Shih-Ping Lai 賴詩萍 (National Tsing Hua University)
Tao-Chung Ching (NTHU->NAOC), Josep Miquel Girart (CSIE-IEEC),
Zhi-Yun Li (Virginia), Akimasa Kataora (NAOJ), Hauyu Baobab Liu (ESO)
Chat Hull (NAOJ), Qizhou Zhang (CfA), Ramprasad Rao (ASIAA),..
Derek Ward-Thompson (UK), Kate Pattle (UK-> NTHU),
Keping Chiu (China), Ray S. Furuya (Japan), Woojin Kwon (Korea),
Pierre Bastien (Canada), Jia-Wei Wang (NTHU), C. Eswaraiah (NTHU)+ > 100 members..

HourglassRandom Fields

Mass collapse along field line,so the dense core becomesflattenedl B field is frozen in the matter,mass dragged field lines andform an hourglass geometryl Ambipolar diffusion reduces
the magnetic pressure in thecore, allowing the ultimate
Image takend from Crutcher (2006), Sciencegravitational collapse andforming a protostarlPolarization of Thermal RadiationB<"3#&(<17"%8()+1"4&3&104;0#&(<17"%8)+1"4&3&104

BE(Partial)
Polarization
Observed!"#$%&'()*#"+,"-((((.,"/&0+(1#(!"#!"$%&'()*#(&0(E
2%34".05.&6".#78(/09204"4&(05((((((:B!

NGC1333

NGC 1333 IRAS 4A: Hourglass shape B-field

SMA

Girart, Rao, Marrone (2006, Science)

Spitzer/IRAC from c2d (Jørgensen et al. 2006) with SCUBA map (yellow contours; Kirk et al. 2006)
5

P

B
Girart, Rao, & Marrone (2006),

what about small scale structure?

NGC 1333 IRAS 4A1/4A2: 50 to 3000 AU
SMA(a) All data, 10 < uv < 520 kλ(d) 100 kλ < uv < 520 kλ

10 %(b) 10 kλ < uv < 220 kλ(c) 50 kλ < uv < 220 kλSimulated SMA mapsPure¡ Hourglass

Hourglass + Toroidal

Ching (2011, master thesis)Hourglass + Toroidal

Ching (2011, master thesis)

Machida et al.(2008)
Hourglass + Toroidal

Ching (2011, master thesis)

SMA

ALMA

SMA

ALMA

Yang & Li (2016)

Kataora et al. (2016)

Polarization from Scatteringcannot be ignored due to dust growth!

𝑷=​𝑷↓𝒅𝒖𝒔𝒕 𝒆𝒎𝒊𝒔𝒔𝒊𝒐𝒏 +​𝑷↓𝒔𝒄𝒂𝒕𝒕𝒆𝒓𝒊𝒏𝒈

𝑷=​𝑷↓𝒅𝒖𝒔𝒕 𝒆𝒎𝒊𝒔𝒔𝒊𝒐𝒏 +​𝑷↓𝒔𝒄𝒂𝒕𝒕𝒆𝒓𝒊𝒏𝒈

Kataora et al. (2016)

Observations at multi-wavelengths and detailed
modeling are needed to disentangle scattering anddust emission.
Cycle 5 Proposal Accepted!

Hourglass

Random Fields

IRAS16293

6293: A MAGNETIC TALE OF TWO CORES

60931

W51 e2/e890

ation vectors aroundP.A. distribution of
the average value,arabolic fitting doneng source B), which-absorption andood tracer to try
ry environment.
line detected bya better tracer ofoutflow and theesence of a free–erived indirectlys (Loinard et al.

BIMA: Lai et al 2001
Rao, Girart, Marrone, Lai, Schnee 2009
Figure 9. Top panel: overlap of the 0.88 mm dust emission and the B-vectors(same as Figure 2) with the best solution for the parabolic family of functions(blue solid lines). Bottom panel: the same as the top panel, but the best family offunctions is shown as B-vectors (in blue) at the same position as the measuredvalues.

1993, for definitions and descriptions of the various classes of

SMA: Tang,…,Lai et al 2009

¡Previous observations show that
protostars are warped by strong
magnetic fields¡

Our ALMA observations show thatnew stars can form in a weakly
magnetized environment
dominated by turbulence

Press: ALMA News Press, Jun 14, 2017
Reference:¡ Hull+, Lai, ApJ Letter, 2017

Serpens Main

Simulation done by Philip Mocz(CfA)

Stars can form from weakly magnetized cores
relatively random B fields!!

¡Map polarized 850 micron emission towards
Gould Belt star-forming regions¡

Instrument: SCUBA 2 + POL 2

¡

PIs:
§§
§
§
§
§

¡

Derek Ward-Thompson (UK)
Pierre Bastien (Canada)
Tetsuo Hasegawa (Japan)
Woojin Kwon (Korea)
Shih-Ping Lai (Taiwan)
Keping Qiu (China)

Publications:§ Ward-Thompson+, Lai+, ApJ, 2017
§ Pattle+, Lai+, ApJ, 2017

SCUBA pol.
Matthews et al. (2009)
POL 2
Ward-Thompson et al. (2017)
Pattle et al. (2017)

JCMT beam = 14”
ALMA field of view = 6”
ALMA beam ~ 0.5”

¡ ALMA: Disk formation¡ JCMT: Filament & Core formation

http://events.asiaa.sinica.edu.tw/workshop/20180206/index.php