The MUSE view of the planetary nebula NGC 3132

Abstract: ABRIDGED: 2D spectroscopic MUSE data for the whole extent of NGC3132 have been reduced and analised. The dust extinction, electron densities and temperatures of the ionised gas and abundances were determined. The nebula presents a complex reddening structure with high values (c(Hb)~0.4) at the rim. Density maps are compatible with an inner high-ionisation plasma at moderate high density (~1000cm^-3) while the low-ionisation plasma presents a structure in density peaking at the rim with values ~700 cm^-3. Median Te using different diagnostics decreases according to the sequence [NII],[SII]->[SIII]->[OI]->HeI->PJ. Likewise the range of Te covered by recombination lines is much larger than those obtained from CELs, with large spatial variations within the nebula. If these differences were due to the existence of high density clumps, these spatial variations suggest changes in the properties and/or distribution of the clumps within the nebula. We determined a median He/H=0.124. The range of measured ionic abundances for light elements are compatible with literature values. Our kinematic analysis nicely illustrates the power of 2D kinematic information in many emission lines to shed light on the intrinsic structure of the nebula. Our derived velocity maps support a geometry for the nebula similar to the previously propose diabolo model, but oriented with its major axis at P.A.~-22^o. We identified two low-surface brightness arc-like structures towards the northern and southern tips of the nebula, with high extinction, high helium abundance, and strong low-ionisation emission lines. They are spatially coincident with some extended low-surface brightness mid-IR emission. The characteristics of the features are compatible with being the consequence of precessing jets caused by the binary star system. This study illustrates the enormous potential of IFS for the study of Galactic PNe.

• The paper presents a comprehensive analysis of the NGC 3132 planetary nebula using 2D MUSE spectroscopy, covering morphology, kinematics, and physical properties over a large spatial extent.
• Detailed morphological analysis reveals complex structures, including newly identified faint, low-ionisation arcs suggesting potential precessing jets and significant, non-uniform extinction across the nebula.
• The study provides detailed maps of electron temperature, density, and ionic abundances, supporting a diabolo-like kinematic structure and highlighting the need for sophisticated 3D modeling for full understanding.

Analysis of the Planetary Nebula NGC 3132 Using MUSE

The paper provides an extensive examination of the planetary nebula NGC 3132 utilizing data acquired from the Multi-Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope. This study delivers a comprehensive understanding of the nebula's morphological, physical, and kinematic characteristics through 2D spectroscopy.

The spatial coverage of the collected data expands to approximately 0.26 by 0.51 pc, achieving an extraordinary depth that allows for the exploration of a diverse range of line intensities, exceeding three orders of magnitude. The data cube produced is complemented by detailed emission line maps, facilitating refined analyses of the nebula’s features.

Key Findings:

1. Morphological Complexity: The morphological analysis uncovers intricate structures, including a new identification of two faint, low-ionisation arc-like structures at the nebula's poles. These findings suggest that the nebula’s expansion pattern is not simple but involves complexities potentially indicative of precessing jets.
2. Extinction Variability: Extinction across the nebula is significantly structured, with areas revealing extinction values up to 3-4 times greater than median levels. This non-uniformity in extinction may indicate substantial internal dust, offering insight into nebular evolution and stellar mass loss processes.
3. Electron Temperature and Density: The analysis identified a variation in electron density from the inner high-ionisation zones to the outer regions, with the rim showing higher density values of around 700 cm$^{-3}$. The electron temperature maps show variation among different ionisation species, leading to a proposed electron temperature hierarchy: [N, S] $\rightarrow$ [S] $\rightarrow$ recombination lines.
4. Ionisation and Abundance Maps: The study generated maps for multiple ionic species, revealing a median helium abundance of He/H = 0.124. Oxygen, nitrogen, sulfur, argon, and chlorine also show relevant distributions and align with recorded literature values.
5. Kinematic Structure: Through velocity mapping, the study supports a diabolo-like geometry with varying velocity patterns through different ion spectral lines. The results align with a diabolo model with its axis roughly on a P.A. of -22 degrees.
6. Low-Ionisation Structures (LISs): Two newly identified LISs display high extinction and elevated helium abundance. They show alignment with Spitzer-detected mid-IR emission patterns and match the paper's kinematic findings, suggesting a potential origin as precessing jets influenced by the central binary star system.
7. 1D Photoionisation Modelling: A basic 1D Cloudy model, albeit indicative rather than definitive, reproduces some key spectral features with moderate accuracy. Nevertheless, it suggests the necessity of exploring a more sophisticated 3D model to account for density fluctuation and geometric peculiarities.

Implications for Future Research:

• Advancements in Instrumentation: Instruments with higher spectral resolution and extended wavelength coverage like BlueMUSE could enhance the precision of future studies, especially in detailing elemental abundances and unraveling kinematic subtleties not accessible by current MUSE capabilities.
• 3D Modelling: The rich detail of these observations offers a compelling basis for the development of 3D models. Such models would more accurately represent the spatial variations and dynamic processes within the nebula, providing a deeper understanding of its formation and evolution.
• Exploration of LISs: The discovery of extremely faint LISs suggests potential commonality among planetary nebulae, warranting further investigations into their prevalence, formation mechanisms, and their role in the lifecycle of nebulae.

In summary, the paper underscores the capability of MUSE to produce significant insights into the complex structures and processes within NGC 3132. It delineates paths for future research that could further illuminate the nature of planetary nebulae through enhanced observational techniques and modeling accuracy.