Search Publications
Missions
Journals
Publication Years
The Pristine survey: XXVI. Chemical abundances of subgiant stars of the extremely metal-poor stream C-19
Bonifacio, P.; Caffau, E.; Fouesneau, M. +17 more
Context. The C-19 stellar stream is the most metal-poor stream known to date. While its wth and velocity dispersion indicate a dwarf galaxy origin, its metallicity spread and abundance patterns are more similar to those of globular clusters (GCs). If it is indeed of GC origin, its extremely low metallicity ([Fe/H]=‑3.4, estimated from giant stars)…
Testing disc reprocessing models for AGN optical variability by comparison of X-ray and optical power spectra of NGC 4395
Dhillon, V. S.; Knapen, J. H.; Breedt, E. +11 more
It is generally thought that active galactic nucleus (AGN) optical variability is produced, at least in part, by reprocessing of central X-rays by a surrounding accretion disc, resulting in wavelength-dependent lags between bands. Any good model of AGN optical variability should explain not only these lags, but also the overall pattern of variabil…
The Multiple Extended Tidal Tails of NGC 288
Grillmair, Carl J.
Using photometry and proper motions from Pan-STARRS, DECaLS, and Gaia Data Release 3, we detect a ∼35°–70° long trailing stellar debris stream associated with the globular cluster NGC 288. The trajectory of the trailing tail is not well matched by a model stream evolved in a static Galactic potential, but is reasonably well matched by a stream mod…
Dust-extinction-curve Variation in the Translucent Interstellar Medium Is Driven by Polycyclic Aromatic Hydrocarbon Growth
Hensley, Brandon S.; Zhang, Xiangyu; Green, Gregory M.
The first all-sky, high-resolution, 3D map of the optical extinction curve of the Milky Way revealed an unexpected steepening of the extinction curve in the moderate-density, "translucent" interstellar medium (ISM). We argue that this trend is driven by growth of the total mass of polycyclic aromatic hydrocarbons (PAHs) through gas-phase accretion…
Bioverse: Giant Magellan Telescope and Extremely Large Telescope Direct Imaging and High-resolution Spectroscopy Assessment—Surveying Exo-Earth O2 and Testing the Habitable Zone Oxygen Hypothesis
Wagner, Kevin; Apai, Dániel; Schlecker, Martin +4 more
Biosignature detection in the atmospheres of Earth-like exoplanets is one of the most significant and ambitious goals for astronomy, astrobiology, and humanity. Molecular oxygen is among the strongest indicators of life on Earth, but it will be extremely difficult to detect via transmission spectroscopy. We used the Bioverse statistical framework …
Simultaneous radio and X-ray observations of the transitional millisecond pulsar candidate 3FGL J1544.6-1125
Miller-Jones, J. C. A.; Russell, T. D.; Deller, A. T. +6 more
Transitional millisecond pulsars (tMSPs) are neutron star systems that alternate between a rotation-powered radio millisecond pulsar state and an accretion disc-dominated low-mass X-ray binary (LMXB)-like state on multi-year time-scales. During the LMXB-like state, the X-ray emission from tMSPs switches between 'low' and 'high' X-ray brightness mo…
Shock and SEP Modeling Study for the 2022 September 5 SEP Event
Lario, D.; Jebaraj, I. C.; Mitchell, D. G. +10 more
On 2022 September 5, during Parker Solar Probe's (PSP) 13th encounter, a fast shock wave and a related solar energetic particle (SEP) event were observed as the spacecraft approached the perihelion of its orbit. Observations from the Integrated Science Investigation of the Sun (IS⊙IS) instrument suite show that SEPs arrived at the spacecraft with …
The Rapid Formation of the Metal-poor Milky Way
Conroy, Charlie; Ting, Yuan-Sen; Johnson, Benjamin D. +6 more
Our understanding of the assembly timeline of the Milky Way has been transforming along with the dramatic increase in astrometric and spectroscopic data available over the past several years. Many substructures in chemo-dynamical space have been discovered and identified as the remnants of various galactic mergers. To investigate the timeline of t…
The physical properties of cluster chains
Meingast, Stefan; Alves, João; Ratzenböck, Sebastian +5 more
We explore the kinematics and star formation history of the Scorpius Centaurus (Sco-Cen) OB association following the initial identification of sequential, linearly aligned chains of clusters. Building upon our characterization of the Corona Australis (CrA) chain, we now analyze two additional major cluster chains that exhibit similar characterist…
The Magnetic Field Structure of Coronal Mass Ejections: A More Realistic Representation
Lugaz, Noé; Al-Haddad, Nada
It is often accepted that the magnetic field structure of coronal mass ejections (CMEs) is accurately represented by the highly twisted circular cross-section magnetic flux rope model, which is the basis of all most commonly used sketches and representations of CMEs. This paradigm has been developed based on studies in the 1970s and 1980s, and it …