2017年3月2日-3日
於・国立極地研究所

サブミリ波・テラヘルツ帯での広域銀河探査
Wide-area galaxy surveys
at submm – terahertz wavelengths
河野孝太郎
KOHNO Kotaro(IoA/RESCEU, 東京大学)

Contents• Roles of mulN-color photometric surveys atsubmm to terahertz wavelengths– We observe thermal emission from dust in galaxies– Why dusty objects?
– Why submm/THz?

• Proposed possible survey strategy using
AntarcNc THz 10m/30m telescopes– Lessons from Herschel Astrophysical Terahertz
Large Area Survey (H-ATLAS) etc.
– Synergy with The South Pole Telescope 2500 deg2
surveyOur current understanding of galaxy formationand evolution
Inflation è Tiny density
fluctuation

Growth of dark
matter halos

δ ~10-5

Infall of baryons into dark
matter halos è formation& growth of galaxies
Supermassive
black holes

Gas plasma,ionized, neutral,molecular, ..
Stars

A temperature map of cosmic
microwave background(CMB) imaged by WMAP

redshift ~1100 (13.7 Gyr ago)・most distant galaxy known： z ~ 11.09 (13.3 Gyr ago)・re-ionization： z ~ 6-20 ? (12.8 – 13.5 Gyr ago ?)・first stars： z ~ 30 ?? (13.6 Gyr ago ??)・recombination, “transparent to radiation”： z ~ 1100

Simulation of dark matter & gas
temperature distribution with ΛCDM
hXp://www.illustris-project.org/media/

Dust

Galaxies in their forming & evolving phases areoften heavily obscured by cosmic dust
Young stars

Obscured star formation

dust

infrared
ultraviolet

Star formation rate density

directly “visible” star formationle”
bis“vi nylt
ioc
dire format
starminerals,up to ~1 μm
in size

More obscured starforming ac2vi2es inearlier epoch of theuniverse>70% is obscured
＠7.8 billion yrs ago

Takeuchi et al. 2005,A&A, 440, L17
Present-day

redshift

7.8 Gyr ago (Big Bang was ~13.7 Gyr ago)

What is the cosmological role of dusty
star-formaNon?

Rowan-Robinson et al. 2016,
MNRAS, 461, 1100

Bouwens et al. 2016, ApJ, 833, 72

星形成率一定？

• is dusty star-formaNon signiﬁcantly contribuNng to star formaNon ratedensity at z > 4?
– Lyman break galaxies (LBGs) at ALMA deep survey@HUDF è dusty starformaNon is rather minor role (Bouwens et al.)• Importance of shorter submm bands is emphasized– Herschel-selected red sources è almost constant SFRD at least up to z~6 !?

Uniqueness of mm/submm galaxy surveys
Spitzer
MIPS
24μm
Spitzer
IRAC
3.6μm

Observing Wavelength (µm)

20cm

1cm

5 cm (JVLA/C-band)

1.3mm

870µm

500μm
350μm
250μm
HershelSPIREStrong negaNve K-correcNon @mm/submm gives auniform selecNon funcNon for high-z dusty galaxies
Almost ﬂat ﬂux
for 1 < z < 10around λ ~ 1mm !

Observed ﬂux density
as a funcNon of redshio
L(IR) = 3.2 × 1012 L¤
500μm

850μm
1.1mm
2mm

Casey et al. 2014
Physics Reports
541, 45

The cosmic infrared background (CIB)• The infrared part of the extragalacNc
background, the radiaNon content of theUniverse today, produced by astronomical
objects at all redshios, and seen as isotropic
extragalacNc background radiaNon.
• Discovered by the FIRAS spectrometer on
COBE at long wavelengths λ > 200 μm (Pugetet al. 1996, A&A, 308, L5)
AKARI whole sky survey

CIB: what is the origin?
In contrast, the infrared output of galaxies at z=0 is only 1/3 of the opNcal output.
è infrared galaxies grow more luminous with increasing z faster than opNcal galaxies

The cosmic infrared
background (CIB)

Comparable !!!

The cosmic opNcal
background (COB)

hXp://ned.ipac.caltech.edu/level5/March05/Lagache/Lagache3.html

“Submm galaxies” are bright, but..
Hatsukade et al. 2011, MNRAS, 411, 102

θ ~28”@1.1mmASTE
10m

Bolometer camera
AzTEC

233 sources
0.4 - 0.8 mJy (1σ)
area ~0.25 deg2

0.5 degBright SMGs > a few mJy @1mm
are ubiquitous, but
their contribu2on to EBL
is just ~10-20%

Deep photometric survey strategy• Which is the most unique band in AntarcNc
30-m telescope?
• Do we really need blind surveys at shortsubmm bands?
• How many bands (colors) do we need?
• Where is the right place for AntarcNc 30-m
telescope deep survey?

confusion limits (5σ) of mm/submm telescopes
Unit: mJy
LMT,
LST

IRAM,SST,
南極CCAT

CSO, ASTE,
SPT
GLT, Tsukuba 1.2’@2mm,

Herschel

30m

25m

15m12m10m

3.5m

3.3mm 0.052

0.084

0.098

0.15

0.17

0.20

2.0mm 0.13

0.23

0.28

0.44

0.53

0.61

1.4?

1.22

1.3mm 0.29

0.58

0.72

1.2

1.5

1.7

2 – 4?

3.50

1.1mm 0.36

0.78

0.97

1.7

2.0

2.0, 2.4

4.94860μm 0.42

1.02

1.3

2.3

2.9

3.4

7.36

750μm 0.53

1.37

1.8

3.2

4.0

4.8

10.28

Dish D50m

NRO

45m

JCMT

APEX

1.0’@1.4mm10m※

0.40

30.5#

500μm
450μm 0.26

1.5

2.2

4.8

6.3

7.6

18.0350μm 0.058

1.01.8

4.7

6.4

8.0

27.5# , 20.7

200μm 0.0008

0.04

0.17

1.7

2.9

4.2

17

#: Oliver et al. 2012, MNRAS, 424, 1614
Bold font: based on the measured number counts
Adopted number counts: Bethermin et al. (2012); deﬁniNon of confusion: 30 beams per sourceconfusion limits (5σ) è fracNon of CIB resolved
Unit: mJy
LMT,
LST

IRAM,SST,
南極

CCAT

30m

25m

15m

3.3mm 19.3%

10.5%

8.4%

2.0mm 34.3%

19.6%

15.8%

1.3mm 51.1%

30.7%

25.1%
13.7%
10.3%
8.2%
350 μmband:dramaNc

1.1mm 58.3%

36.0%

860μm 70.2%
750μm 75.5%

Dish D

50m

NRO

45m

JCMT

APEX

CSO, ASTE,
SPT
GLT, Tsukuba 1.2’@2mm,

Herschel

12m

10m

3.5m

4.4%

3.3%

2.6%

8.4%

6.3%

4.9%

1.0’@1.4mm

10m※

0.7%
1.4?

1.2%

2 – 4?

2.0%
2.4%

45.3%

29.6% 16.3% 12.3%
9.8%
improvement
by AntarcNc
37.7% 30-m
21.2%telescope!
16.2% 12.9%

49.7%

41.5%

23.5%

17.9%

14.3%

3.5%

450μm 95.4%

73.8%

64.1%

39.2%

30.6%

24.7%

6.4%

350μm 99.2%

86.3%

77.6%

50.9%

40.6%

33.3%

9.3%

200μm 99.9%

99.6%

98.2%

83.0%

72.6%

63.6%

24.1%

3.2%

500μm

#: Oliver et al. 2012, MNRAS, 424, 1614
Bold font: based on the measured number counts
Adopted number counts: Bethermin et al. (2012); deﬁniNon of confusion: 30 beams per sourceconfusion limits (5σ) è fracNon of CIB resolved
Unit: mJy
LMT,
LST

IRAM,SST,
南極CCAT

30m

25m

15m

3.3mm 19.3%

10.5%

8.4%

2.0mm 34.3%

19.6%

15.8%

1.3mm 51.1%

30.7%

25.1%
13.7%
10.3%
200 μmband:
even8.2%
in 10-m

1.1mm 58.3%

36.0%

860μm 70.2%

45.3%

37.7% 21.2% 16.2%
contributors
can be12.9%
captured

3.2%750μm 75.5%

49.7%

41.5%

23.5%

17.9%

14.3%

3.5%

450μm 95.4%

73.8%

64.1%

39.2%

30.6%

24.7%

6.4%

350μm 99.2%

86.3%

77.6%

50.9%

40.6%

33.3%

9.3%

200μm 99.9%

99.6%

98.2%

83.0%

72.6%

63.6%

24.1%

Dish D

50m

NRO

45m

JCMT

APEX

CSO, ASTE,SPT
GLT, Tsukuba 1.2’@2mm,Herschel

12m

10m

3.5m

4.4%

3.3%

2.6%

8.4%

6.3%

4.9%

1.0’@1.4mm

29.6%
12.3%of 9.8%
dish,16.3%
majority
the CIB

10m※

0.7%
1.4?

1.2%

2 – 4?

2.0%
2.4%

500μm

#: Oliver et al. 2012, MNRAS, 424, 1614
Bold font: based on the measured number counts
Adopted number counts: Bethermin et al. (2012); deﬁniNon of confusion: 30 beams per sourceFrom Herschel to AntarcNc 10m à 30m
terahertz telescope• Herschel SPIRE (350 μm) resolves (only) ~10%of the cosmic infrared background• è AntarcNc 10m surveys: ~30%
• è AntarcNc 30m surveys: ~90% (!)

Confusion-limited deep surveys using theAntarcNc 30m telescope will resolve most of
the cosmic infrared background at 350 μm
into discrete sources for the ﬁrst Nme

Why short-submm?
• A possible approach: do
unbiased survey at λ ~850μm –1mm band, then do mulNwavelength follow up (atshorter wavelengths)– An eﬃcient way for ALMA

• But such long-submm (~850μm– 1mm band) surveys may bebiased to lower dusttemperature galaxies è do
unbiased surveys at both shortand long-submm bands!

Casay et al. 2013,
MNRAS, 436, 1919

How many colors (bands)?

HerMES 274 deg2
S500>S350>S250
5σ cut-oﬀ: S500>52 mJy
è 477 “red” sources

Asboth et al. 2016
MNRAS, 462, 1989

500μm/350μm ﬂux raNo

• SPIRE (3 bands) è good esNmate ofphotometric redshios• “red SPIRE sources” è promising targets for z >4 dusty starburst galaxies

350μm/250μm ﬂux raNo

How many colors (bands)?
Ivison et al. 2016,ApJ, 832, 78

250μm

350μm

500μm

850μm (SCUBA2)• Adding longer
wavelength bands è
more sensiNve forhigher redshio dusty
galaxies + beXer
redshio constraints
zspec = 4.42

RecommendaNon:
4 bands @230μm,350μm, 460μm, and850μm

Last quesNon:
where is the right place for AntarcNc
30-m telescope deep survey?

Synergy
with The South Pole TelescopehXps://indico.cern.ch/event/432527/contribuNons/1072083/aXachments/1321207/1981378/2016_08_06_ICHEP_SPT_Benson.pdf

2
SPT 2500 deg (~6% of sky) survey

AzTEC/ASTE
1.1mm survey:
30” FWHM
0.4 – 2 mJy (1σ)
hXp://www.astro.caltech.edu/~vieira/spt_smg_Caltech_public_redacted.pdf

SPTpol
150 GHz30 deg2

hXp://www.ioa.s.u-tokyo.ac.jp/~ytamura/WS/LSTWS2015/Program_ﬁles/LSTWS2015_Vieira_SPT.pdf

150 GHz
50 deg2

SPTpolPoint Sources

Ac.ve galac.c nuclei, and the mostdistant, star---forming galaxies

z=2.782
HST--WFC3

ALMA

hXp://www.ioa.s.u-tokyo.ac.jp/~ytamura/WS/LSTWS2015/Program_ﬁles/LSTWS2015_Vieira_SPT.pdf

150 GHz
50 deg2

SPTpolClusters of Galaxies“Shadows” in the
microwave background fromclusters of galaxies

hXp://www.ioa.s.u-tokyo.ac.jp/~ytamura/WS/LSTWS2015/Program_ﬁles/LSTWS2015_Vieira_SPT.pdf

Cluster of Galaxies

“Wedding-cake” survey strategy• Widest (andshallowest) survey:
SPT 2500 deg2 area
• Deep survey: SPTdeep 500 deg2 area
• Ultra-deep survey:~10 deg2 area?
(where? è targeNng
SZ-selected clusters?)

Adding SPT bands?
• Adding longer
wavelength bands è
more sensiNve forhigher redshio dusty
galaxies + beXer
redshio constraints• BeXer characterizaNonof “850μm riser”!?
• But 1’ beam…

SPIRE
326 GHz

MUSIC on CSO

272GHz213GHz

ALMA band 3

Asboth et al. 2016
MNRAS, 462, 1989

143GHzExpected mapping speeds
hXp://www.px.tsukuba.ac.jp/~nakai/astroobs/pdf/antarcNc30m-spec.pdf

850μm
750μm
460μm
350μm
230μm
200μm

500 deg2 deep survey plan

5σ 1 mJy@850μm
è L(IR) = 5x1011L¤@z=5 (Tdust = 30K)
è L(IR) = 2x1012L¤@z=5 (Tdust = 50K)

• 850 μm: 44 deg2/hr/mJy2 x 1 unit
è 0.2 mJy (1σ) in 280 hrs – confusion limited ~30x deeper
than Herschel• 460 μm: 9.8 deg2/hr/mJy2 x 1 unit
surveys• è 0.3 mJy (1σ) in 1260 hrs – confusion limited• 350 μm: 4.4 deg2/hr/mJy2 x 1 unit
è 0.2 mJy (1σ) in 2840 hrs – confusion limited• 230 μm: 0.024 deg2/hr/mJy2 x 4 unit More allocaNon of 1.3 THz pixels
may be considered to equalize
è 1.2 mJy (1σ) in 2890 hrs
mapping speeds among 4 bands– Not confusion limited, but ~50% (?) of the CIB will be resolved
3000 hrs deep survey plan:- High cadence 850μm survey(10 confusion-limited maps will
be obtained aoer the survey) èsearch for Nme variable sourcesComparison with previous surveys

Proposed deep survey
using Antarc2c 30m

Lutz 2014, ARAA, 52, 373

Conclusions (for a deep photometric survey plan)• AntarcNc 30-m terahertz telescope, equipped with 350
GHz, 650 GHz, 850 GHz & 1.3 THz bands (850 μm, 460μm, 350 μm & 230 μm) è a ~3,000 hrs deep survey at“SPT-deep 500 deg2 area”– Following successful mulN-band approach by SPIRE 3 colors+ 1 longer photometric point (e.g., SCUBA2 etc.)– and deeper than Herschel surveys by a factor of ~30 !
– MiNgaNng “low dust temperature bias” of 850 μm – 1 mm
single band surveys– 350μm band is really unique for a 30-m telescope; thecosmic infrared background at 350μm will be fully resolved
into discrete sources for the ﬁrst Nme– A high cadence (~10 Nmes during the survey period) 850 μm
confusion-limited-depth photometric survey will also beimplemented automaNcally.

これまでの検討・今後しなければいけない検討• 装置仕様のドライバーとなるような、目玉となるサイエンスになるかどうかは、またさらに要・議論、として。
• いくつかの候補(これまでの議論)– 連続波による銀河探査 è (1) 特にz > 4を超えるような時代での、ダストに隠された星形成活動の寄与、(2) AGNにおける高温ダストの探査/熱源切り分け• THz/subTHzバンドで行う意義は？
• Confusion limitのきっちりした調査は？

– Redshioed H2• まともにやると難しい。でも、すごく強いショックを受けたような領域があればどうか？ Intensity mappingは？

– Fine structure linesによるダストに隠された領域での金属量診断• まだあまり検討できていない候補は？
– 無バイアス輝線銀河探査 è [CII] or [OIII] tomography !?
– OH P-Cyg proﬁleの系統的な探査 è AGN feedback– CH+ absorpNonの系統的な探査 è large scale turbulence è(caused by what??)

Consistency with measured number counts:
Confusion limit at 270GHz/1.1mm“30 beams/source” confusion limit
è 1.9×104 sources/deg2
4.6×103 sources/deg2
7.4×102 sources/deg2

LST 50m5.4” beam
è 5.6×105 beams
in 1 deg2 area
CCAT 25m
11” beamè 1.4×105 beams
in 1 deg2 area
ASTE 10m27” @1.1mm
è 2.2×104 beams
in 1 deg2 area

0.72 mJy
CCAT
0.25 mJy
LST2 mJy ASTE

Number counts at 1.1mm:
Tamura et al. 2014, submiXed遠赤外スペクトル線の強度比で探る
ダストに埋もれた超大光度赤外銀河での金属量
CapuN et al. 2008,
ApJ, 680, 939

Nagao et al. 2011, A&A 526, A149~0.6 Z¤•••

可視域の輝線比で診断すると、ULIRGは金属量が低いことが示唆される。è降着中の「若い」ガスを見ている？それとも、ダストで深い吸収を受けているため、可視域の診断では、金属量勾配の「裾」しか見えていない？（大きな課題）([OIII]51.80+[OIII]88.33)/[NIII]57.21強度比が測定できる赤方偏移の銀河であれば、より正確な金属量の診断が可能。（z<1.3）
各輝線がS/N=5であっても、可視輝線診断で示唆されるような低金属量（sub35solar）なのかどうかの判定が可能。

SPICA

ALMA

Fine structure lines
南極30m?

SAFARI (up to 230 μm)[OIII]52µm[NIII]57µm

B10z<3.0z<1.6[OIII]88µm[NII]121µm
0z<0.91B10B10B923B10z<3.4

redshift

CombinaNon of SAFARI/SPICA and ALMA
band 10 allows us to calibrate theproposed metallicity indicator([OIII]52µm/[NIII]57µm raNo) by adding[OIII]88µm line at z~3.
• It also gives a basis for extension of themethod to galaxies at z~5 and beyond.

B9B9B9B8~
B8/B7/B6~

456•

Nagao et al 2011
A&A 526, A147

78

ALMA [OIII] 88μm detecNon at z=7.21
Inoue, A., Tamura, Y., KK et al. 2016, Sciencef(obs) = 413 GHz (Band8), 41 antennas, 2 hours (on-source)0.45” x 0.38” resoluNon (NA)Elevated
L[OIII]88μm/L[CII]158μm
and L[OIII]/LTIR raNos
Local dwarf galaxies>1.3%(Madden et al. 2013; De Looze et al. 2014;
Cormier et al. 2015)

Localspirals>12

Inoue, A., Tamura, Y., KK et al. 2016,SciencehXp://hubblesite.org/gallery/album/exoNc/black_hole/pr2015031b/

DetecNon of molecular ou…lowsin the local quasar Mrk 231

RelaNve intensity(normalized to the conNnuum level)

39

Fischer et al. 2010, A&A, 518, L41
Herschel/PACS

P-cyg
proﬁleRest-frame wavelength (μm)
absorptionemission
IRAM 30m

Spoon 2013, ApJ, 775, 127

Cicone et al. 2012,A&A, 543, 99

AGN feedback via OH absorption lines
02

Look back time (Gyr)6810412SPICA

CO 4.7µm
H2 5-28µm

SPICA

南極30m?
SPICA

OH 79µm
OH 119µm

ALMASPICA

01

ALMA

ALMA

23

ALMA

ALMA

456Mkn231lOHl
Rest-wavelength (μm)

ALMA will have a complementary redshiftcoverage for study of AGN feedback via OH
P-Cyg profile
High velocity wings in CO (and othermolecules) with ALMA will also help

Flux (Jy)Normalized
spectrumRedshift
Mkn231COVelocity (km/s)

CH+: a unique tracer ofdissipaNve processes

J=1-0@835.08GHz• Fast destrucNon by collisions with H and H2• Once formed, its lifeNme is short: t ~ 1 yr (!)– For nH = 50 cm-3, fH2 = 1• にもかかわらず、太陽近傍のcold diﬀuse gasでは豊富 (70年来のpuzzle?)– UV-driven chemistryでは1桁以上足りない– (fast destrucNonに打ち克つには) supra-thermal
processesによるwarm chemistryが必須– Shocks and/or intense velocity shearsによるturbulenceの散逸が重要 (turbulent energy ﬂuxの10-2~10-3程度で充分)
Falgarone et al. 2015, ASP Conf. Sor, Vol. 499

CH+ @SDP17b (z=2.305)

Falgarone et al. 2015, ASP Conf. Sor, Vol. 499

CH+ @SDP17b (z=2.305)

Falgarone et al. 2015, ASP Conf. Sor, Vol. 499

今後のA/I• 検討すべき具体的な項目の整理• 宿題を割り振りたい。。
• Sub WGの設定？？
• 検討が概ねまとまったところで執筆作業開始？
– いつ・・？