Search Results - "Frebel, Anna"

CHEMICAL SIGNATURES OF THE FIRST GALAXIES: CRITERIA FOR ONE-SHOT ENRICHMENT by FREBEL, Anna, BROMM, Volker

“…We utilize metal-poor stars in the local, ultra-faint dwarf galaxies (UFDs; L sub(tot) [< or =, slant] 10 super(5) L sub([middot in circle])) to empirically…”
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R-process enrichment from a single event in an ancient dwarf galaxy by Ji, Alexander P., Frebel, Anna, Chiti, Anirudh, Simon, Joshua D.

“…It has long been debated whether elements heavier than zinc are formed continually, for example in core-collapse supernovae, or in rare events, such as neutron…”
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From Actinides to Zinc: Using the Full Abundance Pattern of the Brightest Star in Reticulum II to Distinguish between Different r-process Sites by Ji, Alexander P., Frebel, Anna

“…Abstract The ultra-faint dwarf galaxy Reticulum II was enriched by a rare and prolific r -process event, such as a neutron star merger (NSM). To investigate…”
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COMPLETE ELEMENT ABUNDANCES OF NINE STARS IN THE r-PROCESS GALAXY RETICULUM II by Ji, Alexander P., Frebel, Anna, Simon, Joshua D., Chiti, Anirudh

“…ABSTRACT We present chemical abundances derived from high-resolution Magellan /Magellan Inamori Kyocera Echelle spectra of the nine brightest known red giant…”
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Ultra-metal-poor Stars: Spectroscopic Determination of Stellar Atmospheric Parameters Using Iron Non-LTE Line Abundances by Ezzeddine, Rana, Frebel, Anna, Plez, Bertrand

“…We present new ultra-metal-poor stars parameters with [Fe/H] < −4.0 based on line-by-line non-local thermodynamic equilibrium (NLTE) abundances using an…”
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CARBON-ENHANCED METAL-POOR STAR FREQUENCIES IN THE GALAXY: CORRECTIONS FOR THE EFFECT OF EVOLUTIONARY STATUS ON CARBON ABUNDANCES by PLACCO, VINICIUS M, FREBEL, ANNA, Beers, Timothy C, Stancliffe, Richard J

“…We revisit the observed frequencies of carbon-enhanced metal-poor (CEMP) stars as a function of the metallicity in the Galaxy, using data from the literature…”
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Preserving chemical signatures of primordial star formation in the first low-mass stars by Ji, Alexander P., Frebel, Anna, Bromm, Volker

“…We model early star-forming regions and their chemical enrichment by Population III (Pop III) supernovae with nucleosynthetic yields featuring high [C/Fe]…”
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Chemical Abundances in the Ultra-faint Dwarf Galaxies Grus I and Triangulum II: Neutron-capture Elements as a Defining Feature of the Faintest Dwarfs by Ji, Alexander P., Simon, Joshua D., Frebel, Anna, Venn, Kim A., Hansen, Terese T.

“…Abstract We present high-resolution spectroscopy of four stars in two candidate ultra-faint dwarf galaxies (UFDs), Grus I (Gru I) and Triangulum II (Tri II)…”
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The predicted luminous satellite populations around SMC- and LMC-mass galaxies – a missing satellite problem around the LMC? by Dooley, Gregory A., Peter, Annika H.G., Carlin, Jeffrey L., Frebel, Anna, Bechtol, Keith, Willman, Beth

“…Abstract Recent discovery of many dwarf satellite galaxies in the direction of the Small and Large Magellanic Clouds (SMC and LMC) provokes questions of their…”
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HIGH-RESOLUTION SPECTROSCOPY OF EXTREMELY METAL-POOR STARS IN THE LEAST EVOLVED GALAXIES: BOÖTES II by Ji, Alexander P, Frebel, Anna, Simon, Joshua D, Geha, Marla

“…ABSTRACT We present high-resolution Magellan /MIKE spectra of the four brightest confirmed red giant stars in the ultra-faint dwarf galaxy Boötes II (Boo II)…”
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The R-process Alliance: First Release from the Southern Search for R-process-enhanced Stars in the Galactic Halo by Hansen, Terese T., Holmbeck, Erika M., Beers, Timothy C., Placco, Vinicius M., Roederer, Ian U., Frebel, Anna, Sakari, Charli M., Simon, Joshua D., Thompson, Ian B.

“…Abstract The recent detection of a binary neutron star merger and the clear evidence of the decay of radioactive material observed in this event have, after 60…”
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Chemical Abundances of New Member Stars in the Tucana II Dwarf Galaxy by Chiti, Anirudh, Frebel, Anna, Ji, Alexander P., Jerjen, Helmut, Kim, Dongwon, Norris, John E.

“…Abstract We present chemical abundance measurements for seven stars with metallicities ranging from Fe/H] = −3.3 to [Fe/H] = −2.4 in the Tucana II ultra-faint…”
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Collapsar R-process Yields Can Reproduce [Eu/Fe] Abundance Scatter in Metal-poor Stars by Brauer, Kaley, Ji, Alexander P., Drout, Maria R., Frebel, Anna

“…Abstract It is unclear if neutron star mergers can explain the observed r -process abundances of metal-poor stars. Collapsars, defined here as rotating massive…”
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The R-Process Alliance: First Magellan/MIKE Release from the Southern Search for R-process-enhanced Stars by Ezzeddine, Rana, Rasmussen, Kaitlin, Frebel, Anna, Chiti, Anirudh, Hinojisa, Karina, Placco, Vinicius M., Ji, Alexander P., Beers, Timothy C., Hansen, Terese T., Roederer, Ian U., Sakari, Charli M., Melendez, Jorge

“…Abstract Extensive progress has recently been made in our understanding of heavy-element production via the r -process in the universe, specifically with the…”
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Evidence for an Aspherical Population III Supernova Explosion Inferred from the Hyper-metal-poor Star HE 1327–2326 by Ezzeddine, Rana, Frebel, Anna, Roederer, Ian U., Tominaga, Nozomu, Tumlinson, Jason, Ishigaki, Miho, Nomoto, Ken’ichi, Placco, Vinicius M., Aoki, Wako

“…Abstract We present observational evidence that an aspherical supernova explosion could have occurred in the first stars in the early universe. Our results are…”
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THE CATERPILLAR PROJECT: A LARGE SUITE OF MILKY WAY SIZED HALOS by Griffen, Brendan F., Ji, Alexander P., Dooley, Gregory A., Gómez, Facundo A., Vogelsberger, Mark, O'Shea, Brian W., Frebel, Anna

“…ABSTRACT We present the largest number of Milky Way sized dark matter halos simulated at very high mass (∼104 /particle) and temporal resolution (5…”
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Predicting the locations of possible long-lived low-mass first stars: importance of satellite dwarf galaxies by Magg, Mattis, Hartwig, Tilman, Agarwal, Bhaskar, Frebel, Anna, Glover, Simon C. O., Griffen, Brendan F., Klessen, Ralf S.

“…Abstract The search for metal-free stars has so far been unsuccessful, proving that if there are surviving stars from the first generation, they are rare, they…”
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Descendants of the first stars: the distinct chemical signature of second-generation stars by Hartwig, Tilman, Yoshida, Naoki, Magg, Mattis, Frebel, Anna, Glover, Simon C O, Gómez, Facundo A, Griffen, Brendan, Ishigaki, Miho N, Ji, Alexander P, Klessen, Ralf S, O’Shea, Brian W, Tominaga, Nozomu

“…ABSTRACT Extremely metal-poor (EMP) stars in the Milky Way (MW) allow us to infer the properties of their progenitors by comparing their chemical composition…”
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The R-Process Alliance: First Release from the Northern Search for r-process-enhanced Metal-poor Stars in the Galactic Halo by Sakari, Charli M., Placco, Vinicius M., Farrell, Elizabeth M., Roederer, Ian U., Wallerstein, George, Beers, Timothy C., Ezzeddine, Rana, Frebel, Anna, Hansen, Terese, Holmbeck, Erika M., Sneden, Christopher, Cowan, John J., Venn, Kim A., Davis, Christopher Evan, Matijevi, Gal, Wyse, Rosemary F. G., Bland-Hawthorn, Joss, Chiappini, Cristina, Freeman, Kenneth C., Gibson, Brad K., Grebel, Eva K., Helmi, Amina, Kordopatis, Georges, Kunder, Andrea, Navarro, Julio, Reid, Warren, Seabroke, George, Steinmetz, Matthias, Watson, Fred

“…This paper presents the detailed abundances and r-process classifications of 126 newly identified metal-poor stars as part of an ongoing collaboration, the…”
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SEGUE 1-A COMPRESSED STAR FORMATION HISTORY BEFORE REIONIZATION by Webster, David, Frebel, Anna, Bland-Hawthorn, Joss

“…ABSTRACT Segue 1 is the current best candidate for a "first galaxy," a system that experienced only a single, short burst of star formation and has since…”
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