Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.atnf.csiro.au/research/Astro2010/talks/falgarone.pdf Äàòà èçìåíåíèÿ: Wed Jun 16 05:04:45 2010 Äàòà èíäåêñèðîâàíèÿ: Tue Oct 2 14:21:28 2012 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï

Magne&cfieldsandturbulence inmolecularclouds:
observa&onsfrom30parsecto milliparsecscales
EdithFalgarone
ENS&ParisObservatory,France
and

PierreHilyBlant
``CosmicMagne&sm'',711june2010,Kiama



GrenobleObservatory,France


Bimodaldistribu&onof gascolumndensi&esin molecularclouds

Kainulainenetal2009

Av<3­5mag:turbulent+Bdominated Av>35mag:gravity+B+?


Outline
· · · · Sta&s&csofBPOSorienta&onatthe30pcscale BPOSandintensevelocityshearsatthepcscale BPOSandshearlayersatthempcscale B//intensityfromdiffusemediumtodensecores

Tools:

Starlightpolariza&on Spectroimageryathighspectralandspa&al resolu&onintheCOrota&onallines Zeemaneffectobserva&onsintheHI,OHand CN(10)lines


1­Turbulentandmagne&cenergyat the30pcscale
· Comparisonofvirialized(TaurusComplex)and nonvirialized(PolarisFlare)fields · ChandrasekharFermimethod:

B=6.6n

H

1/2(

v/)G
2

E

mag/E

turb

=(38o/)

Validfor<25o(MHDsimula&onsOstrikeretal.01)


Two30pcscalefields:

PolarisFlare

FIRmapMivilleDeschÉnesetal.

TaurusAurigacomplex
N(H2)mapGoldsmithetal.08

v=4.8km/s

v=3.8km/s

Comparablevirialmasses@30pc:MV=4.4x104Msun TaurusComplex:MgasMV PolarisFlare:Mgas=5x103Msun=MV/6




12CO(10)(top) 13CO(10)(borom)

Tauruscomplex



=(24±5)
mag/Eturb

o

E
Polarisa&onmeasurementsHeiles2000

=2.5


PolarisFlare

=19o NonGaussianPDF:3 morecommonPA

E
HilyBlantetal. inprepara&on

mag/Eturb

4.0

At30pcscale,E

mag>Eturb

E

grav


2­BPOSandvelocityshearsatthe parsecscale
· Sta&s&csonvelocityfieldbasedonCOline centroidvelocity(CV)intranslucentfields · DeparturefromGaussiansta&s&cs · Comparisonofplaneofskyprojec&onof magne&cfieldsBPOSandlocusofextremeCV increments(ECVI):extremaofPOS HilyBlant&Falgarone09


ParsecscalefieldinthePolarisFlare

HilyBlant&Falgarone2009


PDFofcentroidvelocityincrements withvariablelags
· NonGaussiantails increaseatsmallerlags: moreandmorerare events · Locusoftheseevents: ECVIsextremaofPOS
(Lisetal1996) · Intermirencyofturbulence

HilyBlant,Falgarone,Pety2008


Spa&aldistribu&onofextremeCVIs(1)

WardThomsonetal.(2010)Herschel/SPIRE


Spa&aldistribu&onofECVIs(2)
Taurusedge

Taurusedge: BPOS//POS:oneclose measurement PolarisFlare: Specificorienta&onsofBPOS SharpPAchanges Noclosemeasurement POS//BPOSatparsecscale


3­BPOSandshearlayersatmilliparsec scales
Dusttemperature

IRAMPdBICO(10)line.Mosaicof13fields,180hoursintegra&on Pixelsize:3mpc(4arcsec) Fieldsize:0.09pcx0.045pc Translucentfieldwithnostructurevisibleat0.01pcresolu&on


Structureatthemilliparsecscale

8straightstructuresdetected,thickness3to11mpc SpecificPA Specificveloci&es(emptychannels)


Falgarone,Pety,HilyBlant2009


Notfilaments:sharpedgesofthinextended sheetsofCOemission

COemissionin2velocityranges:seenbytheIRAMPdB interferometer(lex)andmergedwithshortspacings fromIRAM30m(right)


4edgesformpairsofparallelstructuresofhigh velocityshear:milliparsecscaleshearlayers
ComparisonwithBPOS orienta&onsatthe30 pcscale






Thelessonsofthemilliparsecscales
· Layersofmostintensevelocityshearsatmpcscales andBlieinparallelplanes:quasiparallelprojec&ons ontheplaneofskyBPOS//POS · Coherenceoforienta&onsacrossscales · Velocityincrementsinshearlayersatmpcscalesof sameorderasrmsvelocityoflargescaleturbulence(2 to4kms1)widescalesepara&on · Largestobservedvelocityshear:3.5kms1over7mpc or500kms1pc1orequivalent&mescale2000yr short&mescales


4HI,OH,CNZeemanmeasurements(1)
Line: M/=(M/)

cri&cal

Noevidencefor subcri&caldense cores
Crutcheretalinprep.


HI,OH,CNZeemanmeasurements(2)
Bayesiananalysis:
n<300cm3 Bmax=10G Bnotcompressedby turbulence n>300cm3 Uniformdistribu&onof BTOTbetween0and Bmax n2/3
Crutcheretalinprep.

WeakBindense cores


SummaryandOpenings(1)
· At30pcscales,magne&c>turbulentenergy · Coherentstructuresofvor&city/shearsparallel toBPOSfromparsectomilliparsecscales · Widescalesepara&on · Diffusemedium:Bnotcompressedby turbulence · Noevidenceforsubcri&caldensecores


SummaryandOpenings(2)
· Turbulence(anditspropertyofintermirency) possiblyattheoriginofthelossofmagne&cflux ofmarer
· Ionneutralambipolardrixinthediffusemedium requiredtoexplainitsrichchemistry:Herschel/HIFI resultsFalgaroneetal.2010 · ModelsofwarmchemistryincoldgasGodardetal2009