Pan-STARRS

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• Pan-STARRS

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Context

• National Academys Decadal Review recommended a
  large synoptic survey telescope (LSST)
• 6m class aperture
• dedicated wide-field optical imager
• all-sky survey to enable multiple science goals
• applications from solar system to cosmology
• strategic emphasis in NEO threat
• LSST is assumed to accept natural seeing
• for many applications the figure of merit is then
  simply the etendue A W ? / dW
• an alternative to a single 6m telescope is an
  array of smaller telescopes with the same total
  area A
• many pros and cons, the major advantages are
• single no duplication of detectors, can go
  fainter faster
• distributed cheaper, faster to build, more
  flexible

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Pan-STARRS Design Philosophy

• Given the following constraints
• Construction time 1 year per meter aperture
• Telescope cost rises faster than D2
• Pixel size limited to gt10mm, desire 0.3 pixels
  requires a focal length of lt8m
• Optical design for a large ? becomes very
  expensive for fast f-ratios
• Costs of CCD detectors have been falling
• (O)MEGACAMs 8-10M for 3x108 pixel or
  2-3c/pixel
• Today it is possible to do a factor of 10 better
• We believe it is cheaper and better to build an a
  survey instrument from an array of telescopes and
  detectors.

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Pan-STARRS in a Nutshell

• Detector and controllers
• 109 0.3 pixels per camera
• Image motion compensation
• 512 channel controller
• 2 second readout
• 4e- read-noise
• Data-Processing System
• Multicolor summed images
• Difference images for detection of moving and
  variable objects
• Catalogs of static, moving, transient objects
• Science
• Killer Asteroids (PHAs)
• Huge range of other science topics presently
  imagination limited

• Telescopes
• Four 1.8m R-C corrector
• 7 square degree FOV
• Sited on Mauna Kea or Haleakala
• Operation mode
• Broad band optical imaging
• Four telescopes view the same field to detect
  transient or moving objects and build up a deep
  image of the sky
• Partners
• IfA science, detectors, pipelines
• MHPCC production DP, infrastructure
• SAIC databases and mass storage systems
• MIT-Lincoln Lab detectors

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Puu Poliahu
UH 0.6-m
UH 2.2-m
UH 0.6-m
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CFHT
UKIRT
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Science Overview

• Time domain astronomy
• Transient objects
• Moving objects
• Variable objects
• Static sky science
• Enabled by stacking repeated scans to form a
  collection of ultra-deep static sky images

• Very extensive overlaps between observational
  requirements of science programs!

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Pan-STARRS Surveys

• Solar System (Ecliptic Plane) used primarily to
  satisfy the observing requirements imposed by the
  PHO, NEO, MBA, KBO and other SS programs.
• 3? used primarily to satisfy the observing
  requirements of the WL, LSN census, and EG object
  detection classification programs primary
  cadence drivers are the LSN census (and other
  proper motion studies)
• Medium-Deep the SNe, LSS, and the EG object
  detection classification programs primary
  cadence driver being SNe
• Ultra-Deep EG object detection classification
  and, to some extent, SNe programs
• Object Variability/Auxiliary mostly
  user-defined supporting programs such as stellar
  variability and the search for extra-solar planets

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Design Reference Mission
Mode PSY Area Cad. w g r i z y
SS NEO 1.1d 0.2b 7000 h/d/m 27.3 300
SS KBO 1.0d 0.2b 3? hdmy 26.3 60
Var. 0.8d 0.8b 133 4 min 29.2 22000 28.6 7400 28.5 4400 24.9 4400
3? 1.3d 2.5b 3? 14d 25.9 30 25.6 30 25.4 60 23.9 20 22.3 30
Med. Deep 0.6d 0.9b 1200 4d 27.1 271 27.0 460 27.3 1200 25.0 1900 24.0 600
Ultra Deep 0.5d 0.7b 28 4d 29.1 10000 29.0 18000 28.0 6300 27.0 6700 26.0 26000
5-? limit (AB) Total int. (min)
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Science with Pan-STARRS

• Moving Object Science
• NEO Near Earth Object threat
• OSS/MBO Main Belt and Other Solar System
  science
• KBO Kuiper Belt Objects
• SOL Solar Neighborhood (parallaxes and proper
  motions)
• Static and Invariable Object Science
• WL Weak Lensing
• LSS Large Scale Structure
• LSB Low Surface Brightness and dwarf galaxies
• SPH Spheroid formation
• EGGS Extragalactic and Galactic Stellar science
• Transient and Variable Object Science
• AGN Active Galactic Nuclei
• SNE Supernovae
• GRB Gamma Ray Bursts and afterglows
• EXO Exoplanets (from occulation)
• YSO Young Stellar Objects
• VAR Variability Science (especially stars)
• TGBN (Things that go Bump in the Night)

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Near Earth Asteroids
100m
1km
10km
Size
103
2x105
5x108
year
Time Interval
105
108 Mton
102
Energy
Global
Regional
Local
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Damage vs Size
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Risk Reduction vs Time
(1000m)
(500m)
(200m)
LINEAR
PS
LSST
(50m)
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Inner Solar System Science

• 107 asteroids
• Families
• Orbit parameter space structure
• 104 NEOs
• Phase-space distribution
• Hazardous asteroids
• Comets

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Outer Solar System Science

• Kuiper Belt Objects
• Orbital distribution
• Formation and evolution
• Trans-Neptunian Objects
• Interlopers on hyperbolic orbits

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Stars and the Galaxy

• Parallax survey
• Complete stellar census to 100pc
• Proper motions
• Formation history
  

• Other goals
• Stellar variability
• Low mass stars
• Extra-solar planets

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Moving Objects

• KBO 20,000 KBOs over 10 years all sky,
  unbiased.
• 100 in binary pairs
• OSS many more asteroids and comets (20x)
• 5x106 million main belt, 105 Jupiter Trojans,
  etc.
• SOL parallaxes to 100pc in 10 years
• Best substellar IMF available (better than
  UKIDSS)
• 10-100x more brown dwarfs than SDSS or 2MASS
• EGGS proper motions of most stars in the Milky
  Way
• Accuracy of 2.5 km/s at 1kpc.

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Cosmology Weak Lensing

• Total mass power spectrum P(k) to large scales
• Test of inflation theory
• Evolution of P(k)
• Higher order statistics
• Gravitational instability theory
• Cluster mass function
• Cosmology
• Cosmological parameters
• Geometric tests
• World model

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Static and Invariable Objects

• WL Weak lensing over 1000 sq deg.
• Large-scale structure of mass on large scales
  (wide area) and small scales (high density of
  objects) as a function of redshift, evolution of
  mass clustering.
• Mass profiles of galaxies
• SPH, LSB, AGN Evolution of galaxies
• Pan-STARRS will survey 4x the area of SDSS, will
  have the same photometric accuracy but 3-4 mag
  fainter, good sensitivity at 1um (y band).
• Reionization, metal formation, spheroid
  formation, AGN activity, galaxy merging, and
  cluster formation.

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Cosmology Supernovae

• Hubble diagram
• Dark energy equation of state w(z)
• Cosmological parameters
• Supernova physics
• Star formation history

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Transient and Variable Objects

• SNE 10,000s of SNIa to z1
• Measure time (redshift) evolution of dark energy
• AGN Dropouts to z7, variability identification
• Reionization, metals, spheroid formation, nature
  of radio sources, stellar disruptions, etc.
• GRB Optical counterparts (100 per year)
• Possibly V8 declining to V20 in one day
• EXO Occultations of stars by planets
• Pan-STARRS is sensitive to Jupiters around
  sub-solar mass stars or Earths around brown
  dwarfs.
• VAR Stellar variability
• White dwarfs, binaries, Cepheids, Miras, RR
  Lyrae, microlensing, supergiants, etc, etc.

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TGBN

• The Pan-STARRS survey is 10-20 times SDSS,
  Megacam survey, Vista, etc. in extent, but
• We are repeating it 30 500 times!
• We will be the first to have extensive time
  domain information, designed with useful and
  interesting cadences, well controlled selection
  and systematics, and huge samples.
• There is a high likelihood for unanticipated
  discoveries
• Unexpected variable objects
• Extremely rare objects
• Very large scale patterns

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Data Volume

• Expect 700 images 6 Tb per night raw
  3 Tb per night 1 Pb per year
  reduced!
• We have to be prepared not to save the bits
• We must create a reliable enough pipeline that we
  tap all the science we want as the data flow
  through, and then throw the bits on the floor.
  (This has never been achieved before.)

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Image Processing Pipeline
Chip Level
Chip Level
Telescope and System Level
System Level
System Level
System Level
Image Capture
Phase 0
Phase 4 Augmented Image Processing
Phase 5 Science Client Product Generation
Phase 6 Science Client Interfaces
Phase 1 Detector Calibration (Calibration and
Instrument Correction Processes)
Phase 2 Map and Warp to Sky (Image Manipulation
Processes)
Phase 3 Create Sky Image (Image
Combination Processes)
Science Clients
Scheduler
Data Storage
Data Storage
Data Storage
Data Storage
Data Storage
Data Storage
TCS and Environment Monitoring
Internal Product Generation
Internal Product Generation
NB specifics have changed!
Mission Planningpre-staging of each nights
scheduling and supporting dataTBD
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Confusing Issues

• LSST should not be discussed as an either or
  competitor to Pan-STARRS Pan-STARRS will exist
  before LSST begins construction. Therefore
• Astro-photo precursor survey will have been done,
• A robust data pipeline will have been shaken
  down,
• 50 of 300m PHAs will have been discovered, etc,
  etc.
• What etendue is really needed?
• Etendue is A W ? / dW those last two factors
  are important!
• SDSS at A W 7.5, CFHT at 10, Suprime at 13
  cannot approach LSST science because of limited
  ? and/or dW.
• Pan-STARRS at A W 50 is designed to have
  superb ? and dW and the software and
  scheduling to maintain LSST science.
• Pan-STARRS will improve on the present state of
  the art (SDSS, upcoming synoptic surveys) by at
  least an order of magnitude in science
  productivity.

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Design Reference Mission
Mode PSY Area Cad. w g r i z y
SS NEO 1.1d 0.2b 7000 h/d/m 27.3 300
SS KBO 1.0d 0.2b 3? hdmy 26.3 60
Var. 0.8d 0.8b 133 4 min 29.2 22000 28.6 7400 28.5 4400 24.9 4400
3? 1.3d 2.5b 3? 14d 25.9 30 25.6 30 25.4 60 23.9 20 22.3 30
Med. Deep 0.6d 0.9b 1200 4d 27.1 271 27.0 460 27.3 1200 25.0 1900 24.0 600
Ultra Deep 0.5d 0.7b 28 4d 29.1 10000 29.0 18000 28.0 6300 27.0 6700 26.0 26000
5-? limit (AB) Total int. (min)
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Final Data Products

• Sky, the wallpaper
• 10 Tpix x 6 colors x N versions
• Sky, the movie
• 10 Tpix x 6 colors x 50 epochs
• Sky, the database
• 2x1010 objects (x 6 colors x 20-60 epochs)
• Photometry to lt 0.01 mag, astrometry to lt 50 mas
• Photometric redshifts of most of these objects
• 109 proper motions (complete over 3?)
• 108 variable stars and AGN
• 107 asteroids (104 NEO/PHA)
• 107 transients (SN, GRB, etc.)
• 3x105 stars within 100 pc (with good parallax)