| 1. |
- Sirressi, Mattia, 1995-, et al.
(author)
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CLusters in the Uv as EngineS (CLUES). II. Subkiloparsec-scale Outflows Driven by Stellar Feedback
- 2024
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In: Astronomical Journal. - 0004-6256 .- 1538-3881. ; 167:4
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Journal article (peer-reviewed)abstract
- We analyze the far-ultraviolet (1130−1770 Å rest frame) spectroscopy of 20 young (<50 Myr) and massive (>104M⊙) star clusters (YSCs) in 11 nearby star-forming galaxies. We probe the interstellar gas intervening along the line of sight, detecting several metal absorption lines of a wide range of ionization potentials, from 6.0 to 77.5 eV. Multiple-component Voigt fits to the absorption lines are used to study the kinematics of the gas. We find that nearly all targets in the sample feature gas outflowing from 30 up to 190 km s−1, often in both the neutral and ionized phases. The outflow velocities correlate with the underlying stellar population properties directly linked to the feedback: the mass of the YSCs, the photon production rate, and the instantaneous mechanical luminosity produced by stellar winds and supernovae. We detect a neutral inflow in four targets, which we interpret as likely not associated with the star cluster but tracing larger-scale gas kinematics. A comparison between the outflows' energy and that produced by the associated young stellar populations suggests an average coupling efficiency of 10% with a broad scatter. Our results extend the relation found in previous works between galactic outflows and the host galaxy star formation rate to smaller scales, pointing toward the key role that clustered star formation and feedback play in regulating galaxy growth.
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| 2. |
- Smith, Göran, 1988-, et al.
(author)
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Workshop 5 report : New service models - Governing emerging mobility services
- 2024
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In: Research in Transportation Economics. - : Emerald Publishing. - 0739-8859 .- 1875-7979. ; 103
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Journal article (peer-reviewed)abstract
- The rise of new service models for passenger transport is arguably transforming the mobility landscape. Concurrently, the COVID-19 pandemic has disrupted mobility practices and questioned traditional public transport models. Given the negative externalities of transport, and the key role of shared mobility in reducing these, it is therefore critical to work out what governments can do to ensure that the new service models contribute to making mobility service systems more attractive to users as well as more energy-, space- and cost-efficient. Workshop 5 of the 17th International Conference on Competition and Ownership in Land Passenger Transport set out to address these issues. It included thirteen papers that reported evidence about demand-responsive transport (DRT), ridesourcing, ridesharing, and Mobility-as-a-Service (MaaS) as well as about innovations within traditional public transport, taxi, and paratransit. The workshop discussed what roles governments have adopted, what types of regulations and policies they have been using, and what is known about the impacts of these governance approaches. Drawing on this discussion, the workshop developed a set of policy recommendations designed to cater for democratic governance processes with transformative impacts as well as a list of potential avenues for further research on the governance of emerging mobility services.
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