Search Publications
Controversial age spreads from the main sequence turn-off and red clump in intermediate-age clusters in the LMC
Cabrera-Ziri, I.; Bastian, N.; Kozhurina-Platais, V. +5 more
Most star clusters at an intermediate age (1-2 Gyr) in the Large and Small Magellanic Clouds show a puzzling feature in their color-magnitude diagrams (CMD) that is not in agreement with a simple stellar population. The main sequence turn-off of these clusters is much broader than expected from photometric uncertainties. One interpretation of this…
Cosmological constraint on the light gravitino mass from CMB lensing and cosmic shear
Osato, Ken; Yoshida, Naoki; Kamada, Ayuki +2 more
Light gravitinos of mass lesssim O (10) eV are of particular interest in cosmology, offering various baryogenesis scenarios without suffering from the cosmological gravitino problem. The gravitino may contribute considerably to the total matter content of the Universe and affect structure formation from early to present epochs. After the gravitino…
Erratic Flaring of BL Lac in 2012-2013: Multiwavelength Observations
Stern, Daniel; Baloković, Mislav; Grupe, Dirk +7 more
BL Lac, the eponymous blazar, flared to historically high levels at millimeter, infrared, X-ray, and gamma-ray wavelengths in 2012. We present observations made with Herschel, Swift, NuSTAR, Fermi, the Submillimeter Array, CARMA, and the VLBA in 2012-2013, including three months with nearly daily sampling at several wavebands. We have also conduct…
A Joint Chandra and Swift View of the 2015 X-ray Dust-scattering Echo of V404 Cygni
Brandt, W. N.; Smith, R.; Neilsen, J. +4 more
We present a combined analysis of the Chandra and Swift observations of the 2015 X-ray echo of V404 Cygni. Using a stacking analysis, we identify eight separate rings in the echo. We reconstruct the soft X-ray light curve of the 2015 June outburst using the high-resolution Chandra images and cross-correlations of the radial intensity profiles, ind…
The atmosphere of comet 67P/Churyumov-Gerasimenko diagnosed by charge-exchanged solar wind alpha particles
Kallio, E.; Gunell, H.; Behar, E. +6 more
Context. The ESA/Rosetta mission has been orbiting comet 67P/Churyumov-Gerasimenko since August 2014, measuring its dayside plasma environment. The ion spectrometer onboard Rosetta has detected two ion populations, one energetic with a solar wind origin (H+, He2+, He+), the other at lower energies with a cometary o…
Multi-spacecraft Observations and Transport Modeling of Energetic Electrons for a Series of Solar Particle Events in August 2010
Dresing, N.; Dröge, W.; Klassen, A. +1 more
During 2010 August a series of solar particle events was observed by the two STEREO spacecraft as well as near-Earth spacecraft. The events, occurring on August 7, 14, and 18, originated from active regions 11093 and 11099. We combine in situ and remote-sensing observations with predictions from our model of three-dimensional anisotropic particle …
Global Energetics of Solar Flares. IV. Coronal Mass Ejection Energetics
Aschwanden, Markus J.
This study entails the fourth part of a global flare energetics project, in which the mass m cme, kinetic energy E kin, and the gravitational potential energy E grav of coronal mass ejections (CMEs) is measured in 399 M and X-class flare events observed during the first 3.5 years of the Solar Dynamics Observatory (…
On the Active Region Bright Grains Observed in the Transition Region Imaging Channels of IRIS
De Pontieu, B.; Rouppe van der Voort, L.; Skogsrud, H.
The Interface Region Imaging Spectrograph (IRIS) provides spectroscopy and narrow band slit-jaw (SJI) imaging of the solar chromosphere and transition region at unprecedented spatial and temporal resolutions. Combined with high-resolution context spectral imaging of the photosphere and chromosphere as provided by the Swedish 1 m Solar Telescope (S…
A comparative study of dipolarization fronts at MMS and Cluster
Russell, C. T.; Anderson, B. J.; Nakamura, R. +15 more
We present a statistical study of dipolarization fronts (DFs), using magnetic field data from MMS and Cluster, at radial distances below 12 RE and 20 RE, respectively. Assuming that the DFs have a semicircular cross section and are propelled by the magnetic tension force, we used multispacecraft observations to determine the …
Observation of the Evolution of a Current Sheet in a Solar Flare
Liu, Rui; Alexander, David; McAteer, R. T. James +1 more
We report multi-wavelength and multi-viewpoint observations of a solar eruptive event that involves loop-loop interactions. During a C2.0 flare, motions associated with inflowing and outflowing plasma provide evidence for ongoing magnetic reconnection. The flare loop top and a rising “concave-up” feature are connected by a current-sheet-like struc…