566 citations · 13.8k across the 201 of their papers we have counts for
93 papers · 1 filter
Chemo-dynamical Analysis of a CNO-Enhanced Ultra Metal-poor Star (): Insights into Early Enrichment by Faint Population III Supernova
Guilherme Limberg, Vinicius M. Placco, Alexander P. Ji +10
We report an independent identification of the ultra metal-poor (UMP) star () DR3 $\texttt{source_id}$ 4795913112968206720 (GDR3_479591) in the miss…
Carbon Abundances in Metal-Poor Stars Reveal Distinct Galaxy and Star Formation Pathways in the Early Universe
Alexander Yelland, Anna Frebel, Xiaowei Ou +2
Carbon-enhanced metal-poor (CEMP; with and ) stars preserve information about early chemical enrichment, low-mass star formation, and th…
The Metallicity Distribution of the Ultra-Faint Dwarf Galaxy Segue 1
Daisy Bissonette, Alexander P. Ji, Joshua D. Simon +6
Ultra-faint dwarf galaxies (UFDs; stellar masses ) offer unique insights into early chemical evolution in low-mass systems. However, interpreting their metalli…
The -Process Alliance: The -Process Enhancement of Stars from Chemodynamically Tagged Groups in the Milky Way Halo
Jessica Merritt Agnos, Charli M. Sakari, Pedro Silva +9
As part of the ongoing work of the -Process Alliance (RPA), detailed abundance measurements of 29 heavy elements in three metal-poor stars, 2MASS J145929813852558, 2MASS J194…
Aeos is Mixing it Up: The (In)homogeneity of Metal Mixing Following Population III Star Formation
Jennifer Mead, Kaley Brauer, Greg L. Bryan +7
Stellar surface abundances are records of the state of the gas from which stars formed, and thus trace how individual elements have mixed into the surrounding medium following thei…
Discovery of an Star in XP Spectra
Guilherme Limberg, Vinicius M. Placco, Alexander P. Ji +5
We report on the discovery of GDR3_526285 ( DR3 Source ID 5262850721755411072), a star with and one of the lowest metal ($\text{atomic number} >…
A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II
Alice M. Luna, Alexander P. Ji, Anirudh Chiti +6
Star formation in ultra-faint dwarf galaxies (UFDs, ) is suppressed by reionization, but may not be completely quenched. The metallicity distribution function (MD…
Decoding the Galactic Twirl: The Downfall of Milky Way-mass Galaxies Rotation Curves in the FIRE Simulations
Xiaowei Ou, Lina Necib, Andrew Wetzel +3
Recent measurements of the Milky Way rotation curve found a sharp decline at around - kpc from the center of the Galaxy, suggesting that the Galactic dark matter halo is mu…
Aeos: The Impact of Population III Initial Mass Function and Star-by-Star Models in Galaxy Simulations
Kaley Brauer, Jennifer Mead, John H. Wise +7
We explore the effect of variations in the Population III (Pop III) initial mass function (IMF) and star-by-star feedback on early galaxy formation and evolution using the Aeos sim…
Early r-process Enrichment and Hierarchical Assembly Across the Sagittarius Dwarf Galaxy
Xiaowei Ou, Alexander Yelland, Anirudh Chiti +3
Dwarf galaxies like Sagittarius (Sgr) provide a unique window into the early stages of galactic chemical evolution, particularly through their metal-poor stars. By studying the che…
GLIMPSE: An ultra-faint 10 Pop III Galaxy Candidate and First Constraints on the Pop III UV Luminosity Function at
Seiji Fujimoto, Rohan P. Naidu, John Chisholm +32
Detecting the first generation of stars, Population III (PopIII), has been a long-standing goal in astrophysics, yet they remain elusive even in the JWST era. Here we present a nov…
Metal-Poor Stars in the Milky Way System
Anna Frebel
Ancient, long-lived stars remain present in all components of our home galaxy, the Milky Way. Born a few hundred million after the Big Bang and during a time that marked the very b…
Aeos: Transport of Metals from Minihalos following Population III Stellar Feedback
Jennifer Mead, Kaley Brauer, Greg L. Bryan +7
We investigate how stellar feedback from the first stars (Population III) distributes metals through the interstellar and intergalactic medium using the star-by-star cosmological h…
All the Little Things in Abell 2744: 1000 Gravitationally Lensed Dwarf Galaxies at from JWST NIRCam Grism Spectroscopy
Rohan P. Naidu, Jorryt Matthee, Ivan Kramarenko +31
Dwarf galaxies hold the key to crucial frontiers of astrophysics, however, their faintness renders spectroscopy challenging. Here we present the JWST Cycle 2 survey, All the Little…
AEOS: Star-by-Star Cosmological Simulations of Early Chemical Enrichment and Galaxy Formation
Kaley Brauer, Andrew Emerick, Jennifer Mead +7
The AEOS project introduces a series of high-resolution cosmological simulations that model star-by-star chemical enrichment and galaxy formation in the early Universe, achieving 1…
The -Process Alliance: Enrichment of -process Elements in a Simulated Milky Way-like Galaxy
Yutaka Hirai, Timothy C. Beers, Young Sun Lee +11
We study the formation of stars with varying amounts of heavy elements synthesized by the rapid neutron-capture process (-process) based on our detailed cosmological zoom-in sim…
The oldest stars with low neutron-capture element abundances and origins in ancient dwarf galaxies
Hillary Diane Andales, Ananda Santos Figueiredo, Casey Gordon Fienberg +2
We present a detailed chemical abundance and kinematic analysis of six extremely metal-poor ( [Fe/H] 2.9) halo stars with very low neutron-capture abundances ([Sr…
The Rise of the -Process in the Gaia-Sausage/Enceladus Dwarf Galaxy
Xiaowei Ou, Alexander P. Ji, Anna Frebel +2
Neutron star mergers (NSMs) produce copious amounts of heavy r-process elements after a time delayed inspiral process. Once NSMs are present in a galaxy, r-process elements, such a…
Signatures of tidal disruption of the Hercules ultra-faint dwarf galaxy
Xiaowei Ou, Anirudh Chiti, Nora Shipp +6
The Hercules ultra-faint dwarf galaxy (UFD) has long been hypothesized to be tidally disrupting, yet no conclusive evidence has been found for tidal disruption owing partly to diff…
A Strontium-rich Ultra Metal-poor Star in the Atari Disk Component
Mohammad K. Mardini, Anna Frebel, Anirudh Chiti
We report on the discovery of the first ultra metal-poor (UMP) star 2MASS~J205001946613298 (J20506613; \mbox{[Fe/H] = }) selected from the Gaia BP/RP spectral catalog…
Enrichment by Extragalactic First Stars in the Large Magellanic Cloud
Anirudh Chiti, Mohammad Mardini, Guilherme Limberg +8
The Large Magellanic Cloud (LMC) is the Milky Way's most massive satellite galaxy, which only recently (~2 billion years ago) fell into our Galaxy. Since stellar atmospheres preser…
Metal-poor stars observed with the Magellan Telescope. IV. Neutron-capture element signatures in 27 main-sequence stars
Mohammad K. Mardini, Anna Frebel, Leyatt Betre +3
Based on high-resolution spectra obtained with Magellan/MIKE, we present a chemo-dynamical analysis for 27 near main-sequence turnoff metal-poor stars, including 20 stars analyzed…
The dark matter profile of the Milky Way inferred from its circular velocity curve
Xiaowei Ou, Anna-Christina Eilers, Lina Necib +1
In this paper, we construct the circular velocity curve of the Milky Way out to kpc, providing an updated model of the dark matter density profile. We derive precise para…
Timing the r-Process Enrichment of the Ultra-Faint Dwarf Galaxy Reticulum II
Joshua D. Simon, Thomas M. Brown, Burçin Mutlu-Pakdil +65
The ultra-faint dwarf galaxy Reticulum II (Ret II) exhibits a unique chemical evolution history, with 72 +10/-12% of its stars strongly enhanced in r-process elements. We present d…