From First Stars to (First) Galaxies KAS16/MT - - PowerPoint PPT Presentation

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from first stars to first galaxies kas16 mt lecture iv
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From First Stars to (First) Galaxies KAS16/MT - - PowerPoint PPT Presentation

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From First Stars to (First) Galaxies KAS16/MT Lecture IV - DarkLight 2 KAS16/MT Lecture IV - DarkLight 3 KAS16/MT

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From First Stars to (First) Galaxies

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KAS16/MT Lecture IV - DarkLight

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KAS16/MT Lecture IV - DarkLight

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KAS16/MT Lecture IV - DarkLight

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KAS16/MT Lecture IV - DarkLight

5 Smith et al. (2009) n [cm-3] T [K]

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KAS16/MT Lecture IV - DarkLight

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KAS16/MT Lecture IV - DarkLight

★Goal: Simplest meaningful model to

understand evolution of galaxy formation

A model for galaxy formation

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★Galaxies form within dark-

matter halos

  • Working hypothesis:

Dark matter halo assembly main driver

  • f star formation
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KAS16/MT Lecture IV - DarkLight

★L(Mh,z) depends on:

  • 1. Stellar populations [young

stars brighter]: Age(Mh,z)

  • 2. Stellar mass: Mstar(Mh,z)

Our model for LF evolution

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★DM halos populated by galaxies

with UV luminosity L(Mh,z)

L(Mh,z)~Mstar/Age

[with constant star- formation history]

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KAS16/MT Lecture IV - DarkLight

★Adopted galaxy “age”: DM halo assembly time

Galaxy ages

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★Rapid high-z assembly ★No free parameters

Mh/2 Mh

Halo assembly time

Tacchella, Trenti & Carollo (2013) [MSc project]

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KAS16/MT Lecture IV - DarkLight

★Minimal assumption: Stellar mass does not

depend on redshift: Mstar(Mh,z)

From halo to stellar mass

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★Mstar(Mh)

derived from single redshift calibration

Halo Mass [log Msun] log(Mstar/Mh)

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KAS16/MT Lecture IV - DarkLight

★Minimal assumption: Stellar mass does not

depend on redshift: Mstar(Mh,z)

From halo to stellar mass

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★Mstar(Mh)

derived from single redshift calibration

Halo Mass [log Msun] log(Mstar/Mh)

★Luminosity

defined at all z:

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KAS16/MT Lecture IV - DarkLight

Luminosity function evolution

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Tacchella, Trenti & Carollo (2013) [MSc project]

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KAS16/MT Lecture IV - DarkLight

Luminosity function evolution

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Tacchella, Trenti & Carollo (2013) [MSc project]

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KAS16/MT Lecture IV - DarkLight

Luminosity function evolution

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★Model successful from z=0 to z=10! ★Assumptions validated!

Tacchella, Trenti & Carollo (2013) [MSc project]

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KAS16/MT Lecture IV - DarkLight

Luminosity function evolution

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★Validation from latest z~8-10 data

Mason, Trenti & Treu (2015)

★And

predictions for z>10

[first 500 Myr]

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KAS16/MT Lecture IV - DarkLight

Stellar mass density evolution

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★Modeling based on galaxy light only ★Yet… Evolution of

stellar mass density described extremely well

★Further confirmation

that basic model captures essence of galaxy evolution

Mason, Trenti & Treu (2015)

Observations

Predictions

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KAS16/MT Lecture IV - DarkLight

Star formation history

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★Drivers of star

formation:

★Halo mass function

evolution (galaxy abundance)

★Halo assembly time

(galaxy age)

More halos Increased halo assembly time

L

  • g

S t a r f

  • r

m a t i

  • n

r a t e [ Msun y r

  • 1

M p c

  • 3

]

Trenti et al. (2013)

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KAS16/MT Lecture IV - DarkLight

Summary

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★Dark Matter halo assembly key driver of star

formation

★Basic model reproduces the evolution of the star

formation history

★Halos at fixed mass at different redshift have

similar stellar mass, but different luminosities because galaxy ages change