Search Publications
Model-independent Constraints on Cosmic Curvature: Implication from Updated Hubble Diagram of High-redshift Standard Candles
Li, Xiaolei; Liu, Yuting; Cao, Shuo +4 more
The cosmic curvature (Ωk) is a fundamental parameter for cosmology. In this paper, we propose an improved model-independent method to constrain the cosmic curvature, which is geometrically related to the Hubble parameter H(z) and luminosity distance DL(z). Using the currently largest H(z) sample from the well-known cosmic chr…
Detecting outliers in astronomical images with deep generative networks
Huertas-Company, Marc; Dubois, Yohan; Storey-Fisher, Kate +5 more
With the advent of future big-data surveys, automated tools for unsupervised discovery are becoming ever more necessary. In this work, we explore the ability of deep generative networks for detecting outliers in astronomical imaging data sets. The main advantage of such generative models is that they are able to learn complex representations direc…
Orbital inclination and mass of the exoplanet candidate Proxima c
Kervella, Pierre; Arenou, Frédéric; Schneider, Jean
We analyze the orbital parameters of the recently discovered exoplanet candidate Proxima c using a combination of its spectroscopic orbital parameters and Gaia DR2 astrometric proper motion anomaly. We obtain an orbital inclination of i = 152 ± 14 deg, corresponding to a planet mass of mc = 12-5+12 M⊕, c…
Thermal-nonthermal energy partition in solar flares derived from X-ray, EUV, and bolometric observations. Discussion of recent studies
Mann, G.; Warmuth, A.
Context. In solar flares, energy is released impulsively and is partly converted into thermal energy of hot plasmas and kinetic energy of accelerated nonthermal particles. It is crucial to constrain the partition of these two energy components to understand energy release and transport as well as particle acceleration in solar flares. Despite nume…
The dust-to-gas ratio, size distribution, and dust fall-back fraction of comet 67P/Churyumov-Gerasimenko: Inferences from linking the optical and dynamical properties of the inner comae.
Thomas, Nicolas; Marschall, Raphael; Wu, Jong-Shinn +3 more
In this work, we present results that simultaneously constrain the dust size distribution, dust-to-gas ratio, fraction of dust re-deposition, and total mass production rates for comet 67P/Churyumov-Gerasimenko. We use a 3D Direct Simulation Monte Carlo (DSMC) gas dynamics code to simulate the inner gas coma of the comet for the duration of the Ros…
Global 3D radiation magnetohydrodynamic simulations for FU Ori's accretion disc and observational signatures of magnetic fields
Jiang, Yan-Fei; Zhu, Zhaohuan; Stone, James M.
FU Ori is the prototype of FU Orionis systems that are outbursting protoplanetary discs. Magnetic fields in FU Ori's accretion discs have previously been detected using spectropolarimetry observations for Zeeman effects. We carry out global radiation ideal MHD simulations to study FU Ori's inner accretion disc. We find that (1) when the disc is th…
An X-ray activity cycle on the young solar-like star ɛ Eridani
Ducci, L.; Wolter, U.; Orlando, S. +7 more
Chromospheric Ca II activity cycles are frequently found in late-type stars, but no systematic programs have been created to search for their coronal X-ray counterparts. The typical time scale of Ca II activity cycles ranges from years to decades. Therefore, long-lasting missions are needed to detect the coronal counterparts. The XMM-Newton satell…
Exploring the Galactic Warp through Asymmetries in the Kinematics of the Galactic Disk
Majewski, Steven R.; Cheng, Xinlun; Anguiano, Borja +10 more
Previous analyses of large databases of Milky Way stars have revealed the stellar disk of our Galaxy to be warped and that this imparts a strong signature on the kinematics of stars beyond the solar neighborhood. However, due to the limitation of accurate distance estimates, many attempts to explore the extent of these Galactic features have gener…
TOI-222: a single-transit TESS candidate revealed to be a 34-d eclipsing binary with CORALIE, EulerCam, and NGTS
Henning, Thomas; Latham, David W.; Jordán, Andrés +58 more
We report the period, eccentricity, and mass determination for the Transiting Exoplanet Survey Satellite (TESS) single-transit event candidate TOI-222, which displayed a single 3000 ppm transit in the TESS 2-min cadence data from Sector 2. We determine the orbital period via radial velocity measurements (P = 33.9 d), which allowed for ground-based…
Testing interacting dark matter and dark energy model with cosmological data
Chen, Xuelei; Ma, Yin-Zhe; Cheng, Gong +2 more
We investigate the model of dark matter-dark energy (DM-DE) interaction with coupling strength proportional to the multiplication of dark sector densities with different power indices Q =γ ρcαρdβ. We first investigate the modification of the cosmic expansion history, and then further develop the formalis…