A hot bubble at the centre of M81

Abstract

Context. Messier 81 has the nearest active nucleus with broad H$\alpha$ emission. A detailed study of this galaxy's centre is important for understanding the innermost structure of the AGN phenomenon. Aims. Our goal is to seek previously undetected structures using additional techniques to reanalyse a data cube obtained with the GMOS-IFU installed on the Gemini North telescope (Schnorr Müller et al. 2011). Method. We analysed the data cube using techniques of noise reduction, spatial deconvolution, starlight subtraction, PCA tomography, and comparison with HST images. Results. We identified a hot bubble with T $>$ 43500 K that is associated with strong emission of [N II]$\lambda$5755Å and a high [O I]$\lambda$6300/H$\alpha$ ratio; the bubble displays a bluish continuum, surrounded by a thin shell of H$\alpha$ + [N II] emission. We also reinterpret the outflow found by Schnorr Müller et al. (2011) showing that the blueshifted cone nearly coincides with the radio jet, as expected. Conclusions. We interpret the hot bubble as having been caused by post starburst events that left one or more clusters of young stars, similar to the ones found at the centre of the Milky Way, such as the Arches and the IRS 16 clusters. Shocked structures from combined young stellar winds or supernova remnants are probably the cause of this hot gas and the low ionization emission.

arXiv comment5 pages, 4 figures, accepted for publication in A&A

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Cited by in corpus (6)

• Digging process in NGC 6951: the molecular disc bumped by the jet
• Inflowing Gas in the Central Parsec of M81
• CAHA/PPAK Integral-field Spectroscopic Observations of M81 -- I. Circumnuclear ionized gas
• A Gemini-NIFS view of the merger remnant NGC 34
• Principal component analysis tomography in near-infrared integral field spectroscopy of young stellar objects. I. Revisiting the high-mass protostar W33A
• An Energetic Hot Wind from the Low-luminosity Active Galactic Nucleus M81*