FastSound A BAO Survey in NIR using Subaru/FMOS 戸谷 友則 TOTANI, Tomonori (Kyoto University, Dept. Astronomy) Spectroscopy in Cosmology and Galaxy Evolution Granada, Spain 2007, Oct 3-5

Specification of FMOS 400 fibres in circular FOV (30’ Φ) 400 fibres in circular FOV (30’ Φ) Each fiber (1.25”) covers 1’ radius FOV Each fiber (1.25”) covers 1’ radius FOV wavelength coverage: 0.9um - 1.8um wavelength coverage: 0.9um - 1.8um fully covered in a low resolution mode fully covered in a low resolution mode Spectral resolution Spectral resolution Low resolution mode: R=500 Low resolution mode: R=500 High resolution mode: R=2200 High resolution mode: R=2200 Limiting magnitude (1 hr, S/N=5) Limiting magnitude (1 hr, S/N=5) J ~ 22.0 J ~ 22.0 H ~ 20.0 H ~ 20.0 Line ~ 6 x erg/s/cm 2 (Latest number from M. Tamura) Line ~ 6 x erg/s/cm 2 (Latest number from M. Tamura) OH airglow suppression system OH airglow suppression system Engineering first light: 2008 Jan Engineering first light: 2008 Jan

Quick Look of FastSound BAO search by Subaru/FMOS with NIR spectroscopy BAO search by Subaru/FMOS with NIR spectroscopy Hα emitting galaxies 、 z~ Hα emitting galaxies 、 z~ planned parameters (final): planned parameters (final): ~600,000 galaxies ~600,000 galaxies ~300 deg 2 ~300 deg 2 O(100) Subaru nights O(100) Subaru nights The name stands for... The name stands for... FAST: FMOS 暗黒振動探査 (FMOS Ankoku Shindou Tansa = FMOS dark oscillation survey) FAST: FMOS 暗黒振動探査 (FMOS Ankoku Shindou Tansa = FMOS dark oscillation survey) SOUND: Subaru Observation Understanding Nature of Dark Energy SOUND: Subaru Observation Understanding Nature of Dark Energy Status: Status: Survey design and plan now under study Survey design and plan now under study Recognized as important the potential largest program in the FMOS team Recognized as important the potential largest program in the FMOS team final survey design by using real FMOS data (next year) final survey design by using real FMOS data (next year) Proposal to be submitted to Subaru after that Proposal to be submitted to Subaru after that

Unique/Good Points of FastSound BAO survey in NIR with a 8m telescope BAO survey in NIR with a 8m telescope Unique redshift range by Hα in NIR (z~ ) Unique redshift range by Hα in NIR (z~ ) redshift desert of 1.3 < z < 2.5 in optical spectroscopy redshift desert of 1.3 < z < 2.5 in optical spectroscopy 0.5 < z < 1.3 by [O II] 0.5 < z < 1.3 by [O II] 2.5 < z < 3.5 by Lyα 2.5 < z < 3.5 by Lyα Targeting the first detection of BAO at z>1 by galaxy surveys Targeting the first detection of BAO at z>1 by galaxy surveys would remain as important BAO data even in WFMOS era would remain as important BAO data even in WFMOS era Hα is a better tracer of SFR than [OII] or Lyα Hα is a better tracer of SFR than [OII] or Lyα Photometric target selection likely easier Photometric target selection likely easier Instrument available soon! Instrument available soon!

BAO Search by FMOS. 1 Required Survey Area to achieve V~ 1Gpc 3 Required Survey Area to achieve V~ 1Gpc deg 2 ⇔ ~ 1 Gpc 3 for z~ deg 2 ⇔ ~ 1 Gpc 3 for z~ pointings required for FMOS-FOV (0.2 deg 2 ) 1500 pointings required for FMOS-FOV (0.2 deg 2 ) Required number of galaxies Required number of galaxies ~20,000 galaxies per deg 2 and unit z for the cosmic variance to dominate shot noise (nP >~ 1) ~20,000 galaxies per deg 2 and unit z for the cosmic variance to dominate shot noise (nP >~ 1) ~1,800,000 galaxies in 300 deg 2 ~1,800,000 galaxies in 300 deg 2 1,200 galaxies for 0.2 deg 2 (FMOS-FOV) and Δz=0.3 1,200 galaxies for 0.2 deg 2 (FMOS-FOV) and Δz=0.3 should be compared the 400 fibers of FMOS should be compared the 400 fibers of FMOS

BAO Search by FMOS. 2 Necessary number of nights: ~O(100) Necessary number of nights: ~O(100) 1500 (FOVs) / 10 (FOVs/night) = 150 nights 1500 (FOVs) / 10 (FOVs/night) = 150 nights Sensitivity to the Hα Flux: Sensitivity to the Hα Flux: FMOS S/N=5 (1hr)  F(Hα) ~ 6 x erg/s/cm 2 FMOS S/N=5 (1hr)  F(Hα) ~ 6 x erg/s/cm 2 L(Hα) = 9.1 x erg/s L(Hα) = 9.1 x erg/s galaxy with SFR = 6.9 M sun z=1.5 galaxy with SFR = 6.9 M sun z=1.5

Effective Volume: Comparison with Other Surveys σ P /P~(4πk 2 dk V eff ) -1/2 ~20 nights ~200 nights Eisenstein+ ‘05 BAO peaks

FMOS Survey Simulation (1) 300 deg 2, 600,000 galaxies (400 galaxies per FMOS FOV) b=2

Key Questions Do we have enough number density of galaxies with sufficiently strong Hα flux? Do we have enough number density of galaxies with sufficiently strong Hα flux? Can we select them efficiently by photometric information? Can we select them efficiently by photometric information? Do we have sufficient photometric data, or can we obtain them in the near future? Do we have sufficient photometric data, or can we obtain them in the near future?

Some Tests for Target Selections Estimate Hα flux from photo-z by using SDF/SXDF data (~1deg 2 ) Estimate Hα flux from photo-z by using SDF/SXDF data (~1deg 2 ) BVRizJK+Spitzer BVRizJK+Spitzer There are sufficent number of Hα bright galaxies at z<1.4 There are sufficent number of Hα bright galaxies at z<1.4 z>1.5 galaxies may not be sufficient enough z>1.5 galaxies may not be sufficient enough FMOS line sensitivity (1hr, SN=5)

A Candidate Imaging Catalog for Target Selection: CFHT-Wide Synoptic Survey -almost correct area -deep enough for Fast Sound -five band photometries for target selection

Scientific Goals Stage 1: Stage 1: ~50 nights (not very difficult to get as a Subaru large program) ~50 nights (not very difficult to get as a Subaru large program) may not clearly detect BAO, but may see some evidence may not clearly detect BAO, but may see some evidence precise measurement of P(k) at z~1 precise measurement of P(k) at z~1 P(k) measurement is important for cosmological parameters, even without BAO P(k) measurement is important for cosmological parameters, even without BAO Use P(k) shape to derive cosmological constraints (c.f. WMAP+2dF, WMAP+SDSS, …) Use P(k) shape to derive cosmological constraints (c.f. WMAP+2dF, WMAP+SDSS, …) z~1 is important for dark energy z~1 is important for dark energy Stage 2: Stage 2: ~a few hundreds nights ~a few hundreds nights clear detection of BAO clear detection of BAO more robust constraint on dark energy than Stage 1 more robust constraint on dark energy than Stage 1 Ancillary sciences: Ancillary sciences: Properties of z~1 star formation galaxies Properties of z~1 star formation galaxies A small fraction of fibers for spectroscopic survey of rare objects A small fraction of fibers for spectroscopic survey of rare objects

The Most Crucial Question Can we get such a large observing time of Subaru? Can we get such a large observing time of Subaru?

The Future of Subaru Large Programs So far: So far: Maximum 20 nights for open use Maximum 20 nights for open use A new opportunity: The Subaru Strategic Observation Programs A new opportunity: The Subaru Strategic Observation Programs Two categories Two categories A historical survey program A historical survey program A systematic project with a clear scientific objective A systematic project with a clear scientific objective <~60 nights / yr, up to ~5 yrs  maximally 300 nights <~60 nights / yr, up to ~5 yrs  maximally 300 nights Responding to the commission of a new instrument Responding to the commission of a new instrument the first call for proposal (for HiCiao+AO) now under review process the first call for proposal (for HiCiao+AO) now under review process “Subaru Strategic Exploration of Exoplanets and Disks with HICIAO/AO188”, PI: M. Tamura “Subaru Strategic Exploration of Exoplanets and Disks with HICIAO/AO188”, PI: M. Tamura Next call will be for FMOS! Next call will be for FMOS!

The Roadmap Stage 0: pilot survey using a fraction of FMOS GTO (2008) Stage 0: pilot survey using a fraction of FMOS GTO (2008) test of target selection criteria test of target selection criteria optimization of the survey parameters optimization of the survey parameters formal proposal to Subaru for a large program formal proposal to Subaru for a large program Stage 1: using ~50 nights, ~60 deg 2 (2009-?) Stage 1: using ~50 nights, ~60 deg 2 (2009-?) precise measurement of P(k) at z~1 precise measurement of P(k) at z~1 hopefully evidence for BAO hopefully evidence for BAO Stage 2: complete survey of 170 deg 2 CFTHLS-W field Stage 2: complete survey of 170 deg 2 CFTHLS-W field a good chance for detecting BAO a good chance for detecting BAO Stage 3: ultimate >300 deg 2 survey Stage 3: ultimate >300 deg 2 survey clear detection of BAO clear detection of BAO but needs another source of imaging catalog for target selection but needs another source of imaging catalog for target selection certainly likely possibly Who knows!?

Hα Flux, Stellar Mass, Size Biz Biz 0.2”/pix

Input Imaging Surveys UKIDSS Large Area Survey UKIDSS Large Area Survey 4000 deg deg 2 K < 18.4 K < 18.4 VISTA & VST VISTA & VST Deep Deep 100 deg deg 2 K<21.0 K<21.0 Wide Wide 3000 deg deg 2 K<19.5 K<19.5 plan a special survey of a few hundreds deg 2 for FMOS BAO search? plan a special survey of a few hundreds deg 2 for FMOS BAO search? ＮＩＲサーベイは必ずしも必要ない かもしれない。可視サーベイ？ ＮＩＲサーベイは必ずしも必要ない かもしれない。可視サーベイ？ From S. Warren