ALMA Studies on the Galaxy Chemical Evolution in the High-z Universe

Tohru Nagao (The Hakubi Proj., Kyoto U.)

with R. Maiolino (U. of Cambridge)

C. De Breuck (ESO) P. Caselli (U. of Leeds)

B. Hatsukade (Kyoto U.) K. Saigo (NAOJ/ALMA)

ALMA時代の宇宙の構造形成理論： 第1世代から第n世代へ 2013年1月26-28日、北海道大学

Nagao et al. A&A, 526, A149, (2011) Nagao et al. A&A, 542, L34 (2012)

0 yr 　 0.38 Myr 0

.3 Gyr

2.0 Gyr 1

3.7 Gyr

z=∞ z=1100 z=11 z=3 z=0

WHEN？ WHERE？ HOW MUCH？

Big Bang    

First Stars, First Galaxies

Current Universe

Galaxy Evolution

BigBang Nucleosynthesis ~ first hydrogen ~ first helium

First Heavy Elements ~ first stars, first supernovae ~ second generations ~ third, fourth, …

Chemical Evolution

~ earth-like planets ~ life, human, & you

Structure Formation and Chemical Evolution

Maiolino, Nagao, et al. (2008)

z~0

z~1

z~2 z~3

12+log

(O/H

)

log(Mstar/Msun)

Metallicity scaling relations of galaxies

12+log

(O/H

) log(Mstar/Msun)

Mannucci, Cresci, et al. (2010)

Mass-Metallicity relation and its redshift evolution (downsizing?)

Fundamental metallicity relation (M, Z, and SFR) (universal up to z~2?)

with calibrations in Nagao et al. (2006)

Optical spectrum of star-forming galaxies

“R23” “N2”

“direct”

“Ne3O2”

Gas metallicity is derived through emission lines in rest-frame optical spectra.

Reddening correction is important in some cases; Balmer decrement is used for the correction generally.

How about the metallicity in very dusty galaxies?

Metallicity of dusty galaxies

Rupke et al. (2008)

LIRG ULIRG

LIRG ULIRG

12+log

(O/H

)

12+log

(O/H

)

log ( Mstar/Msun ) log ( Mstar/Msun )

Are IR galaxies “chemically un-evolved” systems !? ...optical lines are from “un-obscured” parts

Caputi et al. (2008)

How about high-z submillimeter galaxies (SMGs) !? ...no attempts have been tried so far

Long-wavelength diagnostics needed.

Le Floc’h et al. (2005)

Total SFR

IR-faint LIRGs ULIRGs

Importance of dusty galaxies

Long-wavelength diagnostics needed.

MidIR-FarIR spectra of star-forming galaxies

ISO/LWS spectrum of M82 Colbert et al. (1999)

[OIII] 5

1.81

[N

III] 5

7.32

[O

I] 63.18

[OIII] 8

8.36

[NII] 121

.90

[O I] 145

.53

[CII] 157

.74

[N

II] 205

.18

...metallicity diagnostics using these fine-structure emission lines?

Fine-Structure Lines?

O2+ Grotrian diagram

1S0

1D2

3P2 3P1 3P0

3P2 – 3P1: [OIII] 51.81 3P1 – 3P0: [OIII] 88.36

Fine-structure lines arise at HII regions and PDRs (and also others)

[OIII] [NII]

3P2 – 3P1: [NII] 121.90 3P1 – 3P0: [NII] 205.18

Osterbrock+06

Diagnostics for high-z dusty galaxies with ALMA?

Colbert et al. (1999)

[OIII] 5

1.81

[N

III] 5

7.32

[O

I] 63.18

[OIII] 8

8.36

[NII] 121

.90

[O I] 145

.53

[CII] 157

.74

[N

II] 205

.18

for Herschel/SPICA for ALMA

Sub-mm diagnostics? [NII]205 / [CII]158 !?

~ analogy with optical [NII]/Ha ~ Ha is “SFR” for normalization ~ [NII]6584 counts N fraction

Nagao+06

~ [CII] is also SFR index ~ [NII]205 counts N fraction

Nagao+12

[NII]20

5 / [CII]15

8

Zgas / Zsolar

PREDICTION with Cloudy runs

for both HIIR & PDR

PDR (photo-dissociated region) ?

HII region

PDR molecular region

Abel+05

Gas Te

mpe

rature (K

)

~1e4 K

a few e2 K a few e1 K

Secondary Element?

10^6 yr

10 min

10^5.5 yr 10^8.5 yr

1 min

10^4 yr

CNO-cycle Process 4 H He + energy CNO are just “catalyst”

(figure from wikipedia)

van Zee et al. (1998)

12 + log(O/H) log(N/O

)

N/O ∝ O/H at Z/Zsun > -0.5 where N/H ∝ (O/H)^2 observed in Galactic HIIR’s

long time!

Our Cycle 0 run: -- ALMA#2011.0.00268.S -- PI: Nagao (East-Asia program) -- CoI: Maiolino (Cambridge), De Breuck (ESO), Caselli (Leeds), Hatsukade (Kyoto) -- 3.6h in Oct.2011‒Jan.2012, band 6, compact configuration -- with 18 antennas (not 16) -- USB for [NII]205 at 253.96 GHz -- LSB for CO(12-11) at 240.14 GHz

Target: -- LESS J033229.4‒275619 at z=4.75 (Coppin et al. 2009) -- One of the most distant SMGs (the most distant SMG: AzTEC3 at z=5.3) -- SFR ~ 1000 Msun/yr (Coppin et al. 2009) -- Mgas ~ 2e10 Msun, Mdyn ~ 5e10 Msun (Coppin et al. 2010) -- Strong [CII] already detected (De Breuck et al. incl. TN, 2011) -- CO(2-1) also detected with ATCA (Coppin et al. 2010) -- hosting a Compton-thick AGN

ALMA Observations

ALMA Results: CO(12-11) CO(12-11): not detected -- 3σ upper limit: 344 mJy km/s -- CO(12-11)/CO(2-1) < 3.8 (3σ) -- spectral line energy distribution?

Ao et al. (2008)

AGN

HIIR LESS J0322

-- Different from CO SLED of APM08279 ( X-ray affected) -- Consistent to other objects -- The partially-ionized zone (PIZ) of LESS J0332 seems PDR, not XDR -- AGN effects are not serious

-- dust cont. also detected

Gilli+11

ALMA Results: [NII]205

Nagao et al. (2012)

[NII] clearly detected with S/N~8 with 3.6 hours ALMA observation!!

Comparison with models Nagao et al. (2012) (model details are given in Nagao+11)

The [NII]/[CII] ratio is comparable with that seen in low-z galaxies

This SMG has a substantially high metallicity (~ Zsun) even at z~4.76 !!

...suggesting that SMGs (or massive galaxies in general?) have experienced their chemical evolution at even higher redshift (z>5).

-24.5>MB>-25.5 (643 QSOs)

-25.5>MB>-26.5 (1497 QSOs)

-26.5>MB>-27.5 (917 QSOs)

-27.5>MB>-28.5 (105 QSOs)

-28.5>MB>-29.5 (5 QSOs)

Early chemical evolution; generally seen in massive galaxies? Matsuoka, Nagao, +09

Z QSO

/ Z

sun

-25 > MB > -28

broad-line regions in quasars

Nagao+06b

narrow-line regions in radio galaxies

Summary Metallicity in dusty galaxies: -- lower metallicity (for given mass) is reported; seeing young phases? -- optical disgnostics could see only the low-metallicity “skin” of galaxies -- longer-wavelength diagnostics needed

Sub-mm metallicity diagnostics: -- [NII]/[CII] ratio, from the analogy with the optical [NII]/Ha (N2) index -- [NII]205/[CII]158 ratio seems useful ( photoionization models) -- APEX and ALMA have observed these lines in a SMG at z~4.8 -- a substantially high metallicity (~1 Zsun) is inferred -- early chemical evolution (in massive galaxies generally?) is suggested

Future prospects -- higher spatial resolution [CII] of this SMG ( cycle 0, delivered) -- adding other lines to give further/tighter constraints ( cycle 1, filler) -- assessing the gas fraction to see the evolutionary stage ( cycle 1) -- metals in other targets, statistics, correlations, ... ( cycle 2, prop)

Thanks so much for your attention!!