Journal Article

Physico-chemical spectroscopic mapping of the planetary nebula NGC 40 and the <span class="smallCaps">2d_neb</span>, a new 2D algorithm to study ionized nebulae

M. L. Leal-Ferreira, D. R. Gonçalves, H. Monteiro and J. W. Richards

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 411, issue 2, pages 1395-1408
Published in print February 2011 | ISSN: 0035-8711
Published online February 2011 | e-ISSN: 1365-2966 | DOI:
Physico-chemical spectroscopic mapping of the planetary nebula NGC 40 and the 2d_neb, a new 2D algorithm to study ionized nebulae

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In this paper we present an analysis of the physical and chemical conditions of the planetary nebula NGC 40 through spatially resolved spectroscopic maps. We also introduce a new algorithm –2d_neb– based on the well-established iraf nebular package, which was developed to enable the use of the spectroscopic maps to easily estimate the astrophysical quantities of ionized nebulae. The 2d_neb was benchmarked, and we clearly show that it works properly, since it compares nicely with the iraf nebular software.

Using this software, we derive the maps of several physical parameters of NGC 40. From these maps, we conclude that Te[N ii] shows only a slight temperature variation from region to region, with its values constrained between ∼8000 and 9500 K. Electron densities, on the other hand, have a much more prominent spatial variation, as Ne[S ii] values vary from ∼1000 to 3000 cm−3. Maps of the chemical abundances also show significant variations. From the big picture of our work, we strongly suggest that analysis with spatial resolution be mandatory for more complete study of the physical and chemical properties of planetary nebulae.

Keywords: methods: data analysis; techniques: spectroscopic; ISM: abundances; planetary nebulae: individual: NGC 40

Journal Article.  8748 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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