星形成ゼミ
The Star Formation Newsletter 339
1~7

徳田一起 (大阪府立大学/NAOJ)

33

Complex structure of a proto-brown dwarf

34

New mid-infrared imaging constraints on companions and protoplanetary disks
around six young stars

35

Undetected Binaries Cause an Observed Mass Dependent Age Gradient in Upper
Scorpius

36

OH mid-infrared emission as a diagnostic of H2O UV photodissociation
I. Model and application to the HH 211 shock

37

Carbon Chain Chemistry in Hot-Core Regions around Three Massive Young
Stellar Objects Associated with 6.7 GHz Methanol Masers

38

Chemical modeling of the complex organic molecules in the extended region
around Sagittarius B2

39

The Anatomy of an Unusual Edge-on Protoplanetary Disk I. Dust Settling in a
Cold Disk

40

Description of turbulent dynamics in the interstellar medium:
multifractal/microcanonical analysis I. Application to Herschel observations of
the Musca filament33(1)
アブストラクト
観測: ALMA 12CO, 13CO, C18O (2-1) + 連続波 分解能は大体1.”4 (= 200 au)
天体 ISO-OPH 200 (へびつかい座 距離 d~144 pc, L_bol~0.08 Lo, L_int ~0.06 Lo)
理論計算: 分子雲コア=>褐色矮星の物理/化学モデリング (Machida+09の改良版)~6000 yrモデル (+inclination ~30deg)が、観測の特徴をよく再現- C18O: 内側の~500 auのpseudo-disc

観測されたC18O
Mom0とMom1

モデル
観測

PD
=>Pseudo-disc

コントア;モデルモデル

33(2)- 13CO: 外側の~1000 auのエンベロープ/pseudo-discをトレースモデル
観測観測された13COのMoment0マップ(0,0)が原始星の位置
Best-fit モデル

OE: outer envelope
PD: Pseudo-disc
CW: outflow cavity wall

33(3)- 12CO: ~1000 au程度のoutflowとshock のノット
12COモデル
12CO観測観測された12COのMoment0マップ(0,0)が原始星の位置

両方ともBlue側は見えていない(隠されて見えていないだけ?非対称outflowの可能性も棄却できない)

Best-fit モデル

まとめ-モデルとの比較より：Class-Flatと思われてたが、outflowがpole-onっぽくてもっと若い-proto-brown dwarfの観測された複雑な構造の解釈を与える (要はviewing angleのせい？)-この天体はきっとClass 0の段階に近い, 褐色矮星矮星が分子雲コアの収縮で生まれる

メモ: 中心星の質量は求めたかったようだが無理だったようだ

34 New Mid-Infrared Imaging Constraints on Companions and Protoplanetary Disks aroundsix Young Stars

D. J. M. Petit dit de la Roche, N. Oberg, M. E. van den Ancker, I. Kamp, R. van Boekel, D. Fedele, V.
D. Ivanov, M. Kasper, H. U. Käufl, M. Kissler-Patig, P. A. Miles-Páez, E. Pantin, S. P. Quanz, Ch. Rab,
R. Siebenmorgen, L. B. F. M. Waters F Mid-infrared imaging traces the sub-micron and micron sized dust grains in
protoplanetary disks and it oﬀers constraints on the geometrical properties of the disks and potential companions, particularly
if those companions have circumplanetary disks. We use the VISIR instrument and its upgrade NEAR on the VLT to takenew mid-infrared images of five (pre-)transition disks and one circumstellar disk with proposed planets and obtain the deepest
resolved mid-infrared observations to date in order to put new constraints on the sizes of the emitting regions of the disks andthe presence of possible companions. We derotate and stack the data to find the disk properties. Where available we compare
the data to ProDiMo (Protoplanetary Disk Model) radiation thermo-chemical models to achieve a deeper understanding of theunderlying physical processes within the disks. We apply the circularised PSF subtraction method to find upper limits on thefluxes of possible companions and model companions with circumplanetary disks. We resolve three of the six disks and calculate
position angles, inclinations and (upper limits to) sizes of emission regions in the disks, improving upper limits on two of theunresolved disks. In all cases the majority of the mid-IR emission comes from small inner disks or the hot inner rims of outerdisks. We refine the existing ProDiMo HD 100546 model SED fit in the mid-IR by increasing the PAH abundance relative to theISM, adopting coronene as the representative PAH, and increase the outer cavity radius to 22.3 AU. We produce flux estimatesfor putative planetary-mass companions and circumplanetary disks, ruling out the presence of planetary-mass companions with
L > 0.0028L for a > 180 AU in the HD 100546 system. Upper limits of 0.5 mJy-30 mJy are obtained at 8 µm-12 µm forpotential companions in the diﬀerent disks.

Undetected Binary Stars Cause an Observed Mass Dependent Age Gradient in Upper
Scorpius

Kendall Sullivan, Adam Kraus F Young stellar associations represent a key site for the study of star formation, but toaccurately compare observations to models of stellar evolution, the age of an association must be determined. The Upper
Scorpius region is the youngest section of the Scorpius-Centaurus OB association, which is the largest collection of nearby,
young, low-mass stars. The true age of Upper Scorpius is not clear, and an observed mass-dependent age gradient in Upper
Scorpius, as well as in other star-forming regions, complicates age measurements. The age gradient may indicate a genuine
astrophysical feature or may be an artifact of unrecognized systematic eﬀects in stellar age measurements. We have conducted
a synthetic red-optical low-resolution spectroscopic survey of a simulated analog to the Upper Scorpius star-forming region toinvestigate the eﬀects of unresolved binary stars (which have mass-dependent demographics) on age measurements of a stellar
population. We find that the observed mass-dependent age gradient in Upper Scorpius can be explained by a population of
undetected binary stars. For a simulated population with an age of 10 (RMS = 2) Myr, we measure an age of 10.5 (RMS =3.5) Myr for F stars, and 7.5 (RMS = 5.8) Myr for M stars. This discrepancy is caused by the mass-dependent mass ratio
distribution and the variable steepness of the mass-luminosity relation. Our results support the previously suggested 10 Myr
age for Upper Scorpius, with a small intrinsic age spread.

35 Undetected Binary Stars Cause an Observed Mass Dependent Age Gradient in Upper
Scorpius

Kendall Sullivan, Adam Kraus F Young stellar associations represent a key site for the study of star formation, but toaccurately compare observations to models of stellar evolution, the age of an association must be determined. The Upper
Scorpius region is the youngest section of the Scorpius-Centaurus OB association, which is the largest collection of nearby,
young, low-mass stars. The true age of Upper Scorpius is not clear, and an observed mass-dependent age gradient in Upper
Scorpius, as well as in other star-forming regions, complicates age measurements. The age gradient may indicate a genuine
astrophysical feature or may be an artifact of unrecognized systematic eﬀects in stellar age measurements. We have conducted
a synthetic red-optical low-resolution spectroscopic survey of a simulated analog to the Upper Scorpius star-forming region toinvestigate the eﬀects of unresolved binary stars (which have mass-dependent demographics) on age measurements of a stellar
population. We find that the observed mass-dependent age gradient in Upper Scorpius can be explained by a population of
undetected binary stars. For a simulated population with an age of 10 (RMS = 2) Myr, we measure an age of 10.5 (RMS =3.5) Myr for F stars, and 7.5 (RMS = 5.8) Myr for M stars. This discrepancy is caused by the mass-dependent mass ratio
distribution and the variable steepness of the mass-luminosity relation. Our results support the previously suggested 10 Myr
age for Upper Scorpius, with a small intrinsic age spread.

OH mid-infrared emission as a diagnosticof H2 O UV photodissociation.
I. Model and
観測される星形成領域(Upper
Sco)の若い星のAge
gradient はリアルなのか？
application to the HH 211 shockBenoît Tabone, Marc C. van Hemert, Ewine F. van Dishoeck, John H. Black F Water is an important molecule in
分解されていない連星で説明できる

interstellar and circumstellar environments. Previous observations of mid-infrared rotational lines of OH suggest that these lines
may be used to probe the photodissociation of water. In this work, cross sections for the photodissociation of H2 O resolving thestate of the OH fragment are collected and incorporated in a new molecular excitation code called GROSBETA, which includes
radiative pumping, collisional (de)excitation, and prompt emission (i.e., following the production of OH in excited states). We
find that the OH rotational line intensities in the range 9-16µm, covering rotational transitions with Nup = 18 to 45, areproportional to the column density of H2 O photodissociated per second by photons in the range 114-143nm and do not dependon other local properties. Provided an independent measurement of the column density of water is available, the strength ofthe local UV radiation field can be deduced with good accuracy. In contrast, the OH lines at longer far-infrared wavelengths

やったこと： 赤外線の擬似観測
10 (RMS = 2) 年の星の集団を観測、F星の年齢は10.5 (RMS = 3.5) 年、M型星の年齢は7.5 (RMS = 5.8) 年となった。
今回の結果は、Upper Scoの年齢が10Myrであることを支持するものであり、固12有の年齢の広がりは小さい。

35(1)

用意する星の質量分布

平均
連星間距離 標準偏差

連星間の質量比
1Moで1になり、軽いほど質量比が大きい星の年齢は10Myr (平均) で分散 2 Myrをinput
PHEONIX と呼ばれる(Husser+13)というコードを用いてスペクトルを計算
これを大体>1."5 (210au at 140 pcの距離)の分解能で観測35(2)

距離は正しくした

Single-star でAvなし

Single-star でAvあり全部入れたのBinaryを入れたものは明らかにAge spread がある

距離正しい

距離正しくない(Gaia 時代以前の精度)

この研究の示唆: 年齢を5-10 Myrで精度で求めるならbinary の存在を考慮(もちろん距離はちゃんと考慮に入れる)
この研究で考えていない物理: 星の磁場

36

OH mid-infrared emission as a diagnostic of H2 O UV photodissociation. I. Model andapplication to the HH 211 shockBenoît Tabone, Marc C. van Hemert, Ewine F. van Dishoeck, John H. Black F Water is an important molecule ininterstellar and circumstellar environments. Previous observations of mid-infrared rotational lines of OH suggest that these lines
may be used to probe the photodissociation of water. In this work, cross sections for the photodissociation of H2 O resolving thestate of the OH fragment are collected and incorporated in a new molecular excitation code called GROSBETA, which includes
radiative pumping, collisional (de)excitation, and prompt emission (i.e., following the production of OH in excited states). We
find that the OH rotational line intensities in the range 9-16µm, covering rotational transitions with Nup = 18 to 45, areproportional to the column density of H2 O photodissociated per second by photons in the range 114-143nm and do not dependon other local properties. Provided an independent measurement of the column density of water is available, the strength ofthe local UV radiation field can be deduced with good accuracy. In contrast, the OH lines at longer far-infrared wavelengths
are primarily produced by IR radiative pumping and collisions. Our model successfully reproduces the OH mid-IR lines in
the 10 16µm range observed by Spitzer toward the tip of the HH 211 bow-shock and shows that the jet shock irradiates its
surroundings, exposing H2 O to a UV photon flux that is about 12
5 ⇥ 103 times larger than the standard interstellar radiation field.
We also find that chemical pumping by the reaction H2 + O may supplement the excitation of lines in the range 16 30µm.
The mid-infrared lines of OH constitute a powerful diagnostic for inferring the photodissociation rate of water and thus the UV
field water is exposed to. Future JWST-MIRI observations will be able to map the photodestruction rate of H2 O in various
dense and irradiated environments and provide robust estimates of the local UV radiation field.

Carbon Chain Chemistry in Hot-Core Regions around Three Massive Young Stellar
Objects Associated with 6.7 GHz Methanol Masers

Kotomi Taniguchi, Eric Herbst, Liton Majumdar, Paola Caselli, Jonathan C. Tan, Zhi-Yun Li, Tomomi Shimoikura, Kazuhito Dobashi, Fumitaka Nakamura, Masao Saito F We have carried out observations of CCH (N = 1 0),
CH3 CN (J = 5 4), and three 13 C isotopologues of HC3 N (J = 10 9) toward three massive young stellar objects (MYSOs),
G12.89+0.49, G16.86–2.16, and G28.28–0.36, with the Nobeyama 45-m radio telescope. Combined with previous results on
HC5 N, the column density ratios of N (CCH)/N (HC5 N), hereafter the CCH/HC5 N ratios, in the MYSOs are derived to be⇠ 15. This value is lower than that in a low-mass warm carbon chain chemistry (WCCC) source by more than one orderof magnitude. We compare the observed CCH/HC5 N ratios with hot-core model calculations (Taniguchi et al. 2019). The
observed ratios in the MYSOs can be best reproduced by models when the gas temperature is ⇠ 85 K, which is higher thanin L1527, a low-mass WCCC source (⇠ 35 K). These results suggest that carbon-chain molecules detected around the MYSOs
exist at least partially in higher temperature regions than those in low-mass WCCC sources. There is no significant diﬀerence incolumn density among the three 13 C isotopologues of HC3 N in G12.89+0.49 and G16.86-2.16, while HCC13 CN is more abundant
than the others in G28.28–0.36. We discuss carbon-chain chemistry around the three MYSOs based on the CCH/HC5 N ratio
and the 13 C isotopic fractionation of HC3 N.

Chemical modeling of the complex organic molecules in the extended region around
Sagittarius B2

Carbon Chain Chemistry in Hot-Core Regions around Three Massive Young Stellar
Objects Associated with 6.7 GHz Methanol Masers

37 Kotomi Taniguchi, Eric Herbst, Liton Majumdar, Paola Caselli, Jonathan C. Tan, Zhi-Yun Li, Tomomi Shi-moikura, Kazuhito Dobashi, Fumitaka Nakamura, Masao Saito F We have carried out observations of CCH (N = 1 0),
CH3 CN (J = 5 4), and three 13 C isotopologues of HC3 N (J = 10 9) toward three massive young stellar objects (MYSOs),
G12.89+0.49, G16.86–2.16, and G28.28–0.36, with the Nobeyama 45-m radio telescope. Combined with previous results on
HC5 N, the column density ratios of N (CCH)/N (HC5 N), hereafter the CCH/HC5 N ratios, in the MYSOs are derived to be⇠ 15. This value is lower than that in a low-mass warm carbon chain chemistry (WCCC) source by more than one orderof magnitude. We compare the observed CCH/HC5 N ratios with hot-core model calculations (Taniguchi et al. 2019). The
observed ratios in the MYSOs can be best reproduced by models when the gas temperature is ⇠ 85 K, which is higher thanin L1527, a low-mass WCCC source (⇠ 35 K). These results suggest that carbon-chain molecules detected around the MYSOs
exist at least partially in higher temperature regions than those in low-mass WCCC sources. There is no significant diﬀerence incolumn density among the three 13 C isotopologues of HC3 N in G12.89+0.49 and G16.86-2.16, while HCC13 CN is more abundant
than the others in G28.28–0.36. We discuss carbon-chain chemistry around the three MYSOs based on the CCH/HC5 N ratio
and the 13 C isotopic fractionation of HC3 N.

野辺山45m望遠鏡による
Chemical modeling of the complex organic molecules in the extended region around
Sagittarius B2
3つの大質量星原始星の観測
G12.89+0.49, G16.86-2.16, G28.28-0.36
Yao Wang, Fujun Du, Dmitry Semenov, Hongchi Wang, Juan Li F The chemical diﬀerentiation of seven COMs in the
decli<-21deg,
距離が3kpc以内,
CH3CNがそこそこ強い
extended region around
Sgr B2 has been observed: CH
OHCHO, CH OCHO, t-HCOOH, Cat
H MopraOH, and CH NH were detectedboth in the extended region and near the hot cores Sgr B2(N) and Sgr B2(M), while CH OCH and C H CN were only detected
6.7
near GHzのメタノールメーザーが付随している
the hot cores. The density and temperature in the extended region are relatively low. Diﬀerent desorption mechanisms
2

3

2

3

5

3

3

2

2

5

have been proposed to explain the observed COMs in cold regions but fail to explain the deficiency of CH3 OCH3 and C2 H5 CN.
We explored under what physical conditions the chemical simulations can fit the observations and explain the diﬀerent spatial
distribution of these species. We used the Monte Carlo method to perform a detailed parameter space study. We investigated
how diﬀerent mechanisms aﬀect the results. All gas-grain chemical models based on static physics cannot fit the observations.
The results based on evolving physical conditions can fit six COMs when T ⇠ 30 60 K, but the best-fit temperature is still
higher than the observed dust temperature of 20 K. The best agreement at T ⇠ 27 K is achieved by considering a short-duration⇠ 102 yr X-ray burst with ⇣CR = 1.3 ⇥ 10 13 s 1 when the temperature is 20 K. The reactive desorption is the key mechanism
for producing these COMs and inducing the low abundances of CH3 OCH3 and C2 H5 CN. The evolution of the extended region
around Sgr B2 may have begun with a cold, T  10 K phase followed by a warm-up phase. When its temperature reachedT ⇠ 20 K, an X-ray flare from Sgr A* with a short duration of no more than 100 years was acquired, aﬀecting strongly the Sgr
B2 chemistry. The observed COMs retain their observed abundances only several hundred years after such a flare, which could
imply that such short-term X-ray flares occur relatively often.

観測輝線: CCH, CH3CN, HC3Nの13C同位体種
過去に得られていたデータ: HC5N
CCH/HC5Nの柱密度比 ~ 15 =>小質量星WCCCソースよりも1桁以上小さい
アバンダンスを説明しようとすると、85 K必要 (L1527の35 Kより高い)
大質量星原始星周りの炭素鎖分子は温度が高い領域にある

13C同位体種の差はない: G12.89+0.49, G16.86-2.16
The Anatomy of an Unusual Edge-on Protoplanetary Disk I. Dust Settling in a Cold
Disk
HCC13CNはG28.28-0.36で多かった

and the 13 C isotopic fractionation of HC3 N.

38 Chemical modeling of the complex organic molecules in the extended region around
Sagittarius B2

Yao Wang, Fujun Du, Dmitry Semenov, Hongchi Wang, Juan Li F The chemical diﬀerentiation of seven COMs in theextended region around Sgr B2 has been observed: CH2 OHCHO, CH3 OCHO, t-HCOOH, C2 H5 OH, and CH3 NH2 were detectedboth in the extended region and near the hot cores Sgr B2(N) and Sgr B2(M), while CH3 OCH3 and C2 H5 CN were only detected
near the hot cores. The density and temperature in the extended region are relatively low. Diﬀerent desorption mechanisms
have been proposed to explain the observed COMs in cold regions but fail to explain the deficiency of CH3 OCH3 and C2 H5 CN.
We explored under what physical conditions the chemical simulations can fit the observations and explain the diﬀerent spatial
distribution of these species. We used the Monte Carlo method to perform a detailed parameter space study. We investigated
how diﬀerent mechanisms aﬀect the results. All gas-grain chemical models based on static physics cannot fit the observations.
The results based on evolving physical conditions can fit six COMs when T ⇠ 30 60 K, but the best-fit temperature is still
higher than the observed dust temperature of 20 K. The best agreement at T ⇠ 27 K is achieved by considering a short-duration⇠ 102 yr X-ray burst with ⇣CR = 1.3 ⇥ 10 13 s 1 when the temperature is 20 K. The reactive desorption is the key mechanism
for producing these COMs and inducing the low abundances of CH3 OCH3 and C2 H5 CN. The evolution of the extended region
around Sgr B2 may have begun with a cold, T  10 K phase followed by a warm-up phase. When its temperature reachedT ⇠ 20 K, an X-ray flare from Sgr A* with a short duration of no more than 100 years was acquired, aﬀecting strongly the Sgr
B2 chemistry. The observed COMs retain their observed abundances only several hundred years after such a flare, which could
imply that such short-term X-ray flares occur relatively often.

The
Anatomy of an Unusual Edge-on Protoplanetary Disk I. Dust Settling in a Cold
Sgr
B2の有機分子をモデリングする
Disk
広がった領域+ホットコアで見える分子:
CH2OHCHO, CH3OCHO, t-HCOOH, C2H5OH, and CH3NH2
S. Wolﬀ, G. Duchêne, K. Stapelfeldt, F. Ménard, C. Flores, D. Padgett, C. Pinte, M. Villenave, G. van der
ホットコア,
Sgr B2(N)とSgr
B2(M)のみで検出される
andandC2H5CN
Plas, M. Perrin
F As the earliest
stage of planet formation, 分子:
massive,CH3OCH3
optically thick,gas rich protoplanetary disks

provide key insights into the physics of star and planet formation. When viewed edge-on, high resolution images oﬀer a unique
opportunity to study both the radial and vertical structures of these disks and relate this to vertical settling, radial drift,
これらのうちどちらかというと広がった領域に興味がある
grain growth, and changes in the midplane temperatures. In this work, we present multi-epoch HST and Keck scattered lightimages, and an ALMA 1.3 mm continuum map for the remarkably flat edge-on protoplanetary disk SSTC2DJ163131.2-242627,
a young solar-type star in ⇢ Ophiuchus. We model the 0.8 µm and 1.3 mm images in separate MCMC runs to investigate the
結論:
10K以下のcold
phase
warmradiativeup phaseがあった。
geometryand dust propertiesof the から始まり=>
disk using the MCFOSTtransfer code. In scattered light, we are sensitive to thesmallerdust
grainsinthesurfacelayers
of
the
disk,
while
the
sub-millimeter
dust continuum observations probe larger grains
Sgr B2の温度が約20Kに達したとき、ブラックホールSgr A*からの<100年の長さのX線フレアが発
closer to the disk midplane. An MCMC run combining both datasets using a covariance-based log-likelihood estimation was
生し、SgrB2の化学反応に強い影響を与えた。
marginally successful, implying insuﬃcient complexity in our disk model. The disk is well characterized by a flared disk model
SgrwithB2で観測されたCOMsは、このフレアから数百年以下しか観測された組成を維持していること
an exponentially tapered outer edge viewed nearly edge-on, though some degree of dust settling is required to reproduceから、このような短時間のX線フレアは比較的頻繁に起きている？Sgr A*の降着活動と関連か？
13

39(1)
観測天体: 2MASS J16313124-2426281 (hereafter Oph163131)のHSTのmulti-epoch (F475W, F606W, F814W), Keck 2.2μm+ ALMA の連続波(Band 6,7)の観測
・天体についてDunham+08がρOph領域 (d~147 pc)見つけたが、高密度領域にはいない天体
Evans+09では赤外の超過を見つけたのでYSOと同定=>赤外や可視光ですごく弱いということは、edge-onの天体である

HST散乱光の図観測
1回目:2012/3/4
ACS/F606W
ACS/F814W
2回目:2013/10/3
WFC3/F475W
WFC2/814W

2回目

1回目

39(2)

F814同士のMulti-epochでの差
Top/bottom Flux Ratio は3.3

カラー: HST F814 ACS
コントア: ALMA 1.3 mm

2.2μmだけプロファイルの凹
み方が違う=>mid-planeに近いlarge grain を捉えている？

39(3)

0."23 x 0."13
3章以降で輻射輸送モデルを行う (詳細は飛ばします)
星のパラメータ: K3.5-K5.5 spectral type, 4500 K, 0.96 Lo, 1.7 Ro, 1.0 Mo
結論・ダストの沈殿のある
比較的フラットなdisk
・ALMAと散乱光両方を合わせこんだfitはmarginal
success =>より複雑なdiskの構造の存在を示唆)residual radial substructures all point to a more complex radial density profile to be probed with future, higher resolution
observations.

40

Description of turbulent dynamics in the interstellar medium: multifractal/microcanonicalanalysis I. Application to Herschel observations of the Musca filament
H. Yahia, N. Schneider, S. Bontemps, L. Bonne, G. Attuel, S. Dib, V. Ossenkopf, A. Turiel, A. Zebadua, D.
Elia, S. K. Maji, F. G. Schmitt, J. -F Robitaille F Observations of the interstellar medium (ISM) show a complex densityand velocity structure which is in part attributed to turbulence. We here present a self-contained introduction to the multifractal
formalism in a microcanonical version which allows us for the first time to compute precise turbulence characteristic parametersfrom a single observational map without the need for averages in a grand ensemble of statistical observables. We focus on
studying the 250 mu-m Herschel map of the Musca filament and make use of MHD simulations. We find a clear signature of amultiplicative cascade in Musca with an inertial range from 0.05 to 0.65 pc. We show that the proposed microcanonical approachprovides singularity spectra which are truly scale invariant as required to validate any method to analyze multifractality. The
obtained, for the first time precise enough, singularity spectrum of Musca is clearly not as symmetric as usually observed in
log-normal behavior. We claim that the ISM towards Musca features more a log-Poisson shape of its singularity spectrum.
Since log-Poisson behavior is claimed to exist when dissipation is stronger for rare events in turbulent flows in contrast to morehomogeneous (in volume and time) dissipation events, we suggest that this deviation from log-normality could trace enhanced
dissipation in rare events at small scales, which may explain or is at least consistent with the dominant filamentary structurein Musca. Moreover we find that sub-regions in Musca tends to show diﬀerent multifractal properties. It strongly suggests that
diﬀerent types of dynamics exist inside the Musca cloud. These diﬀerences between sub-regions appear only after eliminating
noise features which have the tendency to "log-normalize" an observational map. Our study sets up fundamental tools which
will be applied to other galactic clouds and simulations in forthcoming studies.