Search Publications
Calibration of the Tip of the Red Giant Branch
Madore, Barry F.; Freedman, Wendy L.; Lee, Myung Gyoon +6 more
The tip of the red giant branch (TRGB) method provides one of the most accurate and precise means of measuring the distances to nearby galaxies. Here we present a multi-wavelength, VIJHK absolute calibration of the TRGB based on observations of TRGB stars in the Large Magellanic Cloud (LMC), grounded on a geometric distance, determined by detached…
Evidence from the H3 Survey That the Stellar Halo Is Entirely Comprised of Substructure
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +5 more
In the ΛCDM paradigm, the Galactic stellar halo is predicted to harbor the accreted debris of smaller systems. To identify these systems, the H3 Spectroscopic Survey, combined with Gaia, is gathering 6D phase-space and chemical information in the distant Galaxy. Here we present a comprehensive inventory of structure within 50 kpc from the Galactic…
The SunPy Project: Open Source Development and Status of the Version 1.0 Core Package
Ryan, Daniel F.; Murray, Sophie A.; Ireland, Jack +32 more
The goal of the SunPy project is to facilitate and promote the use and development of community-led, free, and open source data analysis software for solar physics based on the scientific Python environment. The project achieves this goal by developing and maintaining the sunpy core package and supporting an ecosystem of affiliated packages. This …
INTEGRAL Discovery of a Burst with Associated Radio Emission from the Magnetar SGR 1935+2154
Tiengo, A.; Sunyaev, R.; Götz, D. +23 more
We report on International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the soft γ-ray repeater SGR 1935+2154 performed between 2020 April 28 and May 3. Several short bursts with fluence of $\sim {10}^{-7}\mbox{--}{10}^{-6}$ erg cm-2 were detected by the Imager on-board INTEGRAL (IBIS) instrument in the 20-200 keV range.…
Rapid Reionization by the Oligarchs: The Case for Massive, UV-bright, Star-forming Galaxies with High Escape Fractions
Conroy, Charlie; Tacchella, Sandro; Naidu, Rohan P. +3 more
The protagonists of the last great phase transition of the universe - cosmic reionization - remain elusive. Faint star-forming galaxies are leading candidates because they are found to be numerous and may have significant ionizing photon escape fractions (fesc). Here we update this picture via an empirical model that successfully predic…
On the Spectral Evolution of Hot White Dwarf Stars. I. A Detailed Model Atmosphere Analysis of Hot White Dwarfs from SDSS DR12
Fontaine, G.; Bergeron, P.; Bédard, A. +1 more
As they evolve, white dwarfs undergo major changes in surface composition, a phenomenon known as spectral evolution. In particular, some stars enter the cooling sequence with helium atmospheres (type DO) but eventually develop hydrogen atmospheres (type DA), most likely through the upward diffusion of residual hydrogen. Our empirical knowledge of …
The Fourth Fermi-GBM Gamma-Ray Burst Catalog: A Decade of Data
Meegan, C. A.; von Kienlin, A.; Kocevski, D. +18 more
We present the fourth in a series of catalogs of gamma-ray bursts (GRBs) observed with Fermi's Gamma-ray Burst Monitor (Fermi-GBM). It extends the six year catalog by four more years, now covering the 10 year time period from trigger enabling on 2008 July 12 to 2018 July 11. During this time period GBM triggered almost twice a day on transient eve…
The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. II. A Statistical Characterization of Class 0 and Class I Protostellar Disks
Kounkel, Marina; Kratter, Kaitlin; Dunham, Michael M. +33 more
We have conducted a survey of 328 protostars in the Orion molecular clouds with the Atacama Large Millimeter/submillimeter Array at 0.87 mm at a resolution of ∼0"1 (40 au), including observations with the Very Large Array at 9 mm toward 148 protostars at a resolution of ∼0"08 (32 au). This is the largest multiwavelength survey of protostars at thi…
Gamma-Ray Burst Afterglows in the Multimessenger Era: Numerical Models and Closure Relations
Piro, Luigi; Ryan, Geoffrey; Troja, Eleonora +1 more
Gamma-ray bursts (GRBs) associated with gravitational wave events are, and will likely continue to be, viewed at a larger inclination than GRBs without gravitational wave detections. As demonstrated by the afterglow of GW 170817A, this requires an extension of the common GRB afterglow models, which typically assume emission from an on-axis top-hat…
Host Galaxy Properties and Offset Distributions of Fast Radio Bursts: Implications for Their Progenitors
Kilpatrick, Charles D.; Simha, Sunil; Mannings, Alexandra +15 more
We present observations and detailed characterizations of five new host galaxies of fast radio bursts (FRBs) discovered with the Australian Square Kilometre Array Pathfinder (ASKAP) and localized to ≲1″. Combining these galaxies with FRB hosts from the literature, we introduce criteria based on the probability of chance coincidence to define a sub…