Search Publications
Rapidly oscillating TESS A-F main-sequence stars: are the roAp stars a distinct class?
Balona, L. A.
From sector 1-44 TESS observations, 19 new rapidly oscillating Ap (roAp) stars, 103 ostensibly non-peculiar stars with roAp-like frequencies, and 617 δ Scuti stars with independent frequencies typical of roAp stars were found. Examination of all chemically peculiar stars observed by TESS resulted in the discovery of 199 Ap stars that pulsate as δ …
Ram pressure candidates in UNIONS
Chambers, Kenneth C.; Wainscoat, Richard J.; Oguri, Masamune +17 more
We present a search for disturbed, candidate ram pressure stripping galaxies across more than 50 spectroscopically selected SDSS groups and clusters. 48 ram pressure candidates are visually identified in these systems using high-quality UNIONS imaging from the Canada-France-Hawaii Telescope, covering ${\sim }6200\, \mathrm{deg^2}$ and ${\sim }2800…
Constraints on the Galactic Centre environment from Gaia hyper-velocity stars
Rossi, E. M.; Marchetti, T.; Evans, F. A.
Following a dynamical encounter with Sgr A*, binaries in the Galactic Centre (GC) can be tidally separated and one member star ejected as a hyper-velocity star (HVS) with a velocity beyond the escape speed of the Milky Way. As GC-born objects located in more observationally accessible regions of the sky, HVSs offer insight into the stellar populat…
The structure of accreted stellar streams
Bovy, Jo; Qian, Yansong; Arshad, Yumna
Many of the Milky Way's globular clusters are likely accreted from satellite galaxies that have long since merged with the Milky Way. When these globular clusters are susceptible to tidal disruption, this process likely starts already inside the parent satellite leading to an early stellar stream within the satellite. When the parent satellite mer…
Estimating the local dark matter density in a non-axisymmetric wobbling disc
Sivertsson, S.; Read, J. I.; Silverwood, H. +6 more
The density of dark matter near the Sun, ρDM, ⊙, is important for experiments hunting for dark matter particles in the laboratory, and for constraining the local shape of the Milky Way's dark matter halo. Estimates to date have typically assumed that the Milky Way's stellar disc is axisymmetric and in a steady-state. Yet the Milky Way d…
The Pristine survey - XVII. The C-19 stream is dynamically hot and more extended than previously thought
Fouesneau, Morgan; Sestito, Federico; Navarro, Julio F. +22 more
The C-19 stream is the most metal-poor stellar system ever discovered, with a mean metallicity [Fe/H] = -3.38 ± 0.06. Its low metallicity dispersion (σ[Fe/H] < 0.18 at the 95 per cent confidence level) and variations in sodium abundances strongly suggest a globular cluster origin. In this work, we use Very Large Telescope (VLT)/UV-Vi…
A double-peaked Lyman-α emitter with a stronger blue peak multiply imaged by the galaxy cluster RXC J0018.5+1626
Charlot, Stéphane; Bradač, Maruša; Strait, Victoria +10 more
We report the discovery of a double-peaked Lyman-α (Ly α) emitter (LAE) at z = 3.2177 ± 0.0001 in VLT/MUSE data. The galaxy is strongly lensed by the galaxy cluster RXC J0018.5+1626 recently observed in the RELICS survey, and the double-peaked Ly α emission is clearly detected in the two counter images in the MUSE field of view. We measure a relat…
Modeling Balmer line signatures of stellar CMEs
Heinzel, P.; Odert, P.; Leitzinger, M.
From the Sun, we know that coronal mass ejections (CMEs) are a transient phenomenon, often correlated with flares. They have an impact on solar mass- and angular momentum loss, and therefore solar evolution, and make a significant part of space weather. The same is true for stars, but stellar CMEs are still not well constrained, although new metho…
The whisper of a whimper of a bang: 2400 d of the Type Ia SN 2011fe reveals the decay of 55Fe
Kochanek, C. S.; Stanek, K. Z.; Ashall, C. +4 more
We analyse new multifilter Hubble Space Telescope (HST) photometry of the normal Type Ia supernova (SN Ia) 2011fe out to ≈2400 d after maximum light, the latest observations to date of a SN Ia. We model the pseudo-bolometric light curve with a simple radioactive decay model and find energy input from both 57Co and 55Fe are ne…
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…