Extragalactic Science Case

1. People who worked on this study

2. Example science cases:– Low redshifts: black hole masses in nearby

galaxies– Intermediate redshifts: field galaxies and mergers– High redshifts: strong gravitational lensing

3. Conclusions

People

• Mark Ammons

• Aaron Barth

• Rich Dekany

• Don Gavel

• David Koo

• Patrik Jonsson

• David Law

• James Larkin

• Claire Max

• Laura Melling

• Greg Novak

• Chuck Steidel

• Tommaso Treu

Black hole masses in nearby galaxies: NGAO contributions

• M- Relation: – Black holes contain only ~ 0.1% of host bulge mass, but

BH growth is tightly coupled to galaxy properties. How?

• Black hole - bulge correlations remain uncertain due to small number statistics– NGAO can increase the pool of measured BH masses

• Very few detections currently exist for black hole masses below 107 or above 109 solar masses– NGAO will push into new mass ranges

• Cross-checks between methods (stellar, gas, AGN reverberation mapping) are still lacking– NGAO will increase the pool of galaxies for which at least

two of these methods can be used to determine BH mass

Black hole masses in nearby galaxies:Fundamental considerations

• Spatial resolution: need to resolve the black hole's dynamical sphere of influence rg = GMBH/2

• If you see the Keplerian rise in the rotation curve, mass determination becomes more accurate

• Analysis requires good knowledge of the PSF structure

NGAO meets these needs

Simulation: 108 Msun BH at 20 Mpc, inclination 60 deg to line of sight

Examples of black hole mass measurements: STIS and current NGS AO

From stellar dynamics From Pa gas)

M32, STISJoseph et al.

Cyg A, NGS AOCanalizo Max et al.

Note: With HST, central Keplerian velocity rise for emission-line disks has been clearly detected in only 2 giant ellipticals

HST no longer has spectroscopic capability to do this science

Near-IR and visible-wavelength spectroscopy will help measure BH masses more accurately

• Spectral features for stellar dynamics:– CO bandhead: 2.29 micron – Ca IR triplet: 8498, 8542, 8662 A

• Spectral features for gas dynamics:– near-IR: H2, Br, [Fe II], Pa

– optical: H

IR IFU such as OSIRIS

Optical IFU to exploit Ca II triplet and H at <1 m

Addition of optical bands:advantage for BH mass determination

• With NGAO, diffraction-limited PSF core at Ca II triplet is major improvement in spatial resolution

– Enables many more low-mass black holes to be detected

– Better for resolving rg in nearby galaxies, leading to more accurate measurements

– NGAO I-band can study high-mass distant galaxies to pin down extreme end of M- relation (farther than TMT K band)

Minimum BH mass detectable vs. distance, assuming local M-

relation and 2 resolution elements across rg

MB

H (

Ms

un)

d (Mpc)

Addition of optical bands:advantage for BH mass determination

Minimum BH mass detectable vs. distance, assuming local M-

relation and 2 resolution elements across rg

Instrument Reduction factor for minimum BH mass

STIS 1

NGAO K band

3

NGAO I band

7

TMT 25

• With NGAO, diffraction-limited PSF core at Ca II triplet is major improvement in spatial resolution

– Enables many more low-mass black holes to be detected

– Better for resolving rg in nearby galaxies, leading to more accurate measurements

– NGAO I-band can study high-mass distant galaxies to pin down extreme end of M- relation (farther than TMT K band)

Studying intermediate-redshift galaxies: space densities

Table 1 Space Densities of Var ious Categories of Extragalactic Targets.

Type of Object Approx density

per square arc minute Reference

SCUBA sub-mm galaxies

to 8 mJy 0.1 Scott et al. 2002

Old and red galaxies wit h 0.85 < z < 2.5 and R < 24.5

2 Yamada et al. 2005; va n Dokkum et al. 2006

Mergers with emission lines in JHK windows & R < 24

2-5 Conselice et al. 2003

Field galaxies w/ em ission lines in JHK windows

0.8 < z < 2.2 & R < 25

> 10 Steidel et al 2004; Coil et al 2004

Center of distant rich cluster of galaxies at z > 0.8

> 20 van Dokkum et al 2000

All galaxies K < 23 > 40 Minowa et al 2005

AO multiplexing can be a breakthrough for galaxy evolution studies• Science projects are usually about specific

subclasses: – Mergers with emission line in JHK bands, R < 24:

2 - 5 per square arc min– Field galaxies with emission line in JHK window, R < 25

and 0.8 < z < 2.2: > 10 per square arc min

• NGAO has appropriate field of view (2 arc min ) for this problem

• In our study we decided to take a conservative approach: ~ 6 IFU units over a 2 arc min diam field

• Reason: reduce cost and complexity

• Will study cost-benefit of number of IFUs during next phase of design

Tip-tilt-star correction gives very broad sky coverage for IFU application• We focused on the “deep fields” that have been heavily observed by HST, Chandra, Spitzer,

GALEX, ....

• Best IFU signal to noise is for IFU “pixel” of order 100 mas

• Predicted H-band FWHM < 50 mas over half the sky < 100 mas almost everywhere:

GOODS N

Tip-tilt blurring predicted to be < 30 mas throughout the “deep fields”

We simulated performance of IFU with NGAO and current LGS AO

• NGAO system shows 3x improvement in SNR over LGS AO

• Enables study of galaxy morphology for large surveys in practical amounts of telescope time

• NGAO allows resolved galaxy kinematics studies over 3x more area within the galaxy than current LGS AO

z ~ 2 galaxy BX 1332, catalog of Erb (2004)

Current LGS AONGAO

Dramatic expansion in throughput: factor

of ~9 for one IFU

Dramatic expansion in throughput: factor

of ~9 for one IFU

NGAO near-IR IFU spectroscopy has dramatically higher throughput

• Plot shows S/N ratio for redshifted H, OSIRIS-like IFU

• For 0.6 < z < 2.3, NGAO shows factor of 3 to 6 improvement in signal to noise ratio.

• Factor of 9 to 36 shorter integration times (!)

• If IFU has 6 deployable units, multiply by another 6x

NGAO + d-IFU has 50-200x higher

throughput than LGS AO today!

NGAO + d-IFU has 50-200x higher

throughput than LGS AO today!

Simulated galaxy mergers at z=2.2

• Top: Images. An order of magnitude more pixels with with SNR 10 (yellow) for NGAO

• Bottom: Kinematic maps. Velocities shown for pixels with SNR > 5.

• Current LGS AO: Hard to determine whether galaxy has ordered rotation velocity.

• NGAO: Shows spatially complex distribution of red to violet colors, characterizing a major merger.

Current LGS AO NGAO

Current LGS AO NGAO

Strong gravitational lensing: route to spatially resolved spectroscopy of z = 6 - 8 galaxies

• Curves show Einstein radius for massive cluster (v = 1250 km/s) and massive elliptical (v = 300 km/s) as function of deflector’s z.

• Typical angular scales are

– 3-4 arc sec for galaxy lensing

– 1-2 arc min for cluster lensing

– Driver for deployable IFUs

Simulation of galaxy-scale lensing, redshift 7

• Simulated observations of a galaxy-scale lensed galaxy at redshift 7.

• HST-NICMOS (top row), NGAO (middle row), current LGSAO (bottom).

• Note that NGAO is superior in all cases.

Magnification by gravitational lensing enables imaging and spectroscopy of the earliest galaxies

Galaxy lensing: big advantage of NGAO over both HST and current LGS AO • Reconstructed 68%

and 95% confidence contours for source galaxy parameters

• NGAO contours are 6 times smaller than for LGS AO, and 2 times smaller than for NICMOS.

• Determine physical properties of z=7 galaxies six times more accurately

NIC1 F110W NIC1 F160W

NGAO J NGAO H NGAO K

LGS AO J LGS AO H LGS AO K

Un

len

sed

sou

rce m

ag

(A

B)

Source scale radius (arc sec)

NGAO will allow us to tackle a broad range of high-impact extragalactic science

1. Near diffraction-limited in the near-IR (Strehl >80%)• Detailed structure/kinematics of high redshift galaxies

at three to six times higher signal to noise ratio

2. Vastly increased sky coverage and multiplexing• Multi-object IFU surveys of GOODS-N, COSMOS, etc.• Factor of 50 - 200 improvement in throughput with 6

IFUs

3. AO correction at red optical wavelengths (0.6-1.0 m)• Kinematic mass determinations for supermassive

black holes at the very highest angular resolutions