2023年2月10日星形成ゼミ：古屋玲；Star Formation News Letters Vol.359, No.1-18

7 Department of Planetary Sciences, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721, USA
8 Department of Physics & Astronomy, 118 Kinard Laboratory, Clemson University, Clemson, SC 29634, USAThe
kinematics and excitation of infrared water vapor emission from planet-forming disks:
9 Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, the Netherlands
resultsfromspectrally-resolved
surveysguidelines
for JWST spectra
10 Kapteyn AstronomicalInstitute,
Universityof Groningen, PO Box 800,
9700 AV and
Groningen,The
Netherlands
11 Department of Astronomy, University of Michigan, 1085 S. University Ave, Ann Arbor, MI 48109

1
2
1
3
1
AndreaBanzatti,
Klaus
M.
Pontoppidan,
Jos
é
P
érez
Ch
ávez,
ColetteSalyk,
Lindsey
Diehl,
12 Center for Astrophysics, Harvard & Smithsonian, 60 Garden St., Cambridge, MA 02138, USA
4
5
6
7
8
8
Simonof Bruderer,
Gregory
J. Herczeg,
AndresCarmona,
IlariaPascucci,
Sean
3 Division
Geological & Planetary
Sciences,
MC 150-21, California
Instituteof Technology,
Pasadena,
CA 91125,
USABrittain, Stanley Jensen,
4
4, 9
10
11
12
14 Department
SierraGrant,Ewine
F.
van
Dishoeck,
Inga
Kamp,
ArthurD.
Bosman,Karin
I.
Öberg,of Earth Sciences, University of Hawaii at Manoa, 1680 East-West Rd, Honolulu, HI 96822, USA
13
11
14
15
15
15 Institute
GeoffforA.Astronomy,
Blake, University
MichaelR. Meyer,
EricDrive,
Gaidos,Adwin
John T. Rayner, andof Hawaii,
2680 Woodlawn
Honolulu,
HI, USABoogert,
96822
16
16 Simons Observatory - Center for Computational Astrophysics,
Caleb
Wheeler
FlatironInstitute, 162 5th Ave, NY 10010
JWSTで若い星(主にclass II)の円盤中の⽔
1 Department of Physics, Texas State University, 749 N Comanche Street, San Marcos, 蒸気分⼦輝線分光
TX 78666, USA

ABSTRACT

2 Space Telescope Science Institute 3700 San Martin Drive Baltimore, MD 21218, USA

This work 3presents ground-based spectrally-resolved water emission at R = 30000–100000 over in- 【結果1】２-9μmの回転振動遷移線は,
Department of Physics and Astronomy, Vassar College, 124 Raymond Avenue, Poughkeepsie,
NY 12604, USA
12μmの回転遷移線より線幅細い
frared wavelengths4 covered by JWST (2.9–12.8 µm). Two new surveys with iSHELL and VISIR are
Max-Planck-Institut für extraterrestrische Physik, Gießenbachstraße 1, 85748 Garching bei München
combined with previous
spectra from CRIRES and TEXES to cover parts of multiple ro-vibrational 【結果2】柱密度~10^18 1/cm^2,
5 Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871,
China
and rotational bands observable within telluric transmission bands, for a total of ⇡ 160 spectra and 4000-9500 Kからの輝線の放射領域はおそ6 Univ. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
85 disks (30 of which are JWST targets in Cycle 1). The general expectation of a range of regions and らく円盤の鉛直⽅向に異なるところから
7 Department of Planetary Sciences, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721, USA
excitation conditions traced by infrared water spectra is for the first time supported by the combined
8 Department of Physics & Astronomy, 118 Kinard Laboratory, Clemson University, Clemson, SC 29634, USA
kinematics and excitation as spectrally resolved at multiple wavelengths. The main findings from this 【結果3】JWSTで観測できるようになった
9 Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden,
5μm輝線は、複数の層(slab)からの励起モ
analysis are: 1) water lines
are progressively narrower from the ro-vibrational bands at 2–9 µm to the Netherlands
10 Kapteyn
デルでうまく説明できた.
Astronomicalof andGroningen,Box
800, 9700
AV Groningen,The
Netherlands
rotational lines
at 12 µm,
and partlyInstitute,match a University
broad (BC)narrow PO(NC)
emissioncomponents,
11 Department
respectively, as extracted
from ro-vibrational
COUniversity
spectra; 2)
diagrams
resolved waterof Astronomy,of rotation
Michigan,1085 S.ofUniversity
Ave, lines
Ann Arbor, MI 48109
12 Centerfrom upper level energies
of 4000–9500
K showHarvard
vertical &spreadand curvaturesindicativeof opticallyMA 02138, USA
for Astrophysics,
Smithsonian,
60 GardenSt., Cambridge,
18
13 Division
thick emission(⇡ of
10Geological
cm 2 ) froma range Sciences,of excitation(⇡ 800–1100
3) the new Pasadena, CA 91125, USA& Planetary
MC temperatures
150-21, California
InstituteK);of Technology,
5 µm spectra14demonstratethatslab Sciences,model fitsUniversity
to the rotationallinesatatManoa,> 10 µm
strongly
over-predict
Department ofEarthof Hawaii
1680
East-WestRd, Honolulu, HI 96822, USA
the ro-vibrational emission
bands
at < 9 µm,University
implying non-LTE
excitation.
discuss HI, USA 96822
15 Institutefor Astronomy,of Hawaii,vibrational
2680 Woodlawn
Drive,We
Honolulu,
these findings 16
in the context of emission from a disk surface and a molecular inner disk wind, andSimons Observatory - Center for Computational Astrophysics, Flatiron Institute, 162 5th Ave, NY 10010
provide a list of guidelines to support the analysis of spectrally-unresolved JWST spectra.

Multi-wavelength water survey

JH K

L

N

M

Q
MIRI

NIRSpecro-vibrational lines(stretching mode)3

ro-vibrational lines(bending mode)iSHELLCRIRESrotational lines

VISIR
TEXES

= 001-000 , Eu ~ 8000-9500 K= 010-000 , Eu ~ 4500-9500 K

NIRSpec model

MIRI modelOH

MIRI model

oﬀset

oﬀset

H2O

= 000-000 , Eu ~ 4000-7000 K

oﬀset

H2O
CO
H2O

H2O

H2O

Multi-wavelength water survey

Spitzer
Figure 1. Overview of near- and mid-infrared water emission bands as observed from space and the ground (see Section 1.1).
Top: Earth’s atmospheric transmission (in green), with observing bands labelled in orange. Middle: water emission model for
illustration of its multi-band structure (not a fit to the data; model fits to the data are instead shown in Sections 2 and 4.4).
The coverage of di↵erent spectrographs is shown with black boxes to illustrate which parts of the spectrum can be observed:
JWST
high-resolution (R > 30000) spectrographs from the ground can spectrally-resolve relatively weak high-energylines in small
H2 O
spectral windows, while JWST from space can observe a much wider spectral range but only at moderate resolution (R ⇠ 1500– C2H23700). Bottom: zoomed-in spectral regions to illustrate the di↵erence in resolution between JWST and ground-based dataOH(theCRIRES, iSHELL, and TEXES spectra are for DR Tau and adopted from this work and Banzatti et al. 2017; Salyk et al. 2019).

Space-based spectrographs provide wide spectral coverage (e.g. 10–37 µm with Spitzer-IRS, and now 4.9–

ro-vibrational transitions in the bending and stretchingmodes present more compact bands at 4–9 µm and 2.5–

HCN

H2O

H2 O
OH

CO2
OH

Spitzer
中間⾚外線12μmの⽔蒸気分⼦輝線(⿊のヒストグラム)；⾚と⻘はスタッキング解析から得たCOの⽰準(？)スペクトルのうち,
狭輝線幅成分NCと広輝線幅成分BC

JWST

HCN

H2O
C 2H 2
OH

H2O

H2O
OH

CO2
OH

狭輝線幅成分NCと広輝線幅成分BCが何に起因するかは解釈が分かれるらしい(see Sect. 5.2.2.)；著者の解釈(この論⽂のひとつの結論)は, 図15

12S￼ は, 輝線形状の太り具合：
S>2.5は三⾓形的で「円盤と円盤⾵」起源
S<2.5は円盤起源を⽰唆

⽔蒸気分⼦輝線を特徴づける、
諸元同⼠の相関：トレンドとして控えめにSect.4.2で議論

Figure 9. Overview of line luminosity for CO and water lines between 2.9 and 30 µm, as a function of stellar and disk
parameters (Section 4.2). Datapoints are classified according to the kinematic shape of the CO line using a line shape parameter
S (Banzatti et al. 2022): “triangular” lines with S > 2.5 associated to disk+wind emission (marked with blue triangles), anddouble-peak lines with S < 2.5 associated to purely Keplerian motion (marked with orange squares). Upper limits are marked
with thin symbols. Line flux measurements included in this figure are reported in Appendix C.

古屋メモ：
・すべての量が独⽴？
・選択バイアスは⼊り込んでいない？
・non-detectionの天体はない？

14

Figure 10. Rotation diagrams of infrared water rotational lines (Section 4.3). Three di↵erent models are used to illustrate thee↵ects of di↵erent excitation temperatures, line opacity, and LTE/non-LTE excitation: a slab model in LTE (Banzatti et al.
2012), a slab model in non-LTE using RADEX (van der Tak et al. 2007), and a two-dimensional disk structure in LTE using
RADLite (Pontoppidan et al. 2009). In each plot and model, larger symbols mark transitions that are stronger than 1% of thestrongest line, to simulate a detection threshold; weaker lines are marked with small dots.
()*)600)+),)-)*)&0&%)./ï2&'

4524p67289:14;133

&0
'
0
ï'
ï&0
ï&'
0

2000

4000

6000
01)2+3

%000

&0000

右上パネルの縦軸：COの広輝線幅領域の線幅に対する、それぞれの輝線幅の⽐
結局, ３つのモデルの組み合わせが必要そうだ

Figure 13. Overview of excitation and kinematics of water emission as spectrally-resolved at multiple wavelengths in this work.
Top left and bottom: representative LTE slab models from results in Table 3; the overall curvature in the observed rotation
diagrams (Figure 12) can be approximated by a series of slab model fits to the di↵erent wavelengths covered by di↵erent
instruments (Section 5.1.1). Non-LTE excitation may cause the suppression of ro-vibrational bands as compared to slab model
fits to the rotational lines (see Section 5.1.2). Top right: observed gradient in line widths as a function of upper level energy
for water and CO (Section 5.1.3); grey datapoints at 100–2400 K are model predictions for three water lines in RNO 90 using
RADLite, from Blevins et al. (2016). Critical densities ncrit are reported for reference (see Table 1).

この相関は、円盤内側ほど⾼温で線幅がひろがるというBlevins et al. (2016)のモデルと合う. (Sect. 5.1.3)

tion.
The main findings of this work are:• ro-vibrational water lines at 2.9 µm and 5 µm (Eu • 2.9 and 5 μmの⽔蒸気回転振動遷移は広い線幅であるのに対し, より低温のガスをトレースする回転遷移の線幅は狭い.
of 4500–10000 K) have larger FWHM and higher
excitation temperature (1000–1100 K), while ro- • slabモデルとの⽐較から(そうは⾔うものの、結局)、すべての輝線は同程度の柱密度をトレース.
tational lines near 12.4 µm (Eu of 4000–6000 K)
have narrower FWHM and lower excitation temperature (800 K); LTE slab model fits suggest thata similar column density is observed in all waterbands (a few ⇥1018 cm 2 , Section 4.4);• the new 5 µm spectra from iSHELL for the first• 新たな5 μmの⽔蒸気回転振動遷移データから、 >10 μmの輝線に対するslabモデルフィットは<9 μmの輝time directly demonstrate that slab model fits to線の強度を過⼤評価していた（今⽇のゼミでこの部分はスキップしている）. この結果は、振動遷移はLTE仮
the rotational lines at > 10 µm strongly over定が成⽴していない領域起源という説明(Bosman+22)を⽀持.
predict the ro-vibrational emission bands at <9 µm; this is interpreted as evidence for non-LTE
vibrational excitation, as discussed in Bosman
et al. (2022);• the picture emerging from combining line kinematics and excitation is in good agreement with therange in critical density for the di↵erent bands:
1) an inner, hotter, and denser disk region exciting the ro-vibrational water bands and the broad
CO component, and 2) a progressively cooler disk
surface (and low-velocity region in an inner diskwind) exciting the rotational lines and the narrow
CO component (with density < 1012 cm 3 so as
to sub-thermally excite the ro-vibrational lines);
the relative contribution of disk vs wind emission
across the di↵erent radial regions remains to beclarified.

• ⼀連の結果は他の観測とも⽭盾なく,(1) 内側の暖かく⾼密度領域で⽔蒸気分⼦回転振動遷移が励起され、(2) より低温の円盤表⾯と円盤内側の冷たい部分で⽔蒸気分⼦回転遷移が励起されている。また、このような領域は, <1e12 1/cm^3でサーマライズしていないCOの狭輝線成分が励起される領域でもある。
(3)しかし, ⽔蒸気分⼦回転振動遷移と回転遷移が円盤起源なのか、円盤⾵起源なのか、両⽅なのか、の問題は決着しなかった.

Horrobin1 , Z. Hubert2 , L. Jocou2 , P. Kervella13 , S. Lacour13 , V. Lapeyrère13 , J.-B. Le Bouquin2 , P. Léna13 , D. Lutz4 , F.
The
GRAVITY
young
stellarobjectsurvey
4
4
13
13
3
4
Mang , T. Ott , T. Paumard , G. Perrin , S. Scheithauer , J. Shangguan , T. Shimizu4 , S. Spezzano4 , O. Straub4 , C.
1 , E. Sturm4 , E. van Dishoeck4, 14 , F. Vincent13 , and F. Widmann4
Straubmeier
IX. Spatially resolved kinematics of hot hydrogen gas in the star-disk interaction(Affiliations
can be found
the references)
regionof Tafter
Tauri
stars

accepted
GRAVITY Collaboration: J. A. Wojtczak1 , L. Received
Labadie1 ,-;K.
Perraut-2 , B. Tessore2 , A. Soulain2 , V. Ganci1, 5 , J. Bouvier2 ,C. Dougados2 , E. Alécian2 , H. Nowacki2 , G. Cozzo2, 15 , W. Brandner3 , A. Caratti o Garatti3, 6, 7 , P. Garcia9, 10 , R.
9, 12 , M. Benisty2 , J.-P. Berger2 , G. Bourdarot4 , P. Caselli4 , Y.
ABSTRACT
Garcia Lopez3, 6, 11 , J. Sanchez-Bermudez3, 8 , A. Amorim
Clénet13 , P. T. de Zeeuw4, 14 , R. Davies4 , A. Drescher4 , G. Duvert2 , A. Eckart1, 5 , F. Eisenhauer4 , F. Eupen1 , N. M.
Context. HotFörster-Schreiber
atomic hydrogen4emission
lines13in
stars
serve
as tracers
forHeißel
physicalprocesses
in 3theof
4 , S. Grant
4 , R.
1 , G.
13 , Th.
, E. Gendron, S.pre-main
Gillessensequence
GrellmannHenning, S.innermost
Hippler3 , regions
M.
circumstellar accretion1 disks, whereinteraction
between13a star and disk
the dominanton the formationof13infalls and4 outflows.
2 , the2 , P. Kervella
13 , is
13 ,influence
2 , P. Léna
Horrobin,Z.
Hubert
L.
Jocou
,
S.
LacourV.
Lapeyrère
J.-B.
Le
Bouquin
,
D.
Lutz
,
F.
In the highly magnetically
activeT Tauri 13stars, this interaction
region is3 particularly shapedby the stellar
magnetic 4field and the4 associated
4
4
13
4
4
Mang
, T. Ott
T. Paumard
Perrin, S.
Scheithauer, J. Shangguan, T. T
Shimizu, S. Spezzano,compact
O. Straub, C. is only
magnetosphere,
covering
the ,inner
five stellar, G.
radiiaroundthecentral
star.
Even
for
the
closestTauri
stars,
aregionasas
this
1 , E. Sturm4 , E. van Dishoeck4, 14 , F. Vincent13 , and F. Widmann4
Straubmeierobserved on the sky plane at sub-mas scales. To resolve it spatially, the capabilities of optical long baseline interferometry are required.
Aims. We aim to spatially and spectrally resolve the Br
hydrogenlinethewiththe methods of interferometry in order to examine the(Affiliations
can emission
be found afterreferences)kinematics of the hydrogen gas emission region in the inner accretion disk of a sample of solar-like young stellar objects. The goal is to identify
Received-; accepted
trends and categories among the sources of our sample and to discuss
whetheror not- they can be tied to di↵erent origin mechanisms associatedwith Br emission in T Tauri stars, chiefly and most prominently magnetospheric accretion.
Methods. We observed a sample of seven T Tauri stars for the first timewith VLTI GRAVITY, recording spectra and spectrally dispersed interABSTRACT
ferometric quantities across the Br line at 2.16 µm in the near-infrared K-band. We used the visibilities and di↵erential phases to extract the
Hot region
atomic hydrogen
emission lines
in pre-main
sequence stars servebasis,
as tracers
for physicalprocesses
in the innermostof radialsize of the BrContext.
emissionand the photocentre
shiftson a channel-by-channel
probing
the variationof spatial
extent at regionsdi↵erent
accretion
disks, whereinteraction
betweena star anddisk is thedominant
influence on the formationand outflows.
velocities. Tocircumstellar
assist in theinterpretation,
wethe
also
made useof radiativetransfermodelsof magnetosphericaccretionoftoinfalls
establish
a baseline of
In the highly magnetically active T Tauri stars, this interaction region is particularly shaped by the stellar magnetic field and the associatedexpected interferometricsignatures
if accretionis the radii
primary
driverof Br star.
emission.
magnetosphere,
covering theinner five stellar
aroundthe central
Even for the closest T Tauri stars, a region as compact as this is only
Results. Fromamongonour
find thatfive Toof theseven
T Taurithe
stars
show anofemission
regionwitha half-flux are
radiusin the four to sevenobserved
the sample,
sky planewe
at sub-mas
scales.
resolveit spatially,
capabilities
optical long
baselineinterferometry
required.
stellar radii range
thataimis broadly
expectedfor magnetospheric
Two ofline
thewith
fivetheobjectsalsoofshow
Br emission
originating
Aims. Weto spatiallyand spectrally
resolve the Br truncation.
hydrogen emission
methods
interferometry
in orderprimarily
to examinethekinematicsof theradius,hydrogengas emission
region in criterion
the inner accretion
disk of a sample
of solar-likestellarobjects.
The goal
is to identify
from within the
co-rotation
which
is an importantfor magnetosphericaccretion.
Twoyoung
objects
exhibitextendedemissionon a scale
categories
among
the sourcesof our sample
and tohalf-flux
discuss whether
they
be observed
tied to di↵erent
origin mechanisms
associatedbeyond 10 Rtrendsof themis evenbeyondthe K-band
continuum
radius orof not
11.3
R⇤can
. The
photocentre
shifts acrossthe line can⇤ , oneandwith toBr whatemissionin T Tauristars,
chiefly
and mostorprominently
magnetosphericaccretion.
be either similar
is expected
for
disks
in rotation
show patternsof higher complexity.
We observed a sample of seven T Tauri stars for the first time with VLTI GRAVITY, recording spectra and spectrally dispersed interConclusions.Methods.
Based onthe observational findings and the comparison with the radiative transfer models, we find strong evidence to suggest thatferometric quantities across the Br line at 2.16 µm in the near-infrared K-band. We used the visibilities and di↵erential phases to extract thefor the two weakest
accretors
in theregion
sample,magnetosphericaccretionis the primary driverof Br theradiation.
resultsextent
for theremainingsourcessize of theBr emission
and thephotocentre shifts
on a channel-by-channel
basis, probing
variationTheof spatial
at di↵erent
radial
imply either velocities.
partial orTostrong
contributions
comingfrommade
additional,
spatially
extendedcomponents
in theto formof outflows,
such asassist in
the interpretation,
we alsouse of radiativetransfermodelsemissionof magnetosphericaccretion
establish
a baseline ofstellar or diskexpected
winds. interferometric
We expect thatin actively
accreting
T Tauristars,
these
signatures
if accretionis theprimary
driverof Brphenomena
emission. typically occur simultaneously on di↵erent spatial scales.
Results.
From modelling,
among our sample,
we find thatfivebeof athekeyseven
T Tauristars show an emission
region witha half-flux radius
the foursevenarisingThrough moreadvancedinterferometry
willfactorin disentangling
their distinct
contributions
to theintotal
Br to flux
stellar radiithat is broadly expected for magnetospheric truncation. Two of the five objects also show Br emission primarily originatingfrom the innermost
diskrange
regions.

GRAVITY Collaboration: First light for GRAVITY
Phase reference
ObjectWavefront reference2” FoV

Metrology fringes

Telescope #1

Metrology
sensor

Telescope #2

MetrologyStarseparator

Starlight

DeformablemirrorIR wavefront
sensorDelay line

2” FoV

Laser

Laser
Guiding

Acquisition
cameraBeam combiner instrument

Tiptilt
Pupil

dOPD
control

IO beam combiner

Spectrometer
A
D

Fiber
couplerB

Phase
shifter
Polarization control

C

Metrology
laser

OPD control

Fig. 1. Overview and working principle of GRAVITY: the instrument coherently combines the light of the four 8 m UTs of the VLTI or thefour 1.8 m ATs. It provides infrared wavefront sensing to control the telescope adaptive optics, two interferometric beam combiners one forfringe-tracking and one for the science object , an acquisition camera and various laser guiding systems for beam stabilization, and a dedicatedlaser metrology to trace the optical path length di↵erences for narrow angle astrometry. The overview illustrates the light path and location of thevarious subsystems. For clarity, we show only two telescopes, one beam combiner, and one wavefront sensor. The wavefront sensor star (green)
can be outside the VLTI field of view. Depending on the brightness of the science object (red), the fringe tracker is either fed by a beam splitter,or as illustrated in this figure by a bright o↵-axis phase reference star (blue). The GRAVITY subsystems (light blue boxes) are embedded andtake advantage of the already existing VLTI infrastructure (light red boxes).

the ATs was carried out in June and September 2016, with first GRAVITY concept. For clarity, only two of four telescopes, that
results published in, for example, Le Bouquin et al. (2017) and is, one out of six baselines, are shown.
Kraus et al. (2017). Science operation with the ATs started in
The working principle of GRAVITY is as follows: a brightA&A 2016,
602, A94(2017)by the UTs in April 2017.
Octoberfollowed
wavefront reference star (e.g., in the Galactic center this isDOI:
10.1051/0004-6361/201730838
00This paper provides a comprehensive description of the in- GC IRS 7, a mK = 6.5 mag star at 5.5&
separation from the suc ESO 201700
strument (Sect. 2) and presents a set of early observations that permassive black hole) outside the 2 field-of-view of the VLTI
illustrate its power (Sect. 3). The detailed description of the in- is picked with the PRIMA star separator (Delplancke et al. 2004)
strument subsystems and software, and of the analysis and inter- and imaged onto the GRAVITY Coudé infrared adaptive oppretation of the observations, will be given in several forthcom- tics (CIAO) wavefront sensors. The wavefront correction is apFirst light for GRAVITY: Phase referencing
opticalinterferometry
ing papers.
plied using the MACAO
deformablemirrors of the UTs. The
00
2 field-of-view of the VLTI contains both the science target
for the Very Large Telescope(Sgr A*) and Interferometerthe phase reference star (GC IRS 16C, 1.2300 separation, mK = 9.7 mag).
Both objects are re-imaged via the main
? : R. Abuter8 , M. Accardo8 , A. Amorim6 , N.
7 , G. Ávila8 , N. Azouaoui2 , M. Benisty5 ,2. TheGRAVITY
instrument
GRAVITY
Collaboration
Anugu
delay lines (Derie 2000) to the GRAVITY beam combiner in-

Astronomy
Astrophysics

Table 1. Properties of the stars of the T Tauri sample.
A&A proofs: manuscript no. SpatiallyResolvedKinematicsWojtczak2022

Name

Sp. Type Te↵
[K]

d
[pc]

M⇤
[M ]

L⇤
[L ]

R⇤
[R ]

Age
Ṁacc
[10 8 M yr 1 ] [Ma]AS 353K54450 399.6 ± 4.2

3.9 ± 0.67 3.32 ± 0.29

7.9 - 45

1

RU LupK74050 157.5 ± 1.3 0.6 ± 0.2 1.64 ± 0.22 2.60 ± 0.17

1.8 - 30

1-2 Hercz

VV CrA SW

K74050 156.6 ±1.2 0.6 ± 0.2 1.73 ± 0.24 2.67 ± 0.19

3.33 - 22

1-2

TW HyaK64200 60.14 ± 0.07 0.9 ± 0.1 0.41 ± 0.05 1.21 ± 0.07

0.13 - 0.23

4-12

K5-K6 4300 160.5 ± 2.2 0.9 ± 0.2 3.82 ± 0.54 3.52 ± 0.25

7.8 - 50

1S4200 125.2 ± 2.3 0.8 ± 0.2 1.58 ± 0.37 2.37 ± 0.28

4.6 - 74

1-2

K2-K3 4840 146.3 ± 0.6 1.5 ± 0.2 1.61 ± 0.21 1.80 ± 0.12

0.63 - 0.9

3-6

W
Whi

S CrA NDG TauDoAr 44K6

1 ± 0.2

星の半径

S

E

Notes. References are referring to the lower and upper limit Ṁacc literature values. We note that R⇤ was computed
stellar luminosity. Other properties were adopted from Gravity Collaboration et al. (2021b).

【通説と疑問】
atmosphere (Lacour et al. 2019). We made use of the FT capa- whereas FT data is only used in￼take輝線は,magnetosphere領域のうち,bility to Brγ
the SC observations
in GRAVITY’s high resolution described further below. For an overmode (R=4000) with a width of ⇠ 5 Å, or 75 km/s, per chan- K-band continuum, based on the sa
共動半径内の安定領域,
円盤や星⾵が駆動するアウトフローなど,
nel, enabling
us to spectrally resolve
the Br feature and trace GRAVITY, we refer to the work of
the gas kinematics over a range of up to ± six channels from the (2021b).
であるが, 共動半径の外側や星の極⽅向からも￼Brγ輝線は放射されていないのか？
centre of the line, depending on the strength of the feature in the Each of the individual files obtai
contains four sets of flux data co
individual
sources.
【この観測】The observations of the di↵erent targets are subdivided into a set Telescopes, six sets of normalised
coming1.6-1.7
from thewas
six UT baselines
shortterm runsof about
5 minutes
in length, each of which
8.2-m
telescopes,
Max.基線⻑130m⇨ resolution
Fig. 1. Schematic depiction of the innermost parts of the circumstellar disk of a T Tauri star. Br emission in T Tauri stars is associatedofwiththe Fourconcept of magnetospheric accretion, but outflows caused by certain types of disk or stellar winds (dashed lines) can heat the hydrogengassavedtowasas a separate file, stretching over a total observation visibility phase data, and four sets
the necessary temperatures to produce Br emission as well. Di↵erent origin mechanisms can be tied to di↵erent spatial scales. Magnetospheric R
￼with= 4000⇨ hours
速度分解能75
km/s；ただし,fringetracker(FT)の￼
R closed= 23 baseline trian
the fouruniquetimeofaround
1
1/2
for
most
of
the
objects,althoughthematic
depictionoftheinnermost
parts
of
the
circumstellar
disk
of
a
T
Tauri
star.
Br
emission
in
T
Tauri
stars
is
associatedtheaccretion flows (depicted in red) can only stably form in a compact region within the co-rotation radius Rco , where the gaseous disk rotates at theagnetosphericaccretion,
butstar.
outflows
types
diskRorstellar winds (dashed lines) can heat theandhydrogengas
oftoDoAr 44 went on for notably longer with a total the UTs.
same angular velocity⌦ as theSpatiallycaused
extendedby
Br certain
emissionfrom ofoutsidemust
co cannot be attributed to magnetospheric accretion observation(観測中の)遅延線の計算の詳細はAppendix
be caused by someother emission
temperaturesto produce
Br component.
emission as well. Di↵erent origin mechanisms can be tied to di↵erent spatial scales.
Magnetospheric
timeof slightly
over 4 hours. Measurements of suitable calibra- The individual files were merged b
figure specificallyshowscommoncaseinofaa compact
non-axisymmetricfeaturing a radiustilt between
stellarthe
rotational
axisdisk⌦⇤ andwsThis(depicted
in red) can
onlythestably
form
region magnetosphere,
within the co-rotation
Rco ,thewhere
gaseousrotates
the
tor
stars
in aatsufficiently
close part of the sky were predominantly the post-processing routine of thethemagnetic
dipoleµ.
Theobliquityofthemagnetosphere
leads
to
the
formationoftwoaccretioncolumns,which
funnel
gas
from
a
wide
arc
at
velocity ⌦ as the star. Spatially extended Br emission from outside Rco cannot be attributed to magnetospheric accretion and must
tively time-averaging our observab
the truncation radius onto one primary hot spot per hemisphere, as first suggested in Bertout et al. (1988) and Calvet & Hartmann (1992).
Theeither up to 45 minutes before the beginning or after the
taken
some
other
emissioncomponent.
equations and physical quantities relevant for the determination of the co-rotation radius Rco and the magnetic truncation radius Rtr are discussed
endhotoftoaxis
the⌦telescope
run and thus potentially probing the sky un- over the 1 1/2 hours of observatio
ecificallytheequations
commonof a non-axisymmetricfeaturinga whichtilt between
the stellar
rotationalin Section shows
5. For theusedcaseto estimate
the sublimation radiusmagnetosphere,
Rsub , which indicatesthe area atthe disk becomes
sufficiently⇤ anddestroyµ.dust
grains,we refer
Gravity
Collaboration leads
et al. (2021b).
dipoleTheobliquity
oftothemagnetosphereto the formation of two accretion columns, which funnel gas der
fromclosea widebut
arc not
at entirely identical atmospheric conditions. For shifted to the local standard of rest5.
Resultsf the AS 353 observation, taken with the four unit

Fig. 3. Total and pure line visibilities for an exemplary baseline fromTI.
the AS 353 observation.
5.1. General results
fore the application of the spectral calibration. The Top: Visibilities before the spectral correction was applied. Blue ands In
the thismeansection
position ofthefirst
line peak.
Beforecor- greyof
shadedwe
presenta thebreakdown
the regions
generalindicate
re- the uncertainties on the total and pure line
al spectra for most of our objects were misaligned visibilities, respectively. Bottom: Same baseline after the correction.
sults
obtainedfrom
the GRAVITY
TauriEspeciallydata, introduce
somethetelluriclines andalso between
each other.TBotwith respect
to the computation of the pure line visibilities,
additional
the interpretation,and give
an in the red wing of the signal.
fter
they were concepts
brought intorelevantalignmenttothroughthe the change appears
significant
The
correctedover
spectrarecomputed
overview
theandglobaltrendsobservables
we were able to identify acrosshiftedto bringsample.
them to thestandard of rest
the entire
In localthe following
sections, we then proceed
A&A proofs: manuscript no. SpatiallyResolvedKinematicsWojtczak2022

to go over each source individually in detailcontextualiseline andto continuumdi↵erence in visibility of only about 0.01 at
even the longest
our findings by drawing upon relevant references,
if and baselines.
wherelevels canwith low continuum
Fig.greatly,
4. Relationships
between Brdis-emission region sizes and selectedavailable. Table 3 summarises key results Noise
concerning
the equallychar- vary
in wavelength
adjacent
to the Br line again fories
on the flux
derivedfrom theinstru-andpersion
stellarproperties.
acteristics
ofratios,
the Bremission
regionaccretion
properties,regions
RU Lup,where wea continuum
standard
deviationof line emission region of the cengivenby the pipeline,
are4ofand
the 5
order
of 0.01
Fitted HWHM
of theBr purerespectively.
Figuresserve
as a visual
overviewof measure
the Top:noisy
dataversus
obtainedfor
VV CrAf the T Tauri sample, although in the case of 0.0023, compared to the verytral
channelthemass-accretion
rate. The latter is depicted insampleresultswithregards
tothemost
importantcriteria
weuse
standard
deviation
can goup
to denotes the range of Ṁ values
a severe increase to around 0.03, even though (Fig. D.6) where the continuum
twoforms:
Once
as
a
grey
bar
which
ヴィジビリティ・スペクトル(⾃⼰相関)の例
interpret our
0.035.
hetocontinuum
flux results.
values remains comparable
found in the literature on the respective source, then as the instantaneous
Theforsampleconsists
Br Weemitters,with norfound non-zerodi↵erential
phases at theof Br
at from the equivalent width of theound
the othersources.of mostly strong• 上下のパネルは(何らかのオフライン)補正前後
mass-accretionrate,position
which wasderivedmalisedpeak
linevicinity
to continuum
ratios between
1.91 andfor1.53
several baselines
each target
in the sample,
with typicalabso-coding represents the classification
sibilitydata
in theof the Brflux
featureGRAVITY
Br
spectra.
The
colour
多くの天体は,for six
outsampleof ourranges
eightfromdatavisibilities
sets and• ofranging
down幅広で低輝度の成分と幅狭く⾼輝度の成分からなる.
to 1.19
for of0.5thetosample
lute phasevaluesof around
1 , although
jects
in theobjectsthe
aslargesteither meaweak (green) or intermediate to strongdi↵erential
up to 6.3(red).
tudes
close to 1,
indicating
that44.
theMany
total line
. S-shaped
as exthe weakest
emitterDoArthesuredobjects
exhibitphaselinegoesaccretors•of
幅狭く⾼輝度の成分は,ブルーシフトしている.
Most offeatures,
the T Tauristars cluster in a 4-7 R⇤ range, whichndthe surrounding
continuum werepartiallyan excess
pected forin rotation,observed
for some
sourcesshapesthat are asymmetric,
featuringof systems
blueshifted
is ofcanthebeorderof typicalmagnetosphericsizes.
•(pole-onで⾒ているものを除外しても)inverse
P-Cygniプロファイ
entireK-bandat approximatebaseline lengths
between
40 atbysomebaselines(e.g. RUBottom:
Lup 2021,
see Fig.
D.3), luminosities. The colour coding
BrUT4-UT1,
HWHM versus
accretion
emission.
We
thisasymmetry
fittinga superpoルは⾒られない.
lsitionof the targets.
TheBr
visibilities
signalsarebut basicallyare rather exceptional
notably absent
from plot.
many othercorresponds
to the upperof two Gaussian functions to the data,
dividing andinFig.
mostcases
well aligned
withtheposition oftargets.
The
featuresappearsinglepeakedin visibilities
many cases,
but
the
2.
Br
spectra
of
the
AS
353
observation,
taken
with
the
four
unit
Fig.
3.
Total
and
pure
line
for
an
exemplary baseline fromthefeatureintoanarrow
centredlowvelocity
component
andig. 2. Br spectra of the
AS 353 observation,
takenwith the four
unit Fig.
3. Totaland pureline visibilities
foran lineexemplarybaselinefromorresponding
spectrum,see, forinstance,Fig.
peak
is notalignedwith
thecentre,suggestingthat in suchtelescopes
of
the
VLTI.
the
AS
353
observation.
lescopesof the VLTI.
AS 353 observation.
a broadero↵set high velocity component.thecases
Whetherthese GausD.
apotential
S-shapemightmaskedone correctionof the twowas applied. Blue andTop:
The spectra
theof applicationof the The
spectralThe
Top:correction
Visibilities
beforespectralop:
The spectra
before thebefore
application
the spectral calibration.
Top: calibration.
Visibilities before
the spectral
was beapplied.
Bluethe
andby
is
also
reflected
intheequivalent
widths.
We
computed
the
line
sian
components
cannecessarilybedirectly
attributed
tospecific
erticalline
indicatesthemeanposition
of
the
line
peak.
Beforethecorgrey
shadedregions
indicatetheuncertainties
on
the
total
and
pure
line
tinctions
in
terms
of
visibility
signalstrengthconstituent
peaks
being
somehow
attenuated.
vertical line indicates the mean position of the line peak. Before the cor- grey shaded regions indicate the uncertainties on the total and pure line
ction, the individual spectra for most of our objects were misaligned visibilities, respectively. Bottom: Same baseline
after the correction.
luminositiesforeach Sameobjectfrom after
the equivalent
widths and Kphysicalphenomena,suchasadditional
outflows
on
top
of
an
acweenthedi↵erent
sources.
Particularly
clear
The
di↵erential
phase
data
is
significantly
more
noisybaseline
whenthetoindividual
spectramostofother.
ourBotobjects
were withmisaligned
visibilities,
respectively.
Bottom:the correction.
othrection,with respect
the telluric lines
and also for
betweeneach
Especiallyrespect to the computationof thepure line visibilities,
Fig.
2.PBr
spectraofvisibilities.
theASobservation,
taken
with
the
Fig.
3. Total
and2003).
pure line
visibilities
for an exemplary baseline from
Samewith
spectraafter theybrought
intolinesalignment
throughthethechangeappears
inEspeciallythered353wingof
the magnitudes
signal.
ヴィジビリティ・スペクトル(相互相関)の例
band
from
2MASS
(Cutriet al.
Wethen usedbothrespecttothetelluric
also
betweeneachother.
Botwithrespect
to thecomputationof thepureline
visibilities,sm:
were
observed
inwerebothepochs
ofand
RU
Lup,
compared
tosignificant
theStandard
deviations
in four
the unit
contincreting
magnetosphere,isnotcertain.
InverseCygni
features,pectral calibration. The corrected spectra and recomputed observables
telescopesof the the
VLTI.
the
ASsignal.
353
observation.
tom:
Same
spectra
after
they
were
brought
intoalignment
throughthechangeappears
significant
in
the
red
wing
of
the
ce
betweenBrpeak
andsurrounding
continuum
adjacent
to
Br
,
even
for
sourceswithclear
di↵erential
theempirical
relationshipfrom
Alcalá
etal. (2014),
as
expected
to
be
seen
when
observingmagnetosphericaccreere then further shifted to bring them to the local standard of rest
seismicな⾊付けをしている□印が,この論⽂でもっとも重要なデータ
Top:
The
spectrabeforetheapplicationofthespectralcalibration.
The
Top:
Visibilities
beforethe spectral correction was applied. Blue anspectralcalibration.
The
corrected
spectraandrecomputed
observables
LSR).
h tionas 0.12(Fig. D.3),
comparedto the relatively
phaseBr
peaks,
aretheon
averagethetheorder
ofat 0.4
. For
the
very
columnsatlow
inclination,aregenerally
absentfromline
to continuumdi↵erenceinvisibilityof onlyabout
0.01
verticalline
indicatesthemeanposition
of
line
peak.
Beforethecorgrey shaded regions indicate the uncertainties on the total and pure lin
were
then
further
shifted
to
bring
them
to
the
local
standardofrest
何かの補正(よく理解できなかった)のオフライン補正をしている.
ted
at profiles
the position
of Br
for DoAr
44for
witha even
noisy
data
of
VV CrAthecontinuumevengoes!dispersion! up tothe longest
baselines.
rection,theindividual
spectra
for
most
of
our
objectsweremisaligned
visibilities, respectively. Bottom: Same baseline after the correction
line
of
the
sample,even
those
objects
observedata(LSR).
Noise levels can equally vary greatly, with low
L continuum disL
acc

Line

own to 1.19 for
ects
line
5.exhibit
Resultss of blueshifted
tting a superpo5.1. dividing
General results
sically
component andInthesethisGaussection we first present a breakdown of the general reher
buted
to specificsults
obtained from the GRAVITY T Tauri data, introduce someon top of an acadditional
Cygni
features, concepts relevant to the interpretation, and give anospheric
accre-over the global trends we were able to identify acrossoverview
absent from theentiretsthe
observed
at a sample. In the following sections, we then proceed
Thego
width
and each source individually in detail and contextualise
toovertotal emission
ourfindings by drawing upon relevant references, if and wheree, even between
available.
ugh
the overall Table 3 summarises key results concerning the charakacteristics
flux ratio and of the Br emission region and accretion properties,

respectively. Figures 4 and 5 serve as a visual overview of thesample results with regards to the most important criteria we use
to interpret our results.
The sample consists of mostly strong Br emitters, with normalised peak line to continuum flux ratios between 1.91 and 1.53
for six out of our eight data sets and ranging down to 1.19 forthe weakest emitter DoAr 44. Many of the objects exhibit line
shapes that are asymmetric, featuring an excess of blueshifted
emission. We approximate this asymmetry by fitting a superposition of two Gaussian functions to the data, basically dividing
the feature into a narrow centred low velocity component anda broader o↵set high velocity component. Whether these Gaussian components can necessarily be directly attributed to specificphysical phenomena, such as additional outflows on top of an accreting magnetosphere, is not certain. Inverse P Cygni features,as expected to be seen when observing magnetospheric accretion columns at low inclination, are generally absent from theline profiles of the sample, even for those objects observed at aFig. 4. Relationships between Br emission region sizes and selected
stellar properties.
Top: Fitted HWHM of the Br pure line emission region of the central channel versus the mass-accretion rate. The latter is depicted in
two forms: Once as a grey bar which denotes the range of Ṁ values
found in the literature on the respective source, then as the instantaneous
mass-accretion rate, which was derived from the equivalent width of the
GRAVITY Br spectra. The colour coding represents the classificationof the sample objects as either weak (green) or intermediate to strong
accretors (red). Most of the T Tauri stars cluster in a 4-7 R⇤ range, which
is of the order of typical magnetospheric sizes.
Bottom: Br HWHM versus accretion luminosities. The colour coding
corresponds to the upper plot.

is also reflected in the equivalent widths. We computed the line
luminosities for each object from the equivalent widths and Kband magnitudes from 2MASS (Cutri et al. 2003). We then usedthe empirical relationship from Alcalá et al. (2014),
Lacc

!

LLine

!

A&A proofs: manuscript no. SpatiallyResolvedKinematicsWojtczak2022

みどりは共動半径
⾚は2μm連続波

J. A. Wojtczak et al.: Spatially resolved kinematics of hot hydrogen gas

matic depiction of the innermost parts of the circumstellar disk of a T Tauri star. Br emission in T Tauri stars is associated with theagnetospheric accretion, but outflows caused by certain types of disk or stellar winds (dashed lines) can heat the hydrogen gas totemperatures to produce Br emission as well. Di↵erent origin mechanisms can be tied to di↵erent spatial scales. Magnetosphericws (depicted in red) can only stably form in a compact region within the co-rotation radius Rco , where the gaseous disk rotates at thevelocity ⌦ as the star. Spatially extended Br emission from outside Rco cannot be attributed to magnetospheric accretion and mustsome other emission component.
ecifically shows the common case of a non-axisymmetric magnetosphere, featuring a tilt between the stellar rotational axis ⌦⇤ anddipole µ. The obliquity of the magnetosphere leads to the formation of two accretion columns, which funnel gas from a wide arc at
radius onto one primary hot spot per hemisphere, as first suggested in Bertout et al. (1988) and Calvet & Hartmann (1992). The
physical quantities relevant for the determination of the co-rotation radius Rco and the magnetic truncation radius Rtr are discussed
For the equations used to estimate the sublimation radius Rsub , which indicates the area at which the disk becomes sufficiently hot torains, we refer to Gravity Collaboration et al. (2021b).

weaker mass-accretion rates, but also exhibits sig- plane is almost completely evacuated from gas particles (Bounetic field strengths of 1-2 kG due their convective vier et al. 2007). Instead of further spiralling inwards, the gas
Johns-Krull 2007). This substantial di↵erence in the particles can only move freely along the field lines, which e↵ecFig.activity
5. Sample
overview
for emission
region sizesof
andphotocenter
shifts.
netic
hasgiven riseto the paradigm
magtively
serve as funnels that channel the gas onto the star. As the
Top: Br half-flux radii (yellow), compared to K-band NIR continuum half-flux radii (red) and co-rotation radii (green) across the sample. We
accretion.
As a theory concerning accretion in low- gas impacts the stellar surface at high latitudes, it creates heatednote that Br region and continuum HWHMs are based on a Gaussian disk and a Gaussian ring model, respectively, which should approximately
it reflect
has attained
preeminence
due to itsof ability
to recshockareregions
the poles (Hartmann
etrate.
al. 2016).
the di↵erencesin the morphology
both regions.
The objects
given incloseorder toof descending
mass-accretion
tionBottom:
properties
with the ofpresenceof stellar
hotacrossspotsthe line
The distribution
photocentre
shift angles
for the entire
sample.lines
The x-axis
the minimumdi↵erenceangle between
Hydrogenemissionserveshows
as tracers
for thekinematics
ofthe relative
shift vectorline
and thepositionangle of the continuum
disk. The white channel serves as the point of reference for the relative shift vector.
rvationsof hydrogen
profiles(Camenzind
1990; thehot gas in the inner star-disk system. In particular the nearAn angleof 0 means
photocentre shift
is aligned
the disk axis, as would for example be expected for a disk in rotation. A di↵erence
artmann1992).
It hasthesuperseded
the vector
earliertheorywithinfrared(NIR)
Br lineat 2.16is directly
relevant
angle of 90 indicates that the shift vector is perpendicular to the disk axis.
A clusteringof points
closeµm,
to a which
certain di↵erence
angle
indicates anlayeraccretion,
which
is
still
thought
togovernthework,requiresthe gas ofto photocentres,
be at temperaturesof 8000
tomorealignment of the photocentre shifts along a preferential axis. VVfor
CrAthisshows
a monoaxial
distribution
while for othertargets
mass
accretioninmagneticallyweakintermediate
complex profiles with multiple alignments are indicated. The number
in brackets afterthe(1998a),
object namegives the averageon the angle
10000stated
K (Muzerolle
et al.
Tambovtseva
et erroral. (2016))
Ae/Be
type
YSOs
(Mendigutía2020).
for the five central channels.
in order to produce strong emission. A heated gaseous disk inof magnetospheric accretion, it is proposed that the↑ Brγ
￼ 輝線は, どこから放射しているのだろうか？

まずはサイズ⽐較（上から降着率順）

R Lupでは, 2018?9?から2021にかけての変動も検出.

灰⾊直線は, 円盤単軸の向き
灰⾊影は, その不定性
⻩⾊⽮印線(ここでは左下向き)は,blue jetの向き; ⻩⾊影は不定性
⾚の楕円は星の位置の不定性
Fig. 7. Spectrum (top), size (middle), and photocentre shift (bottom) profiles for the two epochs of RU Lup in 2019 and 2021. Shaded regions
indicate uncertainties.

ただし, R Lup星の半径￼R* ≃ 2.6R⊙

⻩⾊⽮印線(ここでは左下向き)は,blue jetの向き; ⻩⾊影は不定性

⾚の楕円は星の位置の不定性

灰⾊直線は, 円盤単軸の向き

ただし, R Lup星の半径￼R* ≃ 2.6R⊙

灰⾊影は, その不定性

Fig. 7. Spectrum (top), size (middle), and photocentre shift (bottom) profiles for the two epochs of RU Lup in 2019 and 2021. Shaded regions
indicate uncertainties.

Br wavelengths is small, it is reasonable to assert th
the maximum shiftHydraof 0.009
au and an average shift ofpole-onで⾒ているはずのTW(残念ながら１エポックのみ)
0.003 for the central channels compared to a stellar
0.006 au, the Br photocentre across the line coincides• 他の天体と⽐べ、コンパクトな領域に集中
position of the central star. This suggests that most of t
• ポールオン＆１回の観測なので、このデータだけから⾔えることは
ent photocentre velocity components of Br emission,
少ないが、⾮対称分布であることから…………???のモデルと合う.
almost pole-on, are well centred on the stellar positio
can be inferred directly from such a distribution. At ver
clination, any centrosymmetric brightness distribution
to lead to a similarly compact profile centred on zero,
only in combination with more conclusive evidence, as p
above, does it support the magnetospheric accretion sc
is still noticeable that the distribution, and indeed the diphase signals at the individual baselines, appear to show
larger shifts in the red wing of the line. In the case
⾚の楕円は星の位置の不定性
clined magnetosphere with two accretion columns, theただし, TW Hの星半径￼R* ≃ 1.21R⊙
could be naively expected in a pole-on configuration, as
灰⾊直線は, 円盤単軸の向き
gas
at
the
far
side
of
the
star
at
the
highestblueshiftedv
灰⾊影は, その不定性
would be blocked by the star itself, which should leadaway from the centre for the blue components. The abs
stronger shift in the blue arm could indicate that the ction of the magnetic field in TW Hya is close to an axisy
scenario with a small obliquity angle between dipole
tional axes. Such a case would be in line with the relativ
di↵erence in inclination between the inner NIR continu
Fig. 10. Spectrum (top), size (middle), and photocentre shift (bottom) and the outer disk and also the lack of blueshifted ab
profiles for TW Hya. Shaded regions indicate uncertainties.
However, a previous study by Johnstone et al. (2014)

A&A proofs: manuscript
no. SpatiallyResolvedKinematicsWojtczak2022
J. A. Wojtczak
et al.: Spatially resolved kinematics of hot hydrogen gas

matic depiction of the innermost parts of the circumstellar disk of a T Tauri star. Br emission in T Tauri stars is associated with theagnetospheric accretion, but outflows caused by certain types of disk or stellar winds (dashed lines) can heat the hydrogen gas totemperatures to produce Br emission as well. Di↵erent origin mechanisms can be tied to di↵erent spatial scales. Magnetosphericws (depicted in red) can only stably form in a compact region within the co-rotation radius Rco , where the gaseous disk rotates at thevelocity ⌦ as the star. Spatially extended Br emission from outside Rco cannot be attributed to magnetospheric accretion and mustsome other emission component.
ecifically shows the common case of a non-axisymmetric magnetosphere, featuring a tilt between the stellar rotational axis ⌦⇤ anddipole µ. The obliquity of the magnetosphere leads to the formation of two accretion columns, which funnel gas from a wide arc at
radius onto one primary hot spot per hemisphere, as first suggested in Bertout et al. (1988) and Calvet & Hartmann (1992). The
physical quantities relevant for the determination of the co-rotation radius Rco and the magnetic truncation radius Rtr are discussed
For the equations used to estimate the sublimation radius Rsub , which indicates the area at which the disk becomes sufficiently hot torains, we refer to Gravity Collaboration et al. (2021b).

weaker mass-accretion rates, but also exhibits sig- plane is almost completely evacuated from gas particles (Bounetic field strengths of 1-2 kG due their convective vier et al. 2007). Instead of further spiralling inwards, the gas
Johns-Krull 2007). This substantial di↵erence in the particles can only move freely along the field lines, which e↵ecnetic activity has given rise to the paradigm of mag- tively serve as funnels that channel the gas onto the star. As theaccretion. As a theory concerning accretion in low- gas impacts the stellar surface at high latitudes, it creates heatedit has attained preeminence due to its ability to rec- shock regions close to the poles (Hartmann et al. 2016).
Fig.properties
15. Modelwith
imagesderivedofquantitiesof spots
the Br emission region.
tion
the andpresencestellar hot
Hydrogenemissionlinesimage
serveat as
tracers
for thekinematics
The three
the profiles
left show(Camenzind
the continuum-subtracted
Br emission
regionthree
di↵erent
velocities,
while ofthe two columns onrvationsof columns
hydrogenonline
1990; the hot
gas
in
the
inner
star-disk
system.
In
particularthenearthe right1992).
show thephotocentre
shift theprofileand thesize profile across all velocity components of the Br line, for a range of inclinations between
artmann
It hassuperseded
earliertheoryinfraredred(NIR)
Br marked
line atwith
2.16a µm,
is directly
relevant
5 and 67 . The model images correspond to the blue, whitechannelsbold which
black outline,
and thephotocentres and region
layeraccretion, which is still thought to govern the for and
this
work,
requires
the
gas
to
be
at
temperaturesof8000
sizes in those particular channels are defined by the red dots and the semi-major axes of the red ellipses, respectively. Only thetosemi-major axis ofmassaccretion in magnetically weak intermediate 10000theK approach(Muzerolleet withal. (1998a),
Tambovtseva
et al.16(2016))
the ellipse is left as a free parameter of the fit, which emulates
taken
the observational
data. Fig.
shows the corresponding
Ae/Be
type
YSOs
(Mendigutía2020).
in orderstrong emission. A heated gaseous disk in
profiles if inclination and position angle are also free parametersof totheproduce
fit.
of magnetospheric accretion, it is proposed that theFig. 9. Spectrum (top), size (middle), and photocentre shift (bottom)
profiles for DG Tau. Shaded regions indicate uncertainties.

16

Dipartimento di Fisica, Sapienza Universitá di Roma, Piazzale Aldo Moro 2, I-00185, Rome, Italy
17 Department of Physics
The &
Star
Formation
Rateofof
the Milky
Way as seen
byCalgary,
Herschel
Astronomy,
University
Calgary,
2500 University
Dr. NW,
AB, T2N1N4, Canada

D. Elia,1 S. Molinari,1 E. Schisano,1 J. D. Soler,1 M. Merello,2 D. Russeil,3 M. Veneziani,4 A. Zavagno,3, 5 A. Noriega-Crespo,6 L. Olmi,7M. Benedettini,1 P. Hennebelle,8 R. S. Klessen,9, 10 S. Leurini,11 R. Paladini,12 S. Pezzuto,1 A. Traficante,1 D. J. Eden,13, 14 P. G. Martin,15
Submitted
to
9
1, 16
8
17ApJ
M. Sormani, A. Coletta,
T. Colman, R. Plume, Y. Maruccia,1 C. Mininni,1 and S. J. Liu1
1 INAF - Istituto di Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, I-00133 Roma, Italy

ABSTRACT

2 Departamento de Astronomı́a, Universidad de Chile, Casilla 36-D, Correo Central, Santiago, Chile

We present a new derivation3 Aixof Marseillethe Milky
current
star
formation
Univ.,Way’s
CNRS, CNES,
LAM,
Marseille,
Francerate (SFR) based on the data of
4 Science
the Hi-GAL Galactic
plane& survey.
estimateOlof
thePalmestraat
distribution
of LR
theDelft,
SFR
the Galactic plane fromTechnologyWe
Corporation,
14, 2616
Theacross
Netherlands
Universitairede France,
France the total SFR from the sum of their
the star-forming clumps identified in5 Institut
the Hi-GAL
surveyandParis,
calculate
6 Space Telescope Science Institute, 3700 San Martin Dr., Baltimore,−1MD 21218, USA−1
contributions. The estimate of the global SFR amounts to 2.0 ± 0.7 M! yr , of which 1.7 ± 0.6 M! yr coming
7 INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy
from clumps with8reliable heliocentric distance assignment. This value is in general agreement with estimates
Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191, Gif-sur-Yvette, France
found
in
the
literatureof
last
decades.
The
profileofSFR
density
averagedin
Galactocentric
rings
is
found
9 Universität Heidelberg, Zentrum für Astronomie, Institut für theoretische Astrophysik, Albert-Ueberle-Str. 2, D-69120 Heidelberg, Germanytobe qualitatively
similartootherspreviously
computed,
with
a
peak
corresponding
totheCentral
Molecular
10 Universität
Heidelberg, Interdiszipliäres Zentrum für Wissenschaftliches Rechnen, Im Neuenheimer Feld 205, D-69120 Heidelberg, Germany∼ Scienza
5 kpc,5, followedby anexponential
decrease as
Zone and another11 INAF
one -around
Galactocentric
galdellaOsservatorio
Astronomico di radius
Cagliari, R
Via
I-09047 Selargius
(CA),
Italy
−2
−1
12
kpc Processing]) = a RAnalysis+ b,with aInstitute= −0.28± 0.01.Pasadena,
In thisCAregard,
the fraction of SFR
log(ΣSFR /[M! yr Infrared
gal /[kpc]Center,California
of Technology,
91125, USA
13 Astrophysics
producedwithinandInstitute,outsidethe Solar
84% and16%,
respectively;
theUK
far
Research
LiverpoolJohncircle
Mooresis
University,
IC2,
Liverpool
Science Park,the146fraction
Brownlowcorresponding
Hill, Liverpool, L3to
5RF,
14 Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DB, UK
outer Galaxy (Rgal > 13.5 kpc) is only 1%. We also find that, for Rgal > 3 kpc, our data follow a power law as a
15 Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8, Canada
function of density, similarly to the Kennicutt-Schmidt relation. Finally, we compare the distribution of the SFR
16
Dipartimento di Fisica, Sapienza Universitá di Roma, Piazzale Aldo Moro 2, I-00185, Rome, Italy
density acrosstheface-onGalactic
plane
and
those
of
medianparameters,suchastemperature,luminosity/mass
17 Department of Physics & Astronomy, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N1N4, Canada
ratio and bolometric temperature, describing the evolutionary stage of Hi-GAL clumps. We found no clear
correlation between the SFR and the clump evolutionary stage.
Submitted to ApJ

-2

15

15

10

10

-180

5

5

-120

0

-60

0

60

120

180

0

Galactic latitude [deg]Log(ΣSFR/[MO•deed generally dominated by the Galacticbar(Binney et al.
Elia
et
al.
0.03
1991; Ellsworth-Bowers et al. 2015; Li et al. 2016). As ex0.02
+2
-3
-1.40
plainedby Mège et al. (2021) and Elia et al.Elia(2021),
only in8
et al.
0.01
cases of small deviations, the distance of the corresponding
0
-1.40
-4
10 is assigned to sources, which can therefore betangent point
involved in the calculationof the SFR. Additionally, in the
10-2longitude range corresponding to the void lobe in the fourth
0.00
100
SFR [M yr ]
0.08
-2.10
5
quadrant, Mège
et al. (2021) found a relatively high occur1.5-2.10
5 original spectral survey data which in
rence
of
noise
in
the
0.06
80
many cases prevented an estimation of the radial velocity and0.04
hence of thekinematic distance. In any case, since the two
0
60
0
1.0
0.02
void areas are oriented approximately along Galactocentric
0.00
-2.80
radial directions, their influence is distributed over a certain
-2.80
40
+180
+120
+60
0
-60
-120
-180
number of rings (andtherefore attenuated).
-5
Galactic longitude [deg]
-5
0.5
The
dip
in the SFR density profile is followed by another
20
Figure 4. Top: Star formation rate (SFR) toward the Galactic plane in 3◦ × 0.2◦ bins in Galactic longitude and latitude, respectively. It is tolocal peak at around 5 kpc. A peak in this position was prenotice that in the outer Galaxy the Hi-GAL latitude coverage follows the variations in the midplane position, or Galactic warp (Westerhout
dicted by Krumholz-10 & McKee (2005) as a consequence of1957). For a better rendering of the image dynamic range, the color scale follows0.0
a power law with exponent 0.4. The dotted lines indicate the0-3.50
location of the three most prominent SFR peaks. Bottom: SFR as a function of longitude, estimated from the sum of the results reported in the-10 of the molecular gas surface density, and was-3.50
the distribution
The
SFR
of
the
Milky
Way
as
seen
by
Herschel
9
0
5
10
15
top panel across Galactic latitude.
Crux-Scutum
Galactocentric radius [kpc]found also by Portinari& Chiosi (1999) and Chiappini et al.
lar, in these areas absolute values of radial velocity are exNorma (Outer)Milky Way:NGC 6946:
Crux-Scutum-15
0(2001),
but
at
∼
4
kpc.
It should correspond to the soTable 2. Star
formation rate estimates for the Central Molecular Zone
−1
This work
Schruba et al. (2011)
Carina-Sagittarius(Ellsworth-Bowers
al.
pectedbe larger
100 km srate
Figure6. toTop:
Starthanformation(SFR) density etprofile
estiNorma(Outer)Guesten & Mezger (1982)
calledMolecularRing(which is, more realistically, an efPerseus
-15
2015,
their
Fig.
1),
while
most
of
sources
observed
inthecormated
fromthe
Hi-GALobservations
in
0.5-kpc-wide
concentric
Lee et al. (2016)-4.20-1
Carina-Sagittarius
MethodArea boundaries
SFRCMZ (lit.) Reference
SFRCMZ (this work)
responding
longitude
rangesshow
lower
values.
The
kinefectofspiralarm
arrangement,
see
Dobbs
&
Burkert2012;
rings aroundMtheyr−1Galactic center, shown in black
filled circles. Fit-15
-10
-5
0
5
10
15
PerseusM# yr−1#
matics
of
the
Milky
Way
along
these
lines
of
sight
is
in-4.20
Roman-Duval et al. 2016; Miville-Deschênes
et al. 2017),
ting the relation
2 to theat 0.04
Rgal± 0.02
≥ 5 kpc givesx[kpc]-2counts (Spitzer)
YSO|!| < 1◦ , |b| < 10%
0.14 in Eq.
Yusef-Zadeh
et al.portion(2009)
deed generally dominated by the Galactic bar (Binney et al.
= −0.30± 0.16. The fit
is±plotted
as a black
Continuum emission at 60, 100 µm (IRAS)|!| < 3◦ , |b| < 1◦ a a = −0.28 ± 0.01
0.12 and b
Crocker
et al. (2011)
0.12
0.05
but it does notpeak of source-15mirror exactly-10 the -5
0 number5 dis- 10
15
1991;
Ellsworth-Bowers
et
al.
2015;
Li
et
al.
2016).
As
exContinuum
emission at 60, 100 µm (IRAS)|!| < 0.8◦ , |b| < 0.3◦ dashed line. The
0.08 green
Crocker
etshowsal. (2011)the results
0.04of± 0.02line
theonlyvisible-band-3
x [kpc]% 6 kpc. Finally,
tribution found by Elia et al. (2017) at Rgal
plained
by
Mège
et
al.
(2021)
and
Elia
et
al.
(2021),
in◦◦Figure
5.
Map
of
the
decimallogarithmofSFR
density(dividedbyM yr kpc ), across the Galactic plane. The spatial bins are of 0.5 × 0.5
YSO counts (Spitzer)|!| < 1.5 , |b| < 0.5 observations considered
0.08
Immer
et
al.
(2012)
0.08
±
0.03
in
Guesten&Mezger(1982),
re-scaledbysmall deviations,corresponding
a exponentiating
systematicde- logarithm, and then multiplying by a factor
at larger
distances,ΣSFR
the absolute SFR
insidedefinitely
each pixel can beshows
obtained by
the displayed
kpc , so that
Ionization
rate from radio free-free
2.5◦ < ! < 3.5◦ , |b| < 0.5◦ cases of 0.035
Longmorethe
et al.distance(2013) of the0.11± 0.04 −1-4Kennicutt& point
Evansis (2012)
totothetotal SFR
1.9therefore
M# yr bereported
4 kpc . The Galactic center is at the [0,0] position, while the gray X symbol indicates the position of the Sun. Gray dashed lines mark Galactic
tangent
assignedsources,whichofcan
Ionization rate from radio free-free
as above, but |b| < 1◦ for |!| <1◦
0.06
Longmoreetal.
(2013)
0.12±
0.05
crease.
 (2011). The blue line corresponds to theoctants. Four spiral arms according to the prescription of Hou et al. (2009)
are overplottedwith four different tones of green; the correspondence−1−2in
Chomiuk&
Povich◦◦
involved
inthecalculation
of
the
SFR.
Additionally,inthe
Figure
5.
Map
of
the
decimallogarithmofSFR
density(divided
by
M
yr
kpc
),
acrossthe Galactic plane. The spatial bins are of 0.5 ×!
Continuum emission at 24 µm (Spitzer)|!| < 1 , |b| < 0.5
0.09 ± 0.02 
betweenarms andbehavior
colors is explainedin the legend at the bottom
left corner.
This
globalisqualitatively
similar
to
those
shown
2

b voidobtainedin Barnes
Lee etet al.
(2016)
bylobecombining
YSO NIR kpc , so that the absolute SFR inside each pixel can be obtained by exponentiating the displayed logarithm, and then multiplying by a fa
longitude
tothein
thecfourth
0.06± 0.020.5◦ estimates
0.10 range± 0.02 correspondingal. (2017)
Continuum emission at 70 µm (Spitzer)|!| < 1◦ , |b| < 100
5 of
one canappreciate
that,dashedwith respect
to the
3.2.
SFR
Galactocentric
profile2
byGalactic
Kennicutt&
Evans(2012)(startingfrom indicates
theIn Figure
data
center isat the[0,0]position,while
the gray X symbol
the positionof theSun. Graylines markGal
quadrant,
etal.
(2021) foundrelatively highandMège
cloud
properties
fromamillimeterline occurobservations. 4 kpc . The
Cont. emission at 5.8-500 µm (Spitzer, Herschel) |!| < 1◦ , |b| < 0.5◦ photometry
0.09± 0.03Galactic
center(towhich
weassignthe[0,0]position),
the
Using
informationabout
the heliocentric
a are overplotted with four different tones of green; the correspondoctants. Four spiralarmstheaccording
to theprescriptionof Hou distance,
et al. (2009)
1.5
rence
of
noise
in
the
original
spectralsurvey
data
which
in
Guesten&Mezger
1982)
and
Lee
et
al.
(2016):
an absolute
The red line shows the SFR profile of the galaxy NGC 6946, pre- between arms andSFRshows a certain degree of circular symmetry.
80
pole-onviewofSFR density
in legend
the MilkyWay,mappedoncorner.
acolorsis
explained
in
the
at
the
bottomleft
a Differently from other rectangular areas quoted in the table, this one has an elliptical
many
cases
analong
estimationof theradialvelocity and& Evans
It makessense, therefore, to analyze the behavior of theshapewithprevented
axesaligned! andand b,adapted
andsemi-axesofsentedin
Schrubaetal.
(2011)
byKennicutt
built.
This
is a simplified
grid of 0.5 ×
0.5-kpc2 pixels, can be
maximum
corresponding
to
the
CMZ,
followedbyalocal
in concentric
500-pcrings, toSFRdensity5ΣSFR
3◦ and 1◦ , respectively.
In
Figureone, averaged
can appreciatethat,withwide
respect
3.2.representation
SFR Galactocentric
profilehenceof pink-shaded
the kinematic area
distance.
In region
any case,since theby
twothe mod2-Dof the Galactic
disk which has a structure60(2012).
Theistheoccupied
5 kpc,
minimumand by another local peak at Rgal =1. In Figure
6, toppanel,
vsand
the Galactocentric
radiuswe
Rgalb In 1.0
along the third dimension, an idea of which can be taken from
Galactic
center(to whichassignthe[0,0]position),
voidtheareas
approximately
Galactocentric
Barnes et al. (2011), their Table 2, a further list of SFRCMZ estimates derived withinsameareareaoriented
from monochromatic
fluxes oralong
bolometric
2
Using
the
information
about
the
heliocentric
distance,aels of omitEvansetin al.
(2022).
Bottom:Cumulative SFR profile as aa peakcorresponding to the inner circle is followed by a
Figure 4. The designofathedecreasing
Hi-GAL survey took
into accountrespectively,
withbehavior
atlargerGalactoluminosities available in the literature from 1998 to 2011 are quoted (see text). Weradial
them
this
table
for
the
sake
of
brevity.
SFRshows
a certain degree of circular symmetry.
directions,
theirinfluenceisdistributedoveracertainpole-onviewofSFR
density
in
the
Milky
Way,
mappedona40functionof theGalactocentric
radius,also expressed as a percentthe warp of far-infared emission already observed by IRAS
c The three SFR
It makes sense, therefore, to analyze the behavior of
2
number
of
rings
(and
therefore
attenuated).
centric
distances.
This
generalbehavior
was successfully
estimatesbyBarnesetal.
(2017)
arederivedwithin
the
same
area
in
the
sky
throughdifferent
methods;
obviously,
for
the
CMZ
pixels,canbebuilt.
This
is aissimplified
grid of 0.5 × 0.5-kpc
towards
theouterGalaxy,which
howeverlessprominent
0.5
To correctly compare this plot with Figure 5, it must be considered that inage with
respect
to thetotal
SFR(y-axison the byright-handside).
,density
averagedin concentric 500-pc wide ri
SFRdensityΣi)SFRsame area we can provide only one estimate.
The
dip
in
the
SFR
density
profileisfollowed
another2-D
representationoftheGalactic
disk
which
has
a
structure
this case theSFR
is obtained by dividing by the ring area, proporthan the by
Galactic
warp etobserved
in atomic bygas (Westerhout
modeledEvansal.
(2022)
takingintoaccounta
20
The verticaldottedlines 5indicate,frominleft
right, wasthe GalactocenFigurepa
Galactocentric
radiusRgal . Inconsists
to R , while in Figure
5 the denominatorof a 6,
localtoparea exlocal peakat aroundkpc. A peakthistoposition
preSoler et al.
2022),
correspondingtoGalactocentric
dis- vs thetional
along thedependence
third1957;
dimension,
an
idea
of
which
can
be
taken
from
respectively. The former one is about 3 times larger thanmates from the literature collected in Table 2. The authorsof theby conversion
factorfrom
CO aluminosity
to kpc . Also
2 in Section 2.2.1, thenoticethat, as discussed
tendingover 0.25
tric
radii
corresponding
to
50%,
90%,
and
99%
of
the
total
SFR,
is followed b
peakcorresponding
to
the
inner
circle!
16
kpc,
tancesnotachieved
objectsinoursample(R
dictedbyKrumholz&
McKee(2005)
asaconsequenceofgal
Figure 4. The design of the Hi-GAL survey took into accountdistribution in longitude of sources without a distance assignment shows athat0.0
of Longmore et al. (2013), and not compatible with it0
indeed suggest that the choice of the assumed IMF, which
Voskes& Butler2006).
),
mass
on Burton
metallicity(whichbyinIRAS
turn dependsremarkableon Rgalrespectively.
distributionof thepeculiar
molecular
gas surface
density, and wasconcentration
at 0 " ! " 20 . Assigning the distance of the
5
10
15 of
the warpcloudof far-infaredemissionalready observed
within 0the associated error
bar. Of course,
the estimate
did notthe
account
for possible
conditionsof the CMZ,
Galactic center to all of them would turn out in an even higher value for
Galactocentric radius [kpc]found also by Portinari & Chiosi (1999) and Chiappini et al.
and ii) a dependence of the star formation efficiency
on the8-1Log(ΣSFR/[MO• yr-1 kpc-2])

y [kpc]y [kpc]

!

−1

−2

2

%

15

15

10

10

5

5

0

2

0

∫0Rgal SFR(r) dr [MO• yr-1]%∫0Rgal SFR(r) dr [MO• yr-1]

SFR [MO• yr-1]

•
O

2

2
gal

2

◦

◦

15

10

5

0

Log(ΣSFR/[MO• yr-1 kpc-2])
0

-1

-2

-3

-4