NAOKI YASUDA, MAMORU DOI (UTOKYO),AND

TOMOKI MOROKUMA (NAOJ)

SN Survey with HSC

SN Ia as standard candle

Very bright (MB~-19.3) Observable at cosmological distances (z~1.5)

Light-curve shape (m15, stretch) / luminosity relation Broader light-curve -> intrinsically brighter Accurate to ~7%

Accelerated expansion of the Universe

z

wm

lzz

dz

H

zczD

0 )1(330 )'1()'1(

'1)(

Luminosity Normalization

Jha 2002

Astier et al. 2006

Reiss et al. (2007)

Complementarities

Constraints from SN Ia is complementary to the constraints from LSS

Independent attempt is important

Astier et al. 2006

SN Ia progenitors

Sullivan et al. (2006)SN Ia rate as a

function of SFR of host galaxies

Two components SN rate proportional to

SFR and stellar mass

Light curve shapes depend on host galaxies

Sullivan et al. 2006

BrightFaint

)()()(SNR new0 newIa tMBdttMAtt

PromptDelayed

ESA-ESO Working Groups : Fundamental Cosmology (2006)

List of SN Survey

Advantage of HSC

Large aperture Other SN surveys except for LSST use 4m telescopes SN Ia samples are limited to z<0.9

Extend to z~1.2

Wide field 1FoV is comparable to survey area of SNLS

High sensitivity in red bands (z-, Y-band) Most energy of SN Ia @ z=1 fall in i-, z-, and Y-band

Advantage of HSC

Large aperture Other SN surveys except for LSST use 4m telescopes SN Ia samples are limited to z<0.9

Extend to z~1.2

Wide field 1FoV is comparable to survey area of SNLS

High sensitivity in red bands (z-, Y-band) Most energy of SN Ia @ z=1 fall in i-, z-, and Y-band

1,000 SNe @ z=0.6-1.2from 4FoV and 4month duration observation

Performance of Subaru/Suprime-Cam

Number of candidates i < 25mag

1 month separation 20-30 SNe / deg2 / month 1,000 SNe / 4FoV / 3months

Photometry Good enough for light-

curve fitting for SNe @ z~1

Comparable to HST photometry

Oda et al. (2007)

Proposal

1,000 SN Ia @ z = 0.6-1.2 combined with previous surveys

Expanding history of the Universe Limit on the time variation of dark energy

SN Ia rate and its environmental effect, evolution Clue to the progenitor of SN Ia

Two evolutionary channel?

Observing Strategy

“Multi-color rolling search” Observe the same field repeatedly with multi colors

Maximum brightness photometric typing / redshift

Not enough facilities for spectroscopy

5nights (every 5 days) x 4months x 2 in (r,)i,z, and Y-bands: ~1000 SN light curvesMost SNe are observable over 2months

Comparison with on-going SN Surveys

SDSS-II : ~60nights/yr x 3yrs (2.5m) 0.1 < z < 0.3

SNLS : ~60nights/yr x 5yrs (3.6m) 0.3 < z < 0.8HSC : ~40nights/yr x 1yr (8.2m) 0.6 < z < 1.2

1,000 SNe from 4FoV, 4months Much cheaper than HST

Sample Observation Plan

Photometric typing / redshift

Fitting to multi-epoch spectral templatesTyping

~90% of SN Ia candidates are confirmed spectroscopically from the data of a few epochs (SDSS-II)

-> details in Ihara’s talk

Redshift z/(1+z) ~ 2-3% (SNLS)

Guy et al. 2007

Photometric Redshift

Simulation Cosmology : M = 0.3, = 0.7, w = -1, w’ = 0.0 1hour exposures of i-, z-, and Y-band at (-8, -3, 0, +3,

+8) days from new moon over 3months Stretch parameter : 0.96 +/- 0.11 (Max magnitude : +/-

0.2) Explosion time : from -15 days to +15 days Color is fixed to 0.0 : same intrinsic color and no

extinction Redshift : 0.8, 0.9, 1.0, 1.1, and 1.2

Photo-z by light curve fitting program (SALT) SALT is developed for SNLS analysis

Photo-z Results

Photo-z Results

Photo-z Results

Photo-z Results

Photo-z Results

Photo-z Results

Offset of mean value Difference of spectral templates between light curve

simulation (Hsiao template) and light curve fitting program (SALT)?

Dispersion z/(1+z) ~ 1-2%

Catastrophic errors Misidentification of colors Degeneracy due to wavy feature of SNe spectrum?

Cosmology

Errors on M and w reduce by a factor of 2

Area encircled reduce by a factor of 2

zwwzw 0)(

Contour : 1 Contour : 1

Cosmology

Systematic error due to photo-z error

zwwzw 0)(

Contour : 1 Contour : 1

Cosmology

Redshift should be determined well below 1% level Difficult only with photometric information

Need spectroscopic information Combine with photo-z of host galaxies?

Different error properties are expected Slitless (Grism) spectroscopy?

High sky noise More observing time

Spectroscopy of host galaxies Need large observing time Only for elliptical hosts (no extinction)?

SN Ia rate, progenitor, …

Do not need very accurate redshift

Correlation with host galaxy Brighter SNe are in later

spiralsSN rate

Two component modelProportional to SFR Stellar mass

Two evolutional pathEffect on chemical

evolution Neill et al. 2007

Summary

HSC can detect ~1000 SNe with reasonable observing time (~40 nights).

Photometric Redshift can be determined to 1-2% level.

For cosmology we need more accurate redshift.

Nature of SNe Ia and their evolution can be explored with large sample.