Search Publications
Fast optical flares from M dwarfs detected by a one-second-cadence survey with Tomo-e Gozen
Kobayashi, Naoto; Takita, Satoshi; Arimatsu, Ko +18 more
We report on a one-second-cadence wide-field survey for M-dwarf flares using the Tomo-e Gozen camera mounted on the Kiso Schmidt telescope. We detect 22 flares from M3-M5 dwarfs with a rise time of 5 s ≲ trise ≲ 100 s and an amplitude of 0.5 ≲ ΔF/F⋆ ≲ 20. The flare light-curves mostly show steeper rises and shallower decays t…
EXPRES. III. Revealing the Stellar Activity Radial Velocity Signature of ϵ Eridani with Photometry and Interferometry
Monnier, John D.; Lanthermann, Cyprien; Anugu, Narsireddy +20 more
The distortions of absorption line profiles caused by photospheric brightness variations on the surfaces of cool, main-sequence stars can mimic or overwhelm radial velocity (RV) shifts due to the presence of exoplanets. The latest generation of precision RV spectrographs aims to detect velocity amplitudes ≲ 10 cm s-1, but requires mitig…
Total Solar Irradiance during the Last Five Centuries
Berrilli, Francesco; Bertello, Luca; Criscuoli, Serena +3 more
The total solar irradiance (TSI) varies on timescales of minutes to centuries. On short timescales it varies due to the superposition of intensity fluctuations produced by turbulent convection and acoustic oscillations. On longer timescales, it changes due to photospheric magnetic activity, mainly because of the facular brightenings and dimmings c…
Variation in Cosmic-Ray Intensity Lags Sunspot Number: Implications of Late Opening of Solar Magnetic Field
Li, Gang; Wang, Yuming; Guo, Jingnan +2 more
Galactic cosmic rays (GCRs), the highly energetic particles that may raise critical health issues for astronauts in space, are modulated by solar activity, with their intensity lagging behind the variation in sunspot number (SSN) by about one year. Previously, this lag has been attributed to the combined effect of outward convecting solar wind and…
UV to submillimetre luminosity functions of TNG50 galaxies
Vogelsberger, Mark; Pillepich, Annalisa; Nelson, Dylan +7 more
We apply the radiative transfer (RT) code SKIRT on a sample of ${\sim } 14\, 000$ low-redshift (z ≤ 0.1) galaxies extracted from the TNG50 simulation to enable an apples-to-apples comparison with observations. The RT procedure is calibrated via comparison of a subsample of TNG50 galaxies with the DustPedia observational sample: we compare several …
Three new brown dwarfs and a massive hot Jupiter revealed by TESS around early-type stars
Bieryla, Allyson; Latham, David W.; Brahm, Rafael +45 more
Context. The detection and characterization of exoplanets and brown dwarfs around massive AF-type stars is essential to investigate and constrain the impact of stellar mass on planet properties. However, such targets are still poorly explored in radial velocity (RV) surveys because they only feature a small number of stellar lines and those are us…
The X-ray emission of Be+stripped star binaries★
Smith, Myron A.; Nazé, Yaël; Rauw, Gregor +1 more
Using observations from Chandra, Swift, and XMM-Newton, we investigate the high-energy properties of all known (18) Be+sdO systems as well as seven additional Be binaries suspected to harbour stripped stars. The observed X-ray properties are found to be similar to those observed for other Be samples. The vast majority of these systems (15 out of 2…
Magnetospheric Response To Solar Wind Forcing: Ultra-Low-Frequency Wave-Particle Interaction Perspective
Zong, Qiugang
Solar wind forcing, e.g., interplanetary shock and/or solar wind dynamic pressure pulses impacting Earth's magnetosphere, manifests many fundamental important space physics phenomena, including producing electromagnetic waves, plasma heating, and energetic particle acceleration. This paper summarizes our present understanding of the magnetospheric…
The physical origin for spatially large scatter of IGM opacity at the end of reionization: The IGM Lyα opacity-galaxy density relation
Cai, Zheng; Kashino, Daichi; Onoue, Masafusa +9 more
The large opacity fluctuations in the z > 5.5 Lyα forest may indicate inhomogeneous progress of reionization. To explain the observed large scatter of the effective Lyα optical depth (τeff) of the intergalactic medium (IGM), fluctuation of UV background (Γ model), or the IGM gas temperature (T model) have been proposed, which predict…
Lack of other molecules in CO-rich debris discs: is it primordial or secondary gas?
Henning, Thomas; Hughes, A. Meredith; Moór, Attila +5 more
The nature of the gas in CO-rich debris discs remains poorly understood, as it could either be a remnant from the earlier Class II phase or of secondary origin, driven by the destruction of icy planetesimals. The aim of this paper was to elucidate the origin of the gas content in the debris discs via various simple molecules that are often detecte…