Infrared High-Resolution Integrated Light Spectral Analyses of M31 Globular Clusters from APOGEE

Abstract

Chemical abundances are presented for 25 M31 globular clusters (GCs), based on moderately high resolution (R = 22, 500) H-band integrated light spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). Infrared spectra offer lines from new elements, of different strengths, and 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 infrared integrated light 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 infrared within the 1σ uncertainties. The first integrated K abundances are also presented, and demonstrate that K tracks the alpha-elements. The combination of infrared 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.

Accepted for publication in the Astrophysical Journal

References in corpus (14)

• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Population Synthesis in the Blue IV: Accurate Model Predictions for Lick Indices and UBV Colors in Single Stellar Populations
• DAOSPEC: an automatic code for measuring equivalent widths in high-resolution stellar spectra
• Exploring Anticorrelations and Light Element Variations in Northern Globular Clusters Observed by the APOGEE Survey
• A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the full Asymptotic Giant Branch phase and Web tools for stellar population analyses
• Measuring Ages and Elemental Abundances from Unresolved Stellar Populations: Fe, Mg, C, N, and Ca
• Star Clusters in M31: I. A Catalog and a Study of the Young Clusters
• Structural parameters for globular clusters in M31 and generalizations for the fundamental plane
• Globular Cluster Abundances from High-Resolution Integrated Light Spectra, I: 47 Tuc
• The Detailed Chemical Properties of M31 Star Clusters I. Fe, Alpha and Light Elements
• VLT Spectroscopy of Globular Clusters in Low Surface Brightness Dwarf Galaxies
• Integrated Light Chemical Tagging Analyses of Seven M31 Outer Halo Globular Clusters from the Pan-Andromeda Archaeological Survey
• Chemical abundances in the globular clusters NGC 5024 and NGC 5466 from optical and infrared spectroscopy
• Optimal Integrated Abundances for Chemical Tagging of Extragalactic Globular Clusters

Cited by in corpus (17)

• Final Targeting Strategy for the SDSS-IV APOGEE-2S Survey
• Final Targeting Strategy for the SDSS-IV APOGEE-2N Survey
• APOGEE Chemical Abundances of Globular Cluster Giants in the Inner Galaxy
• The chemical composition of globular clusters in the Local Group
• On the Nitrogen variation in ~2 Gyr old massive star clusters in the Large Magellanic Cloud
• Elemental abundances in M31: Individual and Coadded Spectroscopic [Fe/H] and [α/Fe] throughout the M31 Halo with SPLASH
• The APOGEE Library of Infrared SSP Templates (A-LIST): High-Resolution Simple Stellar Population Spectral Models in the H-Band
• The Massive M31 Cluster G1: Detailed Chemical Abundances from Integrated Light Spectroscopy
• Searching for Multiple Populations in the Integrated Light of the Young and Extremely Massive Clusters in the Merger Remnant NGC~7252
• Leveraging HST with MUSE: II. Na-abundance variations in intermediate age star clusters
• The Chemodynamics of the Stellar Populations in M31 from APOGEE Integrated Light Spectroscopy
• Metallicities of Outer Halo M31 Globular Clusters from Integrated Light Calcium-II Triplet Spectroscopy
• Synthetic stellar spectra to study multiple populations in globular clusters: an extended grid and the effects on the integrated light
• Study of Integrated Spectra of Four Globular Clusters in M31
• Horizontal branch structure, age, and chemical composition for very metal-poor extragalactic globular clusters
• Extragalactic globular cluster near-infrared spectroscopy: I. Integrated near-infrared spectra of Centaurus A/NGC 5128
• Chemical composition and ages of four globular clusters in M31 from the analysis of their integrated-light spectra