Search Publications
Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics beyond ΛCDM
Casertano, Stefano; Riess, Adam G.; Yuan, Wenlong +2 more
We present an improved determination of the Hubble constant from Hubble Space Telescope (HST) observations of 70 long-period Cepheids in the Large Magellanic Cloud (LMC). These were obtained with the same WFC3 photometric system used to measure extragalactic Cepheids in the hosts of SNe Ia. Gyroscopic control of HST was employed to reduce overhead…
The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch
Madore, Barry F.; Freedman, Wendy L.; Beaton, Rachael L. +10 more
We present a new and independent determination of the local value of the Hubble constant based on a calibration of the tip of the red giant branch (TRGB) applied to Type Ia supernovae (SNe Ia). We find a value of H 0 = 69.8 ± 0.8 (±1.1% stat) ± 1.7 (±2.4% sys) km s-1 Mpc-1. The TRGB method is both precise and accur…
Cluster Cosmology Constraints from the 2500 deg2 SPT-SZ Survey: Inclusion of Weak Gravitational Lensing Data from Magellan and the Hubble Space Telescope
Gladders, M. D.; Schrabback, T.; Rest, A. +77 more
We derive cosmological constraints using a galaxy cluster sample selected from the 2500 deg2 SPT-SZ survey. The sample spans the redshift range 0.25 < z < 1.75 and contains 343 clusters with SZ detection significance ξ > 5. The sample is supplemented with optical weak gravitational lensing measurements of 32 clusters with 0.29 …
Kinematics in Young Star Clusters and Associations with Gaia DR2
Sills, Alison; Feigelson, Eric D.; Hillenbrand, Lynne A. +2 more
The Gaia mission has opened a new window into the internal kinematics of young star clusters at the sub-km s-1 level, with implications for our understanding of how star clusters form and evolve. We use a sample of 28 clusters and associations with ages from ∼1-5 Myr, where lists of members are available from previous X-ray, optical, an…
How to Constrain Your M Dwarf. II. The Mass-Luminosity-Metallicity Relation from 0.075 to 0.70 Solar Masses
Gaidos, Eric; Rizzuto, Aaron C.; Kraus, Adam L. +11 more
The mass-luminosity relation for late-type stars has long been a critical tool for estimating stellar masses. However, there is growing need for both a higher-precision relation and a better understanding of systematic effects (e.g., metallicity). Here we present an empirical relationship between {M}{KS} and M * sp…
An Improved Distance to NGC 4258 and Its Implications for the Hubble Constant
Riess, A. G.; Reid, M. J.; Pesce, D. W.
NGC 4258 is a critical galaxy for establishing the extragalactic distance scale and estimating the Hubble constant ({H}0). Water masers in the nucleus of the galaxy orbit about its supermassive black hole, and very long baseline interferometric observations of their positions, velocities, and accelerations can be modeled to give a geome…
Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b
Fortney, Jonathan J.; Knutson, Heather A.; Howard, Andrew W. +13 more
Results from the Kepler mission indicate that the occurrence rate of small planets (<3 R ⊕) in the habitable zone of nearby low-mass stars may be as high as 80%. Despite this abundance, probing the conditions and atmospheric properties on any habitable-zone planet is extremely difficult and has remained elusive to date. Here, we repo…
An Older, More Quiescent Universe from Panchromatic SED Fitting of the 3D-HST Survey
Franx, Marijn; van Dokkum, Pieter; Conroy, Charlie +8 more
Galaxy observations are influenced by many physical parameters: stellar masses, star formation rates (SFRs), star formation histories (SFHs), metallicities, dust, black hole activity, and more. As a result, inferring accurate physical parameters requires high-dimensional models that capture or marginalize over this complexity. Here we reassess inf…
MOSFIRE Spectroscopy of Quiescent Galaxies at 1.5 < z < 2.5. II. Star Formation Histories and Galaxy Quenching
Ellis, Richard S.; Belli, Sirio; Newman, Andrew B.
We investigate the stellar populations for a sample of 24 quiescent galaxies at 1.5 < z < 2.5 using deep rest-frame optical spectra obtained with Keck MOSFIRE. By fitting templates simultaneously to the spectroscopic and photometric data and exploring a variety of star formation histories, we obtain robust measurements of median stellar ages…
An Analysis of the Shapes of Interstellar Extinction Curves. VII. Milky Way Spectrophotometric Optical-through-ultraviolet Extinction and Its R-dependence
Gordon, Karl D.; Fitzpatrick, E. L.; Clayton, Geoffrey C. +2 more
We produce a set of 72 NIR-through-UV extinction curves by combining new Hubble Space Telescope/STIS optical spectrophotometry with existing International Ultraviolet Explorer spectrophotometry (yielding gapless coverage from 1150 to 10000 Å) and NIR photometry. These curves are used to determine a new, internally consistent NIR-through-UV Milky W…