Physical properties of high-z star-forming galaxies with FMOS-COSMOS

Transcription

1 Physical properties of high-z star-forming galaxies with FMOS-COSMOS John Silverman Kavli IPMU Daichi Kashino, Alvio Renzini, Emanuele Daddi, Giulia Rodighiero, Nobuo Arimoto, Tohru Nagao, Dave Sanders, Jeyhan Kartaltepe, Jason Chu, and the FMOS-COSMOS and COSMOS teams

2 What are the processes controlling the global evolution of galaxies and their supermassive black holes? Observables from multi-wavelengths surveys Star-formation (accretion) rate distribution Mass (galaxy and SMBH) function ISM properties? SF MS: Speagle et al Mass function: Ilbert et al. 2013

3 Wide-area surveys Massive galaxies Environment Starbursts AGN Whitaker et al Chiang, Overzier et al. 2015

4 What are the ISM conditions (at high redshift)? Chemical composition O/H (metallicity) Metal enrichment from stellar evolution Dust/extinction Ionization state [OIII]/Hβ vs. [NII]/Hα Density/pressure [SII] or [OII] ratio Stellar populations; star formation rate; AGNs Thermodynamics Implications on metallicity calibrations and their application to high-z galaxies Future cosmological experiments will use emission-line galaxies (eboss, PFS, DESI, Euclid, WFIRST)

5 Emission-line studies (SDSS: z < 0.3) Mass - metallicity relation BPT diagram Tremonti et al Kewley, Groves, Kauffmann & Heckman 2006 Kauffmann et al. 2003

6 The Era of NIR multi-object spectrographs Keck/MOSFIRE Steidel et al. 2014; Shapley et al VLT/KMOS Wisnioski et al Subaru/FMOS Yabe et al. 2014; Kashino et al. 2013; JDS et al. 2015; Tonegawa et al Rest-frame optical spectroscopic surveys of >1000 galaxies with z > 1 are now feasible and efficient in terms of observing time Detect all four key diagnostic emission lines (Hβ, [OIII]5007, Hα, [NII]) in the IR FMOS Hα window Cucciati et al. 2011

7 Subaru - Fiber Multi-object Spectrograph (FMOS) Built by Kyoto University, UK & NAOJ (PI: T. Maihara) lifetime μm 400 fibers; 1.2 diameter 30 diameter FOV Airglow/OH suppression system (Iwamuro et al. 2006) Low (R=500) and high (R=2600) resolution 2048x2048 HgCdTe Hawaii-2 detectors Cross-beam switching (~200 fiber pairs can be assigned) two spectrographs (irs1 and irs2) J-short J-long LR Throughput H-short H-long HR

8 A Subaru/FMOS NIR survey of SF galaxies in COSMOS at z ~ 1.6 JDS et al. 2015, ApJS, 220, 12 Emission-line survey of star-forming galaxies COSMOS 60 nights ( ) (split between NAOJ and University of Hawaii) 3 Intensive Subaru programs (PI JDS) Multiple regular IfA programs (PI Dave Sanders) H-long grating ( μm) Hα, [NII] and [SII] J-long grating ( μm) Hβ, [OIII]5007

9 Target selection star-forming galaxies - K-selected (K < 23.5) - M > M - sbzk - along the star-forming main sequence - fhα > 4 x erg cm -2 s -1 SFR: B-band E(B-V): B-z color E(B-V) neb =E(B-V) stellar /0.44 (Calzetti et al. 2000) Herschel/PACs sources - highly obscured SF galaxies - above or on M-S - near bright stars for future IFU/AO observations AGNs Rodighiero et al. 2010

10 J-long ( μm) H-long ( μm) Hβ Hβ Hα Fiber [OIII] Hα [NII] Wavelength [NII]

11 FMOS performance ~40% redshift success rate 1.4 < zphot < 1.6 Hβ [OIII]

12 1449 redshifts Le Fevre et al. 2015

13 Hα number counts WFIRST Euclid Implications on cosmology experiments at high-z (BAO, redshift space distortions) Tasca, JDS, Le Fevre et al. in prep

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15 Dust extinction and star formation rates Kashino et al f=estar/eneb f-factor in disagreement with local starbursts - Calzetti et al. (2000) see Price et al. 2014; Puglisi et al ; Reddy et al. 2015

16 Dust extinction and star formation rates Kashino et al Daddi+07 Zahid+12 Elbaz+07 f=estar/eneb f-factor in disagreement with local starbursts - Calzetti et al. (2000) see Price et al. 2014; Puglisi et al ; Reddy et al. 2015

17 Erb et al. 2006; Maiolino et al. 2008; Steidel et al. 2014; Maier et al. 2014; Yabe et al. 2014, 2015; Sanders et al. 2015; Onodera et al Mass - metallicity relation at high-z log (Z/Z ) = 12+log (O/H) Zahid et al. 2014

18 Emission line ratios and their evolution SDSS z < 0.3 Kewley et al. 2013

19 Ionization conditions in high-z galaxies Kashino et al. 2016; arxiv: Kewley et al. 2013; Masters et al. 2014; Steidel et al. 2014; Zahid et al. 2014; Shapley et al. 2015; Coil et al. 2015; Kartaltepe et al. 2015; Sanders et al. 2016

20 Mass excitation diagram Kashino et al. 2016

21 Physical quantities capable of generating BPT offsets Ionization parameter Kewley et al q = Nionizing photons NH atoms -3.5 < log U (q/c) < -2.9 Dopita et al Density/pressure P ~ 10 5 cm -3 K assuming T=10 4 K (local HII regions) Kewley et al Spectrum/hardness of the radiation field Steidel et al Varying abundance ratios (i.e., N/O) Masters et al. 2015; Shapley et al. 2015

22 Electron density with [SII] Sanders et al (MOSDEF) Kashino et al. 2016

23 Change in the ionization parameter with redshift Models from Dopita et al See Kewley et al (0.2 < z < 0.6) Kashino et al. 2016

24 Change in the ionization parameter with redshift Models from Dopita et al Kashino et al. 2016

25 Summary of rest-frame optical line properties at high-z Level of extinction of high-z SF (main-sequence) galaxies are similar to SF galaxies at z ~ 0 result of an evolving gas-to-dust ratio (Magdis et al. 2012; Tan et al. 2014) More even dust distribution between stellar and nebular region roughly follows extrapolation with ssfr (Wild et al. 2011) A clear SFR - M relation is present at z ~ 1.6 using Hα-based SF indicator agrees with radio and mean FIR emission (Rodighiero et al. 2014) Is there an increase in dispersion or turnover (Whitaker et al. 2012; Lee et al. 2015) at the high mass end (signs of quenching)? BPT offsets are present over a broad range of stellar mass due to an increase in the ionization parameter, electron density/pressure of the ISM and hardness of the radiation field Significant evolution of the mass - metallicity relation (using new indicator; Dopita et al. 2016) most massive galaxies at local level of enrichment; likely to be quenched on short timescales log [OIII]/Hβ log [NII]/Hα

26 Concluding remarks FMOS spectroscopy fills a void in the wide spectroscopic redshift coverage of COSMOS, a key extragalactic survey field and an HSC Ultradeep field ISM conditions evolve with redshift; implications for future spectroscopic efforts (i.e., Subaru Prime-Focus Spectrograph - PFS, MOONS) FMOS spectroscopy is improving photo-z estimation for COSMOS (Ilbert et al. 2013; Laigle et al. 2016) Additional studies underway: [OII]3727 (VLT-S. Juneau; Keck - L. Kewley), clustering, starbursts with ALMA CO 2-1 (JDS et al. 2015, 1016 in prep) All high-level data are released to the public - Flux calibrated 1D spectra in fits format (object + error spectra) - Redshift catalogs - Line flux measurements