GSMT SWG - Nov 8 & 9 2007 1

Science With the GMTP. McCarthy

GMT Science Working Group

GMT Board

• Status and strengths of the GMT

• Potential for national participation

• Example science use cases

GSMT SWG - Nov 8 & 9 2007 2

Context of the GMT Science Goals

Balance between wide-field and diffraction-limited science

• 25′ diameter fov,

• Viable corrector designs for up to 22′

• 10mas diffraction-limit at 1µm

• Gregorian secondary conjugates ~ 150m above primary mirror - ideal for ground-layer adaptive optics

• Adaptive secondary mirror provides low-background high StrehlAO modes as well as GLAO and the first DM for ExAO

Natural Strengths of the GMT Design

GSMT SWG - Nov 8 & 9 2007 3

First segment on the large optics grinder at the Steward mirror lab

Status of Primary Mirror Segments

GSMT SWG - Nov 8 & 9 2007 4

LCO Selected as GMT Site in October 2007

Magellan (Manqui) Campanas Pk.

Alcaino Pk.

Ridge (Manquis)

GSMT SWG - Nov 8 & 9 2007 5

Instrument Concepts

McGregor1.5”3000-50000.9-2.5NIR AO-fed IFU

JaffeSingle obj20K-200K1.2- 5.0Near-IR High-ResolutionSpectrometer

Close30”5-50000.9-5.0Near-IR AO Imager

Hinz30′′20K-120K1.0-5.0Near-IR High-ResolutionSpectrometer

MacQueen3′′ + fibremode

45K1” slit

0.3-1.05Optical High ResolutionSpectrometer

Fabricant7′ x 7′1200-50001.0-2.5Near-IR Multi-ObjectSpectrometer

Shectman9′ x 10′2500-50000.35-1.0Optical Multi-ObjectSpectrometer

P.I.FOVResolutionλ range(microns)

Instrument

GSMT SWG - Nov 8 & 9 2007 6

Instrument Selection Timescale

Call for new and continuing concept studies Winter 07/08

Design reviews Spring 2009

Selection of first generation instruments Summer 2009

Detailed design and construction contracts Fall 2009

Second generation instruments defined Mid 2012

First instruments delivered to Chile Fall 2014

There remains time and opportunity for the community to be engaged inthe instrument development and selection process

GMT is open to considering complementarity with TMT in firstgeneration instrument suites

GSMT SWG - Nov 8 & 9 2007 7

Gregorian Instrument Mounting

Large survey instruments mount below

AO instruments - always “hot” - above

Rapid instrument changes, queue observing

GSMT SWG - Nov 8 & 9 2007 8

How much time could be available through federal participation?

25-30% NSF share ~ 80 - 100 nights

GMT use cases focused on ~ 3 - 10 night programs - suitable for a PhD thesis

GSMT SWG - Nov 8 & 9 2007 9

GMT Science Use Cases

Imaging of terrestrial planets and debris disks at 5 - 10µm

mid-IR AO imager

Bulge-Black hole mass relationship at high redshifts

GMT AO-fed IFU

Lyα luminosity function at z ~ 6

GMACS

Stellar content of galaxies at z ~ 2-3

NIRMOS

Dynamics of Galaxies at 1 < z < 3

Use cases are built around instrument-specific exposure time calculatorsand spectral simulators

GSMT SWG - Nov 8 & 9 2007 10

GMT Survey InstrumentsIMACS f/2

GMACS

NIRMOS

18′

GSMT SWG - Nov 8 & 9 2007 11

Use Case: Lyα Luminosity Function at z ~ 6

GOAL: Measure the faint end of the Lyα luminosity function at z ~ 6 as a probe of the end of reionization

Instrument Used: GMT Wide-Field Optical Spectrograph - GMACS

Number of Nights: 4 in queue mode

Supporting observations: Deep imaging survey

Approach: multi-slit spectroscopy of Lyα emission lines

GSMT SWG - Nov 8 & 9 2007 12

Use Case: Lyα Luminosity Function at z ~ 6

Ly α luminosity functionfrom Malhotra & Rhoads

Wide-field NB imagingStrong Lensing

GSMT SWG - Nov 8 & 9 2007 13

Use Case: Lyα Luminosity Function at z ~ 6

GSMT SWG - Nov 8 & 9 2007 14

Use Case: Lyα Luminosity Function at z ~ 6

6986350-1.8640.5

2502300-2.3041.0

1491357-2.5341.2

70635-2.8641.5

18163-3.4542.0

329-4.2042.5

N(5.7 < z < 5.8)N(5 < z < 6)φ(α = -2)Log L(Lyα)

GSMT SWG - Nov 8 & 9 2007 15

Use Case: Lyα Luminosity Function at z ~ 6

35 hour integrationswith GMOS onGemini S. Faintestobjects haveF = 5E-18.

Stanway et al. 2006.

GSMT SWG - Nov 8 & 9 2007 16

Use Case: Lyα Luminosity Function at z ~ 6

500 km/s FWHM

Wλ = 100Å

30hr integration with GMACSusing 0.5” slits in 0.5” seeing

30% throughput

Gemini sky spectrum

Nod & Shuffle sky rejection

R = 5000 rebinned to

R = 1200, Gaussian smoothing

GSMT SWG - Nov 8 & 9 2007 17

Use Case: Lyα Luminosity Function at z ~ 6

GSMT SWG - Nov 8 & 9 2007 18

Use Case: Stellar Content of DRGs at z > 2

GOAL: Probe the role of feed-back in the genesis of massive galaxies. Near-IRspectra provide a probe of star formation histories, ages and abundances

Instrument Used: GMT Near-IR MOS - NIRMOS

Number of Nights: 4 in queue mode

Supporting observations: Existing near-IR imaging surveys

Approach: Multi-slit spectroscopy of passive galaxies in the J-band and star forming galaxies in the K-band

GSMT SWG - Nov 8 & 9 2007 19

Current State of the Art

Kreik et al.

GNIRS

GSMT SWG - Nov 8 & 9 2007 20

Use Case: Stellar Content of DRGs at z > 2

2 magnitudes!

GSMT SWG - Nov 8 & 9 2007 21

Use Case: Stellar Content of DRGs at z > 2

290Total

75871625.0

70751124.5

6065624.0

5060323.5

3540123.0

N(4 nights)N(1 < z < 2)N(2 < z < 4)J(AB)

GSMT SWG - Nov 8 & 9 2007 22

Use Case: Stellar Content of DRGs at z > 2

Simulated GMT spectraof old galaxies at z = 2

R = 3000 rebinned to R =1200

7.5e- read noise

Median J-band seeing

0.45” FWHM

Five-hour integrations

900 second unit exposure

GLAO Correction!

GSMT SWG - Nov 8 & 9 2007 23

Use Case: Stellar Content of DRGs at z > 2

Erb et al.

3E-17

2E-17

GSMT SWG - Nov 8 & 9 2007 24