despec survey strategy : realistic mock catalogue and target selection stephanie jouvel, filipe...

DESpec survey strategy :realistic mock catalogue

and target selection

Stephanie Jouvel, Filipe Abdalla, Huan Lin, James Annis, Richard Kron

22 jun 2011

PLAN : Investigate DESpec survey strategy

• Build realistic Mock Catalogues of the DES + VISTA survey

• Derive spectrograph/fibers sensitivities for ground-based observation

• Investigate redshift distribution and galaxy density for DESpec science

• Which tragetting strategy ? What criterion in photoz or color-color space ?

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Galaxy Properties from Deep Surveys

the VVDS “Deep” survey

• VIMOS/VLT deep spectroscopic survey on ~0.5 sq.deg

• ~9000 spectra from 0<z<5 down to IAB ~24 (magnitude selected)

the COSMOS survey

• 2deg2 (representative)• 30 photometric bands

from UV to IR with HST, Galex, Spitzer, Subaru, VLA, NOAO

• HST/ACS I band observation: galaxy sizes & shapes

• zCosmos spectroscopic survey

Le fèvre et al. 2005

Koekemoer et al. 2007

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Building Mock Catalogues

GOODS Luminosity Function catalogue

COSMOS Mock catalogue

COSMOS catalogue(position, size, photometry)

1 million galaxies

Photoz, SED, emission lines

Photometry in DE mission filter sets+ Photometric errors

DE Forecast

Simulated Catalogue based on GOODS LF(z,type)

COSMOS size distribution, emission lines

Jouvel et al. 2009

Jouvel et al 2010

GOODS LF from Dahlen et al. 2005

COSMOS photoz from Ilbert et al. 2009

Stephanie Jouvel

- Realistic redshift distribution,- Realistic size distribution,- Emission line fluxes catalogue

Use this catalogue

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COSMOS Mock Catalog (CMC)

Construction using the properties of the COSMOS-ACS WL catalog using :- realistic photometric redshift distribution

30 photometric bands calibrated with spectroscopic redshift :

> zCOSMOS bright (I~22 AB) > zCOSMOS faint (I~25 AB) > MIPS-spectro-z sample

- best-fit template from this photoz distribution- galaxy size measured by Sextractor from Leauthaud et al 2007

Validation of the CMC using :- GOODS N&S visible - UDF visible + jh band- VVDS Ks band + spectro-z- GOODS-MUSIC Ks band

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COSMOS Mock Catalogue(CMC)

Stephanie Jouvel

We want precision cosmology Need for realistic mock catalogues to test photoz codes :

- Realistic redshift distributionImpacts DE FoM from WL - Realistic distribution of galaxy sizes in redshift and magnitude=> Realistic noise distribution impact photoz results-Emission line catalogue Create spectroscopic catalogue to study photoz calibration

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COSMOS Mock Catalog (CMC) :Validation

Emission line prediction :Kennicutt et al. 1998 :UV-OII relation

Validation of the redshift distribution and emission line fluxes using the VVDS-DEEP I~24 AB (Lamareille et al 2008)

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log[OII]= −0.4MUV +10.57DM z( )

2.5

Jouvel et al. 2009

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Spectroscopic Success Rate (SSR) :Validation using VVDS

Validation : reproducing the VVDS SSR

SSR : galaxy rate for which we will be able to measure a redshift

Jouvel et al. 2009

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PhotoZ Calibration Survey (PZCS): Spectroscopic Success Rate (SSR)

WIDE NIRphotometric calibration(BAO–RD survey)

templatecalibration: - DEEP-visible-NIR- DEEP-NIR

Jouvel et al. 2009

In the context of theJDEM survey we simulated different spectroscopic surveys :

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SSR Forecast for PZCS

Forecast :-DEEP-NIR space survey (PZCS)

DEEP-NIR :I~27 0.5<z<3.5 35gal/arcmin2

Jouvel et al. 2009

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DEEP-vis-NIR :I~27 0<z<3.5 60gal/arcmin2

SSR forecast for PZCS

Forecast :DEEP-visible-NIR space survey (PZCS)

Jouvel et al. 2009

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WIDE-NIR : H ~22 0.5<z<1.5 5gal/arcmin2

SSR Forecast for PZCS

Forecast :WIDE-NIR space survey (BAO like)

Jouvel et al. 2009

DESpec survey strategy :

1. Mock catalogue and photoz

DES+VISTA photometric redshift

ANNz training with 10000 galaxies

Le Phare with COSMOS templates

DESpec survey strategy :

2. Target selection

Line sensitivities from Huan Lin

- Sensitivities for 30 mins exposure time on 2 arcsec ø fibers (70% light fraction)- Resolution R=2500 at 0.9um.- Calculation include DES throughput + sky noise and atmospheric lines from Hanuschik (2003)

Redshift distribution from em linesRedshift distribution of emission line galaxies selected with :- I (DES) < 23- 1 < photoz < 2- at least one em line detected at 5 sigma

Photoz with Le Phare (template fitting method) u DES+VISTA

Can we select the emission line galaxies based on DES+VISTA photometry only ?

Total of roughly12000 gal/deg2

Multidimensional method based on NN selection

Use of NN to select em line galaxies

We assign a value of :- 1 for targetted em line galaxies- 0 for non targetted galaxies

We then use ANNz and train a NN on a sample of 10000 galaxies from the CMC (DES+VISTA)

Results for i(DES) < 24

Which ANNz selection criterion ?

Fig : Cumulated nbr galaxies/deg2 fct ANNz target probability

We suggest a selection criterion of 0.8 yielding to : -7500 emission line galaxies / deg2 i(DES)<24- and a contamination of 800 gal/deg2 i(DES)<24

0.8

Which ANNz selection criterion ?Solid : percentage of galaxies for which we will measure a redshift/total nbr gal & Dashed : SSR fct ANNz target probability

We suggest a selection criterion of 0.8 yielding to : -7500 emission line galaxies / deg2 i(DES)<24- and a contamination of 800 gal/deg2 i(DES)<24

Redshift distribution of ANNz sel 0.8

Redshift distribution / em lines gal

Redshift distribution / em lines gal

Redshift distribution / em lines gal

Line sensitivities from Huan Lin 0.6-1um

- Sensitivities for 30 mins exposure time on 2 arcsec ø fibers (70% light fraction)- Resolution R=2500 at 0.9um.- Calculation include DES throughput + sky noise and atmospheric lines from Hanuschik (2003)

Use of NN to select em line galaxies

We assign a value of :- 1 for targetted em line galaxies- 0 for non targetted galaxies

We then use ANNz and train a NN on a sample of 10000 galaxies from the CMC (DES+VISTA)

Results for i(DES) < 24

Using Huan Lin sensitivities cut between 0.6-1um

Which ANNz selection criterion ?

Fig : Cumulated nbr galaxies/deg2 fct ANNz target probability

We suggest a selection criterion of 0.8 yielding to : -7500 emission line galaxies / deg2 i(DES)<24- and a contamination of 800 gal/deg2 i(DES)<24

0.8Using Huan Lin sensitivities cut between 0.6-1um

Which ANNz selection criterion ?Solid : percentage of galaxies for which we will measure a redshift/total nbr gal & Dashed : SSR fct ANNz target probability

We suggest a selection criterion of 0.8 yielding to : -7500 emission line galaxies / deg2 i(DES)<24- and a contamination of 800 gal/deg2 i(DES)<24

Using Huan Lin sensitivities cut between 0.6-1um

Redshift distribution of ANNz sel 0.8

Using Huan Lin sensitivities cut between 0.6-1um

Photoz for the NN target galaxies

Can we do color-color cut ?g-r vs r-i r-i vs i-z

It looks difficult to select the OII line in a coloc-color cut. We need a higher dimensional kind of cut such as photoz codes can provide

Conclusion• We simulated a DES+VISTA catalogue using the

CMC which include emission line fluxes.• Huan Lin derived a fiber sensitivities including all

instruments troughput and sky noise including astmospheric lines for a DESpec instrument.

• Using Huan Lin sensitivities we can select emission line galaxies from DES+VISTA photometry using ANNz.

• We suggest a selection criterion of 0.8 with a yield of 8000gal/deg2 for i(DES)<24 and a success rate of 93% or 5000gal/deg2 i(DES)<23 and a success rate of 95% (to verify).

• A color-color cut does not seem the optimal solution to select target for DESpec.

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COSMOS Mock Catalog (CMC): Validation

Jouvel et al. 2009

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COSMOS Mock Catalogue(CMC)

Stephanie Jouvel

We want precision cosmology Need for realistic mock catalogues to test photoz codes :

- Realistic redshift distributionImpacts DE FoM from WL - Realistic distribution of galaxy sizes in redshift and magnitude=> Realistic noise distribution impact photoz results-Emission line catalogue Create spectroscopic catalogue to study photoz calibration

Emission lines

• z = 0H-a 6563 ALy-a 1215 AOII 3726-3729 A doubletH-b 4861 AOIII 4959A and 5007A

• z~2.5 : Ly-a 4250 OII 13000

• z~3.5 : Ly-a 5460

Results from CMC : Photoz calibration

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work with Gary Bernstein as part of the SNAP-WL group - Simulation of spectroscopic

survey using forecast survey sensitivities for : optical/+NIR surveys, SHALLOW or DEEP.

=> No photoz calibration possible for z<0.5 & z>1.6 galaxies.

=> Need of visible + NIR spectroscopy to cover the whole redshift range of future photometric surveys. Jouvel et al. 2009

Stephanie Jouvel

u* +0.019

g’ -0.079

r’ -0.002

i’ 0

Z’ -0.008

Photoz : Need for spectroscopic calibrationSuccessful method to remove systematic trends

Importance of the zero-point calibration

Further improvement of the templatesIlbert et al.2006