Search Publications
Detection of Flare Multiperiodic Pulsations in Mid-ultraviolet Balmer Continuum, Lyα, Hard X-Ray, and Radio Emissions Simultaneously
Li, Gang; Gan, Weiqun; Li, Xiaobo +7 more
Quasi-periodic pulsations (QPPs), which usually appear as temporal pulsations of the total flux, are frequently detected in the light curves of solar/stellar flares. In this study, we present the investigation of nonstationary QPPs with multiple periods during the impulsive phase of a powerful flare on 2017 September 6, which were simultaneously m…
Molecular remnant of Nova 1670 (CK Vulpeculae). II. A three-dimensional view of the gas distribution and velocity field
Menten, K. M.; Bujarrabal, V.; Steffen, W. +3 more
CK Vul is the remnant of an energetic eruption known as Nova 1670 that is thought to be caused by a stellar merger. The remnant is composed of (1) a large hourglass nebula of recombining gas (of 71'' in size), very similar to some classical planetary and pre-planetary nebulae (PPNe), and (2) a much smaller and cooler inner remnant that is prominen…
Stellar Parameterization of LAMOST M Dwarf Stars
Tian, Haijun; Qiu, Dan; Tian, Hao +3 more
The M dwarf stars are the most common stars in the Galaxy, dominating the population of the Galaxy at faint magnitudes. Precise and accurate stellar parameters for M dwarfs are of crucial importance for many studies. However, the atmospheric parameters of M dwarf stars are difficult to determine. In this paper, we present a catalog of the spectros…
Dust/ice mixing in cold regions and solid-state water in the diffuse interstellar medium
Henning, Thomas; Bouwman, Jeroen; Jäger, Cornelia +1 more
Whether ice in cold cosmic environments is physically separated from the silicate dust or mixed with individual silicate moieties is not known. However, different grain models give very different compositions and temperatures of grains. The aim of the present study is to compare the mid-infrared spectra of laboratory silicate grain/water ice mixtu…
A dearth of young and bright massive stars in the Small Magellanic Cloud
Menten, K. M.; Crowther, P. A.; de Koter, A. +7 more
Context. Massive star evolution at low metallicity is closely connected to many fields in high-redshift astrophysics, but is poorly understood so far. Because of its metallicity of ∼0.2 Z⊙, its proximity, and because it is currently forming stars, the Small Magellanic Cloud (SMC) is a unique laboratory in which to study metal-poor massi…
Testing Evolutionary Models with Red Supergiant and Wolf-Rayet Populations
Massey, Philip; Dorn-Wallenstein, Trevor Z.; Levesque, Emily M. +3 more
Despite the many successes that modern massive star evolutionary theory has enjoyed, reproducing the apparent trend in the relative number of red supergiants (RSGs) and Wolf-Rayet (WR) stars has remained elusive. Previous estimates show the RSG/WR ratio decreasing strongly with increasing metallicity. However, the evolutionary models have always p…
The Nature of Soft Excess in ESO 362-G18 Revealed by XMM-Newton and NuSTAR Spectroscopy
Walton, Dominic J.; García, Javier A.; Harrison, Fiona A. +3 more
We present a detailed spectral analysis of the joint XMM-Newton and NuSTAR observations of the active galactic nuclei (AGNs) in the Seyfert 1.5 Galaxy ESO 362-G18. The broadband (0.3-79 keV) spectrum shows the presence of a power-law continuum with a soft excess below 2 keV, iron Kα emission (∼6.4 keV), and a Compton hump (peaking at ∼20 keV). We …
The White Dwarf Binary Pathways Survey - IV. Three close white dwarf binaries with G-type secondary stars
Gänsicke, B. T.; Rebassa-Mansergas, A.; Raddi, R. +12 more
Constraints from surveys of post-common envelope binaries (PCEBs) consisting of a white dwarf plus an M-dwarf companion have led to significant progress in our understanding of the formation of close white dwarf binary stars with low-mass companions. The white dwarf binary pathways project aims at extending these previous surveys to larger seconda…
The Fundamental Plane in the LEGA-C Survey: Unraveling the M/L Ratio Variations of Massive Star-forming and Quiescent Galaxies at z ∼ 0.8
Bell, Eric F.; Maseda, Michael V.; D'Eugenio, Francesco +10 more
We explore the connection between the kinematics, structures and stellar populations of massive galaxies at 0.6 < z < 1.0 using the fundamental plane (FP). Combining stellar kinematic data from the Large Early Galaxy Astrophysics Census (LEGA-C) survey with structural parameters measured from deep Hubble Space Telescope imaging, we obtain a …
The (im)possibility of strong chemical tagging
Castro-Ginard, A.; Casamiquela, L.; Anders, F. +1 more
Context. The possibility of identifying co-natal stars that have dispersed into the Galactic disc based on chemistry alone is called strong chemical tagging. It has been debated for a long time whether this is indeed feasible; it holds the promise of reconstructing the detailed star formation history of a large fraction of stars in the Galactic di…