Search Publications
Star-forming content of the giant molecular filaments in the Milky Way
Henning, Th.; Zhang, M.; Fang, M. +2 more
Context. Through observations numerous giant molecular filaments (GMFs) have been discovered in the Milky Way. Their role in the Galactic star formation and Galaxy-scale evolution of dense gas is unknown.
Aims: We investigate systematically the star-forming content of all currently known GMFs. This allows us to estimate the star formation rat…
A Gaia-Enceladus Analog in the EAGLE Simulation: Insights into the Early Evolution of the Milky Way
Helmi, Amina; Tissera, Patricia B.; Bignone, Lucas A.
We identify a simulated Milky Way analog in the EAGLE suite of cosmological hydrodynamical simulations. This galaxy not only shares similar global properties as the Milky Way, but was specifically selected because its merger history resembles that currently known for the Milky Way. In particular we find that this Milky Way analog has experienced i…
Evidence for the Third Stellar Population in the Milky Way’s Disk
Beers, Timothy C.; Lee, Young Sun; Carollo, Daniela +6 more
The Milky Way is a unique laboratory in which stellar properties can be measured and analyzed in detail. In particular, stars in the older populations encode information on the mechanisms that led to the formation of our Galaxy. In this article, we analyze the kinematics, spatial distribution, and chemistry of a large number of stars in the solar …
A discontinuity in the Teff-radius relation of M-dwarfs
Jordán, Andrés; Espinoza, Néstor; Brahm, Rafael +7 more
We report on 13 new high-precision measurements of stellar diameters for low-mass dwarfs obtained by means of near-infrared long-baseline interferometry with PIONIER at the Very Large Telescope Interferometer. Together with accurate parallaxes from Gaia DR2, these measurements provide precise estimates for their linear radii, effective temperature…
Clouds in arms
Belokurov, Vasily A.; Erkal, Denis
We use astrometry and broad-band photometry from Data Release 2 of the ESA's Gaia mission to map out low surface-brightness features in the stellar density distribution around the Large and Small Magellanic Clouds. The LMC appears to have grown two thin and long stellar streams in its Northern and Southern regions, highly reminiscent of spiral arm…
Euclid preparation. IV. Impact of undetected galaxies on weak-lensing shear measurements
Lilje, P. B.; Scott, D.; Schrabback, T. +22 more
In modern weak-lensing surveys, the common approach to correct for residual systematic biases in the shear is to calibrate shape measurement algorithms using simulations. These simulations must fully capture the complexity of the observations to avoid introducing any additional bias. In this paper we study the importance of faint galaxies below th…
The Near-ultraviolet Continuum Radiation in the Impulsive Phase of HF/GF-type dMe Flares. I. Data
Kowalski, Adam F.; Hawley, Suzanne L.; Valenti, Jeff A. +8 more
We present near-UV (NUV) flare spectra from the Hubble Space Telescope (HST)/Cosmic Origins Spectrograph during two moderate-amplitude U-band flares on the dM4e star GJ 1243. These spectra are some of the first accurately flux-calibrated, NUV flare spectra obtained over the impulsive phase in M dwarf flares. We observed these flares with a fleet o…
Benchmarking CME Arrival Time and Impact: Progress on Metadata, Metrics, and Events
Jian, L. K.; Temmer, M.; Dumbović, M. +9 more
Accurate forecasting of the arrival time and subsequent geomagnetic impacts of coronal mass ejections (CMEs) at Earth is an important objective for space weather forecasting agencies. Recently, the CME Arrival and Impact working team has made significant progress toward defining community-agreed metrics and validation methods to assess the current…
LRG-BEASTS: Transmission Spectroscopy and Retrieval Analysis of the Highly Inflated Saturn-mass Planet WASP-39b
Kirk, James; López-Morales, Mercedes; Espinoza, Néstor +5 more
We present a ground-based transmission spectrum and comprehensive retrieval analysis of the highly inflated Saturn-mass planet WASP-39b. We obtained low-resolution spectra (R ≈ 400) of a transit of WASP-39b using the ACAM instrument on the 4.2 m William Herschel Telescope as part of the LRG-BEASTS survey. Our transmission spectrum is in good agree…
CME-HSS Interaction and Characteristics Tracked from Sun to Earth
Veronig, Astrid M.; Dumbović, Mateja; Temmer, Manuela +9 more
In a thorough study, we investigate the origin of a remarkable plasma and magnetic field configuration observed in situ on June 22, 2011, near L1, which appears to be a magnetic ejecta (ME) and a shock signature engulfed by a solar wind high-speed stream (HSS). We identify the signatures as an Earth-directed coronal mass ejection (CME), associated…