Deep spectroscopy of the emission-line populations in NGC185

Abstract

Dwarf galaxies are crucial to understand the formation and evolution of galaxies, since they constitute the most abundant galaxy population. Abundance ratios and their variations due to star formation are key constraints to chemical evolution models. The determination of these abundances in the dwarf galaxies of the Local Universe is thus of extreme importance. However, these objects are intrinsically faint and observational constraints to their evolution can be obtained only for very nearby galaxies. NGC 185 is one of the four brightest dwarf companions of M31, but unlike than the other three, NGC 147, NGC 205, and NGC 221 (M32) it has an important content of gas and dust. We obtained deep spectroscopic observations of the H$\alpha$ emitting population of NGC 185 using GMOS-N at Gemini. As a result, in addition to the bright planetary nebulae (PNe) previously found in the galaxy and reported in the literature, we found other, much fainter, PNe. We then re-calculated the electron temperatures and chemical abundances of the brightest ones, and derived, for the first time, their electron densities. Our characterisation of the PN population properties is interpreted in terms of the chemical evolution of NGC 185, which suggests that it has suffered a significant chemical enrichment within the last $\sim$8 Gyr. We also discovered the first symbiotic star in the galaxy and enlightened the properties of a known supernova remnant located close to the centre of NGC 185.

13 pages, 7 Figures, Accepted for publication by MNRAS

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Cited by in corpus (18)

• A census of symbiotic stars in the 2MASS, WISE and Gaia surveys
• A PAndAS view of M31 dwarf elliptical satellites: NGC147 and NGC185
• Metallicity gradients in Local Universe galaxies: time evolution and effects of radial migration
• The GALAH Survey and Symbiotic Stars. I. Discovery and follow-up of 33 candidate accreting-only systems
• Discovery of true, likely and possible symbiotic stars in the dwarf spheroidal NGC 205
• Gaia18aen: First symbiotic star discovered by Gaia
• Optical supernova remnants in nearby galaxies and their influence on star formation rates derived from H$\alpha$ emission
• Planetary nebulae: the universal mass-metallicity relation for Local Group dwarf galaxies and the chemistry of NGC 205
• Symbiotic stars in the era of modern ground- and space-based surveys
• The interstellar medium in Andromeda's dwarf spheroidal galaxies: I. Content and origin of the interstellar dust
• The nature of the symbiotic candidate 2MASS J07363415+6538548 in the field of NGC 2403
• RAMSES II - RAMan Search for Extragalactic Symbiotic Stars. Project concept, commissioning, and early results from the science verification phase
• A kinematic study of planetary nebulae in the dwarf irregular galaxy IC10
• A study of extragalactic planetary nebulae populations based on spectroscopy. I. Data compilation and first findings
• The interstellar medium in Andromeda's dwarf spheroidal galaxies: II. Multi-phase gas content and ISM conditions
• Extragalactic Planetary Nebulae: tracers of the chemical evolution of nearby galaxies
• What do planetary nebulae and H II regions reveal about the chemical evolution of nearby dwarf galaxies?
• Revealing the nature of central emission nebulae in the dwarf galaxy NGC 185