Molecular clouds in M51 from high-resolution extinction mapping

Faustino Vieira, Helena, Duarte Cabral, Ana ORCID: https://orcid.org/0000-0002-5259-4774, Davis, Timothy A. ORCID: https://orcid.org/0000-0003-4932-9379, Peretto, Nicolas ORCID: https://orcid.org/0000-0002-6893-602X, Smith, Matthew W. L. ORCID: https://orcid.org/0000-0002-3532-6970, Querejeta, Miguel, Colombo, Dario and Anderson, Michael ORCID: https://orcid.org/0000-0001-7237-3488 2024. Molecular clouds in M51 from high-resolution extinction mapping. Monthly Notices of the Royal Astronomical Society 527 (2) , 3639–3658. 10.1093/mnras/stad3327

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Abstract

Here, we present the cloud population extracted from M51, following the application of our new high-resolution dust extinction technique to the galaxy. With this technique, we are able to image the gas content of the entire disc of M51 down to 5 pc (0.14 arcsec), which allows us to perform a statistical characterization of well-resolved molecular cloud properties across different large-scale dynamical environments and with galactocentric distance. We find that cloud growth is promoted in regions in the galaxy where shear is minimized; i.e. clouds can grow into higher masses (and surface densities) inside the spiral arms and molecular ring. We do not detect any enhancement of high-mass star formation towards regions favourable to cloud growth, indicating that massive and/or dense clouds are not the sole ingredient for high-mass star formation. We find that in the spiral arms there is a significant decline of cloud surface densities with increasing galactocentric radius, whilst in the inter-arm regions they remain relatively constant. We also find that the surface density distribution for spiral arm clouds has two distinct behaviours in the inner and outer galaxy, with average cloud surface densities at larger galactocentric radii becoming similar to inter-arm clouds. We propose that the tidal interaction between M51 and its companion (NGC 5195) – which heavily affects the nature of the spiral structure – might be the main factor behind this.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Publisher:	Oxford University Press
ISSN:	0035-8711
Funders:	STFC
Date of First Compliant Deposit:	20 December 2023
Date of Acceptance:	27 October 2023
Last Modified:	12 Apr 2024 01:24
URI:	https://orca.cardiff.ac.uk/id/eprint/164983

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