Transcript SEDS: Spitzer Extended Deep Survey

AEGIS Meeting, Toledo Spain
Status of the Spitzer Warm Mission
Spitzer Extended Deep Survey (SEDS)
Giovanni G. Fazio
Harvard Smithsonian Center for Astrophysics
and the SEDS Team
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
SEDS Co-Investigators
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 Rigopoulou
University of California, Riverside: Gillian Wilson
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 Events
Original 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
It became apparent that the IRAC heaters were driving the MIC temperature
July
higher than power-off equilibrium.
• IWIC completed 28 July 2009
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
Spitzer Warm Mission
Variances from the Expected
• 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
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
Flatfield
– currently
recalibrated
to better
than
cryo
(0.2%). time.
Instrument
calibration
load
down to about
4% of
total
observing
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
Planetary Nebulae
NGC 4361
NGC 2899
Star-Forming Regions
Cygnus DR22
Summary
• 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