Search Publications
Diagnostics of the Prominence Plasma from Hα and Mg II Spectral Observations
Heinzel, Petr; Schmieder, Brigitte; Chen, Yao +5 more
The goal of this paper is to derive the physical conditions of the prominence observed on 2017 March 30. To do so, we use a unique set of data in Mg II lines obtained with the space-borne Interface Region Imaging Spectrograph (IRIS) and in Hα line with the ground-based Multi-Channel Subtractive Double Pass spectrograph operating at the Meudon sola…
High Forbidden-to-resonance Line Ratio of O VII Discovered from the Cygnus Loop
Tanaka, T.; Mori, K.; Gu, L. +5 more
Charge exchange (CX) is an important process in shock physics because it indicates an interaction between downstream ions and ambient neutral hydrogen, suggesting the presence of a collisionless shock. We present a high-resolution spectroscopy of an X-ray bright spot in a nearby supernova remnant (SNR), the Cygnus Loop, with the Reflection Grating…
Preflare Processes, Flux Rope Activation, Large-scale Eruption, and Associated X-class Flare from the Active Region NOAA 11875
Joshi, Bhuwan; Mitra, Prabir K.
We present a multiwavelength analysis of the eruption of a hot coronal channel associated with an X1.0 flare (SOL2013-10-28T02:03) from the active region NOAA 11875 by combining observations from Atmospheric Imaging Assembly/Solar Dynamics Observatory (SDO), Helioseismic and Magnetic Imager/SDO, Reuven Ramaty High Energy Solar Spectroscopic Imager…
Testing of the Taylor Frozen-in-flow Hypothesis at Electron Scales in the Solar Wind Turbulence
Sahraoui, F.; Huang, S. Y.
In single-spacecraft observations the Taylor frozen-in-flow hypothesis is usually used to infer wavenumber spectra of turbulence from the frequency ones. While this hypothesis can be valid at MHD scales in the solar wind because of the small phase speeds of the fluctuations in comparison with the solar wind flow speed, its validity at electron sca…
Diagnosing 0.1-10 au Scale Morphology of the FU Ori Disk Using ALMA and VLTI/GRAVITY
Henning, Thomas; Mérand, Antoine; Takami, Michihiro +11 more
We report new Atacama Large Millimeter/submillimeter Array Band 3 (86-100 GHz; ∼80 mas angular resolution) and Band 4 (146-160 GHz; ∼50 mas angular resolution) observations of the dust continuum emission toward the archetypal and ongoing accretion burst young stellar object FU Ori, which simultaneously covered its companion, FU Ori S. In addition,…
Stealth Coronal Mass Ejections from Active Regions
Long, David M.; O'Kane, Jennifer; Green, Lucie +1 more
Stealth coronal mass ejections (CMEs) are eruptions from the Sun that have no obvious low coronal signature. These CMEs are characteristically slower events but can still be geoeffective and affect space weather at Earth. Therefore, understanding the science underpinning these eruptions will greatly improve our ability to detect and, eventually, f…
IRIS Observations of Magnetic Interactions in the Solar Atmosphere between Preexisting and Emerging Magnetic Fields. II. UV Emission Properties
Young, Peter R.; Guglielmino, Salvo L.; Zuccarello, Francesca
Multiwavelength ultraviolet (UV) observations by the Interface Region Imaging Spectrograph satellite in active region NOAA 12529 have recently pointed out the presence of long-lasting brightenings, akin to UV bursts, and simultaneous plasma ejections occurring in the upper chromosphere and transition region during secondary flux emergence. These s…
Spectral Energy Distributions of Companion Galaxies to z ∼ 6 Quasars
Walter, F.; Rix, H. -W.; Fan, X. +10 more
Massive, quiescent galaxies are already observed at redshift z ∼ 4, i.e., ∼1.5 Gyr after the big bang. Current models predict them to be formed via massive, gas-rich mergers at z > 6. Recent ALMA observations of the cool gas and dust in z ≳ 6 quasars have discovered [C II]- and far-infrared-bright galaxies adjacent to several quasars. In this w…
Mass Loss of Different Stellar Populations in Globular Clusters: The Case of M4
Milone, A. P.; Cordoni, G.; Marino, A. F. +3 more
In a Globular Cluster (GC), the mass loss during the red giant branch (RGB) phase and the helium content are fundamental ingredients to constrain the horizontal-branch (HB) morphology. While many papers have been dedicated to the helium abundance in different stellar populations, small efforts have been made to disentangle the effects of mass loss…
Peculiar Velocities of Galaxies Just Beyond the Local Group
Anand, Gagandeep S.; Shaya, Edward J.; Tully, R. Brent +2 more
The Milky Way lies in a thin plane, the Local Sheet, a part of a wall bounding the Local Void lying toward the north supergalactic pole. Galaxies with accurate distances both above and below this supergalactic equatorial plane have systematically negative peculiar velocities. The interpretation of this situation is that the Local Void is expanding…