Search Publications
Generalized model-independent characterization of strong gravitational lenses VIII. Automated multiband feature detection to constrain local lens properties
Griffiths, Richard E.; Wagner, Jenny; Lin, Joyce
As established in previous papers of this series, observables in highly distorted and magnified multiple images caused by the strong gravitational lensing effect can be used to constrain the distorting properties of the gravitational lens at the image positions. If the background source is extended and contains substructure, like star forming regi…
S-PLUS: exploring wide field properties of multiple populations in galactic globular clusters at different metallicities
Chies-Santos, Ana L.; Mendes de Oliveira, Claudia; Bastian, Nate +9 more
Multiple stellar populations (MSPs) are a ubiquitous phenomenon in Galactic globular clusters (GCs). By probing different spectral ranges affected by different absorption lines using the multiband photometric survey S-PLUS, we study four GCs - NGC 104, NGC 288, NGC 3201, and NGC 7089 - that span a wide range of metallicities. With the combination …
Impact of point spread function higher moments error on weak gravitational lensing
Mandelbaum, Rachel; LSST Dark Energy Science Collaboration; Zhang, Tianqing
Weak gravitational lensing is one of the most powerful tools for cosmology, while subject to challenges in quantifying subtle systematic biases. The point spread function (PSF) can cause biases in weak lensing shear inference when the PSF model does not match the true PSF that is convolved with the galaxy light profile. Although the effect of PSF …
Chemo-dynamics and asteroseismic ages of seven metal-poor red giants from the Kepler field
Monty, Stephanie; Freeman, Ken C.; Stello, Dennis +5 more
In this work, we combine information from solar-like oscillations, high-resolution spectroscopy, and Gaia astrometry to derive stellar ages, chemical abundances, and kinematics for a group of seven metal-poor red giants and characterize them in a multidimensional chrono-chemo-dynamical space. Chemical abundance ratios were derived through classica…
Non-parametric spherical Jeans mass estimation with B-splines
Vasiliev, Eugene; Valluri, Monica; Rehemtulla, Nabeel
Spherical Jeans modelling is widely used to estimate mass profiles of systems from star clusters to galactic stellar haloes to clusters of galaxies. It derives the cumulative mass profile, M(<r), from kinematics of tracers of the potential under the assumptions of spherical symmetry and dynamical equilibrium. We consider the application of Jean…
The velocity distribution of white dwarfs in Gaia EDR3
McMillan, Paul J.; Hobbs, David; Wimarsson, John +1 more
Using a penalized maximum likelihood, we estimate, for the first time, the velocity distribution of white dwarfs in the solar neighbourhood. Our sample consists of 129 675 white dwarfs within 500 pc in Gaia Early Data Release 3. The white dwarf velocity distributions reveal a similar structure to the rest of the solar neighbourhood stars, reflecti…
The Galactic high mass X-ray binary population with Fermi-LAT
Chadwick, Paula M.; Harvey, Max; Rulten, Cameron B.
We search for γ-ray emission from 114 Galactic high-mass X-ray binaries, including four well studied catalogued sources, in 12.5 yr of Fermi-LAT data in conjunction with the 10-yr point source catalogue. Where a γ-ray excess appears to be spatially coincident with an X-ray binary, further investigation is performed to ascertain whether this excess…
Quantifying the cool ISM in radio AGNs: evidence for late-time retriggering by galaxy mergers and interactions
Daddi, E.; Morganti, R.; Tadhunter, C. N. +5 more
We use deep Herschel observations of the complete 2Jy sample of powerful radio active galactic nuclei (AGNs) in the local Universe (0.05 < z < 0.7) to probe their cool interstellar medium (ISM) contents and star-forming properties, comparing them against other samples of nearby luminous AGNs and quiescent galaxies. This allows us to investig…
Periodic stellar variability from almost a million NGTS light curves
Jackman, James A. G.; Wheatley, Peter J.; Bayliss, Daniel +25 more
We analyse 829 481 stars from the Next Generation Transit Survey (NGTS) to extract variability periods. We utilize a generalization of the autocorrelation function (the G-ACF), which applies to irregularly sampled time series data. We extract variability periods for 16 880 stars from late-A through to mid-M spectral types and periods between ~0.1 …
Wide binaries from the H3 survey: the thick disc and halo have similar wide binary fractions
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip +8 more
Due to the different environments in the Milky Way's disc and halo, comparing wide binaries in the disc and halo is key to understanding wide binary formation and evolution. By using Gaia Early Data Release 3, we search for resolved wide binary companions in the H3 survey, a spectroscopic survey that has compiled ~150 000 spectra for thick-disc an…