INFRARED HIGH-RESOLUTION INTEGRATED LIGHT SPECTRAL ANALYSES OF M31 GLOBULAR CLUSTERS FROM APOGEE

Journal Article · Sat Oct 01 00:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/829/2/116· OSTI ID:22667379

Sakari, Charli M. ^[1]; Shetrone, Matthew D. ^[2]; Schiavon, Ricardo P. ^[3]; Bizyaev, Dmitry; Pan, Kaike ^[4]; Prieto, Carlos Allende; García-Hernández, Domingo Aníbal ^[5]; Beers, Timothy C. ^[6]; Caldwell, Nelson ^[7]; Lucatello, Sara ^[8]; Majewski, Steven; O’Connell, Robert W. ^[9]; Strader, Jay ^[10]

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1. Department of Astronomy, University of Washington, Seattle WA 98195-1580 (United States)
2. McDonald Observatory, University of Texas at Austin, HC75 Box 1337-MCD, Fort Davis, TX 79734 (United States)
3. Gemini Observatory, 670 N. A’Ohoku Place, Hilo, HI 96720 (United States)
4. Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States)
5. Instituto de Astrofísica de Canarias (IAC), Va Lactea s/n, E-38205 La Laguna, Tenerife (Spain)
6. Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556 (United States)
7. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
8. INAF Osservatorio Astronomico di Padova, Vicolo dellOsservatorio 5, I-35122 Padova (Italy)
9. Dept. of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)
10. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

Chemical abundances are presented for 25 M31 globular clusters (GCs), based on moderately high resolution ( R = 22,500) H -band integrated light (IL) spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). Infrared (IR) spectra offer lines from new elements, lines of different strengths, and lines at higher excitation potentials compared to the optical. Integrated abundances of C, N, and O are derived from CO, CN, and OH molecular features, while Fe, Na, Mg, Al, Si, K, Ca, and Ti abundances are derived from atomic features. These abundances are compared to previous results from the optical, demonstrating the validity and value of IR IL analyses. The CNO abundances are consistent with typical tip of the red giant branch stellar abundances but are systematically offset from optical Lick index abundances. With a few exceptions, the other abundances agree between the optical and the IR within the 1 σ uncertainties. The first integrated K abundances are also presented and demonstrate that K tracks the α elements. The combination of IR and optical abundances allows better determinations of GC properties and enables probes of the multiple populations in extragalactic GCs. In particular, the integrated effects of the Na/O anticorrelation can be directly examined for the first time.

• OSTI ID: 22667379
• Journal Information: Astrophysical Journal, Vol. 829, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CARBON
CARBON MONOXIDE
COMPARATIVE EVALUATIONS
ELEMENT ABUNDANCE
EXCEPTIONS
EXCITATION
GALACTIC EVOLUTION
GALAXIES
GALAXY CLUSTERS
INFRARED SPECTRA
ISOCHRONOUS CYCLOTRONS
RESOLUTION
STAR CLUSTERS
STARS
VISIBLE RADIATION