!"#$%&'(#)*'+*,+ %#--./&+0&'-&+1*"&-+ 0*2'+(*+! #"#1(&".9.'$+:"*(*1;<(&"-+

Transcription

1 !"#$%&'(#)*'+*,+ %#--./&+0&'-&+1*"&-+ 0*2'+(*+! #"#1(&".9.'$+:"*(*1;<(&"-+ 5.'#+=#;#<+!"#$%&'("')*(+&*,$%&#&-.*'/'0,$%&1,+2*'' '689+2&:' ;'

2 !"#$%&'(#)*'+*,+ %#--./&+0&'-&+1*"&-+ 0*2'+(*+! V'

3 >'("*0<1)*'+ 6"$M&('W'C+%,$')",A>$,' X#"',$"S'Y&%Z*%(['("#,+$/'*#('F' \'

4 Cone Nebula and Snowflake cluster, Spitzer, NASA, JPL-Caltech, P. S. Teixeira?*2+#"&+ -("<1(<"&-+,*"%&0+ 2.(8.'+%*;&1<;#"+ turbulence-regulated, quasi-equilibrium scenario (Mac Low & Klessen 04; Vázquez- Semadeni +00) global-hierarchical chaotic gravitational contraction (Hartmann +01; Vázquez-Semadeni 14) ]'

5 'A<"B<;&'1&C"&$<;#(&0D+E<#-.C&E<.;.B".<%+-1&'#".*+! 6!,'*%"'P>&I*>>/',ASS&%$"('I/',AS"%,&#+2'$A%IA>"#2"'*#(' 2>&,"'$&'"BA+>+I%+A-'! 6!,'"_&>_"'+#'>&#P'`-",2*>",'3,"_"%*>'$ 2%&,, :'! KAS"%,&#+2'$A%IA>"#2"'"'>&2*>'2&-S%",,+&#,'"''Y%*P-"#$,' 6!,'+#$&'("#,"',M""$,7'a>*-"#$,'*#('2&%",'3M+PM>/'%*(+*`_"',M&2b,:'! U*%P"O,2*>",['$A%IA>"#2"'P+_",',ASS&%$'*P*+#,$'P%*_+$/'+#' *((+`&#'$&'$M"%-*>',ASS&%$''''' ^'

6 'A<"B<;&'1&C"&$<;#(&0D+E<#-.C&E<.;.B".<%+-1&'#".*+ Chandrasekhar+53 see Mac Low & Klessen 04 Fragmentation: turbulent-jeans! very few grav. unstable density fluctuations in a core! naturally yields massive fragments c'

7 'F;*B#;G8.&"#"18.1#;G18#*)1+$"#/.(#)*'#;+1*'("#1)*'+! 6!,'%*S+(>/'"_&>_+#P'3;'$ 2%&,, :7'A#,$*I>"7'(/#*-+2',$%A2<'! =9S"2$"('Y%&-'6!'Y&%-*`&#['! >*%P"O,2*>"'2&-S%",,+&#,'+#'e*%-'5"A$%*>'6"(+A-'!,A(("#'SM*,"'$%*#,+`&#'$&'!&>('56'"'6 D"*#, '("2%"*,",' I/';f ] g'"'!s%",,a%">",,'fhij5h'2&>>*s,"'! 0-S>+a2*`&#'&Y'*#/'*#+,&$%&S/'"'2&>>*S,"'a%,$'*>&#P',M&%$",$' (+-"#,+&#'3U+#Wc^:['">>+S,&+('"',M""$'"'a>*-"#$'! h#$"%#*>'$a%ia>"#2"'"'2>a-s,w2&%",['2&%",'2&>>*s,"'y*,$"%' $M*#'"#`%"'2>&A('"'?>KL5LM?>M5H+#'0+M?5IA>M+ d'

8 'F;*B#;G8.&"#"18.1#;G18#*)1+$"#/.(#)*'#;+1*'("#1)*'+ Fragmentation: thermal-jeans! efficient to produce low-mass fragments! formation of massive fragments through! accretion from regions not originally bound to the protostellar core! radiative feedback?! magnetic field? M crit = M J + M " = M J + c " #R 2 B/G 1/2 i'

9 MHD simulations of the collapse of a turbulent and magnetized cloud: higher B supresses fragmentation Hennebelle et al. 2011, Commerçon et al Increasing magnetization degree Also: e.g., Vázquez-Semadeni+05,+11, Ziegler+05, Banerjee & Pudritz 06, Price & Bate 07, Peters+11, Myers+13, etc., etc.

10 !"#$%&'(#)*'+1#'+B&+%#.';N+1*'("*;;&0+BN7+! $A%IA>"#2"'3$A%IO%"PA>*$"('BA*,+O"BA+>+I%<',2"#*%+&:'! P%*_+$/'3P>&I*>OM+"%*%2M+2*>O2M*&`2'P%*_<'2&#$%*2`&#:'! Is any of these ingredients dominating? ;f'

11 h#$%&(a2`&#' O&(8*0+G+!."-(+L&-<;(-+ X#"',$"S'Y&%Z*%(['("#,+$/'*#('F' ;;'

12 Lagoon Nebula (M8), Fred Vanderhaven (image processed to remove stars) IB-&"/#)*'#;+ #::"*#187+ Y%*P-"#$*`&#'&Y' -*,,+_"'("#,"'2&%",' Massive dense core ~ M sun 0.1 pc fragment XI,"%_"'$M"-['! (&Z#'$&'!;fff'04'! (&Z#'$&'6 -+#!f<^'6,a#'

13 Literature (5 yr ago): massive star-forming regions studied with mm interferometers down to M min ~0.5 M sun Already 5 regions with ~1000 AU Select 6 new regions:! < 2.5 kpc! associated with strong mm emission! cover range of L bol! very similar evolutionary stages Total: ~10 regions

14 We used most extended A configuration " beam ~ 0.4 High observational pressure! Observed 4 out of 6 regions

15 Single-dish submm/mm continuum archive observations of dense cores of all the sample: JCMT, Hawaii, USA SCUBA bolometer 450 & 850 μm Di Francesco et al IRAM30m Granada, Spain MAMBO bolometer 1.2 mm Motte et al. 2007

16 In the meantime: 10 regions more in the literature! Total: 19 regions (Palau+13, +14, including Bontemps+10)

17 CB3-mm NGC7129-FIRS2

18

19

20

21

22

23

24 ~30% low fragmentation level: 1 source dominating ~50% high fragmentation: split up into ~4 fragments or more Spatial resolution: 300 AU Mass sensitivity: 0.1 M sun Spatial resolution: 700 AU Mass sensitivity: 0.9 M sun

25 Using the mm/submm single-dish emission: Flux Half power contour Mass (T d, opacity) Avg surface density: M/!R 2 Avg density entire core: 3M/4!R 3

26 SEDs: IRAC,MIPS, MSX, IRAS, AKARI, SCUBA Calculate: L bol and L bol /M sd

27 In addition M max : mass of strongest mm source measured by an interf in extended config. Core Formation Efficiency: CFE = Σ m i M sd

28 Dependence of N mm with L bol, M sd Dependence of N mm with evolutionary stage and density of entire core, and CFE Palau et al. 2013, ApJ, 762, 120

29 h#$%&(a2`&#' 6"$M&('W'C+%,$')",A>$,' I'&+-(&:+,*"2#"07+0&'-.(N+#'0+A+ Vj'

30 Model density and temperature structure of the dense cores Assumptions: spherically symmetric envelope dust opacity! $ % $ " density profile # = # 0 (r/r 0 ) -p temperature profile T = T 0 (r/r 0 ) q, with q = 2/(4+") external heating: T = 10 K in the outer envelope no assumption of optically thin emission no R-J approximation First approximation (R-J, optically thin, no external heating): power-law radial intensity profile, I $ % b 1-(p+q) Meaningful comparison: convolution with beam (main+error model beams) chopping with 120" chop-throw (circularly averaged) Fit simultaneously: intensity profiles at 850 and 450!m SED from cm to 60!m wavelengths (sensitive to T)

31 Model density and temperature profiles of the dense cores Assumptions: spherically symmetric envelope dust opacity! $ % $ " density profile # = # 0 (r/r 0 ) -p temperature profile T = T 0 (r/r 0 ) q, with q = 2/(4+") external heating: T = 10 K in the outer envelope no assumption of optically thin emission no R-J approximation First approximation (R-J, optically thin, no external heating): power-law radial intensity profile, I $ % b 1-(p+q) Meaningful comparison: convolution with beam (main+error model beams) chopping with 120" chop-throw (circularly averaged) Fit simultaneously: intensity profiles at 850 and 450!m SED from cm to 60!m wavelengths (sensitive to T)

32 Model density and temperature profiles of the dense cores Palau et al. 2014, ApJ, 785, 42

33 Model density and temperature profiles of the dense cores Palau et al. 2014, ApJ, 785, 42

34 Model density and temperature profiles of the dense cores Palau et al. 2014, ApJ, 785, 42

35 Dependence of N mm with density power law index p Dependence of N mm with density at r=1000 AU Palau et al. 2014, ApJ, 785, 42

36 Dependence of N mm with density within diameter of 0.1 pc 0.1 pc is the region where fragmentation (N mm ) was assessed! Palau et al. 2014, ApJ, 785, 42

37 From the modeled n, T profiles: M 0.1pc n 0.1pc T 0.1pc Palau, Ballesteros-Paredes, Vázquez-Semadeni et al. 2015, in prep.

38 According to global-hierarc.-chaotic gravit. contract. scenario: T calculated from model (avg in 0.1pc) Palau, Ballesteros-Paredes, Vázquez-Semadeni et al. 2015, in prep.

39 According to global-hierarc.-chaotic gravit. contract. scenario: T calculated from model (avg in 0.1pc) consistent with Louvet+14 for n~10 5 cm -3 Palau, Ballesteros-Paredes, Vázquez-Semadeni et al. 2015, in prep.

40 h#$%&(a2`&#' 6"$M&('W'C+%,$')",A>$,' X#"',$"S'Y&%Z*%(['("#,+$/'*#('F' L*;&+*,+(<"B<;&'1&+#'0+J+ ]f'

41 What about turbulence? VLA, USA Archive + Sánchez-Monge, Palau et al. 2013, MNRAS + literature IRAM30m, Spain Fontani, Palau et al literature NH3(1,1): VLA, beam~5, largest angular scale ~30 N2H+(1 0): IRAM30m, beam~26

42 NH3(1,1) emission with the VLA Study the kinematics of the massive dense cores Sánchez-Monge, Palau et al. 2013, MNRAS, 432, 3288

43 NH3(1,1) emission with the VLA Moment 2 maps: " no-th : non-thermal velocity dispersion

44 From the modeled temperature profile... estimate non-thermal contribution NH 3 (1,1) N 2 H + (1 0) Palau, Ballesteros-Paredes, Vázquez-Semadeni et al. 2015, in prep.

45 Relation of N mm with non-thermal vel. dispersion Correl coeff: 0.26 Reminder: Correl coeff: 0.89 Correl coeff: 0.39 Palau, Ballesteros-Paredes, Vázquez- Semadeni et al. 2015, in prep.

46 assuming CFE=100% According to turbulence-regulated quasi-equilibrium scenario: Palau, Ballesteros-Paredes, Vázquez-Semadeni et al. 2015, in prep.

47 Correl coeff: 0.66 Correl coeff: 0.23 Slope: 0.13 According to turbulence-regulated quasi-equilibrium scenario: Palau, Ballesteros-Paredes, Vázquez-Semadeni et al. 2015, in prep.

48 assuming CFE=100% According to turbulence-regulated quasi-equilibrium scenario: Palau, Ballesteros-Paredes, Vázquez-Semadeni et al. 2015, in prep.

49 Correl coeff: 0.66 Correl coeff: 0.19 Slope: 0.18 According to turbulence-regulated quasi-equilibrium scenario: Palau, Ballesteros-Paredes, Vázquez-Semadeni et al. 2015, in prep.

50 I<"+0#(#+#"&+B&P&"+0&-1".B&0+BN+:<"&+(8&"%#;+ -<::*"(Q+A8.-+%&#'-+(8#(7+ ;: "+$M"%'Z"'*%"'#&$'S%&S"%>/'-"*,A%+#P'$M"' $A%IA>"#2"'>"_">'&Y'("#,"'2&%",' V: &%'$A%I'2*##&$'I"'$%"*$"('*,'*#'*((+`&#*>' S%",,A%"'$"%-'$&'$M"%-*>'S%",,A%"'3+"7'6 D"*#, ',M&A>('I"'(",2%+I"('+#'*'(+k"%"#$'Z*/:' \: &%''$A%IA>"#2"'(&",'#&$'M*_"'*'2%A2+*>'%&>"'+#' ("$"%-+#+#P'$M"'Y%*P-"#$*`&#'>"_">'&Y'("#,"' 2&%",' ^f'

51 What about magnetic field? B knwon to suppress fragmentation: How would simulations including different B compare in this plot?

52 Magnetohydrodynamical simulations including radiation transport: Commerçon et al. 2011, after Hennebelle et al Strongly magnetized core Weakly magnetized core

53 Convolution with Plateau de Bure A uv-coverage Compare fragmentation level

54 Palau et al. 2013, ApJ, 762, 120 Compare fragmentation level

55 Compare density profiles Red line: µ=130 Green line: µ=2 Palau et al. 2014, ApJ, 785, 42

56 Compare density within 0.1 pc Palau et al. 2014, ApJ, 785, 42

57 Need to constrain B from observations CSO, Hawaii Palau et al., in prep. SMA, Hawaii Palau et al., in prep. Observations of polarized submm emission: work in progress

58 M*'1;<-.*'-+!,*-S>"'&Y';j'-*,,+_"'("#,"'2&%",[',$A(/' Y%*P-"#$*`&#'>"_">'_,',"_"%*>'S%&S"%`",'&Y'$M"' 2&%",'! 0#(#+-&&%+(*+B&+B&P&"+0&-1".B&0+BN+:<"&+ (8&"%#;+R&#'-+,"#$%&'(#)*'+! J+:*(&')#;;N+8&;:-+,*"%+1*'1&'("#(&0+:"*S;&-+ #'0+-%#;;&"+0&'-.)&-+.'-.0&+#+$./&'+"#0.<-+ ^i'

59 Thanks! ^j'

60 T fixed at 20 K T calculated from model (avg in 0.1pc) Distribution of masses of the 75 fragments (in the 19 cores) M min of Pillai+11 and Zhang+09