Search Publications
Investigating the Effect of Galaxy Interactions on Star Formation at 0.5 < z < 3.0
Hathi, Nimish P.; Kartaltepe, Jeyhan S.; Kocevski, Dale D. +24 more
Observations and simulations of interacting galaxies and mergers in the local universe have shown that interactions can significantly enhance the star formation rates (SFRs) and fueling of active galactic nuclei (AGN). However, at higher redshift, some simulations suggest that the level of star formation enhancement induced by interactions is lowe…
Measuring sloshing, merging, and feedback velocities in the Virgo cluster
Fabian, A. C.; Pinto, C.; Sanders, J. S. +5 more
We present a detailed analysis of the velocity structure of the Virgo cluster using XMM-Newton observations. Using a novel technique which uses the Cu K α instrumental line to calibrate the EPIC-pn energy scale, we are able to obtain velocity measurements with uncertainties down to Δv ~ 100 km s-1. We created 2D projected maps for the v…
Lithium depletion boundary, stellar associations, and Gaia
Montesinos, B.; Bayo, A.; Huélamo, N. +9 more
Context. Stellar ages are key to improving our understanding of different astrophysical phenomena. However, many techniques to estimate stellar ages are highly model-dependent. The lithium depletion boundary (LDB), based on the presence or absence of lithium in low-mass stars, can be used to derive ages in stellar associations of between 20 and 50…
CMEs and SEPs During November-December 2020: A Challenge for Real-Time Space Weather Forecasting
Maksimovic, Milan; Möstl, Christian; Galvin, Antoinette B. +20 more
Predictions of coronal mass ejections (CMEs) and solar energetic particles (SEPs) are a central issue in space weather forecasting. In recent years, interest in space weather predictions has expanded to include impacts at other planets beyond Earth as well as spacecraft scattered throughout the heliosphere. In this sense, the scope of space weathe…
The magnetic drivers of campfires seen by the Polarimetric and Helioseismic Imager (PHI) on Solar Orbiter
Schmidt, W.; Woch, J.; Peter, H. +56 more
Context. The Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter (SO) spacecraft observed small extreme ultraviolet (EUV) bursts, termed campfires, that have been proposed to be brightenings near the apexes of low-lying loops in the quiet-Sun atmosphere. The underlying magnetic processes driving these campfires are not understood.
Aim…
Low-cost Access to the Deep, High-cadence Sky: the Argus Optical Array
Law, Nicholas M.; Mann, Andrew W.; Corbett, Hank +16 more
New mass-produced, wide-field, small-aperture telescopes have the potential to revolutionize ground-based astronomy by greatly reducing the cost of collecting area. In this paper, we introduce a new class of large telescope based on these advances: an all-sky, arcsecond-resolution, 1000 telescope array which builds a simultaneously high-cadence an…
Alpha-Proton Differential Flow of the Young Solar Wind: Parker Solar Probe Observations
Bale, S. D.; Allen, R. C.; Raouafi, N. E. +5 more
The velocity of alpha particles relative to protons can vary depending on the solar wind type and distance from the Sun. Measurements from the previous spacecraft provided the alpha-proton differential velocities down to 0.3 au. The Parker Solar Probe (PSP) now enables insights into differential flows of the newly accelerated solar wind closer to …
Discovery of Eight "Main-sequence Radio Pulse Emitters" Using the GMRT: Clues to the Onset of Coherent Radio Emission in Hot Magnetic Stars
Neiner, Coralie; Wade, Gregg A.; Chandra, Poonam +6 more
Main-sequence radio pulse emitters (MRPs) are magnetic early-type stars from which periodic radio pulses, produced via electron cyclotron maser emission (ECME), are observed. Despite the fact that these stars can naturally offer suitable conditions for triggering ECME, only seven such stars have been reported so far within a span of more than two …
A Tilt in the Dark Matter Halo of the Galaxy
Conroy, Charlie; Ting, Yuan-Sen; Johnson, Benjamin D. +9 more
Recent observations of the stellar halo have uncovered the debris of an ancient merger, Gaia-Sausage-Enceladus (GSE), estimated to have occurred ≳8 Gyr ago. Follow-up studies have associated GSE with a large-scale tilt in the stellar halo that links two well-known stellar overdensities in diagonally opposing octants of the Galaxy (the Hercules-Aqu…
Identifying resonances of the Galactic bar in Gaia DR2: II. Clues from angle space
Trick, Wilma H.
The Milky Way disc exhibits intricate orbit substructure of still debated dynamical origin. The angle variables (θϕ, θR) - which are conjugates to the actions (L$z$, JR), and describe a star's location along its orbit - are a powerful diagnostic to identify l:m resonances via the orbit shape relation Δθ<…