Search Publications
Signatures of an eccentric disc cavity: Dust and gas in IRS 48
Pinte, Christophe; Christiaens, Valentin; van der Marel, Nienke +5 more
We test the hypothesis that the disc cavity in the `transition disc' Oph IRS 48 is carved by an unseen binary companion. We use 3D dust-gas smoothed-particle hydrodynamics simulations to demonstrate that marginally coupled dust grains concentrate in the gas overdensity that forms in the cavity around a low binary mass ratio binary. This produces h…
Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: GJ 832, GJ 176, and GJ 436
Peacock, Sarah; Barman, Travis; Baron, E. +3 more
Correct estimates of stellar extreme ultraviolet (EUV; 100-1170 Å) flux are important for studying the photochemistry and stability of exoplanet atmospheres, as EUV radiation ionizes hydrogen and contributes to the heating, expansion, and potential escape of a planet’s upper atmosphere. Contamination from interstellar hydrogen makes observing EUV …
WISDOM project - V. Resolving molecular gas in Keplerian rotation around the supermassive black hole in NGC 0383
Williams, Thomas G.; Sarzi, Marc; Cappellari, Michele +7 more
As part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM), we present a measurement of the mass of the supermassive black hole (SMBH) in the nearby early-type galaxy NGC 0383 (radio source 3C 031). This measurement is based on Atacama Large Millimeter/sub-millimeter Array (ALMA) cycle 4 and 5 observations of the 12CO(…
Dayside Aurora
Strangeway, Robert J.; Frey, Harald U.; Nishimura, Yukitoshi +5 more
Dayside aurora is related to processes in the dayside magnetosphere and especially at the dayside magnetopause. A number of dayside aurora phenomena are driven by reconnection between the solar wind interplanetary magnetic field and the Earth's internal magnetic field at the magnetopause. We summarize the properties and origin of aurora at the cus…
A UV and optical study of 18 old novae with Gaia DR2 distances: mass accretion rates, physical parameters, and MMRD
Selvelli, Pierluigi; Gilmozzi, Roberto
We combine the results of our earlier study of the UV characteristics of 18 classical novae (CNe) with data from the literature and with the recent precise distance determinations from the Gaia satellite to investigate the statistical properties of old novae. All final parameters for the sample include a detailed treatment of the errors and their …
Resolved Neutral Carbon Emission in Nearby Galaxies: [C I] Lines as Total Molecular Gas Tracers
Tan, Qinghua; Salak, Dragan; Gao, Yu +6 more
We present maps of atomic carbon [C I]({}3{{{P}}}1\to {{}3{{P}}}0) and [C I]({}3{{{P}}}2\to {{}3{{P}}}1) emission (hereafter [C I] (1-0) and [C I] (2-1), respectively) at a linear resolution ∼1 kpc scale for a sample of one H II, six LINER, three Seyfert, and f…
Transition Probabilities of Sc I and Sc II and Scandium Abundances in the Sun, Arcturus, and HD 84937
Sneden, C.; Wood, M. P.; Lawler, J. E. +3 more
New branching fraction (BF) measurements for lines of Sc I and Sc II from 24 Fourier transform spectra calibrated using standard lamps and the Ar branching ratio method are reported. The BFs for 259 lines are converted to absolute atomic transition probabilities using published radiative lifetimes from laser-induced fluorescence measurements. Deta…
Crossing the Line: Active Galactic Nuclei in the Star-forming Region of the BPT Diagram
Salim, Samir; Agostino, Christopher J.
In this work, we investigate the reliability of the BPT diagram for excluding galaxies that host an active galactic nucleus (AGN). We determine the prevalence of X-ray AGNs in the star-forming region of the BPT diagram and discuss the reasons behind this apparent misclassification, focusing primarily on relatively massive ({log}({M}* )≳…
Dramatic spectral transition of X-ray pulsar GX 304-1 in low luminous state
Doroshenko, Victor; Tsygankov, Sergey S.; Mushtukov, Alexander A. +5 more
We report on the discovery of a dramatic change in the energy spectrum of the X-ray pulsar GX 304-1 appearing at low luminosity. Particularly, we found that the cut-off power-law spectrum typical for accreting pulsars, including GX 304-1 at higher luminosities of LX ∼ 1036-1037 erg s-1, transformed at lo…
Type Ibn Supernovae May not all Come from Massive Stars
Zabludoff, Ann I.; French, K. Decker; Berger, Edo +5 more
Because core-collapse supernovae are the explosions of massive stars, which have relatively short lifetimes, they occur almost exclusively in galaxies with active star formation. On the other hand, the Type Ibn supernova PS1-12sk exploded in an environment that is much more typical of thermonuclear (Type Ia) supernovae: on the outskirts of the bri…