Browsing by Author "Anguiano, Borja"

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    Disk-like Chemistry of the Triangulum-Andromeda Overdensity as Seen by APOGEE
    (IOP PUBLISHING LTD, 2018) Hayes, Christian R.; Majewski, Steven R.; Hasselquist, Sten; Beaton, Rachael L.; Cunha, Katia; Smith, Verne V.; Price Whelan, Adrian M.; Anguiano, Borja; Beers, Timothy C.; Carrera, Ricardo; Fernandez Trincado, J. G.; Frinchaboy, Peter M.; Garcia Hernandez, D. A.; Lane, Richard R.; Nidever, David L.; Nitschelm, Christian; Roman Lopes, Alexandre; Zamora, Olga
    The nature of the Triangulum-Andromeda (TriAnd) system has been debated since the discovery of this distant, low-latitude Milky Way (MW) overdensity more than a decade ago. Explanations for its origin are either as a halo substructure from the disruption of a dwarf galaxy, or a distant extension of the Galactic disk. We test these hypotheses using the chemical abundances of a dozen TriAnd members from the Sloan Digital Sky Survey-IV's (SDSS-IV's) 14th Data Release (DR14) of Apache Point Observatory Galactic Evolution Experiment (APOGEE) data to compare to APOGEE abundances of stars with similar metallicity from both the Sagittarius (Sgr) dSph and the outer MW disk. We find that TriAnd stars are chemically distinct from Sgr across a variety of elements, (C+N), Mg, K, Ca, Mn, and Ni, with a separation in [X/Fe] of about 0.1 to 0.4 dex depending on the element. Instead, the TriAnd stars, with a median metallicity of about -0.8, exhibit chemical abundance ratios similar to those of the lowest metallicity ([Fe/H] similar to-0.7)stars in the outer Galactic disk, and are consistent with expectations of extrapolated chemical gradients in the outer disk of the MW. These results suggest that TriAnd is associated with the MW disk, and, therefore, that the disk extends to this overdensity-i.e., past a Galactocentric radius of 24 kpc -albeit vertically perturbed about 7 kpc below the nominal disk midplane in this region of the Galaxy.
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    Stellar Astrophysics and Exoplanet Science with the Maunakea Spectroscopic Explorer (MSE)
    (2019) Bergemann, Maria; Huber, Daniel; Adibekyan, Vardan; Angelou, George; Barría, Daniela; Beers, Timothy C.; Beck, Paul G.; Bellinger, Earl P.; Bestenlehner, Joachim M.; Bitsch, Bertram; Burgasser, Adam; Buzasi, Derek; Cassisi, Santi; Catelan, Marcio; Escorza, Ana; Fleming, Scott W.; Gänsicke, Boris T.; Gandolfi, Davide; García, Rafael A.; Gieles, Mark; Karakas, Amanda; Lebreton, Yveline; Lodieu, Nicolas; Melis, Carl; Merle, Thibault; Mészáros, Szabolcs; Miglio, Andrea; Molaverdikhani, Karan; Monier, Richard; Morel, Thierry; Neilson, Hilding R.; Oshagh, Mahmoudreza; Rybizki, Jan; Serenelli, Aldo; Smiljanic, Rodolfo; Szabó, Gyula M.; Toonen, Silvia; Tremblay, Pier-Emmanuel; Valentini, Marica; Van Eck, Sophie; Zwintz, Konstanze; Bayo, Amelia; Cami, Jan; Casagrande, Luca; Gabdeev, Maksim; Gaulme, Patrick; Guiglion, Guillaume; Handler, Gerald; Hillenbrand, Lynne; Yildiz, Mutlu; Marley, Mark; Mosser, Benoit; Price-Whelan, Adrian M.; Prsa, Andrej; Hernández Santisteban, Juan V.; Silva Aguirre, Victor; Sobeck, Jennifer; Stello, Dennis; Szabo, Robert; Tsantaki, Maria; Villaver, Eva; Wright, Nicholas J.; Xu, Siyi; Zhang, Huawei; Anguiano, Borja; Bedell, Megan; Chaplin, Bill; Collet, Remo; Kamath, Devika; Martell, Sarah; Sousa, Sérgio G.; Ting, Yuan-Sen; Venn, Kim
    The Maunakea Spectroscopic Explorer (MSE) is a planned 11.25-m aperture facility with a 1.5 square degree field of view that will be fully dedicated to multi-object spectroscopy. A rebirth of the 3.6m Canada-France-Hawaii Telescope on Maunakea, MSE will use 4332 fibers operating at three different resolving powers (R ~ 2500, 6000, 40000) across a wavelength range of 0.36-1.8mum, with dynamical fiber positioning that allows fibers to match the exposure times of individual objects. MSE will enable spectroscopic surveys with unprecedented scale and sensitivity by collecting millions of spectra per year down to limiting magnitudes of g ~ 20-24 mag, with a nominal velocity precision of ~100 m/s in high-resolution mode. This white paper describes science cases for stellar astrophysics and exoplanet science using MSE, including the discovery and atmospheric characterization of exoplanets and substellar objects, stellar physics with star clusters, asteroseismology of solar-like oscillators and opacity-driven pulsators, studies of stellar rotation, activity, and multiplicity, as well as the chemical characterization of AGB and extremely metal-poor stars....
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    Using APOGEE wide binaries to test chemical tagging with dwarf stars
    (2019) Andrews, Jeff J.; Anguiano, Borja; Chaname, Julio; Agueros, Marcel A.; Lewis, Hannah M.; Hayes, Christian R.; Majewsk, Steven R.