Search Publications
Cloud Atlas: Unraveling the Vertical Cloud Structure with the Time-series Spectrophotometry of an Unusually Red Brown Dwarf
Schneider, Glenn; Apai, Dániel; Marley, Mark +8 more
Rotational modulations of emission spectra in brown dwarf and exoplanet atmospheres show that clouds are often distributed non-uniformly in these ultracool atmospheres. The spatial heterogeneity in cloud distribution demonstrates the impact of atmospheric dynamics on cloud formation and evolution. In this study, we update the Hubble Space Telescop…
Investigation of Coronal Properties of X-Ray Bright G-dwarf Stars Based on the Solar Surface Magnetic Field-Corona Relationship
Takasao, Shinsuke; Mitsuishi, Ikuyuki; Ishihara, Daisuke +4 more
We investigated the coronal properties of G-dwarf stars including the Sun over a wide range of X-ray luminosity LX (3 × 1026 to 2 × 1030 erg s-1). We analyzed the archival data of 10 X-ray bright (LX > 1028 erg s-1) G-dwarf stars to derive their emission measure (EM) a…
Electric Current Evolution at the Footpoints of Solar Eruptions
Barczynski, Krzysztof; Aulanier, Guillaume; Janvier, Miho +2 more
Electric currents play a critical role in the triggering of solar flares and their evolution. The aim of the present paper is to test whether the surface electric current has a surface or subsurface fixed source as predicted by the circuit approach of flare physics, or is the response of the surface magnetic field to the evolution of the coronal m…
Microlensing Analysis for the Gravitational Lens Systems SDSS0924+0219, Q1355-2257, and SDSS1029+2623
Mediavilla, E.; Rojas, K.; Fian, C. +3 more
We use spectroscopic observations of the gravitationally lensed systems SDSS0924+0219(BC), Q1355-2257(AB), and SDSS1029+2623(BC) to analyze microlensing and dust extinction in the observed components. We detect chromatic microlensing effects in the continuum and microlensing in the broad emission line profiles of the systems SDSS0924+0219(BC) and …
AGILE and Konus-Wind Observations of GRB 190114C: The Remarkable Prompt and Early Afterglow Phases
Antonelli, L. A.; Costa, E.; Barbiellini, G. +36 more
GRB 190114C represents a breakthrough for the physics of gamma-ray bursts (GRBs), being the first GRB with delayed emission above 300 GeV, as reported by MAGIC. We present in this paper the sub-MeV/MeV data of the prompt and early afterglow emissions of GRB 190114C, as detected by AGILE and Konus-Wind, in the 20 keV-100 MeV energy range. The first…
On the Metamorphosis of the Bailey Diagram for RR Lyrae Stars
Kovtyukh, V.; Lemasle, B.; Walker, A. R. +37 more
We collected over 6000 high-resolution spectra of four dozen field RR Lyrae (RRL) variables pulsating either in the fundamental (39 RRab) or in the first overtone (9 RRc) mode. We measured radial velocities (RVs) of four strong metallic and four Balmer lines along the entire pulsational cycle and derived RV amplitudes with accuracies better than 1…
Revisiting the Magnetic Field of the L183 Starless Core
Karoly, Janik; Bastien, Pierre; Coudé, Simon +4 more
We present observations of linear polarization from dust thermal emission at 850 µm toward the starless cloud L183. These data were obtained at the James Clerk Maxwell Telescope (JCMT) using the SCUBA-2 camera in conjunction with its polarimeter POL-2. Polarized dust emission traces the plane-of-sky magnetic field structure in the cloud, thu…
The Inner Disk of RY Tau: Evidence of Stellar Occultation by the Disk Atmosphere at the Sublimation Rim from K-band Continuum Interferometry
Monnier, John D.; Kraus, Stefan; Baron, Fabien +13 more
We present models of the inner region of the circumstellar disk of RY Tau that aim to explain our near-infrared (K-band: 2.1 µm) interferometric observations, while remaining consistent with the optical to near-infrared portions of the spectral energy distribution. Our submilliarcsecond-resolution CHARA Array observations are supplemented wi…
Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample. IV. The Kinematic Signature of the Galactic Warp
Wang, H. -F.; Huang, Y.; Chen, B. -Q. +5 more
Using a sample of nearly 140,000 red clump stars selected from the LAMOST and Gaia Galactic surveys, we have mapped mean vertical velocity $\overline{{V}_{z}}$ in the X-Y plane for a large volume of the Galactic disk (6 < R < 16 kpc; -20 < φ < 50°; $| Z| \lt 1$ kpc). A clear signature where $\overline{{V}_{z}}$ increases with R is dete…
Improved Infrared Photometry and a Preliminary Parallax Measurement for the Extremely Cold Brown Dwarf CWISEP J144606.62-231717.8
Meisner, Aaron M.; Cushing, Michael C.; Kirkpatrick, J. Davy +6 more
We present follow-up Spitzer observations at 3.6 µm (ch1) and 4.5 µm (ch2) of CWISEP J144606.62-231717.8, one of the coldest known brown dwarfs in the solar neighborhood. This object was found by mining the Wide-field Infrared Survey Explorer (WISE) and NEOWISE data via the CatWISE Preliminary Catalog by Meisner et al., where an initia…