High Redshift QUASAR HOST Galaxies

(Growing Galaxies with Monstrous Middles)

Jill Bechtold, University of ArizonaKim K. McLeod, Wellesley College

Undergraduates:Frannie D’Arcangelo

Melissa RiceRebecca StollAngela Bivens

(Thanks to K. Luhman, E. Olszewski,

M. Mateo for telescope time and observing)

QUASAR EVOLUTIONQUASAR EVOLUTION

Quasar activity peaked about 10 – 12 billion years ago

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 EVOLUTIONQUASAR EVOLUTION

Kormendy Relation only feasible for the very closest quasars

Kormendy Relation only feasible for the very closest quasars

Hubble Space Telescope

NICMOS images

Quasar host galaxies

McLeod et al

QUASAR EVOLUTIONQUASAR EVOLUTION

Quasar host galaxies studied out to z~1

Quasar host galaxies studied out to z~1

QUASAR EVOLUTIONQUASAR EVOLUTION

What about

these guys?

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-IRAlso usedMagellan + 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

(2) 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

(3) 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

(1) 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

from Bechtold+ 2003 ApJ, 588, 119

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

PANIC at z=4: Stay tuned

For now…

The End