Zobrazeno 1 - 10
of 89
pro vyhledávání: '"Mardini, Mohammad"'
Autor:
Andales, Hillary Diane, Figueiredo, Ananda Santos, Fienberg, Casey Gordon, Mardini, Mohammad K., Frebel, Anna
We present a detailed chemical abundance and kinematic analysis of six extremely metal-poor ($-4.2 \leq$ [Fe/H] $\leq-$2.9) halo stars with very low neutron-capture abundances ([Sr/H] and [Ba/H]) based on high-resolution Magellan/MIKE spectra. Three
Externí odkaz:
http://arxiv.org/abs/2405.07856
Autor:
Ou, Xiaowei, Chiti, Anirudh, Shipp, Nora, Simon, Joshua D., Geha, Marla, Frebel, Anna, Mardini, Mohammad K., Erkal, Denis, Necib, Lina
The Hercules ultra-faint dwarf galaxy (UFD) has long been hypothesized to be tidally disrupting, yet no conclusive evidence has been found for tidal disruption owing partly to difficulties in identifying Hercules member stars. In this work, we presen
Externí odkaz:
http://arxiv.org/abs/2403.00921
We report on the discovery of the first ultra metal-poor (UMP) star 2MASS~J20500194$-$6613298 (J2050$-$6613; \mbox{[Fe/H] = $-4.05$}) selected from the Gaia BP/RP spectral catalog that belongs to the ancient Atari disk component. We obtained a high-r
Externí odkaz:
http://arxiv.org/abs/2402.07046
The Milky Way is a spiral galaxy comprising three main components: the Bulge, the Disk, and the Halo. Of particular interest is the Galactic disk, which holds a significant portion of the baryonic matter angular momentum and harbors at least two prim
Externí odkaz:
http://arxiv.org/abs/2402.07045
Autor:
Chiti, Anirudh, Mardini, Mohammad, Limberg, Guilherme, Frebel, Anna, Ji, Alexander P., Reggiani, Henrique, Ferguson, Peter, Andales, Hillary Diane, Brauer, Kaley, Li, Ting S., Simon, Joshua D.
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 preserve their natal cloud's composition, the LMC's recent infall makes its
Externí odkaz:
http://arxiv.org/abs/2401.11307
Autor:
Hong, Jihye, Beers, Timothy C., Lee, Young Sun, Huang, Yang, Hirai, Yutaka, Garcia, Jonathan Cabrera, Shank, Derek, Xu, Shuai, Yuan, Haibo, Mardini, Mohammad K., Catapano, Thomas, Zhao, Gang, Fan, Zhou, Zheng, Jie, Wang, Wei, Tan, Kefeng, Zhao, Jingkun, Li, Chun
Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target-selection biases often associated with such studies. Photometric-metallicit
Externí odkaz:
http://arxiv.org/abs/2311.02297
Autor:
Placco, Vinicius M., Almeida-Fernandes, Felipe, Holmbeck, Erika M., Roederer, Ian U., Mardini, Mohammad K., Hayes, Christian R., Venn, Kim, Chiboucas, Kristin, Deibert, Emily, Gamen, Roberto, Heo, Jeong-Eun, Jeong, Miji, Kalari, Venu, Martioli, Eder, Xu, Siyi, Diaz, Ruben, Gomez-Jimenez, Manuel, Henderson, David, Prado, Pablo, Quiroz, Carlos, Ruiz-Carmona, Roque, Simpson, Chris, Urrutia, Cristian, McConnachie, Alan W., Pazder, John, Burley, Gregory, Ireland, Michael, Waller, Fletcher, Berg, Trystyn A. M., Robertson, J. Gordon, Hartman, Zachary, Jones, David O., Labrie, Kathleen, Perez, Gabriel, Ridgway, Susan, Thomas-Osip, Joanna
We report on the chemo-dynamical analysis of SPLUS J142445.34-254247.1, an extremely metal-poor halo star enhanced in elements formed by the rapid neutron-capture process. This star was first selected as a metal-poor candidate from its narrow-band S-
Externí odkaz:
http://arxiv.org/abs/2310.17024
Autor:
Mardini, Mohammad K., Frebel, Anna, Betre, Leyatt, Jacobson, Heather, Norris, John E., Christlieb, Norbert
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 for the first time. The sample spans a range in [Fe/H] from -2.5 to -3
Externí odkaz:
http://arxiv.org/abs/2305.05363
Autor:
Zepeda, Joseph, Beers, Timothy C., Placco, Vinicius M., Shank, Derek, Gudin, Dmitrii, Hirai, Yutaka, Mardini, Mohammad, Pifer, Colin, Catapano, Thomas, Calagna, Sean
We construct a sample of 644 carbon-enhanced metal-poor (CEMP) stars with abundance analyses based on moderate- to high-resolution spectroscopic studies. Dynamical parameters for these stars are estimated, based on radial velocities, Bayesian paralla
Externí odkaz:
http://arxiv.org/abs/2209.12224
Autor:
Mardini, Mohammad K., Frebel, Anna, Ezzeddine, Rana, Chiti, Anirudh, Meiron, Yohai, Ji, Alexander P., Placco, Vinicius M., Roederer, Ian U., Meléndez, Jorge
We present a high-resolution ($R\sim35,000$), high signal-to-noise ($S/N=350$) Magellan/MIKE spectrum of the bright extremely metal-poor star 2MASS~J1808$-$5104. We find [Fe/H] = $-$4.01 (spectroscopic LTE stellar parameters), [Fe/H] = $-$3.8 (photom
Externí odkaz:
http://arxiv.org/abs/2208.03891