Naoki Yasuda, Mamoru Doi Utokyo,

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SN Survey with HSC

• Naoki Yasuda, Mamoru Doi (Utokyo),
• ANDTomoki Morokuma (NAOJ)

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SN Ia as standard candle

• Very bright (MB-19.3)
• Observable at cosmological distances (z1.5)
• Light-curve shape (Dm15, stretch) / luminosity
  relation
• Broader light-curve -gt intrinsically brighter
• Accurate to 7
• Accelerated expansion of the Universe

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Luminosity Normalization
Astier et al. 2006
Jha 2002
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Reiss et al. (2007)
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Complementarities

• Constraints from SN Ia is complementary to the
  constraints from LSS
• Independent attempt is important

Astier et al. 2006
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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

Prompt
Delayed
Sullivan et al. 2006
Faint?
?Bright
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List of SN Survey
ESA-ESO Working Groups Fundamental Cosmology
(2006)
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Advantage of HSC

• Large aperture
• Other SN surveys except for LSST use 4m
  telescopes
• SN Ia samples are limited to zlt0.9? Extend to
  z1.2
• Wide field
• 1FoV is comparable to survey area of SNLS
• High sensitivity in red bands (z-, Y-band)
• Most energy of SN Ia _at_ z1 fall in i-, z-, and
  Y-band

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Advantage of HSC

• Large aperture
• Other SN surveys except for LSST use 4m
  telescopes
• SN Ia samples are limited to zlt0.9? Extend to
  z1.2
• Wide field
• 1FoV is comparable to survey area of SNLS
• High sensitivity in red bands (z-, Y-band)
• Most energy of SN Ia _at_ z1 fall in i-, z-, and
  Y-band
• 1,000 SNe _at_ z0.6-1.2from 4FoV and 4month
  duration observation

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Performance of Subaru/Suprime-Cam

• Number of candidates
• i lt 25mag1 month separation? 20-30 SNe / deg2 /
  month? 1,000 SNe / 4FoV / 3months

• Photometry
• Good enough for light-curve fitting for SNe _at_ z1
• Comparable to HST photometry

Oda et al. (2007)
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Proposal

• 1,000 SN Ia _at_ 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?

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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
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Comparison with on-going SN Surveys

• SDSS-II 60nights/yr x 3yrs (2.5m) 0.1 lt z lt
  0.3
• SNLS 60nights/yr x 5yrs (3.6m) 0.3 lt z lt 0.8
• HSC 40nights/yr x 1yr (8.2m) 0.6 lt z lt 1.2
• 1,000 SNe from 4FoV, 4months
• Much cheaper than HST

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Sample Observation Plan
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Photometric typing / redshift

• Fitting to multi-epoch spectral templates
• Typing
• 90 of SN Ia candidates are confirmed
  spectroscopically from the data of a few epochs
  (SDSS-II) -gt details in Iharas talk
• Redshift
• Dz/(1z) 2-3 (SNLS)

Guy et al. 2007
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Photometric Redshift

• Simulation
• Cosmology WM 0.3, WL 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

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Photo-z Results
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Photo-z Results
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Photo-z Results
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Photo-z Results
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Photo-z Results
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Photo-z Results

• Offset of mean value
• Difference of spectral templates between light
  curve simulation (Hsiao template) and light curve
  fitting program (SALT)?
• Dispersion
• Dz/(1z) 1-2
• Catastrophic errors
• Misidentification of colors
• Degeneracy due to wavy feature of SNe spectrum?

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Cosmology

• Errors on WM and w reduce by a factor of 2

• Area encircled reduce by a factor of 2

Contour 1s
Contour 1s
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Cosmology

• Systematic error due to photo-z error

Contour 1s
Contour 1s
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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)?

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SN Ia rate, progenitor,

• Do not need very accurate redshift
• Correlation with host galaxy
• Brighter SNe are in later spirals
• SN rate
• Two component modelProportional to
• SFR
• Stellar mass
• Two evolutional path
• Effect on chemical evolution

Neill et al. 2007
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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.