Search Publications
The period-luminosity relation for δ Scuti stars using Gaia DR2 parallaxes
Bedding, Timothy R.; Murphy, Simon J.; Hey, Daniel R. +2 more
We have examined the period-luminosity (P-L) relation for δ Scuti stars using Gaia DR2 parallaxes. We included 228 stars from the catalogue of Rodríguez et al., as well as 1124 stars observed in the 4-yr Kepler mission. For each star, we considered the dominant pulsation period, and used DR2 parallaxes and extinction corrections to determine absol…
Cluster Difference Imaging Photometric Survey. I. Light Curves of Stars in Open Clusters from TESS Sectors 6 and 7
Winn, J. N.; Bouma, L. G.; Bhatti, W. +2 more
The Transiting Exoplanet Survey Satellite (TESS) is providing precise time-series photometry for most star clusters in the solar neighborhood. Using the TESS images, we have begun a Cluster Difference Imaging Photometric Survey, in which we are focusing both on stars that are candidate cluster members and on stars that show indications of youth. O…
Highly Magnified Stars in Lensing Clusters: New Evidence in a Galaxy Lensed by MACS J0416.1-2403
Miralda-Escudé, Jordi; Frye, Brenda; Dai, Liang +2 more
We examine a caustic-straddling arc at z = 0.9397 in the field of the galaxy cluster MACS J0416.1-2403 (z = 0.397) using archival multiband Hubble Space Telescope images and show that its surface brightness exhibits anomalies that can be explained by a single highly magnified star undergoing microlensing. First, we show that the surface brightness…
NGTS-4b: A sub-Neptune transiting in the desert
Jackman, James A. G.; Wheatley, Peter J.; Bayliss, Daniel +48 more
We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34 d orbit. NGTS-4b has a mass M = 20.6 ± 3.0 M⊕ and radius R = 3.18 ± 0.26 R⊕, which places it well within the so-called `Neptunian Desert'. The mean density of the planet (3.45 ± 0.95 g cm-3) is consistent wi…
A New Technique for Finding Galaxies Leaking Lyman-continuum Radiation: [S II]-deficiency
Heckman, Timothy M.; Leitherer, Claus; Wang, Bingjie +3 more
The source responsible for the reionization of the universe is believed to be the population of star-forming galaxies at z ∼ 6 to 12. The biggest uncertainty concerns the fraction of Lyman-continuum photons that actually escape from the galaxies. In recent years, several relatively small samples of “leaky” galaxies have been discovered, and clues …
Coronal bright points
Madjarska, Maria S.
Coronal bright points (CBPs) are a fundamental class of solar activity. They represent a set of low-corona small-scale loops with enhanced emission in the extreme-ultraviolet and X-ray spectrum that connect magnetic flux concentrations of opposite polarities. CBPs are one of the main building blocks of the solar atmosphere outside active regions u…
ExoEarth yield landscape for future direct imaging space telescopes
Stark, Christopher C.; Mazoyer, Johan; Pueyo, Laurent +19 more
The expected yield of potentially Earth-like planets is a useful metric for designing future exoplanet-imaging missions. Recent yield studies of direct-imaging missions have focused primarily on yield methods and trade studies using "toy" models of missions. Here, we increase the fidelity of these calculations substantially, adopting more realisti…
The mean Hα EW and Lyman-continuum photon production efficiency for faint z ≈ 4-5 galaxies
Bacon, Roland; Boogaard, Leindert A.; Mahler, Guillaume +9 more
We present the first measurements of the Lyman-continuum photon production efficiency ξion, 0 at z ∼ 4-5 for galaxies fainter than 0.2 L* (-19 mag). ξion, 0 quantifies the production rate of ionizing photons with respect to the UV luminosity density assuming a fiducial escape fraction of zero. Extending previous me…
AKARI/IRC near-infrared asteroid spectroscopic survey: AcuA-spec
Hasegawa, Sunao; Onaka, Takashi; Usui, Fumihiko +1 more
Knowledge of water in the solar system is important for the understanding of a wide range of evolutionary processes and the thermal history of the solar system. To explore the existence of water in the solar system, it is indispensable to investigate hydrated minerals and/or water ice on asteroids. These water-related materials show absorption fea…
Merging Cluster Collaboration: A Panchromatic Atlas of Radio Relic Mergers
Bradač, M.; Venturi, T.; Jee, M. J. +13 more
Golovich et al. present an optical imaging and spectroscopic survey of 29 radio relic merging galaxy clusters. In this paper, we study this survey to identify substructure and quantify the dynamics of the mergers. Using a combined photometric and spectroscopic approach, we identify the minimum number of substructures in each system to describe the…