Search Publications
LAMOST Observations in 15 K2 Campaigns. I. Low-resolution Spectra from LAMOST DR6
Shi, Jianrong; Zong, Weikai; Fu, Jian-Ning +12 more
The Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST)-K2 (LK2) project, initiated in 2015, aims to collect low-resolution spectra of targets in the K2 campaigns, similar to the LAMOST-Kepler project. By the end of 2018, a total of 126 LK2 plates had been observed by LAMOST. After cross-matching the catalog of the LAMOST data relea…
Estimating the size of X-ray lamppost coronae in active galactic nuclei
Done, C.; Petrucci, P. -O.; Matt, G. +3 more
Aims: We report estimates of the X-ray coronal size of active galactic nuclei in the lamppost geometry. In this commonly adopted scenario, the corona is assumed for simplicity to be a point-like X-ray source located on the axis of the accretion disc. However, the corona must intercept a number of optical/UV seed photons from the disc consiste…
MOSEL: Strong [OIII] 5007 Å Emitting Galaxies at (3 < z < 4) from the ZFOURGE Survey
Papovich, Casey; Kacprzak, Glenn G.; Glazebrook, Karl +13 more
To understand how strong emission-line galaxies (SELGs) contribute to the overall growth of galaxies and star formation history of the universe, we target SELGs from the ZFOURGE imaging survey that have blended Hβ+[O III] rest-frame equivalent widths of >230 Å and 2.5 < ${z}_{\mathrm{phot}}$ < 4.0. Using Keck/MOSFIRE, we measure 49 redshi…
Zodiacal exoplanets in time - XI. The orbit and radiation environment of the young M dwarf-hosted planet K2-25b
Kuzuhara, M.; Tamura, M.; Kudo, T. +20 more
M dwarf stars are high-priority targets for searches for Earth-size and potentially Earth-like planets, but their planetary systems may form and evolve in very different circumstellar environments than those of solar-type stars. To explore the evolution of these systems, we obtained transit spectroscopy and photometry of the Neptune-size planet or…
Possible ∼0.4 h X-ray quasi-periodicity from an ultrasoft active galactic nucleus
Xue, Y. Q.; Shu, X. W.; Wang, T. G. +6 more
RX J1301.9+2747 is an ultrasoft active galactic nucleus (AGN) with unusual X-ray variability that is characterized by a long quiescent state and a short-lived flare state. The X-ray flares are found to recur quasi-periodically on a timescale of 13-20 ks. Here, we report the analysis of the light curve in the quiescent state from two XMM-Newton obs…
The Blue Compact Dwarf Galaxy VCC 848 Formed by Dwarf-Dwarf Merging: H I Gas, Star Formation, and Numerical Simulations
Gao, Yu; Rong, Yu; Hunter, Deidre A. +12 more
A clear link between a dwarf-dwarf merger event and enhanced star formation (SF) in the recent past was recently identified in the gas-dominated merger remnant VCC 848, offering by far the clearest view of a gas-rich late-stage dwarf-dwarf merger. We present a joint analysis of JVLA H I emission line mapping, optical imaging, and numerical simulat…
Mitigating flicker noise in high-precision photometry. I. Characterization of the noise structure, impact on the inferred transit parameters, and predictions for CHEOPS observations
Veronig, A.; Fossati, L.; Lendl, M. +4 more
Context. In photometry, the short-timescale stellar variability ("flicker"), such as that caused by granulation and solar-like oscillations, can reach amplitudes comparable to the transit depth of Earth-sized planets and is correlated over the typical transit timescales. It can introduce systematic errors on the inferred planetary parameters when …
Bridging the Planet Radius Valley: Stellar Clustering as a Key Driver for Turning Sub-Neptunes into Super-Earths
Kruijssen, J. M. Diederik; Longmore, Steven N.; Chevance, Mélanie
Extrasolar planets with sizes between that of the Earth and Neptune (Rp = 1-4 R⊕) have a bimodal radius distribution. This "planet radius valley" separates compact, rocky super-Earths (Rp = 1.0-1.8 R⊕) from larger sub-Neptunes (Rp = 1.8-3.5 R⊕) hosting a gaseous hydrogen-helium enve…
The Rise and Fall of the King: The Correlation between FO Aquarii's Low States and the White Dwarf's Spin-down
Walker, Gary; Garnavich, Peter; Littlefield, Colin +46 more
The intermediate polar FO Aquarii (FO Aqr) experienced its first reported low-accretion states in 2016, 2017, and 2018, and, using newly available photographic plates, we identify prediscovery low states in 1965, 1966, and 1974. The primary focus of our analysis, however, is an extensive set of time-series photometry obtained between 2002 and 2018…
Uranus in Northern Midspring: Persistent Atmospheric Temperatures and Circulations Inferred from Thermal Imaging
Fletcher, Leigh N.; Irwin, Patrick G. J.; Orton, Glenn S. +2 more
We present results from mid-infrared imaging of Uranus at wavelengths of 13.0 and 18.7 µm, sensing emission from the stratosphere and upper troposphere, acquired using the VISIR instrument at the Very Large Telescope, 2018 September 4-October 20. Using a combination of inverse and forward modeling, we analyze these northern midspring (L