GMT and SKA - Giant Magellan · PDF fileGMT and the SKA P. McCarthy GMT ... 1AU at 100pc - 100...

Astronomical Society of Australia Meeting - Perth July 08 1

Scientific Synergy Between

GMT and the SKA

P. McCarthy

GMT


• Common Science Drivers

• Exoplanets

• Galaxy Evolution

• Dark Energy

• First Light & the Epoch of Reionization

Topics


Three Approaches:

Discovery Space

Contemporary Science Drivers

Synergy with Current and Future Facilities

Scientific Strengths of the GMT Design:

High angular resolution - 10mas at 1μm

1AU at 100pc - 100 pc at z = 1

Large collecting area - 380 m2 - 10 x Magellan 6.5m

Wide Field - practical paths to seeing-limited survey instruments

Gregorian Adaptive Secondary - GLAO, Great mid-IR performance

GMT Science Drivers


GMT SCIENCE: CONTEXT & SYNERGY

JWSTALMA

LSST

SKA

Broad Synergy Across Wavelength, Spatial and Time Domains

Magellan

Physical DiagnosticsDeep/Wide Surveys

High-resolution imagingHigh SNR & Res. Spectroscopy


SKA Key Science Projects

• The Cradle of Life Exoplanets• Strong-Field Test of GR Black Holes/Pulsars• Cosmic Magnetism Galactic/IGM fields• Galaxy Evolution & Cosmology

HI in GalaxiesEvolution of Dark Energy

• Probing the Dark Ages Reionization


GMT Science Goals

• Planets and Their Formation

• Stellar Populations and Chemical Evolution

• Assembly of Galaxies

• Black Holes in the Universe

• The Accelerating Universe

• First Light and Reionization of the Universe

http://www.gmto.org/sciencecase


Imaging Exoplanets

Exoplanets are faint!…

Jupiter reflects 10-9 Lsun

Earth reflects 10-10 Lsun

…and close in

Jupiter 0.5´´ @ 10pc

Earth 0.1´´ @10pc

Suppression of diffraction is essential

Coronagraphy, phase modulation, nulling, μ-lensing, transits, PRV

Image by David Aguilar, CfA


GMT PSF with phase apodization

1.65 μm, 5% bandwidth

10-6 suppression at 4 λ/D, 56 mas

10-5 companion

Young planets are best detected in the 5μm and 10μm bands. There are dozens of young star clusters visible from Chile and hundreds of candidate planetary systems.

Typical mass sensitivities:

Age < 100Myr M < 1Mjup

0.5 Gyr ~2-5 Mj

1.0 Gyr ~5-10 Mj


Internal Structure of Distant Galaxies

Z = 0.1 HST Hα + Continuum Z = 1.4 GMT @1.6μm 1-Hour

|------ 1 arcsecond ------|

GMT- 15mas @1.6μm

150mas with GLAO -8′ fov

SKA - 17mas @5Ghz

140mas @591 MHz


GMT Survey InstrumentsIMACS f/2

GMACS

NIRMOS

18′

… maybe not “wide field” by Australian standards, but large

by ELT standards

GMACS = 10 x Deimos on Keck


Stellar Populations in Massive Galaxies

Kreik et al.

Current State of the Art

Gemini GNIRS


The sky may not be the limit!

Sky subtracted

OH removed inPost processing

OH suppressionBefore dispersion

Photon counting

Detector + OH Suppression

Z = 1.5

Old Galaxy


Dark Energy Studies with GMT

• BAO at z = 5 if w ≠-1 ….. then what?

…….Lyα based BAO study at z = 5 with GMT cost is high (~100 - 200 nights) but possible

• SNe spectroscopy at z > 1

• Identification of LISA sourcesCosmological Distances to ≤ 1%

… may need some help with pre-imaging

SNe Ia at

z = 1


Probing the EOR with GMT & SKA

N. Gnedin

HIIHI

Key Questions:

- What is “the” redshift of reionization?

- What is the source(s) of ionization?

- How does the topology evolve with redshift?


Lyα as a probe of the EOR

- Gunn-Peterson effect

- “Dark” GRBs ?

- Lyα florescence from boundary regions

- Evolution of the Lyα luminosity density

- Spatial correlation between SKA HI maps and LAEs

- Pencil beam surveys targeted from SKA

How can ELTs explore the end of the Dark Ages?


Gunn-Peterson Effect & Reionization Topology

White et al. 2003

High

τGP

High

τGP

11-hour exposures with Keck 10m

Larger aperture needed to sample more sight-lines


Reionization History - Double Reionization?

X. Fan

Z=9.4 QSO

Magellan 8hrs

GMT 8hrs


Lyα Florescence at z ~ 3

Adelberger et al. 2005

There is a strong case for florescence at z ~ 3

Lyα abs

Lyα emission

QSO Cont.

At z = 3 all of the HI is in damped Lyα systems


Lyα Florescence at the EOR?

HI

FUV

Lyα

Lyα at z ~ 9Florescence signal from the metagalactic flux is faint!

Lyα florescence from bright QSO is potentially detectable, if there are bright sources at the reionization epoch.

Sensitive to

local Jν, xHI


Visible Halos at z ~ 9

Fully Ionized

50% Neutral 75% Neutral

25% Neutral

250Mpc = 15 degrees!

Lyα LF & distribution provides a probe of the neutral faction at high z

Scales are very large - impractical at z > 7?

Damping wings are primary escape path

for Lyα photons


Evolving UV Luminosity DensityEvolving UV Luminosity Density

Bouwens et al.A steep drop off for z > 6.5 could signal the end of the

EOR


Lyα Luminosity Function at z ~ 6

Ly α luminosity function from Malhotra & Rhoads

Wide-field NB imagingStrong Lensing


Lyα Luminosity Function at z ~ 6

35 hour integrations with GMOS on Gemini S. Faintest objects have F = 5E-18.

Stanway et al. 2006.


Use Case: Lyα Luminosity Function at z ~ 6

500 km/s FWHM

Wλ = 100Å

30hr integration with GMACS using 0.5” slits in 0.5” seeing

30% throughput

Gemini sky spectrum

Nod & Shuffle sky rejection

R = 5000 rebinned to

R = 1200, Gaussian smoothing


Mock Lyα Luminosity Function at z ~ 6 with GMT

How do we extend this to z > 8?

Move to the near-IR, but fields of view are

smaller, so must target fields using HI

maps


IGM Structure at z ~ 9

130 Mpc

~20

“Pencil beam”surveys can easily miss the important structures

SKA can provide the map needed to make an informed survey for Lyα at the end of the EOR.


Lyα Spectroscopy in the Near-IR

Lyα at z = 8.7

in the J-band

NIRMOS Properties with current Near-IR detectors

200 km/sec line widths

25 hour exposures

7′ x 7′ field of view

Pho

tons

/sec

/cm

2

4Msun/yr

MW Star formation

rate!

MW Star formation

rate?



NIRMOS Properties with OH Suppression and low-noise

Near-IR detectors


25 hour exposures


With OH suppression


Structure at z ~ 10

Numerical simulation of gas cooling at z = 10

Dave’, Katz & Weinberg


Ly alpha image with

GMT GLAO

R=3000 filter

20% escape fraction for

Lyα

8 hour exposure

Laser Tomography

AO

Lyα HeII 1640

Internal Structure in Galaxies at z ~ 10

Very top-heavy IMF!


Things to take away…..

1. Like SKA, the scientific motivation for GMT is compelling

2. The two projects are more powerful together than either is alone

3. Australia can make major contributions to the scientific and technical development

instruments, adaptive optics, photonics….

GMT and SKA - Giant Magellan · PDF fileGMT and the SKA P. McCarthy GMT ... 1AU at 100pc - 100...

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