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

Transcription

1 Unveiling the nature of z 6 galaxies through [CII] emission studies Simona Gallerani in collabora=on with: Livia Vallini, Andrea Ferrara, Andrea PalloMni, Roberto Maiolino, Chiara Feruglio, Dominik Riechers, Bin Yue Molecules and dust as fuel to star forma=on 21 st 24 th June 2016

2 Unveiling the nature of z 6 galaxies through [CII] emission studies Simona Gallerani in collabora=on with: Livia Vallini, Andrea Ferrara, Andrea Pallo2ni, Roberto Maiolino, Chiara Feruglio, Dominik Riechers, Bin Yue Molecules and dust as fuel to star forma=on 21 st 24 th June 2016

3 Searching for galaxies in the epoch of reioniza=on z Dropout tecnique: Lyman Break Galaxies zrec 1100 trec 400,000 yr Narrow band technique: Lyman Alpha Emi`ers zreio 6-7 treio 1 Gyr Keck telescope (e.g.) t

4 Searching for galaxies in the epoch of reioniza=on z INTRINSIC DIFFICULTIES Dropout technique: Lyman Break Galaxies z rec 1100 t rec 400,000 yr HII Uncertain=es on the galaxy redshibs (Δz/z 10%) Contamina=on from foreground red galaxies and Galac=c cool stars HII z reio 6-7 HII t reio 1 Gyr Narrow band technique: Lyman Alpha Emi`ers Ionized bubbles allow Lyα photons to escape. The neutral hydrogen frac=on increases at redshibs approaching the EOR. The HII region sizes decrease. Keck telescope (e.g.) t Is the [CII] emission line a valid alterna:ve?

5 [CII] emission observa=ons in the local Universe Ø Major coolant of the ISM in star forming galaxies local dwarfs by (De Looze et al. 2014) Ø The strongest emission line in most galaxies (L [CII] ~ 0.1-1% L FIR ) At z > 4 is redshibed into the mm à detectable with ALMA

6 [CII] emission observa=ons in 5 < z < 7 galaxies NO DETECTIONS [CII] in Himiko at z = 6.6 (ALMA) t ON = 3.2 h 0.8 x 0.6 Ouchi et al. (2013) Contours levels in steps of 1σ (0.08 mjy beam - 1 ) [CII] in 6.5 < z < 7 LAEs (CARMA+PdBI) Gonxalez et al. (2014)

7 [CII] emission observa=ons in 5 < z < 7 galaxies DETECTIONS [CII] in 6 < z < 7 (ALMA) Maiolino et al. (2015) Willo` et al. (2015) [CII] in Himiko at z = 6.6 (ALMA) Capak et al. (2015)

8 What can we learn from high- z [CII] observa=ons on z 6 galaxy proper=es? DETECTIONS [CII] in 6 < z < 7 (ALMA) Maiolino et al. (2015) Willo` et al. (2015) [CII] in Himiko at z = 6.6 (ALMA) NO DETECTIONS [CII] in Himiko at z = 6.6 (ALMA) t ON = 3.2 h 0.8 x 0.6 Ouchi et al. (2013) [CII] in 6.5 < z < 7 LAEs (CARMA+PdBI) Contours levels in steps of 1σ (0.08 mjy beam - 1 ) Gonxalez et al. (2014) Capak et al. (2015)

9 The mul=- phase structure of the interstellar medium cold neutral medium (CNM) warm neutral medium (WNM) molecular clouds (MCs) HI 2 pressure equilibrium CNM ß à WNM see also talk by Mark Wolfire

10 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) L box = 10 h - 1 Mpc M res = 7 x 10 5 M M halo = M kpc 5 kpc log(z/z ) kpc 5 kpc 2.8 Vallini et al. (2013) Vallini et al. (2015)

11 Simula=ons of [CII] emission in a z 6 galaxy kpc 5 kpc log(z/z ) kpc iko6a HimCM IOK170 H A Log (SFR/M yr ) 1.5 Log (LCII/L ) Yue et al. (2015) Log (Z/Z ) ND SDFJ z8g kpc UCL PDR (Bell et al. 2005, 2007; Bayet et al. 2009) 2.0 log(lcii) = log(sfr) log(z) x log(sfr)log(z) 0.74 log2(z)

12 Simula=ons of [CII] emission in a z 6 galaxy Flux (mjy) PDRs SFR=1.0 M yr 1 CNM SFR=10.0 M yr 1 Flux (mjy) velocity (km/s) Vallini et al. (2015) [CII] emission arises predominantly from PDRs (F diff /F tot <40%) No detec:on of [CII] emission in z 6 galaxies can be explained with low gas metallicity values (Z < 0.2 Z sun ) or by nega:ve stellar feedback disrup:ng MC.

13 Simula=ons of [CII] emission in a z 6 galaxy Deficit of CII at the loca=on of the UV emission Maiolino et al. (2015) Capak et al. (2015) Vallini et al. (2015) The CII is detected in the displaced clump No detec:on of [CII] emission in z 6 galaxies can be explained with low gas metallicity values (Z < 0.2 Z sun ) or by nega:ve stellar feedback disrup:ng MC.

14 Simula=ng cosmic metal enrichment by the first galaxies AMR code (RAMSES) 10 Mpc h - 1 M dm 5 x 10 5 M sun Δx (20-1) kpc h - 1 log [SFR/(M yr 1 Mpc 3 )] t [Gyr] Total Pop III Bouwens et al Zheng et al z PalloMni et al. (2014)

15 The UV luminosity func=on of z 6 galaxies Good greement between simula=ons and UV LF observa=ons (Bouwens et al. 2015) 1 log( UV/mag/Mpc 3 ) Luminosity function at z =6 simulated observed Schechter fit 6 PalloMni et al. (2015) M UV

16 [CII] emission in z 6 galaxies Good greement between simula=ons and UV LF observa=ons (Bouwens et al. 2015) 1 log( UV/mag/Mpc 3 ) Luminosity function at z =6 simulated observed Schechter fit Log (Z/Z ) Vallini et al. (2013/2015) Log (SFR/M yr 1 ) Himiko HCM6A IOK-1 A SDFJ3058 z8gnd Log (LCII/L ) 6 PalloMni et al. (2015) M UV

17 [CII] emission in z 6 galaxies Good greement between simula=ons and UV LF observa=ons (Bouwens et al. 2015) 1 5arcsec X log( UV/mag/Mpc 3 ) Luminosity function at z =6 simulated observed Schechter fit X X X X X X X X X X I/µJy/beam X PalloMni et al. (2015) M UV beam galaxy emission

18 [CII] emission in z 6 galaxies Good greement between simula=ons and UV LF observa=ons (Bouwens et al. 2015) Good greement between simula=ons and [CII] observa=ons 1 6 [CII] flux - M UV relation log( UV/mag/Mpc 3 ) Luminosity function at z =6 simulated observed Schechter fit PalloMni et al. (2015) M UV log(fpeak/µjy) simulated (z = 6) extrapolated (z = 6) Maiolino et al (z ' 7) Capak et al (z ' 5.5) Willott et al (z ' 6) M UV

19 [CII] emission in z 6 galaxies Good greement between simula=ons and UV LF observa=ons (Bouwens et al. 2015) Good greement between simula=ons and [CII] observa=ons 1 6 [CII] flux - M UV relation log( UV/mag/Mpc 3 ) Luminosity function at z =6 simulated observed Schechter fit PalloMni et al. (2015) M UV log(fpeak/µjy) simulated (z = 6) extrapolated (z = 6) Maiolino et al (z ' 7) Capak et al (z ' 5.5) Willott et al (z ' 6) M UV = - 19 à 40 hr ALMA M UV = - 18 à 2000 hr ALMA at 4σ M UV Challenging to detect reioniza=on sources even with ALMA unless lensed galaxies

20 The importance of ou~lows in z 6 galaxies 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 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 D Odorico et al. (2013) Quasar absorp=on studies show that the inter- galac=c medium is enriched with metals up to z 6

21 Signatures of ou~lowing gas in z 6 quasars Detec=on of broad wings in the [CII] line of a z=6.4 quasar Beam: 2 Beam: 1 Maiolino et al. (2012) Cicone et al. (2015) see also talk by Alberto Bola`o

22 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 Maiolino et al. (2012) Cicone et al. (2015) No evidence in single sources Stacking of 9 galaxy spectra

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

24 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?

25 Galaxy emission line profiles Double Gaussian profile Gaussian profile + satellites Double horn profile Maiolino et al. (2012) Flux (mjy) Flux (mjy) PDRs SFR=1.0 M yr 1 CNM SFR=10.0 M yr 1 Vallini et al. (2015) Deblok et al. (2016) velocity (km/s)

26 Evidence for ou~lows in z 6 galaxies with ALMA χ 2 obs =12.6 n dof =17 P(χ 2 > χ 2 obs ) = 0.8 χ 2 obs =16.5 n dof =16 P(χ 2 > χ 2 obs ) = 0.4 χ 2 obs = 69 n dof =18 P(χ 2 > χ 2 obs ) <10 4 The double Gaussian is the favored profile for the observed [CII] emission lines

27 Evidence for ou~lows in z 6 galaxies with ALMA loading factor = M SFR The flux excess we detect is consistent with a loading factor 0.4

28 Comparison with z<0.2 starburst galaxies: Proper=es of the Capak et al. (2015) sample 5 SFR [ M yr 1 ] log 10 M SFR v outflow [km s 1 ] 500 loading factor = M SFR Heckman et al. (2015)

29 Dahlia (PalloMni et al. 2016) Density 16 kpc 4 kpc 1 kpc AMR code (RAMSES) M DM = 1.8 x M sun M star = 1.6 x M sun M H2 = 3.6 x 10 8 M sun SFR = 100 M sun yr - 1 STAR FORMATION H 2 dependent SK rela=on (Krumholz et al. 2009) Molecular hydrogen 3 kpc 5.2 log Σ H2 [M sun kpc - 2 ] log n [cm - 3 ] log n [cm - 3 ] log n [cm - 3 ] 1.8 Temperature 3.3 log T [K] log T [K] log T [K] 6.3 Pressure STELLAR FEEDBACK SN explosion: thermal and kine=c (blast- wave model by Ostriker & McKee) stellar wind radia=on pressure 0.8 log P [K cm - 3 ] 7.2 Metallicity 0 log P [K cm - 3 ] log P [K cm - 3 ] 7.8 L box [Mpc h - 1 ] M DM [Msun h - 1 ] Δx max [kpc h - 1 ] Δx min [pc] cosmo 20 3 x zoom x log Z [Z sun ] log Z [Z sun ] log Z [Z sun ] 0.4

30 Numerical simula=ons of a z 6 galaxy Gallerani et al. (2016) PalloMni et al. (2016)

31 SUMMARY The [CII] emission line is a promising tool for characterizing the ISM of high- z galaxies No detec:on for Z < 0.2 Z sun galaxies Vallini et al. ( )

32 SUMMARY The [CII] emission line is a promising tool for characterizing the ISM of high- z galaxies No detec:on for Z < 0.2 Z sun galaxies Vallini et al. ( ) PalloMni et al. ( ) log(fpeak/µjy) simulated (z = 6) extrapolated (z = 6) Maiolino et al (z ' 7) Capak et al (z ' 5.5) Willott et al (z ' 6) [CII] flux - M UV relation M UV Detec=ons of the [CII] line emi`ed by the sources of cosmic reioniza=on are challenging even for ALMA (unless lensed) M UV = - 19 à 40 hr ALMA M UV = - 18 à 2000 hr ALMA

33 SUMMARY The [CII] emission line is a promising tool for characterizing the ISM of high- z galaxies PalloMni et al. ( ) No detec:on for Z < 0.2 Z sun or MC photoevapora:on log(fpeak/µjy) simulated (z = 6) extrapolated (z = 6) Maiolino et al (z ' 7) Capak et al (z ' 5.5) Willott et al (z ' 6) [CII] flux - M UV relation M UV Tenta+ve detec=on of ou~lowing gas from the [CII] emission line profile in a sample of z 6 galaxies 100 <v oublow < 500 [km/s] Detec=ons of the [CII] line emi`ed by the sources of cosmic reioniza=on are challenging even for ALMA (unless lensed) M UV = - 19 à 40 hr ALMA Vallini et al. ( ) Gallerani et al. (2016) PalloMni et al. ()2016 M UV = - 18 à 2000 hr ALMA

34 Comparison with z<0.2 starburst galaxies: Newman, Genzel et al loading factor = M SFR Heckman et al. (2015)

35 MC photo evapora=on effects on the [CII] emission starburst$ stellar$ metallicity$ (Z * )$ FUV$photons$ (Habing$+$ionizing)$ G 0$ ICM$ gas$ $metallicity$ (Z)$ FIR$line$emission$ $from$icm$ FIR$line$emission$ $from$clumps$ clump$ (n cl,$r cl,$n c )$ $ M GMC = $M!$ Deficit of CII at the loca=on of the UV emission Vallini et al. (2016), submi`ed to MNRAS 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

36 Galaxy emission line profiles