Search Publications
A multiplanet system of super-Earths orbiting the brightest red dwarf star GJ 887
Amado, P. J.; Reiners, A.; Ribas, I. +28 more
The closet exoplanets to the Sun provide opportunities for detailed characterization of planets outside the Solar System. We report the discovery, using radial velocity measurements, of a compact multiplanet system of super-Earth exoplanets orbiting the nearby red dwarf star GJ 887. The two planets have orbital periods of 9.3 and 21.8 days. Assumi…
The multi-thermal chromosphere. Inversions of ALMA and IRIS data
De Pontieu, B.; Leenaarts, J.; da Silva Santos, J. M. +4 more
Context. Numerical simulations of the solar chromosphere predict a diverse thermal structure with both hot and cool regions. Observations of plage regions in particular typically feature broader and brighter chromospheric lines, which suggests that they are formed in hotter and denser conditions than in the quiet Sun, but also implies a nonthermal…
The high-redshift SFR-M* relation is sensitive to the employed star formation rate and stellar mass indicators: towards addressing the tension between observations and simulations
Stalevski, M.; Baes, M.; Gonzalez, V. +9 more
There is a severe tension between the observed star formation rate (SFR)-stellar mass (M⋆) relations reported by different authors at z = 1-4. In addition, the observations have not been successfully reproduced by state-of-the-art cosmological simulations that tend to predict a factor of 2-4 smaller SFRs at a fixed M⋆. We exa…
The ASAS-SN catalogue of variable stars - VII. Contact binaries are different above and below the Kraft break
Kochanek, C. S.; Pinsonneault, M. H.; Stanek, K. Z. +11 more
We characterize ${\sim } 71\, 200$ W Ursae Majoris (UMa) type (EW) contact binaries, including ${\sim } 12\, 600$ new discoveries, using All-Sky Automated Survey for SuperNovae (ASAN-SN)V-band all-sky light curves along with archival data from Gaia, 2MASS, AllWISE, LAMOST, GALAH, RAVE, and APOGEE. There is a clean break in the EW period-luminosity…
Limits on the electromagnetic counterpart to S190814bv
Butler, N. R.; Lee, W. H.; Watson, A. M. +11 more
We derive limits on any electromagnetic counterpart to the compact binary merger S190814bv, whose parameters are consistent with the merger of a black hole and a neutron star. We present observations with the new wide-field optical imager DDOTI and also consider Swift/BAT observations reported by Palmer et al. We show that Swift/BAT would have det…
The single star path to Be stars
Langer, Norbert; Hastings, Ben; Wang, Chen
Context. Be stars are rapidly rotating B main sequence stars that show line emission due to an outflowing disc. By studying the evolution of rotating single star models, we can assess their contribution to the observed Be star populations.
Aims: We identify the main effects that cause single stars to approach critical rotation as functions of…
A Multiwavelength Analysis of the Faint Radio Sky (COSMOS-XS): the Nature of the Ultra-faint Radio Population
Smolčić, V.; Walter, F.; Riechers, D. A. +7 more
Ultra-deep radio surveys are an invaluable probe of dust-obscured star formation, but require a clear understanding of the relative contribution from radio active galactic nuclei (AGNs) to be used to their fullest potential. We study the composition of the µJy radio population detected in the Karl G. Jansky Very Large Array COSMOS-XS survey …
MOVES III. Simultaneous X-ray and ultraviolet observations unveiling the variable environment of the hot Jupiter HD 189733b
Vidotto, A. A.; Ehrenreich, D.; Lecavelier des Etangs, A. +8 more
In this third paper of the MOVES (Multiwavelength Observations of an eVaporating Exoplanet and its Star) programme, we combine Hubble Space Telescope far-ultraviolet (FUV) observations with XMM-Newton/Swift X-ray observations to measure the emission of HD 189733 in various FUV lines, and its soft X-ray spectrum. Based on these measurements we char…
The MUSE Hubble Ultra Deep Field Survey. XV. The mean rest-UV spectra of Lyα emitters at z > 3
Feltre, Anna; Bacon, Roland; Tresse, Laurence +22 more
We investigated the ultraviolet (UV) spectral properties of faint Lyman-α emitters (LAEs) in the redshift range 2.9 ≤ z ≤ 4.6, and we provide material to prepare future observations of the faint Universe. We used data from the MUSE Hubble Ultra Deep Survey to construct mean rest-frame spectra of continuum-faint (median MUV of -18 and do…
Magnification, dust, and time-delay constraints from the first resolved strongly lensed Type Ia supernova iPTF16geu
Cenko, S. B.; Lee, W. H.; Kulkarni, S. R. +14 more
We report lensing magnifications, extinction, and time-delay estimates for the first resolved, multiply imaged Type Ia supernova iPTF16geu, at z = 0.409, using Hubble Space Telescope (HST) observations in combination with supporting ground-based data. Multiband photometry of the resolved images provides unique information about the differential di…