Unveiling(the(nature(of(z≈6(galaxies(...

Unveiling the nature of z≈6 galaxies through [CII] emission studies

Molecules and dust as fuel to star forma=on 21st – 24th June 2016

Simona Gallerani

in collabora=on with:

Livia Vallini, Andrea Ferrara, Andrea PalloMni, Roberto Maiolino, Chiara Feruglio, Dominik Riechers, Bin Yue

Unveiling the nature of z≈6 galaxies through [CII] emission studies

Molecules and dust as fuel to star forma=on 21st – 24th June 2016

Simona Gallerani

in collabora=on with:

Livia Vallini, Andrea Ferrara, Andrea Pallo2ni, Roberto Maiolino, Chiara Feruglio, Dominik Riechers, Bin Yue

Searching for galaxies in the epoch of reioniza=on

zrec≈ 1100

Keck telescope (e.g.)

trec≈ 400,000 yr

zreio≈ 6-‐7 treio≈ 1 Gyr

t

z

Dropout tecnique: Lyman Break Galaxies

Narrow band technique: Lyman Alpha Emi`ers

Searching for galaxies in the epoch of reioniza=on

zrec≈ 1100

Keck telescope (e.g.)

trec≈ 400,000 yr

zreio≈ 6-‐7 treio≈ 1 Gyr

t

z

Dropout technique: Lyman Break Galaxies

Narrow band technique: Lyman Alpha Emi`ers

INTRINSIC DIFFICULTIES

Uncertain=es on the galaxy redshibs (Δz/z≈10%) Contamina=on from foreground red galaxies

and Galac=c cool stars

Ionized bubbles allow Lyα photons to escape. The neutral hydrogen frac=on increases at redshibs

approaching the EOR. The HII region sizes decrease.

HII

Is the [CII] emission line a valid alterna:ve?

HII

HII

local dwarfs by (De Looze et al. 2014)

[CII] emission observa=ons in the local Universe

Ø  Major coolant of the ISM in star forming galaxies

Ø  The strongest emission line in most galaxies (L[CII] ~ 0.1-‐1% LFIR)

At z > 4 is redshibed into the mm à detectable with ALMA

[CII] emission observa=ons in 5 < z < 7 galaxies

NO DETECTIONS

Contours levels in steps of 1σ (0.08 m

Jy beam-‐1)

Ouchi et al. (2013)

0.8’’ x 0.6’’

tON = 3.2 h

[CII] in 6.5 < z < 7 LAEs (CARMA+PdBI)

Gonxalez et al. (2014)

[CII] in Himiko at z = 6.6 (ALMA)

[CII] emission observa=ons in 5 < z < 7 galaxies

DETECTIONS

Capak et al. (2015)


[CII] in 6 < z < 7 (ALMA)

Maiolino et al. (2015) Willo` et al. (2015)

What can we learn from high-‐z [CII] observa=ons on z ≈ 6 galaxy proper=es?

DETECTIONS

Capak et al. (2015)


[CII] in 6 < z < 7 (ALMA)

Maiolino et al. (2015) Willo` et al. (2015)

NO DETECTIONS

Contours levels in steps of 1σ (0.08 m

Jy beam-‐1)

Ouchi et al. (2013)

0.8’’ x 0.6’’

tON = 3.2 h

[CII] in 6.5 < z < 7 LAEs (CARMA+PdBI)

Gonxalez et al. (2014)


cold neutral medium (CNM) warm neutral medium (WNM) molecular clouds (MCs)

The mul=-‐phase structure of the interstellar medium

H2 I

pressure equilibrium CNM ßà WNM

see also talk by Mark Wolfire

Simula=ons of [CII] emission in a z ≈ 6 galaxy

Zoomed hydro RT simula=on with a subgrid model

for the WNM/CNM (Wolfire et al. 2003)

and molecular clouds (Padoan & Nordlund 2011)

(Baek et al. 2013)

5 kpc 5 kpc

5 kpc 5 kpc �2.8

�2.4

�2.0

�1.6

�1.2

�0.8

�0.4

0.0

log(

Z/Z �

)

Lbox = 10 h-‐1 Mpc Mres = 7 x 105 M¤ Mhalo = 1011 M¤

Vallini et al. (2013) Vallini et al. (2015)

UCL PDR

�1.0 �0.5 0.0 0.5 1.0 1.5 2.0Log (SFR/M� yr�1)

�1.2

�1.0

�0.8

�0.6

�0.4

�0.2

0.0

Log

(Z/Z�)

5.000

6.000

7.000

8.000

9.000

Him

ikoIOK-1

HCM6A

A17031

z8GN

DSD

FJ3058

5

6

7

8

9

Log

(LC

II/L�)

log(LCII) = 7.0 + 1.2 × log(SFR) + 0.021 × log(Z) + 0.012 x log(SFR)log(Z) − 0.74 × log2(Z)

Yue et al. (2015)


5 kpc 5 kpc

5 kpc 5 kpc �2.8

�2.4

�2.0

�1.6

�1.2

�0.8

�0.4

0.0

log(

Z/Z �

)

(Bell et al. 2005, 2007; Bayet et al. 2009)


No detec:on of [CII] emission in z≈6 galaxies can be explained with low gas metallicity values (Z < 0.2 Zsun)

or by nega:ve stellar feedback disrup:ng MC.

[CII] emission arises predominantly from PDRs

(Fdiff/Ftot <40%)

0.00

0.02

0.04

0.06

0.08

Flux

(mJy

)

CNM

PDRs

SFR=1.0 M� yr�1

-100 0 100 200 300velocity (km/s)

0.00

0.25

0.50

0.75

Flux

(mJy

)

SFR=10.0 M� yr�1

Vallini et al. (2015)



No detec:on of [CII] emission in z≈6 galaxies can be explained with low gas metallicity values (Z < 0.2 Zsun)

or by nega:ve stellar feedback disrup:ng MC.

Deficit of CII at the loca=on of the UV emission

The CII is detected in the displaced clump

Maiolino et al. (2015)

Capak et al. (2015)

Simula=ng cosmic metal enrichment by the first galaxies

PalloMni et al. (2014)

AMR code (RAMSES) 10 Mpc h-‐1

Mdm≈ 5 x 105 Msun Δx ≈ (20-‐1) kpc h-‐1

1.54 1.20 0.96 0.78 0.65 0.56 0.48 0.42t [Gyr]

�4.5

�4.0

�3.5

�3.0

�2.5

�2.0

�1.5

�1.0

log[SFR/(M�yr�1Mpc�3)]

4 5 6 7 8 9 10 11z

Total

Pop III

Bouwens et al. 2012

Zheng et al. 2012

�22 �20 �18 �16 �14 �12MUV

�6

�5

�4

�3

�2

�1

log(�

UV/m

ag/M

pc3)

Luminosity functionat z = 6

simulated

observed

Schechter fit

The UV luminosity func=on of z ≈ 6 galaxies

Good greement between simula=ons and UV LF observa=ons (Bouwens et al. 2015)


�22 �20 �18 �16 �14 �12MUV

�6

�5

�4

�3

�2

�1

log(�

UV/m

ag/M

pc3)


simulated

observed

Schechter fit

[CII] emission in z ≈ 6 galaxies


�1.0 �0.5 0.0 0.5 1.0 1.5 2.0Log (SFR/M� yr�1)

�1.2

�1.0

�0.8

�0.6

�0.4

�0.2

0.0

Log

(Z/Z�)

5.000

6.000

7.000

8.000

9.000

Him

ikoIOK-1

HCM6A

A17031

z8GN

DSD

FJ3058

5

6

7

8

9

Log

(LC

II/L�)

Vallini et al. (2013/2015)


�22 �20 �18 �16 �14 �12MUV

�6

�5

�4

�3

�2

�1

log(�

UV/m

ag/M

pc3)


simulated

observed

Schechter fit

0 100 200 300 400 500

0

100

200

300

400

500

5 arcsec

beam

X-18.8

X-18.8

X-17.6

X-17.6

X-16.5

X-16.5

X-16.3

X-15.4

X-15.0

X-13.0

X-13.6

X-14.0

galaxy emission

�100

�10�1

�10�2

+10�2

+10�1

+100

�I/µJy/beam




�22 �20 �18 �16 �14 �12MUV

�6

�4

�2

0

2

4

6

log(Fpeak/µ

Jy)

[CII] flux - MUV relation

simulated (z = 6)

extrapolated (z = 6)

Maiolino et al. 2015 (z ' 7)

Capak et al. 2015 (z ' 5.5)

Willott et al. 2015 (z ' 6)

Good greement between simula=ons and [CII] observa=ons

�22 �20 �18 �16 �14 �12MUV

�6

�5

�4

�3

�2

�1

log(�

UV/m

ag/M

pc3)


simulated

observed

Schechter fit




�22 �20 �18 �16 �14 �12MUV

�6

�4

�2

0

2

4

6

log(Fpeak/µ

Jy)


simulated (z = 6)



Capak et al. 2015 (z ' 5.5)


Good greement between simula=ons and [CII] observa=ons

�22 �20 �18 �16 �14 �12MUV

�6

�5

�4

�3

�2

�1

log(�

UV/m

ag/M

pc3)


simulated

observed

Schechter fit



MUV = -‐19 à 40 hr ALMA MUV = -‐18 à 2000 hr ALMA

at 4σ

Challenging to detect reioniza=on sources even with ALMA … unless lensed galaxies


The importance of ou~lows in z ≈ 6 galaxies

Ou~lows shape the galaxy star forma=on histories and can produce cavi=es in their interstellar medium that may allow ionizing photons to escape

Invoked by theore=cal model to explain the discrepancy in the low-‐mass tail of the stellar mass func=on with the dark ma`er halo mass func=on

Quasar absorp=on studies show that the inter-‐galac=c medium is enriched with metals up to z ≥ 6

D’Odorico et al. (2013)

Detec=on of broad wings in the [CII] line of a z=6.4 quasar


Beam: 2” Beam: 1”

Cicone et al. (2015)

Signatures of ou~lowing gas in z ≈ 6 quasars

see also talk by Alberto Bola`o

Signatures of ou~lowing gas in z ≈ 6 quasars

Are broad wings also present in [CII] lines of z≈6 galaxies?


Beam: 2” Beam: 1”

Cicone et al. (2015)

No evidence in single sources Stacking of 9 galaxy spectra

Stacking the residuals of Capak et al (2015) galaxy spectra

We tenta+vely detect ( at ≈ 3σ) a flux excess in the stacked signal that strongly deviates from a standard normal distribu:on

Is this the signature of ou~lowing gas we were looking for?

Stacking the residuals of Capak et al (2015) galaxy spectra

0.00

0.02

0.04

0.06

0.08

Flux

(mJy

)

CNM

PDRs

SFR=1.0 M� yr�1

-100 0 100 200 300velocity (km/s)

0.00

0.25

0.50

0.75

Flux

(mJy

)

SFR=10.0 M� yr�1


Galaxy emission line profiles


Deblok et al. (2016)

Double Gaussian profile

Double horn profile

Gaussian profile +

satellites

Evidence for ou~lows in z ≈ 6 galaxies with ALMA

The double Gaussian is the favored profile for the observed [CII] emission lines

χ 2obs =12.6

ndof =17

P(χ 2 > χ 2obs ) = 0.8

χ 2obs =16.5

ndof =16

P(χ 2 > χ 2obs ) = 0.4

χ 2obs = 69

ndof =18

P(χ 2 > χ 2obs )<10

−4

Evidence for ou~lows in z ≈ 6 galaxies with ALMA

The flux excess we detect is consistent with a loading factor ≈ 0.4

loading factor =M

SFR

Comparison with z<0.2 starburst galaxies:

Heckman et al. (2015)

loading factor =M

SFR

5≤ SFR[ M yr−1]

≤ 70

−1.3≤ log10M

SFR≤ 0.6

100 ≤voutflow[km s−1]

≤ 500

Proper=es of the Capak et al. (2015)

sample

Dahlia (PalloMni et al. 2016) Density

Temperature

Pressure

Metallicity

16 kpc 4 kpc 1 kpc

-‐4 log n [cm-‐3] 2.4 -‐4 log n [cm-‐3] 3.0 -‐3 log n [cm-‐3] 1.8

3.3 log T [K] 5.7 3.2 log T [K] 6.0 3.9 log T [K] 6.3

-‐2.8 log Z [Zsun] 0.4

0 log P [K cm-‐3] 8.0 3.0 log P [K cm-‐3] 7.8 0.8 log P [K cm-‐3] 7.2

-‐2.8 log Z [Zsun] 0.4 -‐2.8 log Z [Zsun] 0.4

Lbox [Mpc h-‐1]

MDM [Msun h-‐1]

Δxmax [kpc h-‐1]

Δxmin [pc]

cosmo 20 3 x 107 78 -‐

zoom 2.1 7 x 104 10 32

STAR FORMATION H2 dependent SK rela=on (Krumholz et al. 2009) STELLAR FEEDBACK •  SN explosion: thermal and kine=c (blast-‐wave model by Ostriker & McKee) •  stellar wind •  radia=on pressure

AMR code (RAMSES) MDM = 1.8 x 1011 Msun Mstar = 1.6 x 1010 Msun MH2 = 3.6 x 108 Msun SFR = 100 Msun yr-‐1

Molecular hydrogen

5.2 log ΣH2 [Msun kpc-‐2] 8.4

3 kpc

Numerical simula=ons of a z ≈ 6 galaxy

Gallerani et al. (2016)


SUMMARY

The [CII] emission line is a promising tool for characterizing the ISM of high-‐z galaxies

Vallini et al. (2013-‐2015)

No detec:on for Z < 0.2 Zsun galaxies

SUMMARY


�22 �20 �18 �16 �14 �12MUV

�6

�4

�2

0

2

4

6

log(Fpeak/µ

Jy)


simulated (z = 6)



Capak et al. 2015 (z ' 5.5)


Detec=ons of the [CII] line emi`ed by the sources of cosmic reioniza=on are challenging even for ALMA (unless lensed)

Vallini et al. (2013-‐2015) PalloMni et a

l. (2014-‐2015)

No detec:on for Z < 0.2 Zsun galaxies

MUV = -‐19 à 40 hr ALMA MUV = -‐18 à 2000 hr ALMA

SUMMARY


�22 �20 �18 �16 �14 �12MUV

�6

�4

�2

0

2

4

6

log(Fpeak/µ

Jy)


simulated (z = 6)



Capak et al. 2015 (z ' 5.5)


Tenta+ve detec=on of ou~lowing gas from the [CII] emission line profile

in a sample of z ≈ 6 galaxies

Vallini et al. (2013-‐2015) Gallerani et al. (2016) PalloM

ni et al. ()2016 PalloMni et a

l. (2014-‐2015)

No detec:on for Z < 0.2 Zsun or MC photoevapora:on

Detec=ons of the [CII] line emi`ed by the sources of cosmic reioniza=on are challenging even for ALMA (unless lensed) MUV = -‐19 à 40 hr ALMA MUV = -‐18 à 2000 hr ALMA

100 <voublow < 500 [km/s]

Comparison with z<0.2 starburst galaxies:

Heckman et al. (2015)

loading factor =M

SFR

Newman, Genzel et al. 2012

MC photo evapora=on effects on the [CII] emission

ICM$

clump$(ncl,$rcl,$Nc)$

$FUV$photons$

(Habing$+$ionizing)$

G0$

FIR$line$emission$$from$clumps$

MGMC=9�104$M!$

FIR$line$emission$$from$ICM$

stellar$metallicity$

(Z*)$gas$

$metallicity$(Z)$

starburst$

Vallini et al. (2016), submi`ed to M

NRAS

Deficit of CII at the loca=on of the UV emission

The CII is detected in the displaced clump

The inclusion of MC photo evapora:on strongly reduces [CII] emission possibly explaining no detec:ons in some of the targeted z≈6 galaxies

Galaxy emission line profiles

Unveiling(the(nature(of(z≈6(galaxies(...

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