Status of the Spitzer Warm MissionSpitzer Extended Deep Survey (SEDS)

Giovanni G. Fazio

Harvard Smithsonian Center for Astrophysics

and the SEDS Team

AEGIS Meeting, Toledo Spain

SEDS: Spitzer Extended Deep Survey

• PI: Giovanni Fazio– 47 Co-I’s from 23 institutions

• Primary Scientific Objective– Galaxy formation in the early Universe– Obtain first complete census of the assembly of stellar mass and

black holes as a function of cosmic time back to the era of reionization

– Series of secondary objectives

• Unbiased survey 12 hrs/pointing at 3.6 and 4.5 microns ([3.6] = 26 AB, 5 ) in five well-studied fields (0.9 sq deg)– 10 times area of deep GOODS survey

• Total Time: 2108 hrs over 1.5 years• No proprietary time on data

SEDS Co-Investigators

Harvard Smithsonian Center for Astrophysics: Lars Hernquist, Matt Ashby, Jiasheng Huang, Kai Noeske, Steve Willner, Stijn Wuyts, T.J. Cox, Yuexing Li, Kamson Lai

Max-Planck-Institut für Astronomie: Hans-Walter Rix, Eric Bell, Arjen van der Wel

University of Califronia, Santa Cruz: Sandy Faber, David Koo, Raja Guhathakurta, Garth Illingworth, Rychard Bouwens

NASA/GSFC: Sasha Kashlinsky, Rick Arendt, John Mather, Harvey Moseley

Carnegie Observatories: Haojin Yan, Ivo Labbe, Masami Ouchi

University of Pittsburgh: Jeff Newman

Space Telescope Science Institute: Anton Koekemoer

University of Arizona: Ben Weiner, Romeel Dave, Kristian Finlator, Eiichi Egami

University of Western Ontario: Pauline Barmby

Imperial College, London: Kirpal Nandra

University of Chicago/KICP: Brandt Robertson

Swinburne University: Darren Croton

Stanford University/KIPAC: Risa Wechsler

University of Florida, Gainesville: Vicki Sarajedini

Astrophysikalisches Institute, Potsdam: Andrea Cattaneo

University of Massachusetts, Amherst: Houjun Mo

Royal Observatory Edinburgh: James Dunlop

Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan: Lihwai Lin

National Research Council, Herzberg Institute of Astrophysics: Luc Simard

Texas A&M University: Casey Papovich

Tohoku University, Japan: Toru Yamada

Oxford University: Dimitra RigopoulouUniversity of California, Riverside: Gillian Wilson

SEDS Co-Investigators

SEDS: Scientific Objectives

• Galaxy Assembly in the Early Universe

– Direct study of the mass assembly back to the era of reionization.• Study stellar masses and mass functions from z = 4 - 6• Constrain high mass end of mass function at z = 7.

– Measurement of spatial clustering of galaxies• Determine the evolution of galaxy properties as a function of halo masses.

– Study of identified Ly emitters at z = 5 - 7.• High z counterparts to dwarf galaxies?• Different sample compared to dropouts

– Black hole evolution at z > 6.• Study of high-z AGN number counts (constrain evolutionary models)• Relationship to stellar growth

– Tests of theoretical models of galaxy assembly• Numerical simulation models to tie observational effects together

SEDS: Scientific Objectives

• Auxiliary Science– Galaxy Evolution from z ~ 1 - 4

• Nature of high-z galaxies• Mass assembly of galaxies• Emergence of quiescent galaxies

– Mid-infrared Variability for AGN Identification• A more universal tracer of AGN

– Measurement of the Cosmic Infrared Background radiation spatial fluctuations

SEDS: Technical Aspects

• Sensitivity– 12 hrs/pointing at 3.6 and 4.5 microns

– [3.6] = 26 AB, 5 (0.15 Jy)

– Robustly measure M* (reach 5 x 109 Msun at z = 6)

• Field Geometry and Configuration– Clustering and large scale structure at z = 6: > 20 - 30 arcmin

– Correlation length: > 5 - 10 arcmin

• Number of Fields– Cosmic variance: 5 fields

• Field Selection– Fields with deep auxiliary data: Extended GOODS-S, Extended

GOODS-N, UDS, EGS, COSMOS/UltraVista

SEDS Survey Fields

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Area Coverage vs Exposure Time

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SEDS: Technical Aspects

• Expected Number of Sources– Statistically meaningful samples– Enough to derive mass functions and perform

clustering studies– Finlator models: 8000, 2000, and 200 at z = 5, 6,

and 7; few at z ~ 9.

• Source Selection– Conventional Ly “dropout” technique

• Z = 4, 5, 6, and 7: B, V, i, and z

Timeline of Warm Mission EventsOriginal IWIC plan affected by unexpected thermal control issues. Significant delay while reworking IRAC thermal control system.• Cryogen exhausted 15 May 2009 22:11:27 UTC

• IRAC Warm Instrument Characterization (IWIC) begins 19 May 2009- Anomaly with IRAC thermal control Standby mode entry 19 May 2009 23:35:48- Observatory returned to normal mode 20 May 2009- Firmware patch initiated- Transition science (GRB image) and instrument characterization during patch development

• Firmware patched and IWIC restarted 19 June 2009 - Temperature setpoint of 31 K and applied bias of 450 mV selected 03 July

• IWIC completed 28 July 2009

It became apparent that the IRAC heaters were driving the MIC temperature higher than power-off equilibrium.

Timeline of Warm Mission Events

• 12 Aug 2009 -- array heaters switched off– Permitted operation 1.3 K cooler than original setpoint; critical noise

boundary

• 18 Sep 2009 -- Final operating setpoints established– 500 mV applied bias, T(array) = 28.7 K; final MIC temperature expected

to be 27.5K

• 23-30 Sep 2009 Recalibration sequence conducted– Flat-field, linearity, bias, photometric calibrations

• 29 Sep 2009 -- First campaign 2 wks of data released to observers• 12 Oct 2009 -- 6th campaign released back on normal 14 day after

campaign ends release cadence

• Bad surprises- Linearity very different than cryogenic- Appearance of intermediate term latents- Column pulldown slightly more complicated

Good surprises- No long term latents at 3.6 m- No muxbleed and muxstripe- We have not derived the first-frame correction yet, but have the data in hand

• As expected- Optical performance remains the same- 3.6 and 4.5 m performance close to cryogenic- AOT worked as expected- Pipeline performed as in cryogenic mission

IWIC calibration and characterization of greater depth and complexity of the IRAC characterization during the original In-Orbit Checkout

Spitzer Warm MissionVariances from the Expected

Warm IRAC Performance

• Deep image noise performance– From dark measurements – 3.6 m 12% worse than cryo– 4.5 m 10% better than cryo – 10% uncertainty in values

• Bright source limit– S/N ~ (throughput)0.5 – 3.6 m 5% lower than cryo – 4.5 m 2% lower than cryo

Absolute Calibration– Currently 5% absolute calibration

uncertainty compared to 3% at end of cryo mission

• Performance supports all warm mission science

Data Calibration

Instrument calibration load down to about 4% of total observing time.Flatfield – currently recalibrated to better than cryo (0.2%).

Darks – recalibrated similarly to cryo. More sturcture than previously, but subtracts well.

Linearization – calibrated at 5% level, difficult to measure, but plan to solve this is underway.

Flux Calibration – currently at few % level, will get better with time as routine calibrations build.

First-Frame Effect – data taken, effect is relatively small for the InSb.

Pixel-Phase Correction – larger than cryo, but significant characterization data taken.

Warm vs. Cryogenic: Deep Imaging of EGS

Warm 3.6 m Cryo 3.6 m

Warm 4.5 m Cryo 4.5 m

5 UDS Field (20 x 20 arcmin)

3.6 micron 4.5 micron

UDS Field (5 x 5 arcmin)

3.6 micron 4.5 micron

NGC 2899NGC 4361

Planetary Nebulae

Cygnus DR22

Star-Forming Regions

• Warm IRAC sensitivity comparable to cryogenic

• IRAC data quality / sensitivity support all current and planned warm science

• Pipelines functional (absolute calibration currently ~5%)

• Science quality data flowing to the community

• Continuing analysis (linearity, bias, absolute calibration) will improve data quality

• Anticipate update to warm calibration and data reprocessing by first of year

• Currently completed one epoch of SEDS data: UDS field (4 hrs)

• Next SEDS observations: EGS and COSMOS/UltraVista

Summary