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VERSION:2.0
PRODID:-//Heidelberg University//HePhySTO//EN
CALSCALE:GREGORIAN
BEGIN:VEVENT
DTEND:20261210T111500Z
UID:0a6a95ab8cdd84e4f7fbe6a4e85609d3@physik.uni-heidelberg.de
DTSTAMP:20261007T223054Z
LOCATION:ARI\, Moenchhofstrasse 12-14\, Seminarraum 1.OG
DESCRIPTION:In this talk\, I will present the SOFIA Legacy Project FEEDBACK
 \, which has provided the first\nlarge-scale\, velocity-resolved view of st
 ellar feedback in galactic star-forming regions. This was achieved by utili
 sing the [CII] 158 micron and [OI] 63 micron lines\, which are key tracers 
 of photodissociation regions (PDRs) at\nthe interface between ionised and m
 olecular gas. By probing feedback across a wide range of physical scales an
 d evolutionary stages\, FEEDBACK provides a comprehensive observational per
 spective on the formation\, evolution and eventual dispersal of molecular c
 louds.\nOne of the project’s major findings concerns cloud formation and di
 spersal. In Cygnus X\, widespread high-\nvelocity [CII] emission predominan
 tly tracing neutral gas reveals the formation of molecular clouds via conve
 rging atomic flows (Schneider et al. 2023). In the same region\, the Diamon
 d Ring exemplifies a distinct\nfeedback geometry: it arises as the terminal
  phase of a stellar wind bubble expanding into a flat molecular\ncloud\, wh
 ere bipolar breakout along the low-density directions above and below the c
 loud plane produces a\ntrue ring - not a sphere - as the observable signatu
 re. This ring morphology is detected in [CII] and confirmed by dedicated HD
  simulations following the evolution of a bubble in a flat molecular sheet 
 (Dannhauer et al. 2025). Cloud dispersal is further evidenced across severa
 l FEEDBACK regions (RCW79\; Bonne et al. 2023\; Bonne et al. submitted)\, w
 here [CII] emission reaches velocities of up to 25 km/s\, organised partly 
 in fragmented shells and partly in flows escaping through low-density chann
 els. Derived mass-loss rates of order 0.01 Msun/yr imply short cloud erosio
 n timescales of less than 5 Myr\, providing direct observational evidence t
 hat stellar feedback can rapidly disperse molecular clouds and regulate sta
 r formation efficiency.\nAcross the full FEEDBACK sample expanding bubbles 
 are a common feature. While classical expanding\nshells are observed\, the 
 [CII] data often reveal fragmented\, incomplete or asymmetrical bubbles\, f
 requently accompanied by high-velocity wings and multiple kinematic compone
 nts. Expansion velocities exceeding 10 km/s are detected in most regions\, 
 but their dynamics often require additional energy input from stellar winds
  beyond pure thermal pressure.\nOverall\, FEEDBACK has provided a revised m
 odel of feedback-driven cloud evolution across scales: (i) molecular clouds
  form and disperse efficiently on short timescales\; (ii) the geometry of f
 eedback is fundamentally anisotropic and is governed by the turbulent\, por
 ous structure of the interstellar medium (ISM)\; (iii) [CII] can be used to
  trace both expanding shells and escaping gas flows\; and (iv) individual e
 mbedded systems\, such as S106 and the Diamond Ring\, demonstrate that feed
 back can be detected from protostellar to cloud scales.\nAlongside other ob
 servations presented in this talk it highlights the power of FIR observatio
 ns.\nBuilding on these results\, the next step will be taken by the GEco su
 rvey on the CCAT/FYST telescope\, with\nexpected first light autumn this ye
 ar. GEco will extend the FEEDBACK studies by mapping the [CII] and\nmid-J C
 O lines across entire molecular cloud complexes and the broader Galactic ec
 osystem on a large scale.\nTogether with FEEDBACK\, GEco will also probe th
 e carbon cycle in the galactic interstellar medium.\n\nImported from https:
 //www.physik.uni-heidelberg.de/hephysto/ (no warranty for accuracy).
URL;VALUE=URI:https://www.physik.uni-heidelberg.de/hephysto/index.php?s=tal
 k&id=13013
SUMMARY:ARI Institute Colloquium: Simon Dannhauer - Climbing the Ladder: St
 ellar Feedback from SOFIA to CCAT/FYST
DTSTART:20261210T101500Z
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