest approach, the electron spectrometer (ELS), part of the Cassini Plasma Spectrometer (CAPS) detected a field-aligned electron population originating from the direction of the moon's surface…