Search Publications
The lively accretion disc in NGC 2992 - I. Transient iron K emission lines in the high-flux state
Bianchi, S.; De Marco, B.; Matt, G. +5 more
We report on one of the brightest flux levels of the Seyfert 2 galaxy NGC 2992 ever observed in X-rays, on 2019 May. The source has been monitored every few days from 2019 March 26 to 2019 December 14 by Swift-X-Ray Telescope (XRT), and simultaneous XMM-Newton (250 ks) and NuSTAR (120 ks) observations were triggered on 2019 May 6. The high count r…
Solar Intensity X-Ray and Particle Spectrometer SIXS: Instrument Design and First Results
Schmidt, W.; Andersson, H.; Grande, M. +25 more
The Solar Intensity X-ray and particle Spectrometer (SIXS) on the BepiColombo Mercury Planetary Orbiter ("Bepi") measures the direct solar X-rays, energetic protons, and electrons that bombard, and interact with, the Hermean surface. The interactions result in X-ray fluorescence and scattering, and particle induced X-ray emission (PIXE), i.e. "glo…
A DESGW Search for the Electromagnetic Counterpart to the LIGO/Virgo Gravitational-wave Binary Neutron Star Merger Candidate S190510g
Smith, M.; Lidman, C.; Rest, A. +90 more
We present the results from a search for the electromagnetic counterpart of the LIGO/Virgo event S190510g using the Dark Energy Camera (DECam). S190510g is a binary neutron star (BNS) merger candidate of moderate significance detected at a distance of 227 ± 92 Mpc and localized within an area of 31 (1166) square degrees at 50% (90%) confidence. Wh…
Coronal Electron Density Fluctuations Inferred from Akatsuki Spacecraft Radio Observations
Imamura, T.; Song, P.; Ando, H. +6 more
Trans-coronal radio observations were taken during the 2011 observing campaign of the Akatsuki spacecraft through superior conjunction. The observed X-band (8.4 GHz) signals exhibit frequency fluctuations (FF) that are produced by temporal variations in electron density along the radio ray path. A two-component model for interpretation of the FF i…
Testing the relativistic Doppler boost hypothesis for the binary candidate quasar PG1302-102 with multiband Swift data
Stern, Daniel; Graham, Matthew J.; Haiman, Zoltán +4 more
The bright quasar PG1302-102 has been identified as a candidate supermassive black hole binary from its near-sinusoidal optical variability. While the significance of its optical periodicity has been debated due to the stochastic variability of quasars, its multiwavelength variability in the ultraviolet (UV) and optical bands is consistent with re…
Warning Time Analysis From SEP Simulations of a Two-Tier REleASE System Applied to Mars Exploration
Posner, A.; Strauss, R. D.
The sudden exposure to energetic protons from solar energetic particle (SEP) events beyond the Earth's magnetosphere and en route to and from Mars can, in extreme cases, lead to acute radiation sickness, an impairing, mission-endangering condition for astronauts. Timely warnings of their impending occurrence may significantly reduce radiation expo…
Metallicity has followed local gravitational potential of galaxies since z = 3
Christensen, L.; Møller, P.
The MZ relation between stellar mass (M*) and metallicity (Z) of nearby galaxies has been described as both a global and local property, I.e. valid also on sub-galaxy scales. Here, we show that Z has remained a local property, following the gravitational potential, since z = 3. In absorption, the MZ relation has been well studied, and w…
The Lyman Alpha Reference Sample. XI. Efficient turbulence-driven Lyα escape and an analysis of IR, CO, and [C II]158 µm
Östlin, G.; Hayes, M.; Kunth, D. +8 more
Context. Lyman-α (Lyα) is the brightest emission line in star-forming galaxies. However, its interpretation in terms of physical properties is hampered by the resonant nature of Lyα photons. In order to remedy this complicated situation, the Lyman Alpha Reference Sample (LARS) was defined, enabling the study of Lyα production and escape mechanisms…
Near-infrared Spectroscopy of CK Vulpeculae: Revealing a Remarkably Powerful Blast from the Past
Gehrz, R. D.; Shahbandeh, M.; Eyres, S. P. S. +6 more
CK Vulpeculae (CK Vul), which erupted in AD 1670-71, was long considered to be a nova outburst; however, recent observations have required that alternative scenarios be considered. Long-slit infrared spectroscopy of a forbidden line of iron reported here has revealed high line-of-sight velocities (∼±900 km s-1) of the ansae at the tips …
Failed prominence eruptions near 24 cycle maximum
Filippov, B.
We analyse 16 failed filament eruptions observed near 24 solar cycle maximum from 2013 May to 2014 July. No significant rotation of filament spines is observed during the ascent in all studied failed eruptions, which does not support kink-instability mechanism of triggering the eruptions. We calculate potential magnetic field distributions in the …