Search Publications
First semi-empirical test of the white dwarf mass-radius relationship using a single white dwarf via astrometric microlensing
Casertano, Stefano; Anderson, Jay; McGill, Peter +15 more
In November 2019, the nearby single, isolated DQ-type white dwarf LAWD 37 (WD 1142-645) aligned closely with a distant background source and caused an astrometric microlensing event. Leveraging astrometry from Gaia and followup data from the Hubble Space Telescope, we measure the astrometric deflection of the background source and obtain a gravita…
Implications of z ≳ 12 JWST galaxies for galaxy formation at high redshift
Qin, Yuxiang; Balu, Sreedhar; Wyithe, J. Stuart B.
Using a semi-analytic galaxy formation model, we study analogues of eight z ≳ 12 galaxies recently discovered by James Webb Space Telescope (JWST). We select analogues from a cosmological simulation with a (311 cMpc)3 volume and an effective particle number of 1012 enabling the resolution of every atomic-cooling galaxy at z ≤…
Awesome SOSS: atmospheric characterization of WASP-96 b using the JWST early release observations
MacDonald, Ryan J.; Espinoza, Néstor; Parmentier, Vivien +13 more
The newly operational JWST offers the potential to study the atmospheres of distant worlds with precision that has not been achieved before. One of the first exoplanets observed by JWST in the summer of 2022 was WASP-96 b, a hot Saturn orbiting a G8 star. As a part of the Early Release Observations programme, one transit of WASP-96 b was observed …
Binarity and beyond in A stars - I. Survey description and first results of VLTI/GRAVITY observations of VAST targets with high Gaia-Hipparcos accelerations
Katz, Boaz; Waisberg, Idel; Klein, Ygal
The connection between the multiplicity of A stars and that of their white dwarf (WD) descendants is not known and the observational mappings of both multiplicities are far from complete. We are conducting an interferometric survey with VLTI/GRAVITY of 20 out of 108 southern A stars within the VAST sample which show large Gaia-Hipparcos proper mot…
The connection between the escape of ionizing radiation and galaxy properties at z ∼ 3 in the Keck Lyman continuum spectroscopic survey
Steidel, Charles C.; Reddy, Naveen A.; Shapley, Alice +4 more
The connection between the escape fraction of ionizing radiation (fesc) and the properties of galaxies, such as stellar mass ($\rm M_{\rm *}$), age, star-formation rate (SFR), and dust content, are key inputs for reionization models, but many of these relationships remain untested at high redshift. We present an analysis of a sample of …
A wide-field view on multiple stellar populations in 28 Milky Way globular clusters
Cabrera-Ziri, I.; Pancino, E.; Hilker, M. +2 more
The majority of Galactic globular clusters (GCs) contain multiple stellar populations displaying specific chemical abundance variations. In particular, GCs generally contain a 'primordial' population with abundances similar to field stars, along with an 'enriched' population exhibiting light element anomalies. In this paper, we present a homogeneo…
Abell 1201: detection of an ultramassive black hole in a strong gravitational lens
Edge, Alastair C.; Lucey, John R.; Amvrosiadis, Aristeidis +9 more
Supermassive black holes (SMBHs) are a key catalyst of galaxy formation and evolution, leading to an observed correlation between SMBH mass MBH and host galaxy velocity dispersion σe. Outside the local Universe, measurements of MBH are usually only possible for SMBHs in an active state: limiting sample size and int…
The B & V light curves for recurrent nova T CrB from 1842-2022, the unique pre- and post-eruption high-states, the complex period changes, and the upcoming eruption in 2025.5 ± 1.3
Schaefer, Bradley E.
T CrB is one of the most-famous and brightest novae known, and is a recurrent nova with prior eruptions in 1866 and 1946 that peak at V = 2.0. I have constructed light curves spanning 1842-2022 with 213 730 magnitudes, where the B and V magnitudes are fully corrected to the Johnson system. These light curves first reveal a unique complex high-stat…
Dark matter halo cores and the tidal survival of Milky Way satellites
Navarro, Julio F.; Errani, Raphaël; Peñarrubia, Jorge +2 more
The cuspy central density profiles of cold dark matter (CDM) haloes make them highly resilient to disruption by tides. Self-interactions between dark matter particles, or the cycling of baryons, may result in the formation of a constant-density core that would make haloes more susceptible to tidal disruption. We use N-body simulations to study the…
Quasar UV/X-ray relation luminosity distances are shorter than reverberation-measured radius-luminosity relation luminosity distances
Zajaček, Michal; Czerny, Bożena; Khadka, Narayan +5 more
We use measurements of 59/58 quasars (QSOs), over a redshift range 0.0041 ≤ z ≤ 1.686, to do a comparative study of the radius-luminosity (R - L) and X-ray-UV luminosity (LX - LUV) relations and the implication of these relations for cosmological parameter estimation. By simultaneously determining R - L or LX - L