Search Publications
Modeling Solar Wind Variations over an 11 Year Cycle with Alfvén Wave Dissipation: A Parameter Study
Réville, Victor; Hazra, Soumitra; Strugarek, Antoine +3 more
We study the behavior and properties of the solar wind using a 2.5D Alfvén wave (AW)-driven wind model. We first systematically compare the results of an AW-driven wind model with a polytropic approach. Polytropic magnetohydrodynamic wind models are thermally driven, while AWs act as additional acceleration and heating mechanisms in the AW-driven …
Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - XI. CHIRON investigation of long-period binaries
Smith, A. M. S.; Anderson, D. R.; Hellier, C. +8 more
We present the results of a spectroscopic campaign on eclipsing binaries with long orbital period (P = 20-75 d) carried out with the CHIRON spectrograph. Physical and orbital solutions for seven systems were derived from the V band, and I band ASAS, WASP, and TESS photometry, while radial velocities were calculated from high-quality optical spectr…
An Intermediate-age Alpha-rich Galactic Population in K2
García, Rafael A.; Stello, Dennis; Beaton, Rachael L. +9 more
We explore the relationships between the chemistry, ages, and locations of stars in the Galaxy using asteroseismic data from the K2 mission and spectroscopic data from the Apache Point Galactic Evolution Experiment survey. Previous studies have used giant stars in the Kepler field to map the relationship between the chemical composition and the ag…
MeerCRAB: MeerLICHT classification of real and bogus transients using deep learning
Paterson, Kerry; Körding, Elmar; Woudt, Patrick +13 more
Astronomers require efficient automated detection and classification pipelines when conducting large-scale surveys of the (optical) sky for variable and transient sources. Such pipelines are fundamentally important, as they permit rapid follow-up and analysis of those detections most likely to be of scientific value. We therefore present a deep le…
A Long Stream of Metal-poor Cool Gas around a Massive Starburst Galaxy at z = 2.67
Cooray, A.; Fu, Hai; Prochaska, J. X. +5 more
We present the first detailed dissection of the circumgalactic medium (CGM) of massive starburst galaxies at z > 2. Our target is a submillimeter galaxy (SMG) at z = 2.674 that has a star formation rate of 1200 M⊙ yr-1 and a molecular gas reservoir of 1.3 × 1011 M⊙. We characterize its CGM with two ba…
A random forest-based selection of optically variable AGN in the VST-COSMOS field
Bauer, F. E.; Brandt, W. N.; Vaccari, M. +6 more
Context. The survey of the COSMOS field by the VLT Survey Telescope is an appealing testing ground for variability studies of active galactic nuclei (AGN). With 54 r-band visits over 3.3 yr and a single-visit depth of 24.6 r-band mag, the dataset is also particularly interesting in the context of performance forecasting for the Vera C. Rubin Obser…
Recurrence of galactic cosmic-ray intensity and anisotropy in solar minima 23/24 and 24/25 observed by ACE/CRIS, STEREO, SOHO/EPHIN and neutron monitors. Fourier and wavelet analysis
Modzelewska, R.; Gil, A.
Aims: We studied the 27-day variations of galactic cosmic rays (GCRs) based on neutron monitor (NM), ACE/CRIS, STEREO, and SOHO/EPHIN measurements in the solar minima 23/24 and 24/25, which are characterized by the opposite polarities of solar magnetic cycle. We used the opportunity to reanalyze the polarity dependence of the amplitudes of th…
Radiative Driving of the AGN Outflows in the Narrow-line Seyfert 1 Galaxy NGC 4051
Fischer, Travis C.; Crenshaw, D. Michael; Schmitt, Henrique R. +5 more
We explore the properties of ionized gas in the nuclear and circumnuclear environment of the narrow-line Seyfert 1 galaxy NGC 4051 using spectroscopic and imaging observations from the Hubble Space Telescope (HST) and Apache Point Observatory's ARC 3.5 m Telescope. We identify an unresolved moderate-density intermediate-width component and a high-…
Nebular Hα emission in Type Ia supernova 2016jae
Cappellaro, E.; Benetti, S.; Morrell, N. +7 more
There is a wide consensus that Type Ia supernovae (SNe Ia) originate from the thermonuclear explosion of CO white dwarfs (WDs), with the lack of hydrogen in the observed spectra as a distinctive feature. Here, we present supernova (SN) 2016jae, which was classified as an SN Ia from a spectrum obtained soon after its discovery. The SN reached a B-b…
Dielectric Properties of the Medusae Fossae Formation and Implications for Ice Content
Campbell, Bruce A.; Morgan, Gareth A.; Watters, Thomas R.
The extensive Medusae Fossae Formation (MFF) along the dichotomy boundary on Mars has geologic features indicative of wind erosion of low density material. There is evidence suggesting a water ice component, but with considerable uncertainty linked to the unknown MFF porosity and compaction behavior. We use SHARAD radar sounder data to estimate th…