The Birth and Assembly of Galaxies: the Relationship Between Science Capabilities and Telescope Aperture Betsy Barton Center for Cosmology University of

The Birth and Assembly of Galaxies: the The Birth and Assembly of Galaxies: the Relationship Between Science Capabilities Relationship Between Science Capabilities

and Telescope Apertureand Telescope Aperture

Betsy BartonBetsy Barton

Center for CosmologyCenter for Cosmology

University of California, IrvineUniversity of California, Irvine

J.-D. Smith, Casey Papovich, Romeel Davé, Jean Brodie, Bev Oke, Brad Whitmore, Rob Kennicutt

Grateful acknowledgements to:Grateful acknowledgements to:

Galaxy formation and evolutionGalaxy formation and evolution

How did galaxies like the Milky How did galaxies like the Milky Way form?Way form?

Using the early universe to “see” it happeningUsing the early universe to “see” it happening

(http://zebu.uoregon.edu/images)

M31M31

Galaxy evolutionGalaxy 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 Internal variations in kinematics, metallicity, star

formation history to z~5 (and beyond)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-Detailed internal properties of high-redshift galaxiesredshift galaxies

Science goals: Science goals: • Dynamical massesDynamical masses• Enrichment and star Enrichment and star

formation history as a formation history as a function of positionfunction of position

• Direct observations of Direct observations of the build-up of mass the build-up of mass through mergingthrough merging

(z=3 galaxy from Hubble Deep Field; HST psf ~ 0.1” ~ 770 pc)

Near-IR case: for chemical abundances, Near-IR case: for chemical abundances, star formation historiesstar formation histories

Lines in the optical and near-infrared

[OII] to z > 5

Ha to z = 3

JH

K

L/M

optical

weak absorption

•Few strong lines in opticalbetween redshifts of about 1 to 3•NEED near-IR

Plot from Oke & Barton (2000)

Unresolved line flux sensitivity estimatesUnresolved line flux sensitivity estimates

(10,000 seconds, high-order AO, R=3000)(10,000 seconds, high-order AO, R=3000)

Kinematics of Lyman break galaxiesKinematics of Lyman break galaxies

At R < 25, ~3-4 At R < 25, ~3-4 LBGs per square LBGs per square arcminute at 2.5 arcminute at 2.5 < z < 3.5; ~1 at z < z < 3.5; ~1 at z > 3.5> 3.5

High-mass mergers are frequent High-mass mergers are frequent at high redshiftat high redshift

2-2.4 2-2.4 m ism isz ~ 1z ~ 1

Plot by Joel Berrier;Plot by Joel Berrier;Models in Berrier Models in Berrier et al. (2005);et al. (2005);Zentner et al. 2004Zentner et al. 2004

Galaxy evolution at very high redshifts: Galaxy evolution at very high redshifts: watching merging in actionwatching merging in action

The Antennae simulation: a luminous, lumpy local The Antennae simulation: a luminous, lumpy local starburststarburst

8 hours sec.with large-aperturetelescope,z=4.74

30-meter20-meter8-meter

Individual star-forming regions arevisible in emission lines at high

redshifts with large-aperture telescopes

Galaxy evolution at very high redshifts: Galaxy evolution at very high redshifts: watching merging in actionwatching merging in action

The Antennae simulation: a luminous, lumpy local The Antennae simulation: a luminous, lumpy local starburststarburst

8 hours sec.with large-aperturetelescope,z=4.74

100-meter50-meter30-meter

Individual star-forming regions arevisible in emission lines at high

redshifts with large-aperture telescopes

Cluster detections throughout KCluster detections throughout K

30-meter20-meter

Cluster detections throughout KCluster detections throughout K

100-meter50-meter

Can we use the clusters to measure, say, Can we use the clusters to measure, say, a velocity dispersion?a velocity dispersion?

30-meter 100-meter

A 20-meter isn’t big enough at z~5A 20-meter isn’t big enough at z~5

z~5 Antennae star cluster velocity z~5 Antennae star cluster velocity dispersion measurementsdispersion measurements

z~3 (H-band) is a better regime for a 20-mz~3 (H-band) is a better regime for a 20-m

z=4.74z=4.74 z=3.34z=3.34

(However, H-band not as open w.r.t. night-sky lines.)(However, H-band not as open w.r.t. night-sky lines.)

Role of Adaptive OpticsRole of Adaptive Optics

Diffraction limit at 1.2 microns:Diffraction limit at 1.2 microns:

8-meter8-meter 0.0380.038 290 pc290 pc 240 pc240 pc 200 pc200 pc




100-100-metermeter 0.0030.003 23 pc23 pc 19 pc19 pc 16 pc16 pc

(arcsec) z=3 z=5 z=7(arcsec) z=3 z=5 z=7

Hints of internal structure at Hints of internal structure at high redshifthigh redshift

color/agecolor/agevariationvariationinside inside high-zhigh-zgalaxiesgalaxies

Figure fromFigure fromCasey PapovichCasey Papovich

HST/WFPC2HST/WFPC2HST/NICMOSHST/NICMOScolorscolors

Summary of High-z Galaxy Internal Summary of High-z Galaxy Internal Emission-line MeasurementsEmission-line Measurements

If forming star clusters ubiquitous, like Antennae, If forming star clusters ubiquitous, like Antennae, then 30-meter can measure kinematics (and SFR) then 30-meter can measure kinematics (and SFR) to z~5.to z~5.• Main gain of > 30-meter is in coverage throughout Main gain of > 30-meter is in coverage throughout

redshift range (limited utility).redshift range (limited utility). Beyond K-band (z=5.4), a mid-IR optimized 100-Beyond K-band (z=5.4), a mid-IR optimized 100-

meter might be able to follow [OII] to higher meter might be able to follow [OII] to higher redshifts; greatly depends on thermal properties redshifts; greatly depends on thermal properties of telescope. of telescope.

Improvement may come from continuum Improvement may come from continuum sensitivity (light bucket).sensitivity (light bucket).

High-order AO of limited for D > 50 meters; only High-order AO of limited for D > 50 meters; only unresolved objects are small star clusters (and unresolved objects are small star clusters (and individual stars, SN, etc.).individual stars, SN, etc.).

First LightFirst Light

Hydrodynamic simulations of Davé, Katz, & WeinbergHydrodynamic simulations of Davé, Katz, & Weinberg• Lyman Lyman cooling radiation ( cooling radiation (greengreen))• Light in LyLight in Ly from forming stars ( from forming stars (redred, yellow), yellow)

z=10z=10 z=8z=8 z=6z=6

Diffraction LimitsDiffraction Limits

Diffraction limit at Lyman Diffraction limit at Lyman ::

8-meter8-meter 160 pc160 pc




100-100-metermeter 13 pc13 pc

z=7z=7

Bright star-forming regionsBright star-forming regions

30 Dor (LMC): even central 30 Dor (LMC): even central region resolved for D > 30region resolved for D > 30

Really only compact star Really only compact star clusters that remain clusters that remain unresolvedunresolved

60 pc60 pc

Le Delliou et al. Lyman Le Delliou et al. Lyman source sizes source sizesfrom a semi-analytic modelfrom a semi-analytic model

8-meter8-meter

20-meter20-meter30-meter30-meter50-meter50-meter

100-meter: -1.74100-meter: -1.74

z=7z=7

All but 8-meterAll but 8-meterresolve almost resolve almost all predicted all predicted galaxiesgalaxiesfrom Le Dellioufrom Le Delliouet al. (2005) atet al. (2005) atdiffraction limit.diffraction limit.

(Hydro (Hydro simulationssimulationsdon’t resolve.)don’t resolve.)

Physical elements of star formation Physical elements of star formation beyond reionizationbeyond reionization

{{

{{stellar initialstellar initialmass functionmass function

star formation ratestar formation rate

penetration through penetration through intergalactic mediumintergalactic medium

escape ofionizing andLy photons

partially neutral IGM(above z ~ 6.2)

The IMF, the ISM, and the IGMThe IMF, the ISM, and the IGM

Recent theoretical work favorable to LyRecent theoretical work favorable to Ly detection: detection:

IMF:IMF: low-metallicity gas leads to top-heavy IMF low-metallicity gas leads to top-heavy IMF• Abel et al. (2000)Abel et al. (2000) [how fast do you enrich?][how fast do you enrich?]• Top-heavy to explain Top-heavy to explain WMAPWMAP results results (e.g., Cen (e.g., Cen

2003a,b)2003a,b) IGM:IGM: Ly Ly can escape if bubble of IGM ionized locally; can escape if bubble of IGM ionized locally;

winds help winds help (Haiman 2002; Santos 2003)(Haiman 2002; Santos 2003) ISM:ISM: f fescesc high for high for WMAPWMAP (Cen 2003a,b)(Cen 2003a,b)

• good for ionizing IGM locallygood for ionizing IGM locally• lower fraction good for number of photons lower fraction good for number of photons

converted to Lyconverted to Ly [peak ~ f [peak ~ fesc esc = 0.1-0.8 from = 0.1-0.8 from Santos Santos (2003)(2003)]]

Two favorable scenariosTwo favorable scenarios

““optimistic”:optimistic”: • Top-heavy IMF with only 300-1000Top-heavy IMF with only 300-1000 solar mass solar mass

starsstars• no metalsno metals

• ffescesc=0.35 (fraction of ionizing photons that escape =0.35 (fraction of ionizing photons that escape

from the galaxy; Lyfrom the galaxy; Ly flux is proportional to 1-f flux is proportional to 1-fescesc))

• no dustno dust

• ffIGMIGM = 1 (fraction of Ly = 1 (fraction of Lyphotons that hit the IGM photons that hit the IGM

and still get to us)and still get to us)

Two favorable scenariosTwo favorable scenarios

““plausible”:plausible”: • Top-heavy IMF with Salpeter slope but onlyTop-heavy IMF with Salpeter slope but only

50-500 solar mass stars50-500 solar mass stars• no metalsno metals• ffescesc=0.1 (fraction of ionizing photons that escape =0.1 (fraction of ionizing photons that escape

from the galaxy; Lyfrom the galaxy; Ly flux is proportional to 1-f flux is proportional to 1-fescesc))• no dustno dust• ffIGMIGM = 0.25 (fraction of Ly = 0.25 (fraction of Ly photons that hit the IGM photons that hit the IGM

and still get to us)and still get to us)

““heavy Salpeter”/”Salpeter”:heavy Salpeter”/”Salpeter”: • Same as “plausible” but over 1-500 or 1-100 solar Same as “plausible” but over 1-500 or 1-100 solar

massesmasses

Lyman Lyman Luminosity Function Luminosity Function

8m8m30+ hrs30+ hrs Models: BartonModels: Barton

et al. (2004)et al. (2004)

Data: variousData: varioussources sources compiledcompiledin Santos in Santos et al. (2004)et al. (2004)

Simulation: heavy Salpeter IMFSimulation: heavy Salpeter IMF

Adapted modelsAdapted modelsfrom Bartonfrom Bartonet al. (2004)et al. (2004)

z=8.227z=8.2278 hours8 hours100-m 100-m telescopetelescope

Simulation: Salpeter IMFSimulation: Salpeter IMF









Weighing z=10 starsWeighing z=10 stars

HeII (HeII (1640 Å)1640 Å)Salpeter 1-500 MSalpeter 1-500 M

Zero metallicityZero metallicity

HeII (HeII (1640 Å)1640 Å)Heavy starsHeavy stars

Simulation through 30m telescope, 8 hours, R=3000

First Light in the Near IRFirst Light in the Near IR

Discovery of z > 7 objects: probably done with Discovery of z > 7 objects: probably done with JWSTJWST

Larger ground-based telescopes willLarger ground-based telescopes will• Map reionization in Lyman Map reionization in Lyman • Measure Lyman Measure Lyman line profiles line profiles• Look for HeII(1640) as indicator of Pop III star Look for HeII(1640) as indicator of Pop III star

formationformation Advantages for > 30-meter aperture:Advantages for > 30-meter aperture:

• Needed sensitivity when IGM nearly impenetrable Needed sensitivity when IGM nearly impenetrable (completely unknown; penetration is the (completely unknown; penetration is the interesting quantity for topology of reionization)interesting quantity for topology of reionization)

• Needed sensitivity when HeII weak (but this is not Needed sensitivity when HeII weak (but this is not Pop III anyway)Pop III anyway)

What is beyond a 30-meter telescope?What is beyond a 30-meter telescope?

Older or lower-surface-brightness stars and star Older or lower-surface-brightness stars and star formation at z > 2; dwarf galaxies at z > 2formation at z > 2; dwarf galaxies at z > 2

Faint emission lines and absorption lines at z > 5-Faint emission lines and absorption lines at z > 5-6; lines in the mid-IR6; lines in the mid-IR

Extremely high-z star formation with normal IMF Extremely high-z star formation with normal IMF (if it exists)(if it exists)• Upcoming WMAP data release may tell us how high Upcoming WMAP data release may tell us how high

we have to go in zwe have to go in z

These are issues for “down the road”; a 30-m can address These are issues for “down the road”; a 30-m can address many of the questions we have now.many of the questions we have now.

Documents

The Birth and Assembly of Galaxies: the Relationship Between Science Capabilities and Telescope Aperture Betsy Barton Center for Cosmology University of