Search Publications
Exploring the connection between ultraviolet/optical variations and radio emission in radio-quiet quasars: clues about the origin of radio emission
Liao, Mai; Wang, Junxian; Zhou, Minhua +1 more
Radio emission in radio-quiet quasars (RQQs) has long been a mystery and its physical origin remains unclear. In previous work, we have found that quasars that are more variable in ultraviolet (UV)/optical have stronger X-ray emission, indicating a link between disc turbulence and X-ray corona heating. In this work, for the first time, we investig…
Optimal Differential Astrometry for Multiconjugate Adaptive Optics. I. Astrometric Distortion Mapping using On-sky GeMS Observations of NGC 6723
McConnachie, Alan W.; Bono, Giuseppe; Fiorentino, Giuliana +7 more
The Extremely Large Telescope and the Thirty Meter Telescope will use state of the art multiconjugate adaptive optics (MCAO) systems to obtain the full D 4 advantage that their apertures can provide. However, to reach the full astrometric potential of these facilities for on-sky science requires understanding any residual astrometric di…
Precision measurement of a brown dwarf mass in a binary system in the microlensing event. OGLE-2019-BLG-0033/MOA-2019-BLG-035
Bennett, D. P.; Bryden, G.; Soszyński, I. +94 more
Context. Brown dwarfs are transition objects between stars and planets that are still poorly understood, for which several competing mechanisms have been proposed to describe their formation. Mass measurements are generally difficult to carry out for isolated objects as well as for brown dwarfs orbiting low-mass stars, which are often too faint fo…
Detection of p-mode Oscillations in HD 35833 with NEID and TESS
Mahadevan, Suvrath; Wright, Jason T.; Logsdon, Sarah E. +15 more
We report the results of observations of p-mode oscillations in the G0 subgiant star HD 35833 in both radial velocities and photometry with NEID and TESS, respectively. We achieve separate, robust detections of the oscillation signal with both instruments (radial velocity amplitude A RV = 1.11 ± 0.09 m s-1, photometric amplit…
A cautionary tale of Ly C escape fraction estimates from high-redshift galaxies
Ryan-Weber, E. V.; Arnouts, S.; Sawicki, M. +7 more
Measuring the escape fraction, fesc, of ionizing, Lyman continuum (Ly C) radiation is key to our understanding of the process of cosmic reionization. In this paper, we provide a methodology for recovering the posterior probability distribution of the Ly C escape fraction, $f_{\rm esc}^{\rm PDF}$, considering both the observational uncer…
V410 Puppis: A useful laboratory for early stellar evolution
Erdem, Ahmet; Sürgit, Derya; Blackford, Mark G. +6 more
New spectrometric (HERCULES) and ground-based multicolour photometric data on the multiple star V410 Puppis are combined with satellite photometry (HIPPARCOS and TESS), as well as historic astrometric observations. Absolute parameters for V410 Pup Aab are derived: MAa = 3.15 ± 0.10, MAb = 1.83 ± 0.08 (M⊙); RAa…
Hierarchical structure of YSO clusters in the W40 and Serpens South region: group extraction and comparison with fractal clusters
Wang, Hongchi; Gutermuth, Robert A.; Zhang, Shuinai +2 more
Young stellar clusters are believed to inherit the spatial distribution like hierarchical structures of their natal molecular cloud during their formation. However, the change of the structures between the cloud and the young clusters is not well constrained observationally. We select the W40-Serpens South region (~7 × 9 pc2) of the Aqu…
The ExoMars Schiaparelli Entry, Descent and Landing Demonstrator Module (EDM) System Design
Bayle, Olivier; Ball, Andrew J.; Blancquaert, Thierry +3 more
The Entry, Descent and Landing Demonstrator Module (EDM) named Schiaparelli, was the ESA-led Mars lander element of the ESA-Roscosmos ExoMars 2016 mission. Following launch on 14 March 2016 with the ExoMars Trace Gas Orbiter (TGO) and cruise to Mars, Schiaparelli separated for encounter with Mars to demonstrate entry, descent and landing technolog…
XMM and NuSTAR Observations of an Optically Quiescent Quasar
Gandhi, Poshak; Stern, Daniel; Mainieri, Vincenzo +3 more
Optically quiescent quasars (OQQs) represent a recently systematized class of infrared-luminous active galactic nuclei (AGNs) that have galaxy-like optical continua. They may represent an interesting, brief phase in the AGN life cycle, e.g., either cocooned within high-covering-factor media or indicative of recent triggering, though their nature r…
Solar System Science with the Orbiting Astronomical Satellite Investigating Stellar Systems (OASIS) Observatory
Hartogh, Paul; Anderson, Carrie M.; Tielens, Alexander +6 more
The overarching theme of the Orbiting Astronomical Satellite for Investigating Stellar Systems (OASIS), an Astrophysics MIDEX-class mission concept, is Following water from galaxies, through protostellar systems, to Earth's oceans. The OASIS science objectives address fundamental questions raised in "Pathways to Discovery in Astronomy and Astrophy…