MUSE spectroscopy of planetary nebulae with high abundance discrepancies

Abstract

We present MUSE deep integral-field unit spectroscopy of three planetary nebulae (PNe) with high abundance discrepancy factors (ADF > 20): NGC 6778, M 1–42 and Hf 2–2. We have constructed flux maps for more than 40 emission lines, and use them to build extinction, electron temperature (Te), electron density (ne), and ionic abundances maps of a number of ionic species. The effects of the contribution of recombination to the auroral [N ii] and [O ii] lines on Te and the abundance maps of low-ionization species are evaluated using recombination diagnostics. As a result, low Te values and a downward gradient of Te are found toward the inner zones of each PN. Spatially, this nearly coincides with the increase of abundances of heavy elements measured using recombination lines in the inner regions of PNe, and strongly supports the presence of two distinct gas phases: a cold and metal-rich and a warm one with “normal” metal content. We have simultaneously constructed, for the first time, the ADF maps of O+ and O2 + and found that they centrally peak for all three PNe under study. We show that the main issue when trying to compute realistic abundances from either ORLs or CELs is to estimate the relative contribution of each gas component to the H i emission, and we present a method to evaluate it. It is also found that, for the studied high-ADF PNe, the amount of oxygen in the cold and warm regions is of the same order.

Physical Conditions and Chemical Abundances of the Variable Planetary Nebula IC 4997

“…Alternatively, large abundance discrepancies in PNe could be linked to binary central stars (Corradi et al 2015;Jones et al 2016;Bautista & Ahmed 2018;Wesson et al 2018;Jacoby et al 2020;García-Rojas et al 2022). In particular, Corradi et al (2015) found ADFs higher than 50 in the PNe Abell 46 and Ou 5 surrounding post common-envelope binary stars.…”

Spectroscopic Analysis Tool for intEgraL fieLd unIt daTacubEs (satellite): Case studies of NGC 7009 and NGC 6778 with MUSE

“…This discrepancy in abundances is associated to a combination of the different extinction, physical conditions, atomic data sets and ICFs adopted. A more detailed analysis of such differences has been presented in García-Rojas et al (2022). All chemical abundances derived from the pseudo-slits and the central region (Table 6) show small variations, within their uncertainties.…”

“…These advances have boosted the number of works devoted to spatially resolved studies of planetary nebulae (PNe) using IFS over the last decade; some representative examples of these studies are, e. g. Tsamis et al (2008), Monteiro et al (2013), Ali et al (2016), Walsh et al (2016), Walsh et al (2018), Ali & Dopita (2019), Monreal-Ibero & Walsh (2020), Akras et al (2020a), andGarcía-Rojas et al (2022).…”

Morphologies of Wolf–Rayet Planetary Nebulae Based on IFU Observations

“…A number of integral field unit (IFU) spectrographs on modest telescopes, such as the Wide Field Spectrograph (WiFeS [24,25]) on the Australian National University (ANU) 2.3-m telescope have made it possible to constrain the kinematic and ionization properties of several PNe [26][27][28][29][30][31][32]. Moreover, the Multi Unit Spectroscopic Explorer (MUSE) and the VIsible Multi-Object Spectrograph (VIMOS) on the European Southern Observatory's (ESO) Very Large Telescope (VLT) have recently enabled the constraint of the ionization structures of some PNe [33][34][35][36]. IFU spectroscopy allows us to spatially resolve the physical and kinematic properties of PNe, which is an important step toward understanding their morphological features in different ionization stratification layers.…”