Search Publications
A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km s-1 Mpc-1 Uncertainty from the Hubble Space Telescope and the SH0ES Team
Casertano, Stefano; Filippenko, Alexei V.; Jones, David O. +15 more
We report observations from the Hubble Space Telescope (HST) of Cepheid variables in the host galaxies of 42 Type Ia supernovae (SNe Ia) used to calibrate the Hubble constant (H 0). These include the complete sample of all suitable SNe Ia discovered in the last four decades at redshift z ≤ 0.01, collected and calibrated from ≥1000 HST o…
Two Remarkably Luminous Galaxy Candidates at z ≈ 10-12 Revealed by JWST
Strait, Victoria; van Dokkum, Pieter; Conroy, Charlie +22 more
The first few 100 Myr at z > 10 mark the last major uncharted epoch in the history of the universe, where only a single galaxy (GN-z11 at z ≈ 11) is currently spectroscopically confirmed. Here we present a search for luminous z > 10 galaxies with JWST/NIRCam photometry spanning ≈1-5 µm and covering 49 arcmin2 from the public…
A Long Time Ago in a Galaxy Far, Far Away: A Candidate z ∼ 12 Galaxy in Early JWST CEERS Imaging
Papovich, Casey; Cole, Justin W.; Yang, Guang +119 more
We report the discovery of a candidate galaxy with a photo-z of z ~ 12 in the first epoch of the James Webb Space Telescope (JWST) Cosmic Evolution Early Release Science Survey. Following conservative selection criteria, we identify a source with a robust z phot = ${11.8}_{-0.2}^{+0.3}$ (1σ uncertainty) with m F200W = 27.3 an…
Early Results from GLASS-JWST. III. Galaxy Candidates at z 9-15
Santini, Paola; Calabrò, Antonello; Castellano, Marco +27 more
We present the results of a first search for galaxy candidates at z ~ 9-15 on deep seven-band NIRCam imaging acquired as part of the GLASS-James Webb Space Telescope (JWST) Early Release Science Program on a flanking field of the Frontier Fields cluster A2744. Candidates are selected via two different renditions of the Lyman-break technique, isola…
The JWST Early Release Observations
Koekemoer, Anton M.; Ravindranath, Swara; Henry, Alaina +34 more
The James Webb Space Telescope (JWST) Early Release Observations (EROs) is a set of public outreach products created to mark the end of commissioning and the beginning of science operations for JWST. Colloquially known as the "Webb First Images and Spectra," these products were intended to demonstrate to the worldwide public that JWST is ready for…
A Guide to Realistic Uncertainties on the Fundamental Properties of Solar-type Exoplanet Host Stars
van Saders, Jennifer; Huber, Daniel; Claytor, Zachary R. +1 more
Our understanding of the properties and demographics of exoplanets critically relies on our ability to determine the fundamental properties of their host stars. The advent of Gaia and large spectroscopic surveys has now made it possible, in principle, to infer the properties of individual stars, including most exoplanet hosts, to very high precisi…
An Isolated Stellar-mass Black Hole Detected through Astrometric Microlensing
Ferguson, Henry C.; Brown, Thomas M.; Casertano, Stefano +91 more
We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration (t E ≃ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as …
The Global Dynamical Atlas of the Milky Way Mergers: Constraints from Gaia EDR3-based Orbits of Globular Clusters, Stellar Streams, and Satellite Galaxies
Sharma, Sanjib; Malhan, Khyati; Ibata, Rodrigo A. +7 more
The Milky Way halo was predominantly formed by the merging of numerous progenitor galaxies. However, our knowledge of this process is still incomplete, especially in regard to the total number of mergers, their global dynamical properties and their contribution to the stellar population of the Galactic halo. Here, we uncover the Milky Way mergers …
An Isolated Mass-gap Black Hole or Neutron Star Detected with Astrometric Microlensing
Lu, Jessica R.; Udalski, Andrzej; Mróz, Przemek +42 more
We present the analysis of five black hole candidates identified from gravitational microlensing surveys. Hubble Space Telescope astrometric data and densely sampled light curves from ground-based microlensing surveys are fit with a single-source, single-lens microlensing model in order to measure the mass and luminosity of each lens and determine…
Cluster Cepheids with High Precision Gaia Parallaxes, Low Zero-point Uncertainties, and Hubble Space Telescope Photometry
Casertano, Stefano; Riess, Adam G.; Breuval, Louise +7 more
We present Hubble Space Telescope (HST) photometry of 17 Cepheids in open clusters and their cluster mean parallaxes from Gaia EDR3. These parallaxes are more precise than those from individual Cepheids (G < 8 mag) previously used to measure the Hubble constant because they are derived from an average of >300 stars per cluster. Cluster paral…