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Extragalactic Science Case

Extragalactic Science Case. People who worked on this study Example science cases: Low redshifts: black hole masses in nearby galaxies Intermediate redshifts: field galaxies and mergers High redshifts: strong gravitational lensing Conclusions. People. Mark Ammons Aaron Barth Rich Dekany

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Extragalactic Science Case

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  1. Extragalactic Science Case • People who worked on this study • Example science cases: • Low redshifts: black hole masses in nearby galaxies • Intermediate redshifts: field galaxies and mergers • High redshifts: strong gravitational lensing • Conclusions

  2. 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

  3. 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

  4. Black hole masses in nearby galaxies:Fundamental considerations Simulation: 108 Msun BH at 20 Mpc, inclination 60 deg to line of sight • Spatial resolution: need to resolve the black hole's dynamical sphere of influence rg = GMBH/s2 • 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

  5. Examples of black hole mass measurements: STIS and current NGS AO From stellar dynamics From Pa (gas) Cyg A, NGS AO Canalizo Max et al. M32, STIS Joseph 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

  6. 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, Brg, [Fe II], Pa a • optical: Ha • IR IFU such as OSIRIS • Optical IFU to exploit Ca II triplet and Ha at l <1 mm

  7. 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-s relation (farther than TMT K band) MBH (Msun) d (Mpc) Minimum BH mass detectable vs. distance, assuming local M-  relation and  2 resolution elements across rg

  8. 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-s relation (farther than TMT K band) Minimum BH mass detectable vs. distance, assuming local M-  relation and  2 resolution elements across rg

  9. Studying intermediate-redshift galaxies: space densities

  10. 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

  11. 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

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

  13. We simulated performance of IFU with NGAO and current LGS AO Current LGS AO NGAO • 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 Dramatic expansion in throughput: factor of ~9 for one IFU z ~ 2 galaxy BX 1332, catalog of Erb (2004)

  14. 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!

  15. 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. NGAO Current LGS AO NGAO Current LGS AO

  16. 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

  17. Simulation of galaxy-scale lensing, redshift 7 Magnification by gravitational lensing enables imaging and spectroscopy of the earliest galaxies • 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.

  18. Galaxy lensing: big advantage of NGAO over both HST and current LGS AO NIC1 F160W NIC1 F110W • 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 NGAO J NGAO K NGAO H Unlensed source mag (AB) LGS AO K LGS AO J LGS AO H Source scale radius (arc sec)

  19. NGAO will allow us to tackle a broad range of high-impact extragalactic science • 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 • 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 • AO correction at red optical wavelengths (0.6-1.0 mm) • Kinematic mass determinations for supermassive black holes at the very highest angular resolutions

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