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تسجيل مستخدم جديدProposed nomenclature for Extragalactic Planetary Nebulae
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The ability to identify and distinguish between the wide variety of celestial objects benefits from application of a systematic and logical nomenclature. This often includes value-added information within the naming convention which can aid in placing the object positionally either via an RA/DEC or l,b concatenation. All new nomenclatures should be created following IAU guidelines. However as the number density of specific object types on the sky increases, as in the case of PN in external galaxies, a useful positional identifier becomes problematic. This brief but timely paper attempts to progress the debate on this vexing issue for the case of extragalactic planetary nebulae (EPN). There is a clear need to rationalise the current ad-hoc system now that many thousands of Extragalactic PN are being discovered.
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The study of extragalactic planetary nebulae (EPN) is a rapidly expanding field. The advent of powerful new instrumentation such as the PN spectrograph has led to an avalanche of new EPN discoveries both within and between galaxies. We now have thous
ands of EPN detections in a heterogeneous selection of nearby galaxies and their local environments, dwarfing the combined galactic detection efforts of the last century. Key scientific motivations driving this rapid growth in EPN research and discovery have been the use of the PNLF as a standard candle, as dynamical tracers of their host galaxies and dark matter and as probes of Galactic evolution. This is coupled with the basic utility of PN as laboratories of nebula physics and the consequent comparison with theory where population differences, abundance variations and star formation history within and between stellar systems informs both stellar and galactic evolution. Here we pose some of the burning questions, discuss some of the observational challenges and outline some of the future prospects of this exciting, relatively new, research area as we strive to go fainter, image finer, see further and survey faster than ever before and over a wider wavelength regime
We present kinematic data for 211 bright planetary nebulae in eleven Local Group galaxies: M31 (137 PNe), M32 (13), M33 (33), Fornax (1), Sagittarius (3), NGC 147 (2), NGC 185 (5), NGC 205 (9), NGC 6822 (5), Leo A (1), and Sextans A (1). The data wer
e acquired at the Observatorio Astronomico Nacional in the Sierra de San Pedro Martir using the 2.1m telescope and the Manchester Echelle Spectrometer in the light of [ion{O}{3}]$lambda$5007 at a resolution of 11 km/s. A few objects were observed in H$alpha$. The internal kinematics of bright planetary nebulae do not depend strongly upon the metallicity or age of their progenitor stellar populations, though small systematic differences exist. The nebular kinematics and H$beta$ luminosity require that the nebular shells be accelerated during the early evolution of their central stars. Thus, kinematics provides an additional argument favoring similar stellar progenitors for bright planetary nebulae in all galaxies.
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I review the progress in research on intracluster planetary nebulae over the last five years. Hundreds more intracluster planetary nebulae have been detected in the nearby Virgo and Fornax galaxy clusters, searches of several galaxy groups have been
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