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High Redshift QUASAR HOST Galaxies (Growing Galaxies with Monstrous Middles). Jill Bechtold, University of Arizona Kim K. McLeod, Wellesley College Undergraduates: Frannie D’Arcangelo Melissa Rice Rebecca Stoll Angela Bivens (Thanks to K. Luhman, E. Olszewski,
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High Redshift QUASAR HOST Galaxies (Growing Galaxies with Monstrous Middles) Jill Bechtold, University of Arizona Kim K. McLeod, Wellesley College Undergraduates: Frannie D’Arcangelo Melissa Rice Rebecca Stoll Angela Bivens (Thanks to K. Luhman, E. Olszewski, M. Mateo for telescope time and observing)
QUASAR EVOLUTION Quasar activity peaked about 10 – 12 billion years ago
Black hole v. Spheroid Mass • The “Kormendy Relation” • Mbh= 0.006 MGal • Kormendy & Richstone 1995 • Magorrian et al 1998 • Haring & Rix 2004
QUASAR EVOLUTION Kormendy Relation only feasible for the very closest quasars
Hubble Space Telescope NICMOS images Quasar host galaxies McLeod et al
QUASAR EVOLUTION Quasar host galaxies studied out to z~1
QUASAR EVOLUTION What about these guys?
Taking the big step to high-z:PANIC! (Persson’s Auxilliary Nasmyth Infrared Camera) Bechtold and McLeod have been using Magellan (6.5m) to image z=4 quasars in the near-IR Also used Magellan + Classicam; Gemini-N + NIRI
Why PANIC at Magellan? Observing Strategy: Require • deep observations • large sample (10’s of quasars minimum; radio loud/radio quiet etc) • near-IR or longward to sample rest frame optical for host galaxy • excellent image quality • well-defined PSF for PSF subtraction (1) What observing band? > For z=5-6, Ks is short of the 4000A break in the host galaxy Need space telescope to observe longward of Ks, but Spitzer is too small (IRAC: 1.2 arcsec/pixel) > For z=4, Ks and H straddle the 4000A break K-H photo-z of candidate hosts
Observing Strategy, continued • Why not use NICMOS on HST? At K-band PANIC beats NICMOS on HST, with better image quality PANIC: 0.125 arcsec/pixel NICMOS: 0.203 arcsec/pixel PANIC has bigger FOV comparison PSF stars simultaneously 6.5m telescope deeper faster HST time oversubscribed; hard to get big sample e.g. Ridgeway + 2001 ApJ 550, 122 5 z~2-3 hosts Kukula+ 2001 MNRAS 326, 1553 9 z~2 hosts Suggested result: hosts of radio-quiet quasars are 2-4 times less massive at z=2 than z= 0.2
Observing Strategy, continued • Why not use AO? e.g. Croom+ 2004 ApJ 606, 126 9 quasars observed with Gemini-N, z~2 FWHM ~ 0.12 – 0.25 arcsec; PANIC: FWHM 0.25-0.30 at Ks, routine Z=4 quasars are rare; hard to find ones near natural guide stars FOV small, variable PSF across the field
Z=4 quasars are all very luminous, so have huge black holes compared to black holes studied locally. If they follow the Kormendy Relation, then the host galaxies should be HUGE, and easy to see.
Growing up with a monster in the middle Kauffmann & Haehnelt 2000 Hierarchical structure formation: black holes are fueled, and galaxies grow, through mergers Z=0.4 Z=3
How do we know the black hole mass? Observed spectrum depends on Mbh and maccretion • FWHM of emission lines (assume Keplerian velocity; radius scaled from reverberation mapping ) + L(UV continuum) (2) Fit IR to X-ray continuum spectral energy distributions from Sobolewska+ 2004 ApJ, 617 102
PANIC Observations • 1024^2 Rockwell Near-IR HgCdTe Camera • So far, 23 Quasars observed with z=4 at Ks ½ night per image follow up H band on 3 host candidates • More time end of January • Extend to quasar environment study