THE STAR FORMATIONNEWSLETTER
No. 280 (#46-50)
塚越崇(茨城大)6 Jun. 2016

1. WISEA J114724.10−204021.3: A Free-Floating Planetary Mass
Member of the TW Hya Association
2. Star formation in Galactic flows
3. Slingshot Mechanism in Orion: Kinematic Evidence For Ejection ofProtostars by Filaments
4. The Bolocam Galactic Plane Survey. XIV. Physical Properties ofMassive Starless and Star Forming Clumps
5. Discovery of periodic and alternating flares of the methanol andwater masers in G107.298+5.639

2Schneider et al.

WISEA J114724.10−204021.3: A Free-Floating Planetary Mass Member of the TW Hya
Association
Table 1WISEA J114724.10 204021.3 Properties
Adam C. Schneider et al.

• WISE+2MASSで見出された赤いL dwarf
Parameter

ValueRef.

Identifiers• 追観測により星の性質を調べる
AllWISE2MASSJ114724.10-204021.3
11472421 2040204

12

Observed Properties↵ (J2000)
11:47:24.10
VISTA/VHS• IRTF spectrograph,(J2000)
20:40:21.3

11µ↵122.1±12.0 mas yr 1
4µ74.5±11.3 mas yr 1
4
J (2MASS)>17.511 mag
2H (2MASS)
15.764±0.112mag
WISEA14.872
J114724.10
204021.3: 22A Planetary Mass Member of the TW Hya AssociationKS (2MASS)± 0.106 mag
Y (VHS)19.160 ± 0.067 mag
3J (VHS)17.445 ± 0.029 mag
3KS (VHS)14.872 ± 0.011 mag
3
W1
13.718 ± 0.026 mag
1
W2
13.090 ± 0.030 mag
1
Figure 1. Three color composite VHS image centered on theW3>12.155 mag
1position of WISEA 1147 2040 (Y = blue, J = green, KS = red).
W4>8.913 mag
1
J KS (2MASS)>2.64 mag2son et al. 2004) in the Y , J, and KS photometricJ KS (VHS)2.57 ± 0.03 mag
3bands (Figure 1) as part of the VISTA Hemisphere
J KS (synthetic)
2.61 ± 0.03 mag
4Survey (VHS; PI McMahon, Cambridge, UK). WISEA
W1 W2
0.63 ± 0.04 mag
1• スペクトル型: L7• 天体は若い• 形成中につきlow gなのでdusty atmosphere• H, K bandsでCIA of H2が支配的でない•

Inferred Propertiesgが得られる
実際のスペクトルフィットでlowSpectral Type (NIR)
Photometric Distance
Kinematic DistancePredicted DistanceTe↵ alog ga
Massa
Te↵ b
MassbAge• TWAへ付随• いくつかの方法で評価

L7 ± 1 (red)31.2 ± 1.5 pc
32 33 pc
31.3 ± 3.8 pc
1500 ± 100 K
4.0 ± 0.5
6 13 MJup
1100 1200 K
5 6 MJup
10 ± 3 Myr4444,5444446• proper motion
References. — (1) AllWISE; (2) 2MASS; (3) VHS; (4) Thiswork; (5) BANYAN II (Malo et al. 2013, Gagné et al. 2014a); (6)Bell et al. (2015)a From model fitting (Section 4.2).

• photometric distance, kinematic distance etc.

1147 2040 was well detected in all three bands and thephotometry from VHS is listed in Table 1. These observations confirm the very red J KS color of WISEA
1147 2040 (J KS = 2.57 ± 0.03 mag).
4. ANALYSIS
4.1. Spectral Typing

We determined a spectral type for WISEA 1147 2040
following the method outlined in the Appendix of Schneider et al. (2014). A comparison of the SpeX spectrumof WISEA 1147 2040 with several near-infrared spectralstandards (Kirkpatrick et al. 2010) from the Spex Prism
Spectral Library (SPL, Burgasser 2014) is shown in theleft panel of Figure 2. While none of the L-type stan-Figure 4. Top: The position of WISEA 1147 2040 (red star) in the sky relative to known TWA members (blue circles), high probability(>50%) candidates from Gagné et al. (2015) (orange hexagons), and 2MASS J11193254 1137466 (light blue square) from Kellogg et al.
(2015). Bottom: The XYZ positions of WISEA 1147 2040, known TWA members, high probability (>50%) candidates from Gagné et al.
(2015), and 2MASS J11193254 1137466. Symbols are the same as the upper panel.

• Lbolを使用して質量見積もり -> 5-6 Mjup

Murphy, S. J., Lawson, W. A., & Bento, J. 2015, MNRAS, 453,2220
Rayner, J. T., Toomey, D. W., Onaka, P. M., et al. 2003, PASP,115, 362
Reid, I. N., Lewitus, E., Burgasser, A. J., & Cruz, K. L. 2006,ApJ, 639, 1114

Schneider, A. C., Cushing, M. C., Kirkpatrick, J. D., et al. 2014,AJ, 147, 34
Skrutskie, M. F., Cutri, R. M., Stiening, R., et al. 2006, AJ, 131,1163
Vacca, W. D., Cushing, M. C., & Rayner, J. T. 2003, PASP, 115,389

lowest mass free floating BD in TWA

Star formation in Galactic flows
R. Smilgys & I. A. Bonnell• 星形成の現実的なモデル計算には、現実的な初期条件を与えることが重要=>Galactic flow - spiral shockによるgas compression• 高分解能によるSPH計算で個々の雲における星形成を分解
Bonnell+2013の継続で、後半5.8Myrの星形成部分に着目
2• 磁場なし+feedbackなし• flowによる低密度ガスの圧縮で生成された高密度領域において星形成
効率が高い

R. Smilgys & I. A. Bonnell

Slingshot Mechanism in Orion: Kinematic Evidence For Ejection of Protostars by Filaments
A. M. Stutz & A. Gould• Orionのintegral shapeに対してSlingshot mechanismを検証• Herschelをベースに既存データを使用• フィラメント同定• 線密度や重力ポテンシャル導出

A. Stutz & A. Gould: Slingshot Mechanism in Orion: Kinematic Evidence For Ejection of Protostars by Filaments• 原始星のほうがフィラメント上に分布

A. Stutz & A. Gould: Slingshot Mechanism in Orion: Kinematic Evidence For Ejection of Protostars by Filaments

A. Stutz & A. Gould: Slingshot Mechanism in Orion: Kinematic• 速度でもフィラメントからのずれ量がある原始星で<1km/s、class2は~several km/s

• ずれから年齢(turnaround time)を見積もると0.44Myr• 重力と磁場のエネルギー比較
ISFスケールではsubcritical、L1641全体ではsuper critical->’slingshot mechanism’は磁場によって励起されている• L1641は星形成のfirst stage (straightfilament、低星形成率)
ISFはsecond stage (高星形成率)

2

Svoboda et al.

on studying the physical properties of starless and star forming
clumps identified in the BGPS.
The BGPS survey identified 8294 clumps with 1.1 mm flux
densities above 100 mJy and 8594 clumps cataloged in total(Rosolowsky et al. 2010; Aguirre et al. 2011; Ginsburg et al.
2013). The second data release (v2.0) of the Bolocam images
and source catalog (Ginsburg et al. 2013) used improved analysis of the time-stream data to improve angular flux recovery
with full recovery out to ⇠ 8000 and partial recovery out to⇠ 30000 . The v2.0 data also resolves systematic flux and pointing calibration offsets and includes new fields in the second
quadrant. In this work we exclusively use the BGPS v2.0 data
products, and all clumps are referenced to the BGPS v2.0 maps
and Bolocat clumps.
Extensive followup observations of BGPS clumps have been
carried out to determine unique velocities, kinematic distances,and gas kinetic temperatures to use in calculations of physicalproperties. Followup spectroscopic observations of the BGPS
catalog in dense molecular gas tracers HCO+ 3 2 and N2 H+
3 2 with the Arizona Radio Observatory’s Heinrich Hertz
Submillimeter Telescope (HHSMT; Schlingman et al. 2011;
Shirley et al. 2013) detected about half of the objects in theBGPS catalog (> 97% of those clumps have a single velocitycomponent) from which kinematic distances may be derived.
A novel Bayesian technique has been developed to calculate
a continuous function of the probability that a source lies ata given heliocentric
12 distance (Ellsworth-Bowers et al. 2013,2014). The posterior Distance Probability Density Function(DPDF) is constructed by multiplying the bimodal likelihood
240function (with equal probabilityof being located at the near or160
2223
far kinematic distance) with80 prior distributions that account forthe source positions relative to the known H2 distribution in
1802460
the Galaxy and the coincidence
and contrast of 8 µm absorp120
60
tion features (Ellsworth-Bowers
et al. 2013). Since the dense
molecular gas lines are 120
only
detected
toward approximately
90995
60
half of BGPS clumps, Ellsworth-Bowers
et al. (2014) extended
30
the number of sources withbimodallikelihood
functions by de751022 technique between 13 COveloping a morphological50matching
1 0 from the Galactic25Ring Survey (Jackson et al. 2006)45
and the BGPS 1.1 mm emission.
This technique assigns a30556
clump the dominant 13 CO
15 velocity component that matches
the 1.1 mm morphology.24 The DPDF formalism is a power16298
ful tool that permits properaccounting
and propagation of
the distance uncertainty in8 calculations of distance dependent
physical properties (i.e., size,mass,
12170 and luminosity).
Early BGPS papers have84 characterized clump physical properties on modest subsets of the BGPS.
Schlingmanet al. (2011)10 1100101
determined the physical propertiesof 529 sources
drawn uniTotal
S1.1[Jy]thatformly from the BGPS 1.1 mm flux distribution,
finding

ClumpsThe Bolocam Galactic Plane Survey. XIV. Physical Properties of Massive
Starless and Star Forming
covering 80 < ` < 60 and 2.0 < b < +1.0 at 2200
Clumpsresolution. In the far-infrared and submillimeter, the Herschel
BGPS 1.1 mm Survey Data
Infrared Galactic Plane Survey (Hi-GAL; Molinari et al. 2010)
surveyed the entire Galactic plane in the five PACS and SPIRE
B. E. Svoboda et al.
Bolocat v2 Source Extraction
bands from = 60 500 µm. In this paper, we shall focus
Common Survey Overlap 10 < l < 65

• BGPSカタログによる大中質量星形成•

HCO+(3-2), N2H+(3-2) with HHSMTでclumpのガス成分、速度構造などを検出• その他星形成活動のindicator• NH3+H2Oの追観測を実行 with GBT• 文献のMIR,70um観測など• 物理量の導出
indicator毎に比較

N=> starlessとprotostarの切り分け

SF Indicators

1.1mm survey, 8000以上のクランプを同定

Monte Carlo

•

Phys.

領域の調査

Starless Clump Candidates
Protostellar Clumps
HG70 Uniq. : Hi-GAL 70 um UniqueMid. IR: 2{24 um YSO

H2O: Water Maser

CH3OH: Methanol Maser

UCHII: Ultra-Compact HII Reg.

Contamination Resampling
Monte Carlo Random SampledHeliocentric Distance PDF

TKObserved OR Category PDF

S1.1, ¢v, µeq, :::Observed

Physical Properties : M, §, Req, ®, :::Svoboda et al.

Statistical Quantities : ¹1/2, ¹, ¾, :::Starless Cand.
Figure 1. Flow chart describing the BGPS catalog, sorting by star formation
indicator, Monte Carlo random sampling, and property calculation.
Protostellar

which sample cores, clumps, and clouds on different scales andat different distances. Indeed, higher resolution observations
70 µm Unique
at 350 µm indicate that BGPS clumps typically break up intocollections of smaller substructures (Merello et al. 2015). AllMidofIRthese early studies made crude assumptions to resolve thekinematic distance ambiguity (i.e., all sources associated with
H2 8O µm absorption are at the near distance or using the presence or lack of HI self-absorption to distinguish between nearand far kinematic distance; see §4.3). Ellsworth-Bowers et al.
CH(2015)
3 OH
is the first study to utilize the full power of the DPDF
formalism in which they characterize the clump mass distribution for the subset of 1710 clumps with well-constrained
UCHIIDPDFs. They find that the clump mass distribution is best fit
with a2 lognormal distribution with an approximately powerlaw10
distribution for high-mass sources and a power-law index
that is intermediate between that observed for giant molecular• SCCとprotostellar clumpの傾向• SCCのほうが質量(面密度)と半径が小さめ

1• SFR∝Σのcriteriaを満たすのは半数かそれ以下• SCCのlifetime (検出個数的にはprotostellarと同等)
tSCC=tCH3OH*(NSCC/NCH3OH)を使用<450Msunクランプではtffより長い• 質量の違いのoriginw• すべてのSCCが(indicatorで)検出可能な• clumpはparent GMCからの質量供給で成長
indicator毎の傾向はMでは大きいがRでは弱い=>cloudからコンベア的に質量供給？

• SCC phaseの質量↑でtimescaleが↓となる
他のprotostellar clumpの形成メカニズムを考える必要がある。SCCとprotostellarでtimescaleや質量降着率を変えるなど

22710Figure 18. Equivalentradius compared to total mass. Median values foreach clump are computed from MC simulations. Clumps are shown associatedto UCHII or CH3 OH masers (red), other protostellar (black), and SCCs(cyan). The dash-dotted line shows the threshold for high-mass star formation
M (R)580M6 (R pc 1 )1.33 from Kauffmann & Pillai (2010) when
10dust opacities. Solid lines shows thresholds for “effecientscaled to OH5star formation” of 116 M pc 2 (Lada et al. 2010) and 129 M pc 2(Heiderman et al. 2010). The upper and lower dashed gray lines show 0.5g cm 2 and 0.005 g cm 2 respectively. The shaded gray region in theupper left indicates5 the part of parameter space for Young Massive Clusters as
10 et al. (2012).
defined in Bressert⌧phase [yr]protostellar clumpに成長しない

determined from local clouds are over-plotted. Fitting starformation rates
104 to local molecular clouds, Lada et al. (2010)
and Heiderman et al. (2010) find relationships for “effecient”
star formation of ⇡ 116 M pc 2 and 129± M pc 2 , respectively, where above these3 thresholds the4 star formation
5 rate is
10density.
linearly proportional10
to mass surface
The10thresholds
Totalfrom Lada et al. (2010) andMHeiderman[Met ]al. (2010) approxiH2mately bisect the samples, with 50.6% and 42.5% of the fullww

TL2M. Szymczak, M. Olech, P. Wolak, A. Bartkiewicz and M. Gawroński

Discovery of periodic and alternating flares of the methanol and water masers in G107.298+5.639
M. Szymczak
al.
deeplyembeddedetobject
driving a quadrupolar outflow,classified as an intermediate-mass protostar of 370L⊙
et al. 2008, 2010) at the distance of 760 pc(Sanchez-Monge
メタノール/水maserのanti-corr.の例(Hirota et al. 2008). Recently, a periodic (34.6 d) flaring of the 6.7 GHz methanol maser has been reported(Fujisawaet al. 2014).
G107••2• 370L⦿, 760pc, HII region, mol. outflow

OBSERVATIONS• periodic 6.7GHz methanol maser

The observations presented here are part of the ongoingmaser monitoring programme of HMYSO with the Torun 32m radioTorun
telescope32m+EVN(ヨーロッパVLBI)(Szymczak, Wolak & Bartkiewicz 2014).
G107 was monitored in the 6.7 GHz methanol and 22 GHz
water lines
2014H2O
July to2015 December
and from 201522GHzmaser,
6.7GHz methanolmaser• fromJuly to 2015 December, respectively. The methanol observations were usually once per day but increased to approximately eight times per day during flares and decreased toonce per week during quiescent intervals with two gaps of
6.7GHzmethanol
8 and 16d due to schedule
constraints. The water observations were usually once per day with eight gaps of 4−5 d.
34.4±0.8d• Periodicity:
The observational
setup forthe methanol transition observation was the same as reported in Szymczak et al. (2014)-7.4,-8.6, -9.2 km/s components
and resulted•in a spectral resolution of 0.09 km s−1 with atypical rms noise level of 0.35 Jy before 2015 May and thenwater0.22 Jy.22GHz
The methanol
flux density calibration was accurate
to less than 10 per cent.
-18~-1km/s,
variation
in intensity
The• half-power
beam complex
width of the32-m telescopeat22 GHz is 1.7 arcmin. We used two 4096-channel correlator
parts with 8 MHz bandwidth each, which provided a velocity•••−1• フレア時期にずれ(2-5日)• EVN methanol map• 南東-北西方向に分布• 水メーザーとエラーの範囲で一致=>励起条件のANDは範囲が狭いので、(密度)・温度が時間変化したと考えるのが自然• モデル比較• 中心星脈動(Inayoshi+2013)=>予想光度が大きすぎる [x]• Accretion instability(D’Angelo&Spruit2012)=>見つかっているmodulation (≠flare)とconsistent [o]• protobinary systemによるperiodic
accretion=>model依存はあるが可能性あり [o]