A	  Keplerian	  disk	  around	  a	  Class	  0	  source:	  ALMA	  observa8ons	  of	  VLA	  1623A	
Murillo et al. 2013	

麻生有佑	  11月8日 星形成ゼミ	

1.	  Introduc8on	
Ø 星形成において円盤は鍵となる。	  
質量降着、角運動量分布・輸送、惑星形成・・・	  Class	  IIで回転に支えられた円盤、Class	  0で疑似円盤	  Ø 磁場	  磁場なしではClass	  0ではRout<100	  AU,	  R∝t3	  (Terebey	  et	  al.	  1984)	  ideal	  MHDでは円盤形成が抑制される	  (Mellon	  &	  Li	  2008)	  磁場と回転軸が平行でないと形成する	  (Hennebelle	  &	  Ciardi	  2009)	  Ø Class	  0の回転に支えられた円盤	  
HGC1333	  IRAS4A,	  L1527,	  VLA1623	  2つとも磁場が砂時計型、VLA1623はmisaligned	  HGC1333	  IRAS4AとVLA1623はmul8ple	  ーーーー＞進化段階と環境のどっちが円盤形成に効く？	  A&A proofs: manuscript no. nmurillo

2.	  Observa8ons	

1.3 mm continuum fluxes measured with ALMA

SourceVLA1623A
VLA1623B
VLA1623W

R.A.
16:26:26.390
16:26:26.309
16:26:25.636

Decl.
-24:24:30.688-24:24:30.588-24:24:29.488

Peak (mJy beam−1 )
93.1
93.5
21.6

Integrated (mJy)
201.3±1.2
96.3±0.737.3±0.9

VLA1623・・・	  3重原始連星、non-­‐coeval、ρ	  Oph	  (d~120pc)	  nd ifVLA1623A・・・Class	  the combination of thesefactors is more and our recalibrated data shows consistency
0、24µmより短い放射なし、Bから1.1”、Wから10”	  volutionary stage of a protostar when it comes levels. The synthesized beam size is 0.79## ×	  uum and 0.79## × 0.61## for C18 O, providing
a disk.
–1–0.5
回転則がR(Murillo	  &	  Lai	  and2013,	  MA)	   frthe continuum
line Semissiona Ø
triplenon-coeval なのかR
protostellar なのかは不明	  system to resolve

13; Chen et al. 2013) with a prominent outWe compare the ALMA 1.3 mm con1990) located in ρ Ophiuchus (d ∼ 120pc, that obtained with SMA for the same waveØ ALMA	  Cycle	  0,	  2012年4月8日,	  アンテナ16台,	  最長400	  m	  8). VLA1623 is composed of three contin- Murillo & Lai (2013). To compare, VLA1623+	  (3-­‐2),	  C18O	  (2-­‐1),	  12CO	  (2-­‐1)を検出	  Ø DCO
A1623A,a deeplyembedded Class 0 source is used since it was the most sensitive to the flu
18Oで0.0833	  shortwardof 24 µm;CVLA1623B,
a veryuse the same region and task (CASA’s imstat tØ 速度分解能	  km/s	  source separated 1.1## fromVLA1623A; and integrated flux for both datasets. For the SMA
18Oで0.79”×0.61”	  Ø空間分解能	  Css I source at a projected distance of 10" from has an integrated flux of 96.8±0.7 mJy, wh(チャネルマップは4チャネルをバインドしてる？)	  observationsof VLA1623 revealed that the data, VLA1623B has an integrated flux of 9onent, VLA1623A, has a disk-like structure shows that both observations are consistent.
which was mimicked in continuum. FurtherJCMT observations towards VLA1623 bs disk shows a velocity gradient characteristic (2002) detected C18 O (2-1) with a flux of 12.1

3.	  Results	  –	  1.3	  mm	  Con8nuum	

N. M. Murillo et al.: A Keplerian disk around a Class 0 source: ALMA observations of VLA1623A

18
3.	  Results	  –	  C O	  (2-­‐1)	
A&A proofs: manuscript no. nmurillo

18
3.	  Results	  –	  C O	  (2-­‐1)	

Fig. 2. Observed C18 O (2-1): Left: Pure Keplerian rotation curves (v ∝ R−0.5 , red and blue) and infall (v ∝ R−1 , green) are overlaid on the PV
diagram. This suggests that the emission may be rotationally supported with M∗ ∼ 0.1-0.2 M% . Center: C18 O velocity map (Moment 1, halftone)
and intensity integrated (Moment 0, contours) maps. Contours are in steps of 3σ, 5σ, 10σ, 15σ, 20σ and 25σ with σ = 13 mJy beam−1 . VLA1623A
and B’s positions are marked with a square and triangle, respectively. Orange and blue lines indicate the image-space PV diagram cuts at PA =35◦ (left) and 125◦ (right), respectively. Right: Lack of velocity gradient suggests no outflow contamination on the C18 O emission. In both PV
diagrams contours are in steps of 3σ, 5σ, 10σ and 15σ where σ = 19 mJy beam−1 and the black lines indicate the systemic velocity and position
of VLA1623A.
480

OriginalMirrored60−1.0±0.21

183

Radial Velocity - vlsr (km/s)

Integrated Flux (mJy)Ø ρ	  Ophでは前方の分子雲が吸収を起こす。	  
∝RVLA1623A: C O (2-1)Ø ∝ラインプロファイル(黒)を4	  R
km/s付近で反転(橙)させたものと比べることで、システ
ム速度以外に2か所で吸収を確認した(青領域)。	  

40

20−0.5±0.08

20vlsr = 3.7km s−1−20Ø システム速度は3.4,	  3.8	  km/s
P.A. = 35とも言われている。	
◦101234567Velocity (km s−1 )Fig. 3. C18 O (2-1) line profile. The unaltered spectral profile (black) isoverlaid with a portion of the spectral profile mirrored about 4.0 km s−1(orange). Light blue rectangles mark the widths obtained from the best
fit thin disk model (Table 3) of the foreground material (1.6 and 3 kms−1 ) and the envelope (4.0 km s−1 ). The horizontal line between 5 and6.5 km s−1 shows the velocity range used for the UV-space PV diagram.

3040506070Radius (AU)Fig. 4. UV-space PV diagram of C18 O. vlsr = 3.7 km s−1 was used. The
red points indicate the red-shifted (v > 5.0 km s−1 ) emission. The velocity range covered in this diagram is indicated in Figure 3. Blue-shiftedemission (v < 2.8 km s−1 ) is not included in the diagram since it isgreatly affected by foreground emission (see Figure 3 and Section 3.2).
The points are fit with a power law of the form v = aRn . The solidline shows the fit to the high velocity points (v > 5.7 km s−1 ) while thedashed line shows the fit to the low velocity points (v < 5.7 km s−1 ).

※右下の線(5.0-­‐6.5	  km/s)はPVフィットに使った範囲。	

∝ R−0.5 , red and blue) and infall (v ∝ R−1 , green) are overlaid on the PVd with M∗ ∼ 0.1-0.2 M% . Center: C18 O velocity map (Moment 1, halftone)
ps of 3σ, 5σ, 10σ, 15σ, 20σ and 25σ with σ = 13 mJy beam−1 . VLA1623A
Orange and blue lines indicate the image-space PV diagram cuts at PA =ent suggests no outflow contamination on the C18 O emission. In both PV
mJy beam−1 and the black lines indicate the systemic velocity and position

e4.	  Analysis	  –	  P-­‐V	  diagrams	

4∝ R−1.0±0.21

Radial Velocity - vlsr (km/s)

3∝RØ UV上のPVフィット 	  （Lommen	  et	  al.	  2008）	  Ø blue側は含めず、>5	  km/s、
vsys=3.7	  km/s	  VLA1623A: C18O (2-1)−0.5±0.08

2Ø deconvolu8onの効果を防ぐため、マップ上での2次元ガP.A. = 35
ウシアンフィットに相当する作業をuv上でやった。	  
Fig. 4. UV-space PV diagram of C O. v = 3.7 km s was used. The
red points indicate the red-shifted (v > 5.0 km s ) emission. The velocity range
covered in this diagram is indicated in Figure 3. Blue-shifted Ø M*=0.22	  Mo,	  Rbreak~50	  AU	  (エラーバーに比べて冪のemission (v < 2.8 km s ) is not included in the diagram since it isgreatlyエラーが小さ過ぎ・・・)	
affected by foreground emission (see Figure 3 and Section 3.2). Ø 低速側はτや吸収の影響がThe points are fit with a power law of the form v = aR . The solidline shows the fit to the high velocity points (v > 5.7 km s ) while the
あるのでRbreakは広がり得る。	  
dashed line shows the fit to the low velocity points (v < 5.7 km s ).
vlsr = 3.7km s−1
◦

130

4050

6070

Radius (AU)18lsr

−1−1−1n−1−1This suggests that the pure Keplerian disk extends to a radius of 50 AU.

4.	  Analysis	  –	  Modelling	  of	  C18O	  (2-­‐1)	
Ø モデルは輻射輸送を解かない。	  
Ø M*=0.2	  Mo,	  vsys=4.0	  km/sは固定、一様密度、温度はラインプ
ロファイルに合うように決めた。	  
Ø フリーパラメーター	  line	  width	  vwidth	  (0.1-­‐1.0	  km/s),	  i	  (0-­‐90°),	  Rout	  (100-­‐200	  AU)	  吸収はラインプロファイルを再現するように速度上3か所にガウシアンのτを入れた。	  
Ø 見た目及び残差を比較してベストフィットを決めた。	  
(χ2フィットはしていないと思われる)	

4.	  Analysis	  –	  Modelling	  of	  C18O	  (2-­‐1)	
A&A proofs: manuscript no. nmurillo

4.	  Analysis	  –	  Model	  Results	A&A proofs: manuscript no. nmurillo

these conditions the disk’s centrifugal radius Rc is expected togrow proportional to t3 , where t denotes the time since collapse.
To calculate the time since collapse for Rc = 150 AU, we use theequation from Belloche (2013)
Rc (AU) = 39!

Ω5.	  " D# iscussion	
"$!

4 × 10−14 rad s−12a0.2 km s−1

m∗+d1 M#3(6)where Ω is the initial cloud core rotation rate, a is the sound3
speed and m∗+d = 0.975 aG t. Assuming VLA1623 has a rotation
rate Ω = 4 × 10−14 rad s−1 and the sound speed in the core isof a = 0.2 km s−1 , we obtain t = 8.5 × 105 yr for a centrifugal radius of 150 AU. However, the old age obtained throughthis method is inconsistent with the expected age from T bol(Ladd et al. 1998) and the estimated Class 0 lifetime obtainedby Evans et al. (2009), which is of the order of 105 yr, although
they conceded that for ρ Ophiuchus the lifetime is of 4 × 104 yr,
an order of magnitude lower than the above calculated age. Furthermore, based on outflow observations, VLA1623’s dynamical timescale is between 0.2 and 2.5 × 104 yr (André et al. 1990;
Nakamura et al. 2011). This indicates that there are other factorsof VLA1623. Holland et altion with the JCMT, findinfield perpendicular to the oalso observed the field to be
2" resolution with CARMA
carried out polarization obconfiguration, resolution ∼tion. From these results weVLA1623 is not aligned wi
disk, and the field strength6.	  Conclusions	Ø ALMA,	  Cycle	  0,	  Band	  6,	  extended,	  C18O	  (2-­‐1),	  con8nuum,	  VLA1623	  Ø PV図の解析とモデルフィットから150	  AU,	  0.2	  Moのケプラー円盤を同定。	  
Ø 磁場と回転軸のずれが効いているかもしれない。	  
Ø ケプラー円盤が見つかっているClass	  0の中で最も若い。	  
Ø Class	  0でも100	  AUサイズのケプラー円盤ができる。	  
Ø 進化段階よりも環境の影響が円盤形成に効くかもしれない。