星形成ゼミ資料
Dec.8, 2017 古屋玲（徳島⼤学・教養教育院）

THE FLUXCOMPENSATOR: MAKING RADIATIVE TRANSFER MODELS OF HYDRODYNAMICALSIMULATIONS DIRECTLY COMPARABLE TO REAL OBSERVATIONS
Christine M. Koepferl1,2 and Thomas P. Robitaille1,3

1 Max Planck
Christine
M.for
Koepferland Thomas
P. RobitailleInstitute
Astronomy,Königstuhl
17, D-69117 Heidelberg, Germany現実的なシュミレーション
2 University Observatory Munich, Scheinerstr. 1, D-81679 Munich, Germany

Section2.1
3

radiative transfer codese. g. HYPERION

density

Simulation
AnalyticalModels
INPUT
e. g. SPH (Daleet al. 2014)(Received 22nd June 2017;
Accepted
14th August 2017)

The Astrophysical Journal

OUTPUT

multi-wavelength images

flux

1-d spectrum

3-d flux array (position, position, wavelength)
1-d wavelength vector

1-d flux array1-d wavelength vector
ABSTRACT• 任意のビーム(PSF)
When modeling astronomical objects
throughout
theuniverse,itisimportanttocorrectly
treat theSyntheticCube
SyntheticImage
SyntheticSED
SyntheticFlux
Section 2.3
limitations of the data, for instance finite resolution and sensitivity. In order to simulate thesee↵ects,を畳み込み積分wav dim flux dim
wav dim flux dim
wav dim flux dim
wav dim flux dim
and to make radiative transfer models directly comparable to real observations, we have• developed
主な観測装置の透過
main methods
an open-source Python
package called the FluxCompensator that enables the post-processing of
曲線も畳み込める
extinction
the output of 3-d Monte-Carloradiative transfer codes, such as Hyperion. With the FluxCompenSection 2.3.1• ⼤気の透過曲線を畳
sator, realistic synthetic observations can be generated by modeling the e↵ects of convolution
with
idea
idea
l ord
l ord resolution, noise and redarbitrary point-spread-functions(PSFs), transmission
curves,finite
pixel
er o
er o
f
filter
m
み込み積分
f me
e
othe
o
t
h
t
h
thod
o
e
ds
r
r
o
o
s
r
rder
der
Section
2.3.2
poss
poss
dening. Pipelines can be applied to compute synthetic
observations that simulate
observatories, suchible
i bl e
有限サイズのピクセ
pixel resolution
as the Spitzer Space
Telescope or the Herschel Space Observatory. Additionally, this tool •canread in
Section 2.3.3
ルサイズでなまされ
existing observations (e. g. FITS format) and use the same settings for the synthetic observations.
In
PSF convolution
this paper, we describe
the package as well as present examples of such synthetic observations.
た画像を出⼒Section 2.3.4

noise
Section 2.3.5

CompactPipeline & Interface2FITS(e.g. HIGAL_PACS1) Section 2.4

1D

FLUXCOMPENSATOR

observing device (telescope, detector, etc.)

をさらに現実的なものにするためのPythonパッケージを開発した. 今回の実装は,Section 2.2

Freelance Consultant, Headingley Enterprise and Arts Centre, Bennett Road Headingley, Leeds LS6 3HN

interstellar/intergalactic
mediumastronomical object

2

1. INTRODUCTION
output methods

3D

0D

2D

1D

1D

0D

0D

• ガウシャンノイズや

jects but rather provides a genericset of geomeランダムノイズ付加
tries. Hyperion as other dust 機能も追加
radiative transfer
further methods
codes, treats all dust interactions, such as absorp• 星間⾚化補正もunit conversion
tion, re-emission
and scattering.
Hyperion is an
Section 2.6.1
GitHubで公開
LTE code, and, in addition, can• treat(simple) nonfilter plotting
LTE approximations,such as the emission of polySection 2.6.2
cyclic aromatic hydrocarbons (PAHs). It uses the
Lucy method, the modified random walk, peelingo↵ and raytracing.

Theoretical simulations background(e. g. hydrodynamical simulans) are currently used toSection
reproduce
the physical pro2.4
ses in astronomical objects,
fits filessuch as young stellar ob2.5
s (YSOs), star-formingSection
regions
and galaxies. Howfieldr, we cannot use thesestellar
simulations
directly to preSection 2.6.3 / 4t or explain observational features of such objects.
tead, full radiative transfer
calculations need to bedimension method
formed to properly takecollapse
into account e↵ects, such as
Sectionor
2.5 changes in the opticalal temperature variations• MOCASSIN
etc. calculations provide ideth. These radiative transfer
Mocassin, a 3-d photoionization and dust noned observations,which
somewhatcloserto real ob- input/output structure
Fig. 1.— Flow schemeof thearerelevant
Hyperion and
FluxCompensatorand the analogy in reality. The relevant
LTE
Monte-Carlo radiative transfer code (for desectionsthan
are highlighted
within the scheme.
vations
the hydrodynamical
simulations. In theシュミレーション出⼒

FluxCompensator
PACSThe70mic透過曲線を畳み込み

⾚化補正

5

今後の開発計画は,• PSFの波⻑依存性も実装したい。
• ユーザーが指定した装置でのノイズレベ
ル評価機能など(ソースとの分離⼯程も含めるの意味か？)• 検出器がサチッたバ
ンドにも対応させる。
• Gas-radiativetransfer postprocessing (何のことかよくわからなかった)• ⼲渉計の空間フィル
ター機能をCASAとの連携で実装
PACS 70mic PSFを畳み込み
PACS 70 mic のpixel sizeでなまして、ノイズ付加• astropyのaﬃliatedFig. 3.— Snapshots during the ongoing pipeline: a) Hyperion output image slice closest to = 70 µm, b) image after convolution withACS 70 µm transmission curve, c) PACS 70 µm image after reddening, d) PACS 70 µm image with corresponding pixel resolution, e) PACS
package群に加えた
0 µm image after PACS PSF convolution, f) PACS 70 µm with Gaussian noise.
い。
he synthetic image, where Figure 3(a) was weighted
tion of energy. See Table 2 in Appendix A for ↵ andwith a PACS 70 µm filter from the FluxCompensator
atabase. The database currently has 24 transmision curves from Two Micron All-Sky Survey (2MASS),

values of the filters in the database and their references.
To weight the synthetic data with the spectral transmission, the FluxCompensator calculates the e↵ec-

INSIGHTS FROM SYNTHETIC STAR-FORMING REGIONS:
I. RELIABLE MOCK OBSERVATIONS FROM SPH SIMULATIONS
Christine M. Koepferl1,2 , Thomas P. Robitaille1,3 , James E. Dale4 , and Francesco Biscani1
1 Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany

2 Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St Andrews

星形成領域の流体⼒学シュミレーションの結果を「観測」(synthetic
observations)して、星形成現象をトレー
North Haugh, St Andrews, KY16 9SS, UK
3

Freelance Consultant, Headingley Enterprise and Arts Centre, Bennett Road Headingley, Leeds LS6 3HNスする探査針の選択次第では、観測から導かれる物理量に⼤きな差が⽣じうることを調べた。観測⽅法だけでな
4
University Observatory Munich, Scheinerstr. 1, D-81679 Munich, Germany

く、そこから導かれる物理量の較正を⾏うためには、できるかぎり現実的なシュミレーションとの⽐較も⽋かせ(Received 29 January 2016; Accepted 1 March 2016)
The Astrophysical Journal Supplement

ないことを⽰す。本論⽂(Paper I)では、”particle-based simulations ontoa Voronoi mesh”で求められた温度

ABSTRACTおよび密度分布が、輻射輸送の問題を解くにあたって、いかにふさわしいものであるかを述べたのち、その精度

Throughsynthetic observations of a hydrodynamical simulationof an evolving star-forming region,についても報告する。我々は、さらにより現実的なsynthetic
observationsを⾏うために、輻射輸送を解く際のwe assess how the choice of observational techniques a↵ects the measurements of properties which
問題設定の最適化も研究したので、⼿法の詳細と我々が推奨する⽅法についても述べる。ダストの輻射輸送計算
tracestar formation. Testing and calibrating observational measurements requires synthetic observations
which are as realistic as possible. In this part of the paper series (Papermicron付近の輻射流束はかなりI), we explore di↵erent
において、流体⼒学的に推定される温度を盲⽬的に適⽤してしまうと、波⻑20
techniques for how to map the distributions of densities and temperatures from the particle-based
課題評価してしまうこともわかった。そうではなく、背景光に等温ダストを仮定し、輻射加熱を解いたとき、
simulations
onto a Voronoi mesh suitable for radiative transfer and consequently explore their acsynthetic
curacy.
We observationsから再現されたフラックスは現実的な値を⽰すことがわかった。本論⽂では、Spitzer
further test di↵erent ways to set up the radiative transfer in order to produce realistic
synthetic
observations. We give a detailed description of all methods and ultimately
recommend techやHershel衛星の観測波⻑帯に焦点を当て、5800件に近い、「現実的なsynthetic
observations」をの結果を⽰
niques. We have found that the flux around 20 µm is strongly overestimated when blindly coupling
II, III,and IVでは、これらのシュミレーションにもとづき、星形成率(SFR),
ガス質量おtheす。引き続く、Paper
dust radiative transfer
temperature
with the hydrodynamical gas temperature. We find thatwheninstead assuming a constant background dust temperature in addition to the radiative transfer
よび星形成効率(SFE)について論じる計画である。
heating, therecovered flux is consistent with actual observations.
We present around 5800 realistic
Synthetic Star-forming Regions - I. Reliable Mock Observations from SPH Simulations
3
synthetic observations for Spitzer and Herschel bands, at di↵erent evolutionary time-steps, distances【左】WISE衛星による中間⾚外線画像
and orientations. In the upcoming
papers of this series (Paper
II, Paper III and Paper IV), we will
6pc
3pc
(Blue=3.4mic,
Cyanthe4.6star-formation
mic; Green 12 mic,
test and calibrate measurements of the star-formation rate (SFR),
gas mass andefficiency (SFE) using our realistic synthetic observations.
R=22 mic)
1. INTRODUCTION

the last decade, progress in the field of star forhas been fueled by an increasing number of large/optical surveys of our Galaxy (e. g. from space【右】SPHシュミレーションによる柱密度分布;（電離のみを考慮したフィードバック⼊り）
to testand calibrate techniques that are used by

the community to infer properties related to starformation. Since the intrinsic properties of the simulations (e. g. SFRs, gas masses, filament widths)
are known, the accuracy of the observational de-

Fig. 1.— (Left) MIR Wide-field Infrared Survey Explorer (WISE) observationa of the Soul Nebula star-forming region (blue: 3.4 µm,
cyan: 4.6 µm, green: 12 µm, red: 22 µm), (right) column density structure of a simulated star-forming region from the D14 smoothed
particle hydrodynamics (SPH) simulationsb with high-mass stellar feedback (ionization-only).
a Online references accessed: 30.08.2015; http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA13112
Courtesy NASA/JPL-Caltech/UCLA

温度

温度

密度

シュミレーション
エッジからの動径距離Fig. 2.— Temperature relation in density and radius of SPH particles and a 2-d projection showing the temperature increase at the edgesof the simulation at time-step 122 (6.109 Myr).

2.2.1. Method
c1 — Neutral
SPH Particles
which
lie withinfrom
ourSPHselectedbox of 30 pc width. 7 The
Synthetic
Star-forming
Regions in- I.Box
Reliable Mock
Observations
Simulations

While the D14 SPH simulations have high-mass stellar
feedback mechanisms implemented,
the simulations do
フィードバック
not take into account the dust heating from the stars.
In D14 SPH simulations, the external
heating throughを⼊れた時刻the di↵use Galactic radiation field is approximated by
the Larson (2005) EOS8 rather than just an isothermal
approximation. The EOS contains the following regimes(following Equation 1 and Figure 1 of Dale et al. 2012):• line cooling processesP ⇠ ⇢3/4(6)

8 ⇢ < 5.5 ⇥ 10 19 g cm 3

• dust cooling processesP ⇠ ⇢1.0(7)

red points are (partly or fully) ionized particles (c. f. with
Dale et al. 2012, 2007) within the box. The horizontal
フィードバックあり
line at 104 K shows all the fully ionized SPH particles.
The other red points are partly ionized and lie within theselected box. The black points are neutral SPH particles
in the selected box. The state of these neutral particles
is described by the EOS which is describing the dependency of density and temperature (diagonal line: Eq. 6,
Eq. 8, Eq. 9; horizontal: Eq. 7).
In this work, we will use a dust radiative transfer code,
therefore we will only use SPH particles in the box which
are completely neutral since dust gets destroyed during
the ionization process (Diaz-Miller et al. 1998). Hereafter, we call the clipping for size and only neutral SPH
particles, resulting in the black particles in Figure 2(a),method c1.

2.2.2. Method c2 — Neutral SPH Particles in Box &8 5.5 ⇥ 10
g cm < ⇢ < 5.5 ⇥ 10
g cm ,
Temperature Limit
Fig. 3.— Temperature histogram of neutral SPH particles for time-step 024 (3.576 Myr), 032 (4.768 Myr), 072 (5.364 Myr) and 122
19

3

15

3

neutral SPHの時間進化(右パネルへ）ごとのTの頻度分布(6.109 Myr). Feedback gets switched on after time-step 32. The sharp spikes In
at 7.5
K are 2(b),SPH particles
the that
isothermal
phase.temperature
Figurewe caninsee
the SPH

INSIGHTS FROM SYNTHETIC STAR-FORMING REGIONS:
II. VERIFYING DUST SURFACE DENSITY, DUST TEMPERATURE & GAS MASS MEASUREMENTS
WITH MODIFIED BLACKBODY FITTING
Christine M. Koepferl1,2 , Thomas P. Robitaille1,3 , and James E. Dale4
2

1 Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany

Scottish Universities
Physics Alliance (SUPA), School of Physics andobservations)を⾏い、実際の天体から導かれ
Astronomy, University of St Andrews
Paper Iで報告した,
SPH計算による膨⼤なデータの「観測」(synthetic
North Haugh, St Andrews, KY16 9SS, UK
3 Freelance Consultant, Headingley Enterprise and Arts Centre, Bennett Road Headingley, Leeds LS6 3HNる物理量が如何に観測⼿法に依存するかを評価した。本論⽂(Paper II)では、ハーシェル衛星による多波⻑データを画
4 University Observatory Munich, Scheinerstr. 1, D-81679 Munich, Germany
像ピクセルごとにSED ﬁttingする解析から得られる、ガスの全質量、ダスト熱輻射の⾯密度およびダスト温度の信頼(Received 29 January 2016; Accepted 23 June 2016)
The Astrophysical Journal性を論じる。我々の解析によると、画像ピクセルごとのSED解析から得られる、ダストの⾯密度およびダスト温度には、worrisomeな誤差が避けられない。この問題は、とりわけ、星形成領域に隣接する程密度領域で顕著であり、こABSTRACTのような領域では最⼤で３桁も過⼩もしくは課題評価する恐れがある。したがって、星形成が特に盛んな領域に対す
We use a large data-set of realistic synthetic observations (produced in Paper I) to assess how
observational techniques a↵ect the measurement physical properties of star-forming regions. In this
る、画像ピクセルごとのSED解析は慎重に⾏うべきである。銀河⾯によく⾒らえる柱密度の⾼い領域、とくに低質量星
part of the paper series (Paper II), we explore the reliability of the measured total gas mass, dust
形成領域については、遠⾚外線背景光をほとんど評価できないので、信頼できる柱密度推定は不可能であると結論せざ
surface density and dust temperature maps derived from modified blackbody fitting of synthetic
るをえない。moderate背景放射の場合、距離10kpcほどまでの領域ならば、10%ほどの精度で柱密度推定が可能でHerschel observations. We found from our pixel-by-pixel
analysis of the measured dust surface densityある。通常なされる多くの多波⻑データ解析では、もっとも空間分解能の悪い観測のビームサーズにすべてのデータ
and dust temperature a worrisome error spread especially close to star-formation sites and low-density
regions, where for those ”contaminated” pixels the surface densities can be under/over-estimated by up
セットをそろえることが多いが、この処理によって、空間分解能の良い観測データはピクセル内で情報が空間平均されto three orders of magnitude. In light of this, we recommend to treat the pixel-based results from thisてしまうので、この解析によってな発⽣する誤差を⾒積もることには、そもそも⼤きな困難がある。そこで、⼤質量星
technique with caution in regions with active star formation. In regions of high background typicalからのフィードバック機構が効くような領域について、適当なコントールサンプルをつくり、適当な誤差を与え、天体
in the inner Galactic plane, we are not able to recover reliable surface density maps of individual
synthetic regions, since low-mass regions are lost in the FIR background.
When measuring the total
観測と汎⽤解析が、理論計算をどれほど再現できるかを「観測」(synthetic
observations)した。

gas
mass ofregions in Regions
moderate- II.
background,
we find
thatMeasurements
modified blackbody
fitting works
well Fitting
Synthetic
Star-forming
Verifying Dust
& Gas
with Modified
Blackbody(absolute error: +9 %; 13 %)D１の２枚は距離3
up to 10 kpc distancewith distance).
ダスト⾯密度：SPH計算結果(左)kpc, (errors increase
右の２枚は距離10
kpc Commonly, theinitial images are convolved to the largest common beam-size, which smears contaminated pixels overlarge areas. The resulting information loss makes this commonly-used technique less verifiable as now
2-values cannot be used as a quality indicator of a fitted pixel. Our control measurements of the total
gas mass (without the step of convolution to the largest common beam size) produce similar results(absolute error: +20 %; 7 %) while having much lower median errors especially for the high-massstellar feedback phase. In upcoming papers (Paper III; Paper IV) of this series we test the reliabilityof measured star-formation rate with direct and indirect techniques.

5⻩⾊の星：降着中の原始星,
⻘で⽩抜きの星：電離ガスのバブル内の星;
⽩コントア：Chi^2>5 temperatures. U
Fig. 6.— Diagnostic
maps of measured and intrinsic
values for dust surface density, dust meandensities and dust
wo 対
rows for distance D1 at 3 kpc and lower two rows for distance D2 at 10 kpc. Yellow stars are the projected positions of young, acc
tars応while blue stars are stars inside the ionized bubble. 2 > 5-contours are plotted in white. Displayed is the result for versio
ersion R2 will be available as分⼦雲全体
online figure.
星形成サイト星形成サイトの周辺領域

f the transition from gas to stars and can be expressed

munity,hence for entire
galaxies,
assumecharacy the star-formation
efficiency(SFE) atanda certaintime
FROM
SYNTHETIC
STAR-FORMING REGIONS:
tic timescales of INSIGHTSt⇤ = 100 Myr(Kennicutt& Evans
III. CALIBRATIONOF MEASUREMENTTECHNIQUESOF STAR-FORMATION RATES; Murphyet al. 2011; Calzetti
et al. 2010; Rieke
et al.
M⇤ (t)
SFE(t) = have not yet. been
(1) suffi). These techniques
testedM⇤M.
(t) +Koepferl
Mgas (t) 1,2 , Thomas P. Robitaille1,3 , and James E. Dale4
Christine
ly for (smaller,
local) individual regions. Therefore, Synthetic Star-forming Regions - III. Calibration of Measurement Techniques of Star-formation Rates
5
1 Max
Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
Another
importantphysicalproperty
defininga instar2 Scottish
nalyzethereliabilityofthese
techniques
this secUniversities
Physics
Alliance(SUPA),
Schoolof Physics and Astronomy, University of St Andrews
ormingregion
is
the
rate
at
which
it
forms
stars.
The
North Haugh, St Andrews, KY16 9SS, UK
銀河研究で⽤いられているSFR
3 FreelanceverageSFR between
times t0Headingley
and t is definedas: and Arts Centre, Bennett Road Headingley, Leeds LS6 3HNConsultant,Enterprise
Figure 1, we plot
the intrinsic
instantaneous
SFR di4 University
Observatory Munich, Scheinerstr. 1, D-81679 Munich, Germanyy from the simulation
solid
curve),
we callM⇤ (t) M⇤(red(t0 )(ReceivedM⇤ (t)⇤ (twhich
0)29MJanuary
2016;
Accepted 8 March 2016)
SFR(t) ==, (2)t) from
wasAstrophysicalcalculated Journal
t t0now on, sincet⇤it The
sim ( t⇤ =the star-formation timescale t⇤ equal
to over
the timewhere t⇤ = t t0 is the characteristic
timescaleABSTRACT
of には、特徴的な時間尺度があり、これは
thet. There
To compare
it to
the meawhich
the simulation
SFR is measured.
exists a large
varietyextensive
set ofEachrealistic
synthetic
observations (produced in Paper I), we assess in thisdf Throughtechniques,whichcharacteristic
timescales
tracers
to anmeasurethe follow
SFR.
techniqueprobes
通常、δt*=
100
Myrが仮定される。
of100
the Myr,paper
series(Paper
III) howthechoiceof observational techniques a↵ects the measurementtarformation
withinaconvolve
certaincharacteristic
timescale
we
(see
Press
et
al. 1992)⇤art=tf⇤ ,star-formation
tracerto tracer.
can divide
⼀⽅、銀河スケールのSFRの計算にはlocal
rates
in Onestar-forming
regions. We test the accuracy of commonly used(whicht⇤ =variest)fromwitha (SFRs)
normalized
top-hatfunctionsimhedi↵erent
techniques
intotwo
categories:2
echniques
andconstructnewmethods
to extract
Bronstein
et al.
2005) ofwidth
100 Myr. Thethere-SFR, so that these findings can be applied toな星形成が考慮されることはほとんどない。
measurethe SFRin real regions
throughout
thehereafter
Milky Way. We investigate di↵use infrared SFR tracers
ng1.なので、あいだをつなぐ研究が必要。
convolved
function(red dashedcurve),
Indirect Techniquesuch ˆasthoseusing 24starsµm,ionize
70 µmtheandtotal infraredemission, which have been previously calibrated forYounghigh-massmaterialarounddlobal
SFR
(
t
=
100
Myr),
is
aroundthreeorderssimwithscales.
⇤ X-ray andgalaxyWe setup a toy(UV)
model
of a galaxyof
and show that the infrared emission is consistentthem
ultra-violet
radiation.
nitude
lower
since
t/
t
=
149
000
yr/100Myr⇡⇤ tracewith This
the intrinsic
SFR
using
extra-galactic
calibrated
laws (although the consistency does not prove
process canbe usedtostar formationin
観測的銀河研究で、SFRを推定するとき、Fig. 1.— Averaged
measured SFRs
with the techniques
SFR24, SFR70
and SFRIR using the total flux at 24 µm, 70 µm and the total
【上の図】
.
heir
reliability).
For local scales, we show that these techniques
producecompletely
unreliable
results
infrared flux, respectively, in comparison with the intrinsic SFR.
or 代表的な⽅法として、24mic,
single star-forming regions, which
are governedbydi↵erentcharacteristic
timescales.
70mic,
andfromthe simulation
averagedovera similar
timescale We
Weshowderive the total luminosity in the infrared under the
⾚は「δt*=
100
Myrの瞬間」ごとのintrinsicなSFR(計算値)、
ˆ
assumption
ow calibrationofthese
techniques
canbeimprovedforsinglestar-forming
regionsbyadjustingthe that our 7 bands from ⌫0 (IRAC 8 µm) to ⌫1
2.1. Method SFR24 — 24 µm Tracer
SFRsim ( t⇤ = 100 Myr). However, they should match if
total
IR光度から求めらることが多い。例え500 µm) cover most of the infrared emission. We
thetechniqueworked ofaccurately.
We provide the meaharacteristic timescale and the scaling factor and givesuggestions
new calibrationsof the (SPIRE
di↵use星印は背景光なしの場合、
integrate(using Simpson’s rule, see Bronstein et al. 2005,
sured
values
in
Table
1
of
AppendixA.
eke
et al. (2009)
empirically calibrated a SFR-totar-formation
tracers. We show that star-forming regions that are dominated by high-mass Press
stellar
et al. 1992) to calculate the flux density F⌫corr ( ):ば、24mic光度とのスケール則は、
nosity relationof 24a µm
emission:
Method SFR70 — 70 µm TracerZ⌫eedback
experience
rapid
drop in infrared emission下部の⾚い点線が銀河全体での換算値：通常観測されるSFR
once2.2.high-massstellar feedback is turned on,
1

Based on Spitzer data, Calzetti et al. (2010) empirL(IR) = d⌫F⌫corr ( )
(8)
which
impliesdi↵erentcharacteristic
timescales.
Moreover,we
explorethemeasuredSFRs
calculated
icallycalibrated
the
SFR
using
the
total
luminosityin
SFR24 µm ( t⇤ = 100 Myr)
43
42
1
⌫0
70
µm findabove ⌫L
1.4 ⇥ 10 ergspoints := 2.03⇥ 10population.
⇥(5)⌫ (70 µm)
irectly from the observed
youngstellarWe
thatthe measured
sources follow
1
M yrpace of star formation more directly thanWith the total infrared luminosity L(IR), we use Eq. 7
SFR
100 Myr)he evolutionarydi↵usestar-formation
tracers.(6)70 µm ( t⇤ == 5.88 ⇥ 10 44 ⇥to derive the SFRIR ( t⇤ = 100 Myr) for our set of syn1
M yr
⌫L⌫ (24 µm)
thetic observations. Again, in Figure 1 (right panel),⌫L⌫ (70 µm)⇥,
we compare the measurements (black) with the values
1
⇥
1 .
ergs
s
thethesimulations(red). Again the measurements
ergs s
1. INTRODUCTION
The measured star-formation
propertiesfrom
areobserwith combined background (black dots) are higher due
Notethat here
we will use PACS
70 µm to estimate
theand tovationalbenchmarkbetweenreality
Examthe complex
background. The o↵set is comparable
42
1
ar-forming
region,is transformed
h they foundto begasvalid
within 2.3 ⇥into
10 stars.
ergs s SFR
 70 µm ( t⇤ = 100 Myr) with Eq. 6 and again test the totheory.
thetechnique
SFR70 because Herschel bands withples ofincludegas mass
Mgas andSFR70
for properties
luminosities below
1039 ergsthes 1 . total
We show
e24dominating
mechanisms
and the im-we willhigh background have been used (see Paper II). For theµm)  5.0driving⇥ 1043 ergs
s 1 . Nevertheless,thein Figure1 (black
midtheresults
totalagain
stellarmass
M⇤symbols
in a instar-forming
region measurements(asbackground-free(black stars), the simuhe
stellararewithstill a total
hisdi↵erent
techniquefor feedback
syntheticmechanisms
observations
dle panel). We can see that the di↵erence between thelationspreadisagainlarger,which
is due to the MIR
summarized
Dalebackgroundet al. 2014).
The property whichmeasurementwith bycombined(black dots)
40 are di↵erent
1
nless
thethanfield, there
approaches
amongparts of the total infrared flux (see SFR24 and SFR70).
10 ergs s
to test whether the SFR24
andthe background-freemeasurements(black gas
stars)massisconnects
stellar
mass
and
total
is
the efficiency
Overall,
the technique SFRIR produces values of thers to addresstheseforquestions:
In the observathan for the method SFR24. This is again due
nique
can be usedsingle star-forming
regions. larger
SFR
(
t
IR
⇤ = 100 Myr) which are up to three orders ofof thethehightransition
gas toplanestars
tobackground fromof the Galactic(as andex- can be expressed
proach,thecharacteristic
observable
properties
ˆ sim ( t⇤ =magnitude higher than the simulated rate SFR
ing Eq. 5, we derive the SFR24 µm ( t⇤ = 100 Myr)plainedin PaperII) and a result ofefficiency
the non-uniform
back- at a certain timebythestar-formation(SFE)
100 Myr). We provide the measured values in Table 1 ofrming
are used
to study andcompareground during background correction. Again, similarly
ur set regionsof synthetic
observations
in MIPS
24 µm forAppendix A.
t:to what we found for the SFR24 technique, the mearegions in an attempt to disentangle the domi-に相当
縦の点線はmassive starのfeedbackを⼊れた時刻【結果】「δt* ごとの瞬間SFR」値と「通常観測されるSFR」の３桁のギャップ：「They should match if the technique worked
accurately.」としか説明ない。
３つのSFR推定法に顕著な差なし。

Fig. 2.— Instantaneous rate SFRsim ( t⇤ = t) from the simulation (red dots), rate convolved with di↵erent characteristic timescales t⇤(yellow to red) and the scaled measured emission (black stars). Numbers on top represent the time-step IDs and vertical lines highlightthe time-step of the simulations when feedback was switched on.

3.2. Calibration for Small Scales
the scaled emission a24 µm ⌫L⌫ (24 µm), a70 µm ⌫L⌫ (70 µm)【上の図から銀河研究へのレッスン】
or aIR ⌫L(IR) as a thick line. Our fitted parameters for
From
Section
2.1
toSection2.3,
weshowed1.（この程度の時間刻みでは）フィードバックは⼊れたら「すぐに効く」.
t⇤ and a are:that the measured values SFR24 µm ( t⇤ = 100 Myr),
2. フィードバック効果は、24
mic (or total IR)で顕著に⾒える。24micが有利なのは星形成をそこそこ良くトレース
SFR
70 µm ( t⇤ = 100 Myr) and SFRIR ( t⇤ = 100 Myr)
a24 µm = 7 ⇥ 10 45 t⇤ ⇡ 1.0 Myr
(26)
from
the techniques SFR24, SFR70 and SFRIR, respecしつつ、円盤部のISMにはあまり感度がないから(70
micは主にdisk ISM).

ˆ sim ( t⇤ =a70 µm = 3 ⇥ 10 45 t⇤ ⇡ 4.5 Myr(27)
tively, cannot reproduce the actual rate SFR
100 Myr) of the simulation on a size-scale of 30 pc. In【テキストのみでなされている議論】
aIR = 1 ⇥ 10 44 t⇤ ⇡ 0.3 Myr.
(28)
Section 3.1, we showed however that for global scales
分⼦雲コア-->原始星への進化でよくなされるシュミレーションの単純なアンサブルでは、銀河全体のSFRを再現でき
which are governed by timescales of 100 Myr, the techNevertheless, when inspecting Figure 2, one canない。逆に銀河研究でなされるセットアップでcloud程度のローカルSFを再現しようとそても失敗する。なので、銀河
niques work within the loose physical boundaries but resee that it is challenging to pin-down a characteristic
quire further investigation. In this section, we investigate
スケールのSFとローカルSFは別スケールの現象。
timescale, since for simulation time-steps where highwhether the SFR24, SFR70 and SFRIR techniques could
mass stellar feedback is present, the region is governed【古屋メモ＆感想】
be improved for smaller scale star-forming regions.
by di↵erent physical processes which also suppressrayは？
theとは⾔うもの、ローカルでおこるmassive SFのアンサブルである、フィードバック機構は明らかに銀河スケールの星形成を制御する要因のひとつになっている。磁場とcosmic
In Figure 1, we saw a mismatch of the measured prop-

なんてんthgis-fo-enil

FOREST Unbiased Galactic plane Imaging
survey with the Nobeyama 45-m telescope(FUGIN) : Molecular clouds toward W33 ;possible evidence for a cloud-cloud collision
triggering O star formation

arXiv:1706.07964v4 [astro-ph.GA] 25

1∗
1
MikitoKOHNO, Kazufumi
TORII2 ,Larger
Kengo
Publications of the Astronomical Societyof Japan,(2014), Vol.
00, No. 0
cloudTACHIHARA , Tomofumi
2,3
2,3
1

20

U MEMOTO , Tetsuhiro M INAMIDANI , Atsushi N ISHIMURA , Shinji F UJITA1 ,Mitsuhiro M ATSUO2 , Mitsuyoshi YAMAGISHI4 , Yuya T SUDA5 , Mika K URIKI6 ,Nario K UNO6 , Akio O HAMA1 , Yusuke H ATTORI1 , Hidetoshi S ANO1,7 , Hiroaki
YAMAMOTO1 and Yasuo F UKUI1,7v
1

Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601,
Smaller cloudJapan
2
Nobeyama Radio Observatory, National Astronomical Observatory of Japan (NAOJ),
National Institutes of Natural Sciences (NINS), 462-2, Nobeyama, Minamimaki, Minamisaku,
smaller than that in the larger cloud. Different color components in the collision schematics correspond to the different color on the
Nagano384-1305, Japan
Fig. 11. Schematic of a collision between two dissimilar clouds and cartoons position-velocity diagrams, where the gas density in3
Department of Astronomical Science, School of Physical Science, SOKENDAI (TheP
Graduate University for Advanced Studies), 2-21-1, Osawa, Mitaka, Tokyo 181-8588, Japan
4
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency,
Smaller cloud
Chuo-ku, Sagamihara 252-5210, Japan
5
Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino,
Tokyo 191-0042, Japanv
6
Department of Physics, Graduate School of Pure and Applied Sciences, University ofTsukuba, 1-1-1 Ten-nodai, tsukuba, Ibaraki 305-8577, Japan
7
Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya
Larger cloudV
464-8601, Japan

野辺⼭

Mikito KOHNO1 ∗ , Kazufumi TORII2 , Kengo TACHIHARA1 , Tomofumi
U MEMOTO 2,3 , Tetsuhiro M INAMIDANI2,3 , Atsushi N ISHIMURA1 , Shinji F UJITA1 ,Mitsuhiro M ATSUO2 , Mitsuyoshi YAMAGISHI4 , Yuya T SUDA5 , Mika K URIKI6 ,Nario K UNO6 , Akio O HAMA1 , Yusuke H ATTORI1 , Hidetoshi S ANO1,7 , Hiroaki
YAMAMOTO1 and Yasuo F UKUI1,7
1

Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601,
Japan
2
Nobeyama Radio Observatory, National Astronomical Observatory of Japan (NAOJ),
National Institutes of Natural Sciences (NINS), 462-2, Nobeyama, Minamimaki, Minamisaku,
Nagano 384-1305, Japan3
Department of Astronomical Science, School of Physical Science, SOKENDAI (The
Graduate University for Advanced Studies), 2-21-1, Osawa, Mitaka, Tokyo 181-8588, Japan
4
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency,
Chuo-ku, Sagamihara 252-5210, Japan
5
Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino,
Tokyo 191-0042, Japan
6
Department of Physics, Graduate School of Pureand Applied Sciences, University ofFig. 5. R3−2/1−0 maps of the (a) 35 km s−1 , (b) 45 km s−1 , and (c) 58 km s−1 cloud are shown in the color image. Contours show the 12 COJ =3–2
Tsukuba, 1-1-1 Ten-nodai, tsukuba, Ibaraki ′′305-8577, Japan∗ E-mail: mikito@a.phys.nagoya-u.ac.jp
emission, which was spatially smoothed 50 . Plots are same as Figure 1. The clipping level is 8σ.
7Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya
464-8601, Japan
Received 2017 July 10; Accepted 2017 October 25∗ E-mail: mikito@a.phys.nagoya-u.ac.jp

Received 2017 July 10; Accepted 2017 October 25

Abstract

銀緯

速度

Abstract

Turbulent layer

thgis-fo-enil

速
度

銀緯

We observed molecular clouds in the W33 Larger
high-masscloud star-forming region associated with com-

Fig. 2. (a) Longitude-velocity diagram of the 12 COJ = 1–0 emission with the NANTEN2 telescope. The arrows indicate the four velocity components ; black
pact and extended H II regions using the NANTEN2 telescope as well as the Nobeyama 45We observed molecular
clouds in the W33 high-mass star-forming region associated with comarrow : 10 km s−1 , blue arrows : 35 km s−1 , 45 km s−1 , and 58 km s−1 . The dashed box indicate the W33 region as the range of Figure 2(b). (b)pact and extended H II regions using
the
NANTEN2
telescope
as
well
as
the
Nobeyama
45m telescope in the J =1–0 transitions of 12 CO, 13 CO, and C18 O as a part of the FOREST
Longitude-velocity diagram of the 12 COJ =1–0
emissionwith 18
the Nobeyama 45-m telescope. The arrows indicate the three velocity components ; 35 km s−1 ,12
13
m telescope
in
the
J
=1–0
transitions
of
CO,
CO,
and
C
O
as
a
part
of
the
FOREST−1
Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope(FUGIN)legacy45 km s−1
, and 58
km sImaging
.
Dense
layer
Unbiased
Galacticplane
survey with the Nobeyama 45-m telescope (FUGIN) legacy

survey. We detected three velocity components at 35 km s−1 , 45 km s−1 , and 58 km s−1 . The
35 km s−1 and 58 km s−1 clouds are likely to be physically associated with W33 because of
the enhanced 12 CO J = 3–2 to J =1–0 intensity ratio as R3−2/1−0 > 1.0 due to the ultraviolet
irradiation by OB stars, and morphological correspondence between the distributions of molecular gas and the infrared and radio continuum emissions excited by high-mass stars. The two
clouds show complementary distributions around W33. The velocity separation is too large
to be gravitationally bound, and yet not explained by expanding motion by stellar feedback.

line-of-sightc 2014. Astronomical Society of Japan.
⃝

survey. We detected three velocity components at 35 km s−1 , 45 km
s−1 , and 58 km s−1 . The
CavityPublicationsof the Astronomical
Society of Japan, (2014),
Vol. 00, No. 0v−1−1
35 km s and 58 km s clouds are likely to be physically associated with W33 because of
the enhanced 12 CO J = 3–2 to J =1–0 intensity ratio as R3−2/1−0 > 1.0 due to the ultraviolet
Smaller cloud
irradiation by OB stars, and morphologicalbetween the distributions of molecSmaller correspondence
cloudular gas and the infrared and radio continuum emissions excited by high-mass stars. The twoof the Astronomical
Societyof Japan,(2014),
00, No.separation0
varoundclouds Publications
show complementary
distributions
W33.
TheVol.
velocity
is too large
Cavityto be gravitationally bound, and yet not explained by expanding motion by stellar feedback.
Dense layerc 2014. Astronomical Society of Japan.
⃝

Larger cloud

Turbulent layer

V

Larger cloud⻘は35km/s雲(⼤きい雲)、⾚は58km/s(⼩さい雲)：グレイは右パネルが24ミクロン；ポンチ絵と⾊が逆なので注意コントアは野辺⼭で取得C18O(1-0)

Fig. 16. Velocity channel map of the C18 O J = 1–0 emission with a velocity step of 4.0 km s−1 with Nobeyama. Contours show the VLA 90 cm radio
continuum image. Plots are same as Figure 1.