1. EMU: Evolutionary Map of the Universe
Ray Norris
13 September 2011

2. Goals of this meeting: update people on what’s happening
get input into future directions
tap into local expertise
hope to get plenty of round-table discussion as well as presentations
if you are not yet part of EMU and you would like to be, please ask me!

3. ASKAP=Australian SKA Pathfinder
A$170M (=€120m) project now under construction in Western Australia
Completion early 2013
36*12m antennas
Antennas have a 92-pixel phased array feed (PAF)
30 sq. deg FOV!

4. ASKAP Design Specifications
Number of antennas 36 (630 baselines)
Antenna diameter 12 m (3 axis)
Maximum baseline 6 km
Cont. Angular resolution 10 arcsec
Sensitivity 65 m²/K
Frequency range 700 – 1800 MHz
Focal plane phased array 188 elements (92 dual pol)
Field of view 30 deg²
Processed bandwidth 300 MHz
Number of channels

5. Current major 20cm surveys
NVSS
75% of sky
rms=450μJy
EMU
rms=10μJy
EMU+WODAN
100% of sky
Increasing area
Increasing sensitivity

6. Perth
Sydney
Brisbane
Melbourne
Adelaide
Darwin
Alice Springs
WESTERN AUSTRALIA
NORTHERN TERRITORY
SOUTH AUSTRALIA
QUEENSLAND
NEW SOUTH WALES
VICTORIA
TASMANIA
Hobart
ACT
Canberra
Murchison Radio Astronomy Observatory
INDIAN
OCEAN
CORAL
SEA
SOUTHERN OCEAN

7. Australia – WA – Midwest – Murchison
Perth
Sydney
Brisbane
Melbourne
Adelaide
Darwin
Alice Springs
WESTERN AUSTRALIA
NORTHERN TERRITORY
SOUTH AUSTRALIA
QUEENSLAND
NEW SOUTH WALES
VICTORIA
TASMANIA
Hobart
ACT
Canberra
Murchison Radio Astronomy Observatory
INDIAN
OCEAN
CORAL
SEA
SOUTHERN OCEAN
Geraldton

8. Murchison gazetted towns: 0 Geraldton population: “up to 160” Perth
Sydney
Brisbane
Melbourne
Adelaide
Darwin
Alice Springs
WESTERN AUSTRALIA
NORTHERN TERRITORY
SOUTH AUSTRALIA
QUEENSLAND
NEW SOUTH WALES
VICTORIA
TASMANIA
Hobart
ACT
Canberra
Murchison Radio Astronomy Observatory
INDIAN
OCEAN
CORAL
SEA
SOUTHERN OCEAN
gazetted towns: 0
population: “up to 160”
Geraldton

9. Murchison Geraldton gazetted towns: 0 population: “up to 160” Perth
Sydney
Brisbane
Melbourne
Adelaide
Darwin
Alice Springs
WESTERN AUSTRALIA
NORTHERN TERRITORY
SOUTH AUSTRALIA
QUEENSLAND
NEW SOUTH WALES
VICTORIA
TASMANIA
Hobart
ACT
Canberra
Murchison Radio Astronomy Observatory
INDIAN
OCEAN
CORAL
SEA
SOUTHERN OCEAN
gazetted towns: 0
population: “up to 160”
Geraldton

12. Configuration and uv-coverage
−50°
Antenna configuration
2-km core with 30 antennas
6 antennas further out
−10°

13. 36 Antenna Array Configuration
Natural weighting: resolution 20 arcsec
Continuum:
uniform weighting:
resolution 10 arcsec
Spectral Line: Inner 30 dishes only, resolution 30 arcsec
(all at 1.4 GHz)
Maximize sensitivity for extragalactic HI while maintaining high resolution (for continuum) and good surface brightness sensitivity (for diffuse HI and polarisation).
Circle diameter 2km
Gupta et al. 2008, ATNF ASKAP Memo 21 13

14. Sensitivity of EMU to a 1 Mpc
cluster halo:

15. Antennas Antennas built by CETC54 (China)
Delivered and assembled on site
Antenna 1 delivered late 2009

16. Antennas
Antennas 2-6

17. ASKAP – PAF: 188 element unit
The array is a complementary screen sitting above a groundplane with differential feed points at the groundplane between where the diamonds corners almost meet. The sensitivity of this array has been calculated for ASKAP [5] which has prime focus 12m dishes with an F/D of 0.5.

18. First 2 full-size ASKAP PAFs

19. Data Transport
Direct burial of 300km fibre (Boolardy-Geraldton) started Oct 2010
Now complete (June 2011)
Includes 3 repeater huts
NBN network Perth-Geraldton also completed June 2011

20. BETA: Boolardy Engineering Test Array BETA construction on schedule

21. ASKAP current status Construction is on schedule
36 antennas in place by end of 2011
fibre all in place
eVLBI to NZ conducted in July 2011
Parkes PAF is performing well
BETA will be available end of 2011/early 2012

22. PAF performance Performing very well Tsys < 50K at low freq
Tsys ~ 100K at high freq
can be fixed

23. ASKAP – Possible schedule
End of 2011:
36 antennas on site
all hardware on site for 6-antenna BETA array
Early 2012: BETA commissioning starts
ASKAP Design enhancement
Use experience from Mki PAF to develop MkII PAF
Better PAFs at lower cost
March 2013: Science-ready ASKAP available
minimum of 12 antennas equipped with PAFs
2013… Antennas continue to be equipped with PAFs as funding permits
A good target would be:
All antennas equipped with upgraded PAFs by Dec 2013

24. The Science 38 proposals submitted to ASKAP
2 selected as being highest priority
8 others also supported
EMU all-sky continuum (PI Norris)
WALLABY all-sky HI (PI Koribalski & Staveley-Smith)
COAST pulsars etc
CRAFT fast variability
DINGO deep HI
FLASH HI absorption
GASKAP Galactic
POSSUM polarisation
VAST slow variability
VLBI

25. Deep radio image of 75% of the sky (to declination +30°)
Frequency range: MHz
40 x deeper than NVSS
10 μJy rms across the sky
5 x better resolution than NVSS (10 arcsec)
Better sensitivity to extended structures than NVSS
Will detect and image ~70 million galaxies at 20cm
All data to be processed in pipeline
Images, catalogues, cross-IDs, to be placed in public domain
Survey starts 2013
Total integration time: ~1.5 years ?

26. Complementary radio surveys
Westerbork-WODAN
using Apertif PAF on Westerbork telescope
will achieve similar sensitivity to EMU
will observe northern quarter of sky (δ>+30°)
well-matched to EMU
LOFAR continuum surveys
lower frequency
covering Northern half(?) of sky
valuable because yields spectral index
Meerkat-MIGHTEE
Potentially deeper over smaller area, but will be limited by confusion until Meerkat Phase II (2016?)

27. ATLAS=Australia Telescope Large Area Survey
Slide courtesy of Minnie Mao

28. The role of ATLAS as a testbed for EMU
has the same rms sensitivity (10uJy) as EMU
has the same resolution (10 arcsec) as EMU
covers (only!) 7 sq. deg.
has (2000) galaxies
We’re using ATLAS to test many aspects of EMU
Imaging (dynamic range, weighting)
Source extraction
Cross-identification
Source database and VO server
Science!

29. How did galaxies form and evolve?
Science Goals

30. Redshift distribution of EMU sources
Based on SKADS (Wilman et al.2006)

31. Science Goals Evolution of SF from z=2 to the present day,
using a wavelength unbiased by dust or molecular emission.
Evolution of massive black holes
and understand their relationship to star-formation.
Explore the large-scale structure and cosmological parameters of the Universe.
E.g, Independent measurement of dark energy evolution
Explore an uncharted region of observational parameter space
almost certainly finding new classes of object.
Explore Diffuse low-surface-brightness radio objects
Generate an Atlas of the Galactic Plane
Create a legacy for surveys at all wavelengths (Herschel, JWST, ALMA, etc)

32. Science Goal 1:
To trace the evolution of the dominant star-forming galaxies from z=5 to the present day, using a wavelength unbiased by dust or molecular emission.

33. SFR measurable (5σ) by EMU
HyperLIRG
z=4
Arp220
z=2
Measured radio SFR does not need any extinction correction
M82
z=0.4
Milky Way
z=0.1
With 45 million SF galaxies, can stack to measure SFR to much higher z

34. Region occupied by unidentified sub-mJy radio sources?
Redshift
Region occupied by unidentified sub-mJy radio sources?
What dominates SFR at each z?
(From Hopkins et al 2004, Barger et al 2000)
Time since Big Bang (Billions of years)
Present Day

35. Science Goal 2:
To trace the evolution of massive black holes throughout the history of the Universe, and understand their relationship to star-formation.

36. EMU will detect 25 million AGN
We will detect rare objects, such as
high-z AGN
composite AGN/SF galaxies
galaxies in a brief transition phase from quasar-mode to radio-mode accretion.
Norris et al. 2008, arXiv:
S20cm= 9mJy
z = 0.932
L20cm= 4 x 1025 WHz-1
Other questions:
How much early activity is obscured from optical views?
Can we use trace the evolution of MBH with z?
When did the first MBH form?

37. F00183-7111 (ULIRG with L=9.1012 Lo) P=6.1025 W/Hz z=0.327
1 kpc
20kpc
z=0.327
P= W/Hz
Merger of two cool spirals:
SB just turned on - AGN just turned on
radio jets already at full luminosity, boring out through the dust/gas
Almost no sign of this at optica/IR wavelengths
see Norris et al. arXiv:

38. Science Goal 3: To use the distribution of radio sources to explore the large-scale structure and cosmological parameters of the Universe.
Radio surveys are unbiased by dust & sky lines
How similar are the cosmic webs of AGNs and SF galaxies?
Did they have a common origin?
We can use head-tail galaxies as probes of clustering to high z.
We should detect Integrated Sachs-Wolfe (ISW) effect directly, so testing the scale of Dark Energy at z > 1
z=0.22. From Mao et al 2010,MNRAS, in press.

39. Integrated Sachs-Wolfe Effect
From
~10°

40. Science Goal 3: Cosmoology and Fundamental Physics
EMU
EMU (70 million galaxies) has fewer objects than DES (300 million) but samples a larger volume
=> complementary tests

41. Dark Energy Current error ellipse Current best value Standard ΛCDM
EMU error ellipse
See Raccanelli et al. ArXiv
“Current error ellipse” is based on Amanullah et al., 2010, ApJ, 716, 712, plus Planck data

42. Modified Gravity Current error ellipse Current best value Standard GR
EMU error ellipse
See Raccanelli et al. ArXiv

43. Science Goal 4: To explore an uncharted region of observational parameter space, almost certainly finding new classes of object.
6.1 mJy at 20 cm
< 5 µJy at 3.6µm
Norris et al 2007, MNRAS, 378, 1434; Middelberg et al 2008, AJ, 135, 1276; Garn & Alexander, 2008, MNRAS,391,1000; Huynh et al.,2010, ApJ, 710, 698; Norris et al. 2011, ApJ, in press

44. SERVS Warm Spitzer observations of IFRS
3.6 μm Flux density = μJy.
SERVS=>1400 hours on Spitzer
3.6 μm median stacked image
Median of 39 images
Flux density = μJy.
Pixel size = 0.6 arcsec.
SERVS=>1400 hours on Spitzer
Median of μm images
Norris et al. 2011, ApJ, in press.

45. What is the density of new discoveries in parameter space?
Limit of conventional radio-telescopes
SKA pathfinders
ATLAS pushed the boundaries by only a factor of a few, yet discovered two new classes of objects (PRONGS, IFRS).
What happens when we push the boundary by a factor of 40?

46. New WG: Discovering the Unexpected (WTF: Widefield ouTlier Finder)
Instead of hoping to stumble across new types of object, we will systematically mine the EMU database, discarding objects that already fit known classes of object based on their:
morphology
spectral index
polarisation
SED in optical/IR
etc
Objects that remain will be either
processing artefacts (important for quality control)
statistical outliers of known classes of object (interesting!)
New classes of object (WTF)

47. Science goal 6: Produce the most complete catalogue of the Galactic Plane to date.
Much deeper and higher res than any other survey:
CGPS: arcmin, few mJy, 73° of Northern plane
SGPS: arcmin, 35 mJy, most of S plane
MAGPIS: 6 arcsec, 1-2 mJy, 27° of N plane
EMU: 10 arcsec, down to 50 μJy, most of plane
all of plane when linked to WODAN
Build a complete census (and possibly discover new types of):
all phases of HII region evolution
the most compact and youngest supernova remnants
radio-emitting Planetary Nebulae to constrain galactic density and formation rate
Helfand et al 2006, AJ 131, 2525.

48. Science goal 7: Radio stars
HR diagram for 420 radio stars (Gudel, 2002)
Goals
Increase # of known radio stars by
Discover new types and define typical populations (unbiased)
Identify trends and correlations
current samples too small
Understand stellar magnetic activity
Understand coherent emission mechanisms
Algol: Mutel et al 2009

49. New EMU leadership structure
Ray Norris
Project Leader
Andrew Hopkins
Project Scientist
Ilana Feain
Project Scientist
Nick Seymour
Project Scientist
Design Study Working Groups
Science
Working Groups

50. Design Study Working Groups
Observing Strategy (Shea Brown)
Commissioning, BETA, Observing Process (Ilana Feain)
Simulations (Emil Lenc)
Data processing Pipeline (Tom Franzen)
Compact Source Extraction (Andrew Hopkins)
Extended Source Extraction (Tom Franzen)
Quality Control (Lisa Harvey Smith)
Automated cross-IDs (Loretta Dunne)
Galaxy Zoo Cross-IDs (Julie Banfield)
Data Requirements (Ray Norris)
Data Access and VO (Minh Huynh)
Redshifts (Nick Seymour)
WTF (Ray Norris)

51. EMU Roadmap Proposed changes to design study WGs:
more, smaller, groups
WG chairs to lead their WG actively
EMU memo series
Progress will be marked by milestones
Major goals: written reports/papers
Management team will regularly review progress of WG

52. Science Working Groups
Currently unchanged:
Evolution of Galaxies (Nick Seymour)
Cosmology (Matt Jarvis/Shea Brown)
Clusters (Melanie Johnston-Hollitt)
Galactic Plane (Mark Thompson)
Radio Stars (Gracia Umana)
Diffuse Low Surface Brightness objects (Shea Brown)
Stacking (Jose Afonso)
Terminated:
Simulated Radio Sky (=> simulations)
Application to existing data (=> ATLAS)
Collaboration with other SKA Pathfinders (=> SPARCS)

53. Science WGs Specific requests to science WGs
Each WG to produce (at least) a paper/report on the science that will be done with EMU
WG chairs need to involve members, not do things single-handedly!

54. Redshifts WG (WG chair Nick Seymour)
Few of our 70 million galaxies will have spectroscopic redshifts
Not enough photometry for good photometric redshifts
BUT
Have upto 9-band photometry for ~50% of EMU sources
SkyMapper, SDSS, VHS, WISE
Also have radio data that can constrain algorithm
polarisation, spectral index, morphology. radio/Kband ratio, FRC
Expect to be able to produce rough “statistical redshifts” for most sources if we have a good training set
Use ATLAS COSMOS sources to train algorithms
Proposing large spectroscopy programs on all ATLAS sources
Experimenting with different algorithms
Expect to classify in z bins: (e.g.) 0-0.5, 0.5-1, 1-2, 2-4, 4-8

55. Fraction of EMU sources detected at optical/IR

56. Solution: “statistical redshifts”
Photometric redshifts are poor-mans spectroscopic redshifts
Statistical redshifts are poor-mans photometric redshifts.
Useful if you want to know the statistical properties of a sample.
E.g. median z of EMU is 1.1
select polarised sources=> median z = 1.9
select steep-spectrum polarised source => median z =2+(?)
Radio/MIR ratio also correlates with z, so even a K-band non-detection is valauble

57. EMU Survey Design Paper (PASA, in press, http://arxiv. org/abs/1106

58. Western Australia