Chemical Abundances of Planetary Nebulae in the Substructures of M31

Abstract

We present deep spectroscopy of planetary nebulae (PNe) that are associated with the substructures of the Andromeda Galaxy (M31). The spectra were obtained with the OSIRIS spectrograph on the 10.4 m GTC. Seven targets were selected for the observations, three in the Northern Spur and four associated with the Giant Stream. The most distant target in our sample, with a rectified galactocentric distance >100 kpc, was the first PN discovered in the outer streams of M31. The [O III] 4363 auroral line was well detected in the spectra of all targets, enabling electron temperature determination. Ionic abundances are derived based on the [O III] temperatures, and elemental abundances of helium, nitrogen, oxygen, neon, sulfur, and argon are estimated. The relatively low N/O and He/H ratios as well as abundance ratios of alpha-elements indicate that our target PNe might belong to populations as old as ~2 Gyr. Our PN sample, including the current seven and the previous three observed by Fang et al., have rather homogeneous oxygen abundances. The study of abundances and the spatial and kinematical properties of our sample leads to the tempting conclusion that their progenitors might belong to the same stellar population, which hints at a possibility that the Northern Spur and the Giant Stream have the same origin. This may be explained by the stellar orbit proposed by Merrett et al. Judging from the position and kinematics, we emphasize that M32 might be responsible for the two substructures. Deep spectroscopy of PNe in M32 will help to assess this hypothesis.

Accepted for publication in the ApJ. 23 pages, including 13 figures and 7 tables

References in corpus (12)

• The Haunted Halos of Andromeda and Triangulum: A panorama of galaxy formation in action
• The large-scale structure of the halo of the Andromeda Galaxy Part I: global stellar density, morphology and metallicity properties
• The initial-final mass relationship of white dwarfs revisited: effect on the luminosity function and mass distribution
• Keck HIRES Spectroscopy of Extragalactic HII Regions: C and O Abundances from Recombination Lines
• A deep kinematic survey of planetary nebulae in the Andromeda Galaxy using the Planetary Nebula Spectrograph
• Chemical abundances for Hf 2-2, a planetary nebula with the strongest known heavy element recombination lines
• The Nature and Origin of Substructure in the Outskirts of M31 -- II. Detailed Star Formation Histories
• Planetary nebulae abundances and stellar evolution
• Co-spatial Long-slit UV/Optical Spectra of Ten Galactic Planetary Nebulae with HST/STIS I. Description of the Observations, Global Emission-line Measurements, and CNO Abundances
• The chemistry of planetary nebulae in the outer regions of M31
• Predictions of the extent of self-enrichment in oxygen of giant metal-poor HII regions
• A Search for Planetary Nebulae With the SDSS: the outer regions of M31

Cited by in corpus (16)

• De Re Metallica: The cosmic chemical evolution of galaxies
• Revisiting the radial abundance gradients of nitrogen and oxygen of the Milky Way
• Planetary Nebulae: Sources of Enlightenment
• The radial abundance gradient of oxygen towards the Galactic anticentre
• Metallicity gradients in Local Universe galaxies: time evolution and effects of radial migration
• On the radial abundance gradients of nitrogen and oxygen in the inner Galactic disc
• The mysterious cut-off of the Planetary Nebula Luminosity Function
• Carbon, nitrogen and oxygen abundance gradients in M101 and M31
• The survey of planetary nebulae in Andromeda (M31). IV. Radial oxygen and argon abundance gradients of the thin and thicker disc
• Chemical Abundances of Planetary Nebulae in the Substructures of M31 -- II. The Extended Sample and A Comparison Study with the Outer-disk Group
• On the most luminous planetary nebulae of M31
• A study of extragalactic planetary nebulae populations based on spectroscopy. I. Data compilation and first findings
• Metallicity gradients in M31, M33, NGC 300 and the Milky Way using abundances of different elements
• Planetary Nebulae in the Circumnuclear Region of M31: A Spectroscopic Sample
• Gaseous abundances in planetary nebulae: What have we learned in the past five years?
• The survey of Planetary Nebulae in Andromeda (M31): I. Imaging the disk and halo with MegaCam@CFHT