Summary of UK AAOmega Workshop

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Summary of UK AAOmega Workshop

• Matthew Colless, AAOmega workshop, AAO, 18 Feb
  2005

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Peacock Local z-surveys after 2dFSDSS

• There are only 2,000,000 galaxies at z
• No more big local leaps in survey size/volume

2dFGRS SDSS total 500,000
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Achievements of 2dFGRS

• Pure fluctuation issues
• Shape of P(k) and ?h
• Hints of baryon wiggles ? baryon fraction
• Redshift-space distortions ? ?8
• Joint with WMAP ? unique standard model
• Galaxy-formation issues
• LFs and bias as f(type)
• LFs and SFR as f(environment)
• Groups and properties as f(halo mass)

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Outline for AA? survey
Halo mass-to-light ratios

• Science goals
• Halo M/L to local group level measure
  efficiency peak
• Detailed conditional luminosity functions void
  LFs to deeper levels
• Detail model of stochastic biasing
• Survey parameters
• B
• 47,000 new galaxies at z
• 88 fields _at_ 400 fibres 30 nights
• photo-z selection to remove z 0.2
• SDSS Southern repeated strip

Long tcool
Feedback
Efficient
Group luminosity
Stochastic biasing
Joint lognormal model
Wild et al. 2004
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Lahav Challenges for z-surveys

• Galaxy bimodality and relative biasing

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High-order moments

• The two big superclusters in the 2dFGRS mean that
  it is not a fair sample for high-order moments?

7 Abell clusters 77 groups (8)
20 Abell clusters 93 groups (8)
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Limits on ? masses
Wn 0.05

• Free streaming effect gives upper bound on total
  mass from power spectrum
• In table, all upper limits are 95 CL, but
  different priors !

0.01
0.00
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Edge Massive Galaxies

• Goal tracing the formation and evolution of
  massive galaxies with UKIDSS and AAOmega
• Edge 2SLAQ/LRG UKIDSS teams
• Big picture massive, passive galaxies provide
  one of the cleanest tests of galaxy evolution
  models given relative simplicity (cf. SCUBA gals,
  starbursts, AGN)
• Capability UK has unique access to facilities
  required (wide-field NIR imaging plus
  multi-object spectroscopy)

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AA?UKIDSS survey

• UKIDSS has two relevant surveys
• Large Area Survey (J20,K18.4)
• Deep eXtragalactic Survey (J23,K21)
• Depth at z0.8 a 2L gal is K18 at z1.2 a 4L
  gal is K18.5
• Survey options
• LAS-selected objects that are intrinsically as
  luminous as 2SLAQ over 100 deg2 but with low sky
  density
• DXS-selected objects over tens of deg2 with
  larger absolute magnitude range than 2SLAQ and
  higher sky density
• Future to go to z1.2 needs NIR spectroscopy
• This will be available from Subaru FMOS
• DXS can be basis, but will have smaller abs mag
  range

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Shanks w(z) via QSO z-surveys

• Shanks Outram 2SLAQ collaboration
• 2SLAQ science
• Observed redshifts for 1500/10000 20.5QSOs
• Break luminosity-redshift degeneracy in studies
  of QSO clusteringbias evolution
• QSO luminosity evolution at L
• QSO-LRG clustering environment out to z
• QSO line-strengths as function of L and z
• QSO lensing by groups and clusters
• Benefit from UKIDSS (XMM?) surveys in same areas

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AA? (LRG ) QSO Redshift Survey

• Strategy for QSO component of survey
• 2 accurate peak positions require 150,000
  SDSS-2dF z0.5 LRGs in 1000 2dF pointings
• 150,000 g?w?0.15
• Good z-coverage for w(z) ? complements WFMOS at
  z3?
• Need 3000deg2 of CCD photometry in south
  SDSSVST?
• Outcomes from survey
• AAOmega LRGQSO survey will map w(z) from z0.5
  to z2.2 via baryon wiggles
• QSO Survey will give unique constraints on DE EoS
  at z1.4
• AAOmega QSO survey will also map w(z) via QSO
  lensing and the Alcock-Pacynzski test

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Oliver AA?/ASTRO-F Survey

• Seb Oliver with Rich Savage, Bob Nichol and the
  ASTRO-F team
• ASTRO-F mid-far IR satellite
• launch August 2005
• All-sky FIR survey at 60?m 170?m
• 106-107 sources, zs to beyond 1
• AA? follow-up galaxy survey
• 104 sq.deg. survey of 106 gals
• Redshifts 0
• Science from AA?/ASTRO-F z-surveys
• Star-formation in galaxies
• Cosmology and dark energy

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ASTRO-F survey expectations
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ASTRO-F/AA? Science - I

• Star-formation in normal galaxies
• as function of redshift
• as function of scale
• as function of environment
• Star-forming monsters
• the transition from IRAS to SCUBA
• Proposed survey
• for SFR(r,t) and ISW effect
• 300 gals/fld 30mJy _at_ 70?m
• 1,000 deg-2 ? 105 galaxies in 300 fields _at_
  1hr/field ? 40 nights

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ASTRO-F AA? Science II

• Integrated Sachs Wolfe (ISW) effect measures a
  differential redshift of photons in a evolving
  potential well and provides a direct physical
  measurement of dark energy
• Baryon oscillations provide a standard rod for
  mapping the evolution of the geometry of the
  universe with redshift and measure the equation
  of state of the dark energy
• Proposed survey
• for baryon oscillations and dark energy
• 106 redshifts over 104 sq.deg.
• 3000 AAO? fields x 1hr/fld 400 nights
• should measure w0 at 10s

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Colless Galaxy Evolution

• Stellar Populations in Low-Redshift Galaxies
  Characterize the stellar pops and star-formation
  histories of the current galaxy population as a
  function of properties and environment at low-z
  (2dFGRS)
• Resolved Stellar Populations and Dynamics
  Use AA? IFU capability to obtain
  spatially-resolved dynamics, ages and abundances
  in nearby galaxies
• Old Stellar Populations at Early Epochs
  Ages and metallicities of stellar
  populations in luminous red galaxies as a
  function of mass (velocity dispersion) at early
  epochs, from 0.45

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Stellar Populations in Galaxies - I

• Goal survey to characterize the stellar
  populations of galaxies (age, metallicity,
  star-formation history) as a function of global
  properties (luminosity, morphology, mass) and
  environment (local density/structures)
• Sample use 2dF/SDSS to pick 100 galaxies in each
  bin of a grid sampling luminosity (20 bins, M-3
  to M5), local density (10 bins in log?, voids
  to clusters) and morphology (5 bins, E/S0 to Irr)
  ? 105 galaxies
• Method obtain spectra at 1Å resolution and
  S/N50 to measure spectral indices (ages,
  metallicities, SFR) and, where possible, velocity
  dispersions (i.e. masses)

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Stellar Populations in Galaxies - II

• Observations 2hr exposures at 1.4Å resolution
  (R3500, 75 km/s) give S/N45 to bJ19.5 and
  S/N90 at bJ18
• Spectral coverage chosen appropriately by
  type/colour
• Late types red/blue arms cover 3700-4500Å and H?
  resp.
• Early types red/blue arms cover 4600-5400Å and
  CaT resp.
• Old stellar populations determine age
  (distribution?) and metallicity (distribution?)
  from multiple spectral indices
• Star-formation rates obtain both current and
  recent star-formation rates from Balmer lines and
  other SFR indicators
• Masses from velocity dispersions for E/S0
  galaxies and bulge-dominated spirals

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Stellar Populations in Galaxies - II

• Time required with 300 galaxies/field, 4
  fields/clear night and 60 clear fraction, a
  sample of 105 galaxies will take 140 nights (2
  years at 35 nights/semester)
• Problems
• Aperture effects with size, z and seeing
  ameliorate by choosing sample to minimize,
  correcting results via models
• Rotation velocities how best to deal with bulge
  disks?
• Partial solution IFU obsvns for subset allows
  calibration of aperture effects sample of disk
  gals with rotation curves
• Stellar population models must improve to make
  full use of high S/N spectra substantial work
  required

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Resolved Populations and Dynamics - I

• Goal spatially-resolved dynamics, abundances and
  ages in individual nearby galaxies using AA? IFU
• Observations use blue and red setups of pops
  survey to study bulgedisk/oldyoung stellar
  populations
• Dynamics map velocity field (1st to 4th moments)
  at many locations, likewise spectral indices, to
  build picture of the dynamics and the stellar
  populations
• Sample one galaxy in each of 8 bins in
  luminosity (M-3...M5), 5 bins in log? (voids
  to clusters) and 5 bins in morphology (E/S0 to
  Irr) ? 200 galaxies

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Resolved Populations and Dynamics - II

• Exposure times each IFU fibre is only
  0.5 arcsec2, and desired S/N is high (50) so
  exposure times critically depend on extent to
  which IFU pixels can be co-added
• S/N and SB e.g. 4 hour exposures only reach a SB
  limit of 19.25 mag/arcsec2 and (if doing 2
  setups) this means the survey duration is 300
  nights!
• Adaptive sampling need to co-add many IFU pixels
  to reach interestingly faint surface brightness
  levels
• Competition should this be done with AA? on AAT
  or with SAURON on WHT or WIFES on SSO 2.3m?

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Old-Population at Early Epochs - I

• Goal study formation and evolution of the oldest
  stellar populations by observing luminous red
  galaxies (LRGs) over 0.452dF-SDSS LRG survey)
• Sample select from LRG survey of 104 luminous
  (MMz0) galaxies with rest-frame colours of old
  stellar populations (age 5Gyr) n.b. 100
  LRGs/2dF field
• Method obtain spectra at 1Å resolution and
  S/N30 to measure spectral indices (ages,
  metallicities, SFR histories) and velocity
  dispersions (masses) long time baseline resolves
  age-metallicity degeneracy in spectra

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Old-Population at Early Epochs - II

• Setup need new dichroic with split at 8000Å and
  another 1000R VPHG to allow blue arm to cover
  6900-8100Å and red arm to cover 8000-9200Å at
  0.6Å/pixel
• Measurements measure spectral indices H?, Mgb
  and various Fe lines in rest-frame range
  4800-5400Å, plus velocity dispersions with
  resolution ? 50 km/s
• Observations 8 hr exposures give S/N30 to
  i19.5-19.8 (LRG survey limit) superb
  sky-subtraction is needed, but as surface density
  of targets is 100/field can use beam-switching
  and NS to reach Poisson limit
• Duration 50nt x 60 clear x 1 fld/nt x 100/fld
  3000 gal

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Whiteboard from UK Workshop