Masahiro Takada (IPMU) on behalf of the HSC team @GRB conference, - - PowerPoint PPT Presentation

Masahiro Takada (IPMU)

• n behalf of the HSC team

@GRB conference, Kyoto, April 20

• What is the Hyper Suprime-Cam (HSC)?
• HSC surveys
• The major scientific goals
• Synergy with other surveys
• Summary

@ summit of Mt. Mauna Kea (4200m), Big Island, Hawaii

Subaru Telescope

4

Cassegrain Focus Prime Focus Nasmyth Focus Nasmyth Focus FOCAS Optical imager and spectrograph COMICS IR imager and spectrograph MOIRCS NIR imager (7′×4′) and multi-

• bject (50) spectrograph

Suprime-Cam Optical imager (34′×27′) HDS Optical spectrograph (λ/Δλ=100,000) AO188 188-element curvature sensing adaptive optics system with a laser guide star capability

Illustration by Takaetsu Endo, taken from Nikkei Science 1996

IRCS (AO188) Infrared imager and spectrograph (λ/Δλ=20,000) HiCIAO (AO188) Coronagraphic imager with differential imaging techniques

 Only Subaru has the prime focus camera, Suprime- Cam, among other 8-10m class telescope: the wide field-of-view (0.25 sq deg)  Excellent image quality allows accurate shape measurements of galaxies

 Upgrade the prime focus camera  Funded, started since 2006  International collaboration: Japan (NAOJ, IPMU, Tokyo, Tohoku, Nagoya), Princeton, Taiwan  Field-of-View: ~10×Suprime-Cam  Keep the excellent image quality  Instrumentation well underway (S. Miyazaki, NAOJ)  HSC survey starting from 2012- (~5 years)

Developed by Hamamatsu Photonics-NAOJ collaboration

Quantum efficiency

HSC previous S-Cam CCDs

Improved CCDs in red

 Field of view: 1.5 degrees in diameter  Image quality kept same to that of the current camera, Suprime-Cam, in r, i, z, y bands  The CCD chips with improved quantum efficiency in red bands

 Wide-field survey (>1000 sq. deg.; grizy)

• Depth: t_exp~15min, i~26 mag (5σ)
• Probes a comoving volume of ~10Gpc^3 up to z~1.5
• Sciences: later

 Deep survey (~20 sq. deg.; grizy+NIBs)

• Depth: t_exp~1 hour, i~27 mag
• Key sciences: z~6-7 Ly-alpha emitters (survey area >

reionization bubbles), z~6 QSOs, SNe, galaxy evolution studies

• ver z~1-2, GRB orphan afterglow, …

 Ultra-Deep survey (a few sq. deg.; grizy+NIBs)

• Depth: t_exp~20-30 hours, i~28 mag
• Key sciences: z~7 Ly-alpha emitters (for understanding

reionization history), SNe

• Best targets for spectroscopic follow-ups by TMT

Surveys designed fully utilizing its unique capability (wide FoV and depth)

• Ouchi et al. (09): found 22 z~7 z-dropout

candidates (one LEA confirmed spectroscopically) over 0.4 sq. deg. area (~(100Mpc)^3)

Current in ~5 years

UDF (the previous image) The Millennium Simulation (Springel et al., Nature 05)

Exploring the large-scale structure of the Universe

A massive galaxy cluster (>10^3 galaxies) ~10Mpc or ~30Mlight year@z~0.5~0.5deg

Subaru Other 8m telescopes

Hyper-SC

 Gravitational lensing of the hierarchical structures

• Cosmological lensing: cosmological parameters (DE, neutrino mass)
• Cluster lensing (dark matter, cluster physics)
• Galaxy group; not yet fully explored so far
• Galaxy-scale lensing (weak and strong lensing)

 Finding galaxy clusters out to z~1.5 (y-band)

• The expected number of massive clusters with 10^15Msun at z>1
• ver a 1000 sq. deg. area is only O(1) for LCDM model

 QSOs at z~7 (SMBHs; GP test)

• 10-100 QSOs can be expected if extrapolating the results at z<6.5

 Galaxy evolution out to z~1  Dwarf satelites in our Milky Way out to ~100kpc in distance (compared to ~10kpc for SDSS)

• A few satellites expected to be found, for LCDM model
• Constraining the mass of DM (the current constraint MWDM<a few keV)

Lensing strength = (the geometry of the Universe) ×(lensing matter [including DM])

γ ∝Ωm0 dzL

zS

∫

dLS(zL,zS)dL(zL) dS(zS) δ(zL,θ)

for a source galaxy at zs

• Lensing efficiency function: Wgl

– Overall amplitude is sensitive to Ωm, i.e. Ωde if a flat universe is a prior assumed – Sensitive to Hubble expansion through dA, i.e. DE – Depends on source redshift – uncertainty in weak lensing measurements if redshift info is not available

• Mass clustering part: δ

– Allows to reconstruct the dark matter distribution without resting on any assumptions of the dynamical states – Sensitive to primordial power spectrum (amplitude and shape) – Redshift history of the growth rate is sensitive to DE (structure formation arises from the balance between gravitational instability and cosmic expansion

Strong Lensing

• Multiple Images
• Large Arcs, Ring
• Obvious Distortion

Weak Lensing

• Slight Stretching
• Distortion small compared

to initial shape

• Statistical lensing
• The S/N depends on the

number of background gals and the accuracy of shape measurement (PSF)

to center

Reyes et al. Nature 2010

• In gravity metric

theory, lensing is caused by the gravitational potential (g_00) and the curvature perturbation (g_ij)

• Galaxy clustering

measurement is distorted by the peculiar velocity field, caused by the gravitational potential (g_00)

• Reyes et al. used

the SDSS clustering stats to explore the consistency relation

• f GR

Ratio: lensing strength/galaxy cluster strength Distance from the center of lensing galaxies

Subaru (S-Cam) is currently the best instrument for measuring WL signal, thanks to its image quality and depth

Subaru S-Cam CFHT (blue: mass)

Okabe, MT+ 2010, in press Bardeau, Soucail, Kneib et al.07

A209

Okabe, MT+ 2010, in press

A2390

Bardeau, Soucail, Kneib et al.07

Merging Clusters: Bullet Cluster (1E 0657-56)

HSC-W of 2000 deg.: >10^4 clusters with >10^14Msun WL found clusters are ~ a few x 10^3 O(1) clusters with 10^15 Msun at z>1 ALMA follow-up observations of high-z clusters ~10^2 merging clusters like Bullet Cluster (Hayashi & White 06)

• Plan to overlap the HSC survey

region with that of the SZ experiment ACT (around the equator)

• SZ independent of redshift
• HSC can determine the redshift of

SZ found clusters

• Statistical studies of ACT-HSC

data for clusters

Atacama Cosmology Telescope (148GHz, 218GHz, 277GHz)

Abell 3128 (z=0.44)

• ang. res.= 2.34’

SPT-CL0547 (z=0.88)

• BOSS redshifts of LRGs (z< 0.7) available
• LRGs are landmarks of LSS (most likely bright

central galaxies of clusters)

• HSC will add faint galaxies surrounding every

LRG

• Other synergy with Astro-H, ALMA, eROSITA,

TMT…

SDSS-III (BOSS survey)

• Key factors: other datasets, NIR, spec-z, ACT, ALMA

• Cosmological lensing
• The current most massive survey is

CFHT, 170 sq. deg.

• HSC-W: >1000 sq. deg.: dark energy

and neutrino mass

σ8

WL WMAP combined

σ8(Ωm/0.25)0.64=0.785±0.043 σ8=0.771±0.029 Ωm=0.248±0.019 Fu+0712.0884 Ichiki, MT, Takahashi 09 ΣMν<0.54eV (95% C.L.)

ρde(z) ∝(1+ z)3(1+w)

MT & Jain (2004)

DE equation of state： w DE density parameter：Ω_de

0.1 Today(08) 0.05 0.01

σ(w)

2015 2020(?) The first question to be addressed: if or not w=-1? (w=-1: cosmological constant) Complementary to the geometrical tests, SNe, BAO, GRBs.. HSC(+CMB): σ(w)~0.02-0.04 LSST, JEDM σ(w)~0.01 σ(w)~0.1 We may find the evidence of w≠-1 earlier than LSST/JEDM (note: systematics)

From S. Miyazaki

• Hyper Suprime-Cam (HSC) is the next-generation prime focus

camera of Subaru: a factor 10 improvement in the survey speed

• The fabrication well underway: the survey will start from ~2012
• Many science cases available: wide, deep, ultra-deep surveys

– From the local universe to cosmos: dwarf satellites in our Milky Way, distant galaxies, galaxy clusters, QSO, large-scale structure – Weak lensing adds new information on the data: dark matter distribution, which is essential for a quantitative understanding of structure formation

• Major scientific goals: dark energy, dark matter, neutrinos,

cosmic reionization

• Various synergy with future surveys: ACT (SZ effect), ALMA,

Astro-H, BOSS, JWST, TMT,….