Search Publications
ALMA Reveals Hidden Morphologies in the Molecular Envelope of VY Canis Majoris
Humphreys, R. M.; Decin, L.; Richards, A. M. S. +2 more
The J = 2 → 1 transition of CO near 230 GHz and the J = 3 → 2 line of HCN at 265 GHz have been imaged in the envelope of the red hypergiant star, VY Canis Majoris (VY CMa), using the Atacama Large Millimeter Array (ALMA) with angular resolutions 0.″2-1.″5; single-dish data were added to provide sensitivity up to 30″. These images reveal a far more…
The Evryscope Fast Transient Engine: Real-time Detection for Rapidly Evolving Transients
Law, Nicholas M.; Corbett, Hank; Carney, Jonathan +8 more
Astrophysical transients with rapid developments on subhour timescales are intrinsically rare. Due to their short durations, events like stellar superflares, optical flashes from gamma-ray bursts, and shock breakouts from young supernovae are difficult to identify on timescales that enable spectroscopic follow-up. This paper presents the Evryscope…
The Hα Luminosity Function of Galaxies at z 4.5
Illingworth, Garth D.; Labbé, Ivo; Bouwens, Rychard J. +5 more
We present the Hα luminosity function (LF) derived from a large sample of Lyman break galaxies at z ~ 4.5 over the GOODS-South and North fields. This study makes use of the new, full-depth Spitzer/IRAC [3.6] and [4.5] imaging from the GOODS Re-ionization Era wide-Area Treasury from the Spitzer program. The Hα flux is derived from the offset betwee…
Center-to-limb Variation of Transition-region Doppler Shifts in Active Regions
Tripathi, Durgesh; Kashyap, Vinay L.; Ghosh, Avyarthana +2 more
Studying Doppler shifts provides deep insights into the flow of mass and energy in the solar atmosphere. We perform a comprehensive measurement of Doppler shifts in the transition region and its center-to-limb variation (CLV) in the strong-field regions (∣ B ∣ ≥ 50 G) of 50 active regions (ARs), using the Si IV 1394 Å line recorded by the Interfac…
The Pristine survey - XX. GTC follow-up observations of extremely metal-poor stars identified from Pristine and LAMOST
Sestito, Federico; Martin, Nicolas F.; Aguado, David S. +5 more
Ultra-metal-poor stars ($\rm {[Fe/H]} \lt -4.0$) are very rare, and finding them is a challenging task. Both narrow-band photometry and low-resolution spectroscopy have been useful tools for identifying candidates, and in this work, we combine both approaches. We cross-matched metallicity-sensitive photometry from the Pristine survey with the low-…
Application of Deep Reinforcement Learning to Major Solar Flare Forecasting
Moon, Yong-Jae; Yi, Kangwoo; Jeong, Hyun-Jin
In this study, we present the application of deep reinforcement learning to the forecasting of major solar flares. For this, we consider full-disk magnetograms at 00:00 UT from the Solar and Heliospheric Observatory/Michelson Doppler Imager (1996-2010) and the Solar Dynamics Observatory/Helioseismic and Magnetic Imager (2011-2019), as well as Geos…
Surrounded by Giants: Habitable Zone Stability Within the HD 141399 System
Kane, Stephen R.
The search for exoplanets has revealed a diversity of planetary system architectures, the vast majority of which diverge significantly from the template of the solar system. In particular, giant planets beyond the snow line are relatively rare, especially for low-mass stars, placing the solar system within a small category of systems with multiple…
In-orbit performance of LE onboard Insight-HXMT in the first 5 years
Li, Xiaobo; Zhang, Shuang-Nan; Tuo, Youli +18 more
The low-energy X-ray telescope (LE) is a main instrument of the Insight-HXMT mission and consists of 96 swept charge devices covering the 1–10 keV energy band. The energy gain and resolution are continuously calibrated by analyzing Cassiopeia A (Cas A) and blank sky data, while the effective areas are also calibrated with the observations of the C…
The Yarkovsky effect and bulk density of near-Earth asteroids from Gaia DR3
Oszkiewicz, Dagmara; Tanga, Paolo; Carry, Benoit +3 more
Aims: The primary objective of this study is to utilize Gaia DR3 asteroid astrometry to detect the Yarkovsky effect, a non-gravitational acceleration that affects the orbits of small asteroids. We then computed the bulk densities for the sample of objects for which we obtained an estimation of the Yarkovsky effect.
Methods: We used the v…
Multiwavelength observations of PSR J2021+4026 across a mode change reveal a phase shift in its X-ray emission
Harding, A. K.; Kerr, M.; Marelli, M. +6 more
Context. We have investigated the multiwavelength emission of PSR J2021+4026, the only isolated γ-ray pulsar known to be variable, which in October 2011 underwent a simultaneous change in γ-ray flux and spin-down rate, followed by a second mode change in February 2018. Multiwavelength monitoring is crucial to understand the physics behind these ev…