Bimodal regime in young massive clusters leading to formation of subsequent stellar generations Richard Wünsch J. Palouš, G. Tenorio-Tagle, C. Muñoz-Tuñón, S. Ehlerová Astronomical institute, Czech Academy of Sciences 14th August 2015 Wünsch (AsU CAS) 2G with bimodal regime 14.8.2015 1/1
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Bimodal regime in young massive clusters leading to ... · Introduction Motivation: Cooling winds !multiple populations young massive clusters have winds stellar winds, SNe !collisions
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Bimodal regime in young massive clusters leadingto formation of subsequent stellar generations
Richard WünschJ. Palouš, G. Tenorio-Tagle, C. Muñoz-Tuñón, S. Ehlerová
by Chevalier & Clegg (1985, Nat., 317, 44)Ekin of stellar winds and SN ejectathermalized, hot gas fills the clustersources (stars) distributed according totop-hat profilesolution of 1D spherically sym. HDequations, cooling neglectedsonic point at the cluster bordertested by Cantó+00, Raga+01 and othersfor stellar windsinteraction of the wind with the parentalcloud not covered here(harper-clark&murray09, krause+12,14, rogers&pittard13,
by Chevalier & Clegg (1985, Nat., 317, 44)Ekin of stellar winds and SN ejectathermalized, hot gas fills the clustersources (stars) distributed according totop-hat profilesolution of 1D spherically sym. HDequations, cooling neglectedsonic point at the cluster bordertested by Cantó+00, Raga+01 and othersfor stellar windsinteraction of the wind with the parentalcloud not covered here(harper-clark&murray09, krause+12,14, rogers&pittard13,
by Chevalier & Clegg (1985, Nat., 317, 44)Ekin of stellar winds and SN ejectathermalized, hot gas fills the clustersources (stars) distributed according totop-hat profilesolution of 1D spherically sym. HDequations, cooling neglectedsonic point at the cluster bordertested by Cantó+00, Raga+01 and othersfor stellar windsinteraction of the wind with the parentalcloud not covered here(harper-clark&murray09, krause+12,14, rogers&pittard13,
by Chevalier & Clegg (1985, Nat., 317, 44)Ekin of stellar winds and SN ejectathermalized, hot gas fills the clustersources (stars) distributed according totop-hat profilesolution of 1D spherically sym. HDequations, cooling neglectedsonic point at the cluster bordertested by Cantó+00, Raga+01 and othersfor stellar windsinteraction of the wind with the parentalcloud not covered here(harper-clark&murray09, krause+12,14, rogers&pittard13,
Catastrophic cooling of the windfor massive clusters, cooling has to betaken into accountradiative solution by silich+03→ T drops at a certain radiuspredicts different observed X-ray flux(silich+04) - good agreement withobserved X-ray fluxes(NGC4303 nuclear SSC; jiménez-bailón+03)
above certain mass limit, no stationary wind solution exists→catastrophic cooling (silich+03):
Catastrophic cooling of the windfor massive clusters, cooling has to betaken into accountradiative solution by silich+03→ T drops at a certain radiuspredicts different observed X-ray flux(silich+04) - good agreement withobserved X-ray fluxes(NGC4303 nuclear SSC; jiménez-bailón+03)
above certain mass limit, no stationary wind solution exists→catastrophic cooling (silich+03):
hot gas inside cluster seems to be colder than energy / massdeposited by stars→ two new parameters:
ηML: mass loading - additional (pristine) gas added to the hot phaseηHE: heating efficiency - some thermal energy is lost from the hotphase (on the top of standard cooling)
mass loading - evidence for mixing with pristine gas ∼ 1 : 1(e.g. prantzos+07)
obs. evidence for low heating efficiencymissing energy from X-ray luminosities(rosen+14)recombination line profiles of SSCs inAntennae have moderately supersonicwidths (gilbert&graham07)
hot gas inside cluster seems to be colder than energy / massdeposited by stars→ two new parameters:
ηML: mass loading - additional (pristine) gas added to the hot phaseηHE: heating efficiency - some thermal energy is lost from the hotphase (on the top of standard cooling)
mass loading - evidence for mixing with pristine gas ∼ 1 : 1(e.g. prantzos+07)
obs. evidence for low heating efficiencymissing energy from X-ray luminosities(rosen+14)recombination line profiles of SSCs inAntennae have moderately supersonicwidths (gilbert&graham07)
hot gas inside cluster seems to be colder than energy / massdeposited by stars→ two new parameters:
ηML: mass loading - additional (pristine) gas added to the hot phaseηHE: heating efficiency - some thermal energy is lost from the hotphase (on the top of standard cooling)
mass loading - evidence for mixing with pristine gas ∼ 1 : 1(e.g. prantzos+07)
obs. evidence for low heating efficiencymissing energy from X-ray luminosities(rosen+14)recombination line profiles of SSCs inAntennae have moderately supersonicwidths (gilbert&graham07)
Mass budget at 3.5 Myr:1G stellar mass: 107 M�inserted by winds: 4× 105 M�mass loaded: 4× 105 M�2G stellar mass: 7× 105 M�→ very compact, in the centre→ should stay in the cluster during1G tidal removal (khalaj&baumgardt15)
remains in dense phase: 14000 M�→ rapidly removed by SNe
wind cooling leading to bimodal regime is inevitable for high andcompact enough clusterdense gas formed by thermal instability stays in the cluster andself-shields against ionising radiation→ secondary SFheating efficiency⇒ compact/extended 2G
low heating efficiency→ SF in the central clump: 2G concentratedin the cluster centre;high heating efficiency→ SF in streams: 2G dispersed throughoutthe cluster
much more difficult to capture SN ejecta; rapidly removeremaining accumulated gas
wind cooling leading to bimodal regime is inevitable for high andcompact enough clusterdense gas formed by thermal instability stays in the cluster andself-shields against ionising radiation→ secondary SFheating efficiency⇒ compact/extended 2G
low heating efficiency→ SF in the central clump: 2G concentratedin the cluster centre;high heating efficiency→ SF in streams: 2G dispersed throughoutthe cluster
much more difficult to capture SN ejecta; rapidly removeremaining accumulated gas
wind cooling leading to bimodal regime is inevitable for high andcompact enough clusterdense gas formed by thermal instability stays in the cluster andself-shields against ionising radiation→ secondary SFheating efficiency⇒ compact/extended 2G
low heating efficiency→ SF in the central clump: 2G concentratedin the cluster centre;high heating efficiency→ SF in streams: 2G dispersed throughoutthe cluster
much more difficult to capture SN ejecta; rapidly removeremaining accumulated gas
wind cooling leading to bimodal regime is inevitable for high andcompact enough clusterdense gas formed by thermal instability stays in the cluster andself-shields against ionising radiation→ secondary SFheating efficiency⇒ compact/extended 2G
low heating efficiency→ SF in the central clump: 2G concentratedin the cluster centre;high heating efficiency→ SF in streams: 2G dispersed throughoutthe cluster
much more difficult to capture SN ejecta; rapidly removeremaining accumulated gas