[Astronomy seminar] Astro Department Seminar - Fri May 12th 10:30 - Jin Koda (Stony Brook U. & Paris Observatory)

[Astronomy seminar announcements]

Dear all,

The next SU astronomy departmental seminar will take place on Friday May 12th at 10:30 in room FC61 (AlbaNova building, 6th floor) and on zoom (https://stockholmuniversity.zoom.us/s/61002076352 <https://stockholmuniversity.zoom.us/s/61002076352>).
https://www.albanova.se/event/astronomy-departmental-seminar-jin-koda-psl/ <https://www.albanova.se/event/astronomy-departmental-seminar-jin-koda-psl/>


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Speaker: Jin Koda (Stony Brook University, USA - on sabbatical leave - & Paris Observatory - visiting -)
Title: Molecular cloud evolution as the first step for star formation and galaxy evolution


Abstract:
Molecular gas and clouds host virtually all star formation, and therefore, their formation and evolution are the first step leading to star formation and galaxy evolution. On the basis of broad observational data, I will discuss how molecular gas and clouds evolve in the Milky Way and nearby spiral galaxies. In particular, I will argue for a long cloud lifetime (>~100 Myr), as opposed to the recently-suggested short lifetime (<~10-30 Myr). Simply put, we see molecular gas but don't see much atomic gas within galactic disks, even in the inter-arm regions, and thus the gas stays molecular. In this picture, star formation does not occur at the onset of gravitational collapse from atomic gas to molecular clouds, but is triggered in the long-existing molecular clouds. This view contradicts the traditional picture of the spiral density-wave theory, which predicts a rapid gas phase transition -- from atomic to molecular and then to atomic -- through spiral arm passage. Instead, the gas evolves through the coagulation and fragmentation of molecular clouds. The consequences of this revised view of cloud evolution, star formation, and galaxy evolution will be outlined.
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We look forward to seeing many of you there. Thanks!

Eliot and Kris


The calendar for later planned seminars is available here <https://ttt.astro.su.se/ical/astro-seminars.ics>.
(Please note that calendar can be subject to updates)


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Join Zoom Meeting:
https://stockholmuniversity.zoom.us/s/61002076352 <https://stockholmuniversity.zoom.us/s/61002076352>
Meeting ID: 610 0207 6352
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