Search Publications
New Hydrodynamic Solutions for Line-driven Winds of Hot Massive Stars Using the Lambert W-function
Hillier, D. J.; Najarro, F.; Gormaz-Matamala, A. C. +3 more
Hot massive stars present strong stellar winds that are driven by absorption, scattering, and reemission of photons by the ions of the atmosphere (line-driven winds). A better comprehension of this phenomenon, and a more accurate calculation of hydrodynamics and radiative acceleration, is Required to reduce the number of free parameters in spectra…
Airfall on Comet 67P/Churyumov-Gerasimenko
Zacny, Kris; Bodewits, Dennis; Vincent, Jean-Baptiste +11 more
We here study the transfer process of material from one hemisphere to the other (deposition of airfall material) on an active comet nucleus, specifically 67P/Churyumov-Gerasimenko. Our goals are to: 1) quantify the thickness of the airfall debris layers and how it depends on the location of the target area, 2) determine the amount of H2…
Quasi-periodic dipping in the ultraluminous X-ray source, NGC 247 ULX-1
Fabian, A. C.; Pinto, C.; Walton, D. +15 more
Most ultraluminous X-ray sources (ULXs) are believed to be stellar mass black holes or neutron stars accreting beyond the Eddington limit. Determining the nature of the compact object and the accretion mode from broad-band spectroscopy is currently a challenge, but the observed timing properties provide insight into the compact object and details …
Spectroscopic observations of a flare-related coronal jet
Li, D.; Zhang, Q. M.; Huang, Z. H. +3 more
Context. Coronal jets are ubiquitous in active regions and coronal holes.
Aims: In this paper, we study a coronal jet related to a C3.4 circular-ribbon flare in the active region 12434 on 2015 October 16.
Methods: The flare and jet were observed in ultraviolet and extreme ultraviolet wavelengths by the Atmospheric Imaging Assembly on boa…
XMM-Newton observations of the extremely X-ray luminous quasar CFHQS J142952+544717=SRGE J142952.1 + 544716 at redshift z = 6.18
Sunyaev, R.; Sazonov, S.; Schartel, N. +2 more
We present results from a 20 ks XMM-Newton director's discretionary time observation of the radio-loud quasar CFHQS J142952 + 544717 at z = 6.18, whose extreme X-ray luminosity was recently revealed by the SRG/eROSITA telescope in the course of its first all-sky survey. The quasar has been confidently detected with a total of ~1400 net counts in t…
LoCuSS: The Splashback Radius of Massive Galaxy Clusters and Its Dependence on Cluster Merger History
Smith, Graham P.; Babul, Arif; Finoguenov, Alexis +4 more
We present the direct detection of the splashback feature using the sample of massive galaxy clusters from the Local Cluster Substructure Survey (LoCuSS). This feature is clearly detected (above 5σ) in the stacked luminosity density profile obtained using the K-band magnitudes of spectroscopically confirmed cluster members. We obtained the best-fi…
The Anatomy of an Unusual Edge-on Protoplanetary Disk. II. Gas Temperature and a Warm Outer Region
Pinte, C.; Ménard, F.; Duchêne, G. +9 more
We present high-resolution 12CO and 13CO 2-1 ALMA observations, as well as optical and near-infrared spectroscopy, of the highly inclined protoplanetary disk around SSTC2D J163131.2-242627. The spectral type we derive for the source is consistent with a 1.2 M⊙ star inferred from the ALMA observations. Despite its m…
Data-driven Spectroscopic Estimates of Absolute Magnitude, Distance, and Binarity: Method and Catalog of 16,002 O- and B-type Stars from LAMOST
Yuan, Hai-Bo; Xiang, Maosheng; Ting, Yuan-Sen +4 more
We present a data-driven method to estimate absolute magnitudes for O- and B-type stars from the LAMOST spectra, which we combine with Gaia DR2 parallaxes to infer distance and binarity. The method applies a neural network model trained on stars with precise Gaia parallax to the spectra and predicts Ks-band absolute magnitudes ${M}_{K{\…
Iron and nickel atoms in cometary atmospheres even far from the Sun
Jehin, E.; Manfroid, J.; Hutsemékers, D.
In comets, iron and nickel are found in refractory dust particles or in metallic and sulfide grains1. So far, no iron- or nickel-bearing molecules have been observed in the gaseous coma of comets2. Iron and a few other heavy atoms, such as copper and cobalt, have been observed only in two exceptional objects: the Great Comet …
The Aeolian Environment of the Landing Site for the ExoMars Rosalind Franklin Rover in Oxia Planum, Mars
Fawdon, P.; Balme, M. R.; Grindrod, P. M. +4 more
Aeolian features at Oxia Planum—the 2023 landing site for the ExoMars Rosalind Franklin Rover (ERFR)—are important for Mars exploration because they record information about past and current wind regimes, sand transport vectors, and lend insight to the abrasion, deposition, and transport of granular material. To characterize the wind regime and er…