The Birth and Assembly of Galaxies: the Relationship Between Science Capabilities and Telescope Aperture Betsy Barton Center for Cosmology University of California, Irvine J.-D. Smith, Casey Papovich, Romeel Davé, Jean Brodie, Bev Oke, Brad Whitmore, Rob Kennicutt Grateful acknowledgements to:

Galaxy formation and evolution How did galaxies like the Milky Way form? Using the early universe to “see” it happening Using the early universe to “see” it happening ( M31

Galaxy evolution When and how did the build-up of galaxies occur? When and how did the build-up of galaxies occur? Internal variations in kinematics, metallicity, star formation history to z~5 (and beyond)Internal variations in kinematics, metallicity, star formation history to z~5 (and beyond) Where and when did the first stars form? Where and when did the first stars form? When did “first light” happen?When did “first light” happen? When and how was the universe reionized?When and how was the universe reionized? Can we find Pop III star formation?Can we find Pop III star formation?

Detailed internal properties of high- redshift galaxies Science goals: Science goals: Dynamical massesDynamical masses Enrichment and star formation history as a function of positionEnrichment and star formation history as a function of position Direct observations of the build-up of mass through mergingDirect observations of the build-up of mass through merging (z=3 galaxy from Hubble Deep Field; HST psf ~ 0.1” ~ 770 pc)

Near-IR case: for chemical abundances, star formation histories Lines in the optical and near-infrared [OII] to z > 5 H a to z = 3 J H K L/M optical weak absorption Few strong lines in optical between redshifts of about 1 to 3 NEED near-IR Plot from Oke & Barton (2000)

Unresolved line flux sensitivity estimates (10,000 seconds, high-order AO, R=3000)

Kinematics of Lyman break galaxies At R 3.5 At R 3.5

High-mass mergers are frequent at high redshift m is z ~ 1 Plot by Joel Berrier; Models in Berrier et al. (2005); Zentner et al. 2004

Galaxy evolution at very high redshifts: watching merging in action The Antennae simulation: a luminous, lumpy local starburst The Antennae simulation: a luminous, lumpy local starburst 8 hours sec. with large- aperture telescope, z= meter 20-meter8-meter Individual star-forming regions are visible in emission lines at high redshifts with large-aperture telescopes

Galaxy evolution at very high redshifts: watching merging in action The Antennae simulation: a luminous, lumpy local starburst The Antennae simulation: a luminous, lumpy local starburst 8 hours sec. with large- aperture telescope, z= meter 50-meter30-meter Individual star-forming regions are visible in emission lines at high redshifts with large-aperture telescopes

Cluster detections throughout K 30-meter20-meter

Cluster detections throughout K 100-meter50-meter

Can we use the clusters to measure, say, a velocity dispersion? 30-meter100-meter

A 20-meter isn’t big enough at z~5

z~5 Antennae star cluster velocity dispersion measurements

z~3 (H-band) is a better regime for a 20-m z=4.74 z=3.34 (However, H-band not as open w.r.t. night-sky lines.)

Role of Adaptive Optics Diffraction limit at 1.2 microns: Diffraction limit at 1.2 microns: 8-meter pc 240 pc 200 pc 20-meter pc 95 pc 80 pc 30-meter pc 63 pc 53 pc 50-meter pc 38 pc 32 pc 100- meter pc 19 pc 16 pc (arcsec) z=3 z=5 z=7

Hints of internal structure at high redshift color/agevariationinsidehigh-zgalaxies Figure from Casey Papovich HST/WFPC2HST/NICMOScolors

Summary of High-z Galaxy Internal Emission-line Measurements If forming star clusters ubiquitous, like Antennae, then 30-meter can measure kinematics (and SFR) to z~5. If forming star clusters ubiquitous, like Antennae, then 30-meter can measure kinematics (and SFR) to z~5. Main gain of > 30-meter is in coverage throughout redshift range (limited utility).Main gain of > 30-meter is in coverage throughout redshift range (limited utility). Beyond K-band (z=5.4), a mid-IR optimized 100- meter might be able to follow [OII] to higher redshifts; greatly depends on thermal properties of telescope. Beyond K-band (z=5.4), a mid-IR optimized 100- meter might be able to follow [OII] to higher redshifts; greatly depends on thermal properties of telescope. Improvement may come from continuum sensitivity (light bucket). Improvement may come from continuum sensitivity (light bucket). High-order AO of limited for D > 50 meters; only unresolved objects are small star clusters (and individual stars, SN, etc.). High-order AO of limited for D > 50 meters; only unresolved objects are small star clusters (and individual stars, SN, etc.).

First Light Hydrodynamic simulations of Davé, Katz, & Weinberg Hydrodynamic simulations of Davé, Katz, & Weinberg Lyman  cooling radiation (green)Lyman  cooling radiation (green) Light in Ly from forming stars (red, yellow)Light in Ly from forming stars (red, yellow) z=10 z=8z=6

Diffraction Limits Diffraction limit at Lyman : Diffraction limit at Lyman : 8-meter 160 pc 20-meter 64 pc 30-meter 43 pc 50-meter 25 pc 100- meter 13 pc z=7

Bright star-forming regions 30 Dor (LMC): even central region resolved for D > Dor (LMC): even central region resolved for D > 30 Really only compact star clusters that remain unresolved Really only compact star clusters that remain unresolved 60 pc

Le Delliou et al. Lyman  source sizes from a semi-analytic model 8-meter 20-meter 30-meter 50-meter 100-meter: z=7 All but 8-meter resolve almost all predicted galaxies from Le Delliou et al. (2005) at diffraction limit. (Hydrosimulations don’t resolve.)

Physical elements of star formation beyond reionization { { stellar initial mass function star formation rate penetration through intergalactic medium escape of ionizing and Ly  photons partially neutral IGM (above z ~ 6.2)

The IMF, the ISM, and the IGM Recent theoretical work favorable to Ly detection: IMF: low-metallicity gas leads to top-heavy IMF IMF: low-metallicity gas leads to top-heavy IMF Abel et al. (2000) [how fast do you enrich?]Abel et al. (2000) [how fast do you enrich?] Top-heavy to explain WMAP results (e.g., Cen 2003a,b)Top-heavy to explain WMAP results (e.g., Cen 2003a,b) IGM: Ly can escape if bubble of IGM ionized locally; winds help (Haiman 2002; Santos 2003) IGM: Ly can escape if bubble of IGM ionized locally; winds help (Haiman 2002; Santos 2003) ISM: f esc high for WMAP (Cen 2003a,b) ISM: f esc high for WMAP (Cen 2003a,b) good for ionizing IGM locallygood for ionizing IGM locally lower fraction good for number of photons converted to Ly [peak ~ f esc = from Santos (2003)]lower fraction good for number of photons converted to Ly [peak ~ f esc = from Santos (2003)]

Two favorable scenarios “optimistic”: “optimistic”: Top-heavy IMF with only solar mass starsTop-heavy IMF with only solar mass stars no metalsno metals f esc =0.35 (fraction of ionizing photons that escape from the galaxy; Ly flux is proportional to 1-f esc )f esc =0.35 (fraction of ionizing photons that escape from the galaxy; Ly flux is proportional to 1-f esc ) no dustno dust f IGM = 1 (fraction of Lyphotons that hit the IGM and still get to us)f IGM = 1 (fraction of Lyphotons that hit the IGM and still get to us)

Two favorable scenarios “plausible”: “plausible”: Top-heavy IMF with Salpeter slope but onlyTop-heavy IMF with Salpeter slope but only solar mass stars no metalsno metals f esc =0.1 (fraction of ionizing photons that escape from the galaxy; Ly flux is proportional to 1-f esc )f esc =0.1 (fraction of ionizing photons that escape from the galaxy; Ly flux is proportional to 1-f esc ) no dustno dust f IGM = 0.25 (fraction of Ly photons that hit the IGM and still get to us)f IGM = 0.25 (fraction of Ly photons that hit the IGM and still get to us) “heavy Salpeter”/”Salpeter”: “heavy Salpeter”/”Salpeter”: Same as “plausible” but over or solar massesSame as “plausible” but over or solar masses

Lyman  Luminosity Function 8m 30+ hrs Models: Barton et al. (2004) Data: various sourcescompiled in Santos et al. (2004)

Simulation: heavy Salpeter IMF Adapted models from Barton et al. (2004) z= hours 100-mtelescope

Simulation: Salpeter IMF Adapted models from Barton et al. (2004) z= hours 100-mtelescope

Simulation: Salpeter IMF Adapted models from Barton et al. (2004) z= hours 50-mtelescope

Simulation: Salpeter IMF Adapted models from Barton et al. (2004) z= hours 30-mtelescope

Weighing z=10 stars HeII (1640 Å) Salpeter M  Zero metallicity HeII (1640 Å) Heavy stars Simulation through 30m telescope, 8 hours, R=3000

First Light in the Near IR Discovery of z > 7 objects: probably done with JWST Discovery of z > 7 objects: probably done with JWST Larger ground-based telescopes will Larger ground-based telescopes will Map reionization in Lyman Map reionization in Lyman  Measure Lyman  line profilesMeasure Lyman  line profiles Look for HeII(1640) as indicator of Pop III star formationLook for HeII(1640) as indicator of Pop III star formation Advantages for > 30-meter aperture: Advantages for > 30-meter aperture: Needed sensitivity when IGM nearly impenetrable (completely unknown; penetration is the interesting quantity for topology of reionization)Needed sensitivity when IGM nearly impenetrable (completely unknown; penetration is the interesting quantity for topology of reionization) Needed sensitivity when HeII weak (but this is not Pop III anyway)Needed sensitivity when HeII weak (but this is not Pop III anyway)

What is beyond a 30-meter telescope? Older or lower-surface-brightness stars and star formation at z > 2; dwarf galaxies at z > 2 Older or lower-surface-brightness stars and star formation at z > 2; dwarf galaxies at z > 2 Faint emission lines and absorption lines at z > 5- 6; lines in the mid-IR Faint emission lines and absorption lines at z > 5- 6; lines in the mid-IR Extremely high-z star formation with normal IMF (if it exists) Extremely high-z star formation with normal IMF (if it exists) Upcoming WMAP data release may tell us how high we have to go in zUpcoming WMAP data release may tell us how high we have to go in z These are issues for “down the road”; a 30-m can address many of the questions we have now.