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Morpho-kinematic Properties of Wolf-Rayet Planetary Nebulae
Danehkar, A.
The majority of planetary nebulae (PNs) show axisymmetric morphologies, whose causes are not well understood. In this work, we present spatially resolved kinematic observations of 14 Galactic PNs surrounding Wolf-Rayet ([WR]) and weak emission-line stars (wels), based on the Hα and [N II] emission taken with the Wide Field Spectrograph on the Aust…
Strategies for Determining the Cascade Rate in MHD Turbulence: Isotropy, Anisotropy, and Spacecraft Sampling
Shay, Michael A.; Oughton, Sean; Yang, Yan +6 more
Exact laws for evaluating cascade rates, tracing back to the Kolmogorov "4/5" law, have been extended to many systems of interest including magnetohydrodynamics (MHD), and compressible flows of the magnetofluid and ordinary fluid types. It is understood that implementations may be limited by the quantity of available data and by the lack of turbul…
Spectropolarimetry of magnetic Chemically Peculiar stars in the Orion OB1 association
Semenko, Eugene; Romanyuk, Iosif; Yakunin, Ilya +2 more
We summarize the results of a spectropolarimetric survey of 56 chemically peculiar (CP) stars in the association of Orion OB1. We uniformly collected the observational material with the 6-m telescope BTA of the Special Astrophysical Observatory in 2013-2021. We identify 14 new magnetic CP stars with a longitudinal magnetic field exceeding approxim…
An accreting white dwarf displaying fast transitional mode switching
Knigge, C.; de Martino, D.; Groot, P. J. +6 more
Accreting white dwarfs are often found in close binary systems with orbital periods ranging from tens of minutes to several hours. In most cases, the accretion process is relatively steady, with significant modulations only occurring on timescales of ~days or longer1,2. Here we report the discovery of abrupt drops in the optical luminos…
Clues to the Formation of Liller 1 from Modeling Its Complex Star Formation History
Pallanca, Cristina; Dalessandro, Emanuele; Ferraro, Francesco R. +7 more
Liller 1 and Terzan 5 are two massive systems in the Milky Way bulge hosting populations characterized by significantly different ages (Δt > 7-8 Gyr) and metallicities (Δ[Fe/H] ~ 1 dex). Their origin is still strongly debated in the literature and all formation scenarios proposed so far require some level of fine-tuning. The detailed star forma…
First direct dynamical detection of a dual supermassive black hole system at sub-kiloparsec separation
Pechetti, Renuka; Neumayer, Nadine; Seth, Anil C. +7 more
We investigated whether the two recently discovered nuclei in NGC 7727 both host a super-massive black hole (SMBH). We used the high spatial resolution mode of the integral-field spectrograph MUSE on the VLT in adaptive optics mode to resolve the stellar kinematics within the sphere of influence of both putative black holes. We combined the kinema…
Inferring the morphology of AGN torus using X-ray spectra: a reliability study
Markowitz, Alex G.; Buchner, Johannes; Saha, Tathagata
Numerous X-ray spectral models have been developed to model emission reprocessed by the torus of an active galactic nucleus (AGN), e.g. UXCLUMPY, CTORUS, and MYTORUS. They span a range of assumed torus geometries and morphologies - some posit smooth gas distributions, and others posit distributions of clouds. It is suspected that given the quality…
Jovian Auroral Electron Precipitation Budget—A Statistical Analysis of Diffuse, Mono-Energetic, and Broadband Auroral Electron Distributions
Saur, J.; Mauk, B. H.; Salveter, A. +1 more
Recent observations by the Juno spacecraft have shown that electrons contributing to Jupiter's main auroral emission appear to be frequently characterized by broadband electron distributions, but also less often mono-energetic electron distributions are observed as well. In this work, we quantitatively derive the occurrence rates of the various el…
High-precision star-formation efficiency measurements in nearby clouds
Gutermuth, Robert A.; Pokhrel, Riwaj; Hu, Zipeng +1 more
On average molecular clouds convert only a small fraction ϵff of their mass into stars per free-fall time, but different star-formation theories make contrasting claims for how this low mean efficiency is achieved. To test these theories, we need precise measurements of both the mean value and the scatter of ϵff, but high-pre…
LeMMINGs - IV. The X-ray properties of a statistically complete sample of the nuclei in active and inactive galaxies from the Palomar sample
Muxlow, T. W. B.; Argo, M. K.; Knapen, J. H. +22 more
All 280 of the statistically complete Palomar sample of nearby (<120 Mpc) galaxies δ > 20° have been observed at 1.5 GHz as part of the LeMMINGs e-MERLIN legacy survey. Here, we present Chandra X-ray observations of the nuclei of 213 of these galaxies, including a statistically complete sub-set of 113 galaxies in the declination range 40° &l…