Search Publications
A Comparison of Solar X-Ray Flare Timescales and Peak Temperatures with Associated Coronal Mass Ejections
Kahler, S. W.; Ling, A. G.
Recent work has shown that plots of solar flare X-ray peak temperatures, Tm, versus log peak fluxes, Fp, show statistically significant separations of lower Tm flares with fast (Vcme ≥ 1000 km s-1) and wide (Wcme = 360°) strong coronal mass ejections (CMEs) from higher Tm flares with no CMEs or slow (Vcme < 1000 km s-1) or…
Meta-analysis of Photometric and Asteroseismic Measurements of Stellar Rotation Periods: The Lomb–Scargle Periodogram, Autocorrelation Function, and Wavelet and Rotational Splitting Analysis for 92 Kepler Asteroseismic Targets
Suto, Yasushi; Benomar, Othman; Lu, Yuting +1 more
We perform intensity variability analyses (photometric analyses: the Lomb–Scargle periodogram, autocorrelation, and wavelet) and asteroseismic analysis of 92 Kepler solar-like main-sequence stars to understand the reliability of the measured stellar rotation periods. We focus on the 70 stars without reported stellar companions, and classify them i…
Absorption Line Search through Three Local Group Dwarf Galaxy Halos
Bregman, Joel N.; Qu, Zhijie
Dwarf galaxies are missing nearly all of their baryons and metals from the stellar disk, which are presumed to be in a bound halo or expelled beyond the virial radius. The virial temperature for galaxies with M h ~ 109-1010 M ⊙ is similar to the collisional ionization equilibrium temperature for the C IV…
A Massive, Dusty, HI Absorption-Selected Galaxy at z ≈ 2.46 Identified in a CO Emission Survey
Walter, F.; Prochaska, J. X.; Revalski, M. +4 more
We report a NOrthern Extended Millimeter Array (NOEMA) and Atacama Large Millimeter/submillimeter Array search for redshifted CO emission from the galaxies associated with seven high-metallicity ([M/H] ≥ -1.03) damped Lyα absorbers (DLAs) at z ≈ 1.64-2.51. Our observations yielded one new detection of CO(3-2) emission from a galaxy at z = 2.4604 u…
Discovery of NES, an Extended Tidal Structure in the Northeast of the Large Magellanic Cloud
Cignoni, Michele; Ripepi, Vincenzo; Tosi, Monica +4 more
We report on the discovery of a new diffuse stellar substructure protruding for >5° from the northeastern rim of the LMC disk. The structure, which we dub the northeast structure (NES), was identified by applying a Gaussian mixture model to a sample of strictly selected candidate members of the Magellanic System, extracted from the Gaia EDR3 ca…
Slowly Cooling White Dwarfs in NGC 6752
Cadelano, Mario; Pallanca, Cristina; Dalessandro, Emanuele +6 more
Recently, a new class of white dwarfs ("slowly cooling WDs") has been identified in the globular cluster M13. The cooling time of these stars is increased by stable thermonuclear hydrogen burning in their residual envelope. These WDs are thought to be originated by horizontal branch (HB) stars populating the HB blue tail that skipped the asymptoti…
Parallel Plasma Loops and the Energization of the Solar Corona
Tiwari, Sanjiv K.; Golub, Leon; Winebarger, Amy R. +15 more
The outer atmosphere of the Sun is composed of plasma heated to temperatures well in excess of the visible surface. We investigate short cool and warm (<1 MK) loops seen in the core of an active region to address the role of field-line braiding in energizing these structures. We report observations from the High-resolution Coronal imager (Hi-C)…
CWISE J014611.20-050850.0AB: The Widest Known Brown Dwarf Binary in the Field
Shkolnik, Evgenya; Meisner, Aaron M.; Cushing, Michael C. +17 more
While stars are often found in binary systems, brown dwarf binaries are much rarer. Brown dwarf-brown dwarf pairs are typically difficult to resolve because they often have very small separations. Using brown dwarfs discovered with data from the Wide-field Infrared Survey Explorer (WISE) via the Backyard Worlds: Planet 9 citizen science project, w…
Is the Core-cusp Problem a Matter of Perspective? Jeans Anisotropic Modeling against Numerical Simulations
Tian, Hao; Grand, Robert J. J.; Wang, Wenting +14 more
Mock member stars for 28 dwarf galaxies are constructed from the cosmological AURIGA simulation, which reflects the dynamical status of realistic stellar tracers. Axisymmetric Jeans Anisotropic Multi-Gaussian Expansion (JAM) modeling is applied to 6000 star particles for each system to recover the underlying matter distribution. The stellar or dar…
Estimating the Convective Turnover Time
Henry, Todd J.; Wright, Nicholas J.; Jao, Wei-Chun +2 more
The introduction of the Rossby number (R0), which incorporates the convective turnover time (τ), in 1984 was a pioneering idea for understanding the correlation between stellar rotation and activity. The convective turnover time, which cannot be measured directly, is often inferred using existing τ-mass or τ-color relations, typically e…