Search Publications
Cosmic Distances Calibrated to 1% Precision with Gaia EDR3 Parallaxes and Hubble Space Telescope Photometry of 75 Milky Way Cepheids Confirm Tension with ΛCDM
Casertano, Stefano; Riess, Adam G.; Yuan, Wenlong +4 more
We present an expanded sample of 75 Milky Way Cepheids with Hubble Space Telescope (HST) photometry and Gaia EDR3 parallaxes, which we use to recalibrate the extragalactic distance ladder and refine the determination of the Hubble constant. All HST observations were obtained with the same instrument (WFC3) and filters (F555W, F814W, F160W) used fo…
Measurements of the Hubble Constant: Tensions in Perspective
Freedman, Wendy L.
Measurement of the distances to nearby galaxies has improved rapidly in recent decades. The ever-present challenge is to reduce systematic effects, especially as greater distances are probed and the uncertainties become larger. In this paper, we combine several recent calibrations of the tip of the red giant branch (TRGB) method. These calibration…
Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies
Kilpatrick, Charles D.; Foley, Ryan J.; Cenko, S. Bradley +37 more
While tidal disruption events (TDEs) have long been heralded as laboratories for the study of quiescent black holes, the small number of known TDEs and uncertainties in their emission mechanism have hindered progress toward this promise. Here we present 17 new TDEs that have been detected recently by the Zwicky Transient Facility along with Swift …
A Test of the Cosmological Principle with Quasars
Secrest, Nathan J.; Sarkar, Subir; Mohayaee, Roya +3 more
We study the large-scale anisotropy of the universe by measuring the dipole in the angular distribution of a flux-limited, all-sky sample of 1.36 million quasars observed by the Wide-field Infrared Survey Explorer (WISE). This sample is derived from the new CatWISE2020 catalog, which contains deep photometric measurements at 3.4 and 4.6 µm f…
Parallax Systematics and Photocenter Motions of Benchmark Eclipsing Binaries in Gaia EDR3
Torres, Guillermo; Stassun, Keivan G.
Previous analyses of various standard candles observed by the Gaia satellite have reported statistically significant systematics in the parallaxes that have improved from ∼250 µas in the first data release (DR1) to 50-80 µas in the second data release (DR2). Here we examine the parallaxes newly reported in the Gaia early third data rel…
Reconstructing the Last Major Merger of the Milky Way with the H3 Survey
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +8 more
Several lines of evidence suggest that the Milky Way underwent a major merger at z ~ 2 with the Gaia-Sausage-Enceladus (GSE) galaxy. Here we use H3 Survey data to argue that GSE entered the Galaxy on a retrograde orbit based on a population of highly retrograde stars with chemistry similar to the largely radial GSE debris. We present the first tai…
The Hubble Constant from Infrared Surface Brightness Fluctuation Distances
Ma, Chung-Pei; Greene, Jenny E.; Blakeslee, John P. +2 more
We present a measurement of the Hubble constant H0 from surface brightness fluctuation (SBF) distances for 63 bright, mainly early-type galaxies out to 100 Mpc observed with the WFC3/IR on the Hubble Space Telescope (HST). The sample is drawn from several independent HST imaging programs using the F110W bandpass, with the majority of th…
Updated BaSTI Stellar Evolution Models and Isochrones. II. α-enhanced Calculations
Salaris, Maurizio; Mucciarelli, Alessio; Silva Aguirre, Victor +7 more
This is the second paper of a series devoted to presenting an updated release of the BaSTI (a Bag of Stellar Tracks and Isochrones) stellar model and isochrone library. Following the publication of the updated solar-scaled library, here we present the library for an α-enhanced heavy element distribution. These new α-enhanced models account for all…
Charting the Galactic Acceleration Field. I. A Search for Stellar Streams with Gaia DR2 and EDR3 with Follow-up from ESPaDOnS and UVES
Bianchini, Paolo; Martin, Nicolas; Malhan, Khyati +10 more
We present maps of the stellar streams detected in the Gaia Data Release 2 (DR2) and Early Data Release 3 (EDR3) catalogs using the STREAMFINDER algorithm. We also report the spectroscopic follow-up of the brighter DR2 stream members obtained with the high-resolution CFHT/ESPaDOnS and VLT/UVES spectrographs as well as with the medium-resolution NT…
A Large Fraction of Hydrogen-rich Supernova Progenitors Experience Elevated Mass Loss Shortly Prior to Explosion
Cenko, S. Bradley; Duev, Dmitry A.; Riddle, Reed +45 more
Spectroscopic detection of narrow emission lines traces the presence of circumstellar mass distributions around massive stars exploding as core-collapse supernovae. Transient emission lines disappearing shortly after the supernova explosion suggest that the material spatial extent is compact and implies an increased mass loss shortly prior to expl…