THE STAR FORMATIONNEWSLETTER
No. 266 (#36-40)
塚越崇(茨城大)17 Apr. 2015

The Spatial Structure of Young Stellar Clousters. II. Total Young Stellar Populations
M.I.A. Kuhn et al.

• MYStIXプロジェクトデータによる大質量星形成領域のstellar
populationの調査観測の2つめ•

MYStIX: Massive Young Star-forming complex Study in Infrared and X-ray••

ChandraのX線と2MASS,SpitzerのIRを使ったカタログ(MPCMカタログ)•

銀河アームの領域にフォーカスしている•

d<3.6 kpc

Paper1では感度の近い領域を切り出して議論していたが、この論文では全て含める• 星密度測定の重要性•

星形成モード(cluster,isolated)を切り分ける’scale’の調査•低質量星ではthresholdは存在しない[Bressert+2010]=>大質量では？

3.5
3.0
2.5
2.0
1.0

1.5

log N [stars] (IMF)

1.0

1.5

2.0

2.5

3.0

3.5

log N [stars] (XLF)• XLFとIMFからstellar population. 4.— Intrinsic numbers of stars within the MYStIX subclusters estimated via the IMF
dinate) vs. XLF (abscissa). The y = x line where both methods produce the samemate is indicated.

を比較=> よく一致している• X線カタログから作成した星密度
マップ•

多くの領域でクラスター•

RCW38が最も星密度大Orion

150

Flame

300
200

Rosette

400

Number of Stars

800
600
400
200

50

2000

NGC6334

1500= 「多くの星はクラスターで生まれている」

NGC6357
1500

1000

1000

500

500

• Paper1のモデルを使用して、クラスターに属する星を定義=> 80-90%がsubclusterに付随

NGC2362

200
RCW38

1200
1000
800
600
400
200

150
100

400

200
DR21

Lagoon

600

400

100

1000

20

800

600

200

1000

60

50

800

300

RCW36

40

50

NGC2264

100
80

100

100

1200

W40

150

100

500

200

Gaia-ESO Survey: The analysis of pre-main sequence stellar spectra
A.C. Lanzafame et al.

• Gaia-ESO Public Spectroscopy Surveyプロジェクト• VLTのFRAMES分光計を使用• オープンクラスターを狙い、銀河面~100000天体の高品質なスペクトルを取得• 最終的な狙いの一つはradial velocity測定• 最初の18ヶ月のデータを紹介しており、測定方法や解析戦略、エラー
評価について述べている• UVESとGIRAFFE天体に対するスペクトルを示す• GIRAFFE: 比較的暗いF~M型星のPMSおよびMS (12<V<9mag)• UVES: 比較的明るいG-K型星 (9<V<15mag)• スペクトルから星のパラメータを導出• 良いSNで算出できた• プロジェクトはまだon-goingSulfur-Bearing Molecules in Massive Star-Forming Regions: Observations of OCS, CS, H2S and SO
J. Li et al.

• 大質量星コアに対してS系分子のサーベイ的観測=>S系分子はchemical clockとして使えるかも• S系分子•warm gasトレーサー•

大質量星に対してはよく分かっていない•

様々な分子のアバンダンス比を調べることが重要• 観測•

CSO 10mサブミリ波望遠鏡•

230GHz帯のOCS,O13CS,13CS,H2S,SO, C18O•

水メーザーが付随する36個の大質量星形成領域•

ホットコアあり/なしのHII領域 (切り分け方は後述)

スペクトル例• 励起温度の大きい分子CH3CNの検出(同時取得)=> ホットコアの証拠とみなす: HII-HC , HII-onlyとする• 同位体データのあるOCSで光学的厚みを導出=>τ~5-16• LTE, Tex=50Kを仮定して柱密度を導出•

τデータが無い場合は光学的に薄い仮定=>質量下限値

(a) H2 for H II−HC(e) OCS for H II−HC (g) H2S for H II−HC1010(c) CS for H II−HC1010

各分子の柱密度(左図)

10
5

5
0
22

23

24

(b) H2 for H II−onlyNumber of Sources(i) SO for H II−HC

5

0
13

14

5

– 26 – 0

15

14

0
13

16

5

14

15

16

0

アバンダンス(左下図)
13

14

15

10

(d) CS for H II−only10(f) OCS for H II−only (h) H2S for H II−only (j) SO for H II−only
10
10
10

5

5

5

-ホットコアありからなしにかけて減少がみられる

0
22

23

24

0
13

14

5

0

15

14

0
13

16

5

14

15

16

0

−2

log (Column Density) [cm ]10-S分子として最も多いのは
13

14

15

H2S

(e) H2S for H II−HC(a) CS for Hof
II−HC(c) OCSdistributionsfor H II−HC
for H II−HC
5.— Histograms
the numberof
H2 , CS, OCS, H(g)2 SSOand
SO column densities
1010
10
H II-HC10and H II-only sources. The vertical dashed lines indicate the median values of themn densities for each distribution. Median values of the column densities are given in Table 3.
55
55
vertical bars
stand for sources undetected in particular molecular line emission.
0
−9.5

−9

−8.5

−8

0
−10

Number of Sources(b) CS for H II−only

−9

−8

−7

0
−10

−9

−8

−7

0
−10

(f) H S for H II−only(d) OCS for H II−only−9−8(h) SO for H II−only• アバンダンス比の比較(Table7)

10

10

10

10

• OrionKLモデル[Esplunges+2014]と比較

5

5

5

5

• [OCS]/[H2S], [CS]/[H2S], [SO]/[OCS],

0−9.5 −9 −8.5 −8log (abundance)

0
−10

10

−9

−8

−7

2

0
−10

−9

−8

−7

0
−10

[CS]/[SO], [OCS]/[CS]−9−8• HII-HCの天体は典型的に70000-85000yrのモデルで再現出来そうSearch for methylamine in high mass hot cores
N.F.W. Ligterink et al.
• 大質量星に対するメチルアミン(CH3NH2)の探査観測=> non-detection

A&A proofs: manuscript no. Methylamine_hotcores_Ligterink• メチルアミン• 生成にUVフォトンが重要 [Garrod+2008]• CO iceを経由しない• ホルムアミド(NH2CHO)との比較で
UVフォトン or thermal interactionの比較• CO iceから生成されるので• JCMT• 230-260GHzの複数のメチルアミン狙い• 分解能20~21”• ノイズレベル~10mKくらい
Fig. 1. JCMT spectra of the massive hot cores G31.41+0.31, G24.75, NGC 7538 IRS1 and W3(H2 O). The 229310 and 229452 MHz transitionsin the lower sideband are indicated in red and that at 236408 MHz in the upper sideband in blue. In green is the baseline, obtained by fitting line
free portions of the spectrum. In all spectra the H2 CS 71 ! 61 transition at 236726 MHz is fitted to determine the typical linewidth in the sources,
as listed in Table 1.

• 9つのホットコアを含む大質量星形成領域• Trot=120Kを仮定して柱密度を導出

the warm methanol column density derived from optically thinlines. Abundances relative to methanol rather than H2 are preferred since the H2 column depends on extrapolation of dust
models to smaller scales than actually observed (Bisschop et al.

served column density of formamide would be lower than that
listed here and thus result in a higher CH3 NH2 /NH2 CHO ratio.
We note, however, that there is no observational evidence that
T rot is systematically lower than 100 K for formamide (Bisschop

Table 3. Upper limit column densities and abundance ratios for methylamine.

上限値からアバンダンス比を導出

SourceModel F
Model M
Model SAFGL 2591
G24.78G31.41+0.31
G75.78IRAS 18089-1732
IRAS 20216+4104
NGC 7538 IRS1
W3(H2 O)W3(H2 O)*
W 33A
Sgr B2a
Sgr B2(M)b
Sgr B2(N)b
Sgr B2(N)cOrion Compact Ridged

NS,CH3 NH2cm 2<1.9E+16<2.4E+16<5.8E+16<3.5E+16<4.2E+16<6.4E+16<2.0E+16<5.0E+16<1.7E+16<5.7E+16
1.2E+144.5E+16
6.0E+17
5.0E+17-

CH3 NH2 /NH2 CHO

CH3 NH2 /CH3 OH

NH2 CHO/CH3 OH

NH2 CHOupper /CH3 OH

1.1
1.7
1.3
<3.3E+01<2.8E+01<1.7E+02<5.0E+01<3.5E+01<3.9E+01<1.3E+01<2.7E+01
5.7E-01
3.2
4.3E-01
2.1-

3.4E-02
1.0E-01
1.3E-01<8.5E-02<4.9E-02<3.1E-01<1.9E-01<2.2<1.8E-01<5.0E-02<1.7E-02<2.9E-01
1.7E-02
1.7E-02
3.3E-02
1.0E-01-

3.1E-02
7.3E-02
1.0E-01<3.9E-01
2.6E-03
1.8E-03
1.8E-03
3.8E-03
4.8E-03
1.3E-03
1.3E-03
1.1E-02
1.3E-02
5.2E-03
7.8E-02
4.8E-02
1.6E-03

3.1E-02
7.3E-02
1.0E-01
9.0E-04
3.8E-03
2.6E-02
7.9E-03
2.1E-04
6.4E-04
6.4E-04
4.6E-03

Garrod+2008のホットコア進化モデル

参考のSgr B2とOrion

Notes. Column densities for the assumed source size and upper limit abundance ratios for methylamine, derived from the 22 21 line assuming Trot
= 120 K. The values for NH2 CHO and CH3 OH where taken from Bisschop et al. (2007) and Isokoski et al. (2013). The upper limits of NH2 CHO
were determined by our own re-analysis of the Bisschop et al. (2007) data and taken from the appendix of Isokoski et al. (2013).
* Column density calculated for the 82 81 line.
References. a Turner (1991), beam sizes between 65" and 107", assuming no beam dilution; b Belloche et al. (2013), beam sizes between 25" and30", assuming a 300 source size for (N) and 500 source size for (M); c Neill et al. (2014), beam sizes between 10" and 40", assuming source size of
2.500 ; and d Crockett et al. (2014) beam sizes between 44" and 11" and assuming a 1000 size of the Compact Ridge.

• CH3NH2/NH2CHOはモデルとconsistent。一方でCH3NH2/
CH3OHはほぼモデル=上限値であり、モデル計算ではCH3NH2がalternative solution would be that the high-mass sources studied

that the two molecules may not co-exist. An alternative route
would therefore be to form these molecules by two di↵erent gasphase reaction pathways (CH• (g) + NH3 (g) ! CH2 NH + H andCH•3 (g) + NH3 (g) ! CH3 NH2 + H), with CH being present primarily in the colder outer envelope and CH3 in the warmer center. Further modeling is needed to determine whether these gasphase reactions can reproduce the observed abundances quantitatively.

多すぎるhere have not gone through a long (pre-stellar) phase in which
the dust temperature was low enough for CO to be frozen out
and turned into other molecules.
5.3. CH3 CN

The clear mismatches between theory and observations for theratios involving CH3 CN point toward an underproduction of acetonitrile by more than an order of magnitude in the models. As
with formamide, gas-phase, radical and atom addition reactions
contribute to the formation of CH3 CN in the models, making it
difficult to determine the cause. The main formation route in themodels by radical addition of solid CH•3 and solid CN• has neverexperimentally been investigated. It would therefore be useful todetermine if this is a viable solid state formation route and if it
potentially has a higher efficiency than assumed.
Alternatively it is possible that photodestruction of solid ace-

• NH2CHO/CH3OHはモデルより小さい観測値。これもモデル計算

5.2. NH2 CHO

Formamide also appears to be overproduced in the hot coremodel. Since Garrod et al. (2008) use both gas-phase, radical
and atom addition reactions to form formamide, it is difficult topin down where the discrepancies could come from. It is known
that NH2 CHO is formed in CO:NH3 mixtures after UV and electron irradiation (Grim et al. 1989; Demyk et al. 1998; Jones et al.
2011) and it has also been proposed that it can form from H- andでは作りすぎている。

• アセトニトリル(CH3CN)との比較•

CH3*+CH*->CH3CNなので、CH3NH2とメチル基を奪い合う• CH3NH2/CH3CNはモデルの方が大きすぎ、CH3CN/CH3OHはモデルの方が小さすぎ=> モデルではCH3CNが少なすぎる

small so
SourceCH3 NH2 /CH3 CN CH3 CN/CH3 OH 0.64 km
tennasapproprModel F
5.5E+01
6.3E-04
Model M
3.8E+01
2.6E-03
Model S
1.5E+01
8.6E-03
6. ConAFGL 2591<5.3<7.5E-02
We hav
G24.78<5.1E-01
2.1E-01
lamine.
G31.41+0.31<3.6
5.9E-02*
upper
G75.78<1.9E+01
1.6E-02
From tIRAS 18089-1732<8.9
1.1E-02*(NH2 CIRAS 20216+4104<4.3E+01
5.2E-02
pared w
NGC 7538 IRS1
<2.5
6.8E-02are as f
W3(H2 O)
<7.2
7.0E-03
W 33A<2.1
1.4E-01
1. TreSgr B2a1.2
1.5E-02
mam
Sgr B2(N)b
3.0E-01
1.1E-01(20
Sgr B2(M)b
2.5E-01
6.7E-02
mod
Sgr B2(N)c
5.9E+01
1.7E-02
2. AbuOrion Compact Ridged 1.1E-02
nitu
gen
fou
Notes. Abundance ratios for methylamine. The values for CH3 OH and3. Mo
CH3 CN were taken from Bisschop et al. (2007) and Isokoski et al.
path(2013).
sim
13*Ratio derived from optically thin C isotope.
exte
References. a Turner (1991), b Belloche et al. (2013), c Neill et al.
d
4.
The(2014) and Crockett et al. (2014).
futu
Bas
destroyed. However, the gas phase photoabsorption cross secliketions of CH3 CN are well determined and if the bulk of these ablam
sorptions lead to dissociation this would result in a photodissotion
ciation rate of gaseous CH3 CN at least as fast as that of CH3 OH
Acknowle(van Dishoeck et al. 2006).
Drozdovs
Another important parameter for all molecules studied here doseev, ais the mobility of radicals and neutral molecules on the sur- comment
face assumed in the gas-grain models. For many species no ported byexperimental data are available on di↵usion barriers, only Netherlan
theoretically-inspired guesses. Observational evidence suggests Europeanthat at least parts of the ice mantles are segregated in CO-rich andCO-poor layers (Tielens et al. 1991; Pontoppidan et al. 2008).
Therefore, more knowledge of the structure of ice mantles and Refere• Garrod+2008のモデルではCH3NH2とNH2CHOを作りすぎており、またCH3CNは少なすぎる• 前者はCH4とNH3のphotodissociationからCH3,NH2ラジカルを生成するプロセスでoverproduceしているのかも• さらなるモデリング&実験室実験が必要• ALMAでCH3NH2の観測をするべき=>W33Aなら1時間程度で受かるA long-lasting quiescence phase of the eruptive variable V1118 Ori
D. Lorenzetti et al.

• EXorタイプの変光星V1118Oriの静的フェーズにおける長期サンプリ
ング(~8年)の可視赤外のフォトメトリ観測– 16 –• 静的フェーズでの星パラメータを導出• V1118Ori• 過去に5回ほどバースト• 静的フェーズでの観測は無い• 観測• NIR imaging• 1.1m AZT24m望遠鏡• Optical spectroscopy• 8.4m LBT (R=2000)と3.6m TNG (R=700)• NIR spectroscopy• 3.6m TNG (R=500)

NIRの測光結果

Fig. 1.— JHK light-curves of V1118 Ori. In the lower panel (J band) data points corresponding to the highest flux levels are depicted in red, while in blue those typical of a morequiescent state.

観測期間中Jバンドでわずかな増光

輝線強度から降着率を算出
中バースト時で降着率↑
ルミノシティも増大している– 18 –

Fig. 5.— Mass accretion rate determinations computed from the flux of the indicated tracers
using Alcalá et al. (2014) relationships, by assuming a visual extinction AV = 1 (blue circles)
and AV = 2 (red squares). The median Ṁacc values are marked for both cases with a solidline.

• Av=1~2くらい• 中バースト時は明らかに異なった分布•

extinction rawに垂直な方向の移動=>Avの変化ではない• additionalなcomponentの可能性? [Lorenzetti+2012]• 連続波と輝線線幅の関係を調べた•

連続波と輝線強度の相関性はすでに見つかっている•

過去のデータをコンパイル• 連続波と線幅に反相関(特にoptical)

Fig. 6.— EW of optical (upper panels) and IR (lower panels) HI recombination lines as afunction of the underlying continuum expressed in magnitudes. To avoid a possible confusion, the EW values are labelled (in the y-axis) with a positive sign, although they areconventionallyaccretion
negative for emission
lines, as reported in Tables 3 and 4.
drivenな増光現象••

連続波と輝線でcooling/heatingプロセスが異なり、連続波の方が早く変動している