Search Publications
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…
Spin Parity of Spiral Galaxies. I. Corroborative Evidence for Trailing Spirals
Tadaki, Ken-ichi; Iye, Masanori; Fukumoto, Hideya
Whether the spiral structure of galaxies is trailing or leading has been a subject of debate. We present a new spin parity catalog of 146 spiral galaxies that lists the following three pieces of information: whether the spiral structure observed on the sky is S-wise or Z-wise; which side of the minor axis of the galaxy is darker and redder, based …
Manifestations of Three-dimensional Magnetic Reconnection in an Eruption of a Quiescent Filament: Filament Strands Turning to Flare Loops
Aulanier, Guillaume; Dudík, Jaroslav; Lörinčík, Juraj
We report on observations of the conversion of bright filament strands into flare loops during the 2012 August 31 filament eruption. Prior to the eruption, individual bright strands composing one of the legs of the filament were observed in the 171 Å filter channel data of the Atmospheric Imaging Assembly. After the onset of the eruption, one of t…
New Constraints on Early-type Galaxy Assembly from Spectroscopic Metallicities of Globular Clusters in M87
Romanowsky, Aaron J.; Strader, Jay; Brodie, Jean +1 more
The observed characteristics of globular cluster (GC) systems, such as metallicity distributions, are commonly used to place constraints on galaxy formation models. However, obtaining reliable metallicity values is particularly difficult because of our limited means to obtain high quality spectroscopy of extragalactic GCs. Often, “color-metallicit…