Search Publications
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…
A geometric distance measurement to the Galactic center black hole with 0.3% uncertainty
Förster Schreiber, N. M.; Genzel, R.; Sturm, E. +52 more
We present a 0.16% precise and 0.27% accurate determination of R0, the distance to the Galactic center. Our measurement uses the star S2 on its 16-year orbit around the massive black hole Sgr A* that we followed astrometrically and spectroscopically for 27 years. Since 2017, we added near-infrared interferometry with the VLTI beam combi…
A distance to the Large Magellanic Cloud that is precise to one per cent
Smolec, R.; Kudritzki, R. P.; Bresolin, F. +19 more
In the era of precision cosmology, it is essential to determine the Hubble constant empirically with an accuracy of one per cent or better1. At present, the uncertainty on this constant is dominated by the uncertainty in the calibration of the Cepheid period-luminosity relationship2,3 (also known as the Leavitt law). The Larg…
Microlensing constraints on primordial black holes with Subaru/HSC Andromeda observations
Oguri, Masamune; More, Surhud; Takada, Masahiro +8 more
Primordial black holes (PBHs) have long been suggested as a viable candidate for the elusive dark matter. The abundance of such PBHs has been constrained using a number of astrophysical observations, except for a hitherto unexplored mass window of MPBH = [10-14, 10-9] solar masses. Here we carry out a dense-cadence…
Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data
Strauss, Michael A.; Wang, Shiang-Yu; Sifón, Cristóbal +34 more
We measure cosmic weak lensing shear power spectra with the Subaru Hyper Suprime-Cam (HSC) survey first-year shear catalog covering 137 deg2 of the sky. Thanks to the high effective galaxy number density of ∼17 arcmin-2, even after conservative cuts such as a magnitude cut of i < 24.5 and photometric redshift cut of 0.3 ≤ …
Star Clusters Across Cosmic Time
Bland-Hawthorn, Joss; Krumholz, Mark R.; McKee, Christopher F.
Star clusters stand at the intersection of much of modern astrophysics: the ISM, gravitational dynamics, stellar evolution, and cosmology. Here, we review observations and theoretical models for the formation, evolution, and eventual disruption of star clusters. Current literature suggests a picture of this life cycle including the following sever…
The Faintest Dwarf Galaxies
Simon, Joshua D.
The lowest luminosity (L < 105L⊙) Milky Way satellite galaxies represent the extreme lower limit of the galaxy luminosity function. These ultra-faint dwarfs are the oldest, most dark matter-dominated, most metal-poor, and least chemically evolved stellar systems known. They therefore provide unique windows into the formati…
Second data release of the Hyper Suprime-Cam Subaru Strategic Program
Ono, Yoshiaki; Ouchi, Masami; Harikane, Yuichi +62 more
This paper presents the second data release of the Hyper Suprime-Cam Subaru Strategic Program, a wide-field optical imaging survey using the 8.2 m Subaru Telescope. The release includes data from 174 nights of observation through 2018 January. The Wide layer data cover about 300 deg^2 in all five broad-band filters (grizy) to the nominal survey ex…
Growth model interpretation of planet size distribution
Vanderburg, Andrew; Cao, Hao; Berger, Travis A. +13 more
The radii and orbital periods of 4,000+ confirmed/candidate exoplanets have been precisely measured by the Kepler mission. The radii show a bimodal distribution, with two peaks corresponding to smaller planets (likely rocky) and larger intermediate-size planets, respectively. While only the masses of the planets orbiting the brightest stars can be…
Evidence for two early accretion events that built the Milky Way stellar halo
Myeong, G. C.; Evans, N. W.; Belokurov, V. +2 more
The Gaia Sausage is the major accretion event that built the stellar halo of the Milky Way galaxy. Here, we provide dynamical and chemical evidence for a second substantial accretion episode, distinct from the Gaia Sausage. The Sequoia Event provided the bulk of the high-energy retrograde stars in the stellar halo, as well as the recently discover…