The gas turbulence in planetary nebulae: quantification and multi-D maps from long-slit, wide-spectral range echellogram

Abstract

This methodological paper is part of a short series dedicated to the long-standing astronomical problem of de-projecting the bi-dimensional, apparent morphology of a three-dimensional distribution of gas. We focus on the quantification and spatial recovery of turbulent motions in planetary nebulae (and other classes of expanding nebulae) by means of long-slit echellograms over a wide spectral range. We introduce some basic theoretical notions, discuss the observational methodology, and develop an accurate procedure disentangling all broadening components of the velocity profile in all spatial positions of each spectral image. This allows us to extract random, non-thermal motions at unprecedented accuracy, and to map them in 1-, 2- and 3-dimensions. We present the solution to practical problems in the multi-dimensional turbulence-analysis of a testing-planetary nebula (NGC 7009), using the three-step procedure (spatio-kinematics, tomography, and 3-D rendering) developed at the Astronomical Observatory of Padua. In addition, we introduce an observational paradigm valid for all spectroscopic parameters in all classes of expanding nebulae. Unsteady, chaotic motions at a local scale constitute a fundamental (although elusive) kinematical parameter of each planetary nebula, providing deep insights on its different shaping agents and mechanisms, and on their mutual interaction. The detailed study of turbulence, its stratification within a target and (possible) systematic variation among different sub-classes of planetary nebulae deserve long-slit, multi-position angle, wide-spectral range echellograms containing emissions at low-, medium-, and high-ionization, to be analyzed pixel-to-pixel with a straightforward and versatile methodology, extracting all the physical information stored in each frame at best.

11 page, 10 figures, A&A in press

References in corpus (20)

• Interstellar Turbulence I: Observations and Processes
• Nonlinear Instabilities in Shock-Bounded Slabs
• The Dynamical Evolution of the Circumstellar Gas around Low- and Intermediate-Mass stars.II. The Planetary Nebula formation
• From the Owl to the Eskimo: the Radiation-Gasdynamics of Planetary Nebulae IV
• Bipolar Outflows and the Evolution of Stars
• Planetary nebulae with emission-line central stars
• Diffuse X-ray emission from the planetary nebula NGC 7009
• Evolution of Planetary Nebulae I. An improved synthetic model
• White dwarf masses derived from planetary nebulae modelling
• The Dynamical Evolution of Planetary Nebulae After the Fast Wind
• The 3-D ionization structure and evolution of NGC 7009 (Saturn Nebula)
• Kinematics, turbulence and evolution of planetary nebulae
• Atmospheres and Winds of PN Central Stars
• High-velocity regions in planetary nebulae
• The structure of Planetary Nebulae: theory vs. practice
• Structure and clumping in the fast wind of NGC6543
• The 3--D ionization structure of NGC 6818: a Planetary Nebula threatened by recombination
• The 3-D shaping of NGC 6741: a massive, fast-evolving Planetary Nebula at the recombination--reionization edge
• 3-D ionization structure (in stereoscopic view) of Planetary Nebulae: the case of NGC 1501
• The 3-D ionization structure of the planetary nebula NGC6565

Cited by in corpus (4)

• ALMA imaging of the nascent planetary nebula IRAS 15103-5754
• The evolution of planetary nebulae. VIII. True expansion rates and visibility times
• Tangential Motions and Spectroscopy within NGC 6720, the Ring Nebula
• Abundance Discrepancy Factors in high density planetary nebulae