arXiv:1905.06927

Shotaro Kikuchihara (U. Tokyo)
Masami Ouchi, Yoshiaki Ono, Ken Mawatari,
Jacopo Chevallard, Yuichi Harikane, Takashi Kojima,
Masamune Oguri, Gustavo Bruzual, Stephane Charlot©HubbleSite (Abell S1063)©Chiba Pref.

①
Early Low-Mass Galaxies

Why Early Low-Mass Galaxies?
・Dominant components in early UniverseStellar Mass (M⦿)

・Progenitors to MW?
from Behroozi+18(Mhalo＝1012M⦿ case)

MW

Progenitors?
Redshift

BUT;
Only a few constraints on
number counts at
M★＜107M⦿

Deep HST-Spitzer＋Lensing Magnification

Data ― Hubble Frontier Fields (HFF)
6 galaxy-cluster fields + 6 parallel fields

F606W
F435W

Throughputs

http://cosmos.phy.tufts.edu/~danilo/HFF/Home.html

HST/ACS

HST/WFC3-IR
F105W

F814W

VLT/HAWK-I
Keck-I/MOSFIRE
Spitzer/IRAC

F140W

F125W

F160W

ch1

ch2

Ks

Opt

MIR

NIR
Wavelength (μm)

5σ〜29-30

25-26

24-25

SamplesLens Models
Oguri10・357 Lyman break galaxies(LBGs) at z~6-9✓Original from Kawamata+18 &Ishigaki+18 (color selection)

・GLAFIC models fromKawamata+18 & Ishigaki+18Lens Modelse.g., NFW halo:

Predictχ2(α,δ) ofmultiple images
Kawamata+16

Intrinsic SED
Ishigaki+15

Estimate Stellar Mass (M★)
・LBGs too faint to directly estimate M★ (MUV〜­19)…

@ch1

Intrinsic Magnitude

Stack

Chevallard&Charlot16

25
27

BEAGLE model

Templates

Stellar : BC03
Nebular : CLOUDY
Dust: Calzetti+94
IGM: Inoue+14

Parameters z, Age, Uion, M★, Z, τV

29
31

Fit SED

0.5

12
Observed Wavelength [µm]5(M★, MUV) for each MUV binM★ーMUV Relations
This WorkGalaxy Stellar Mass Functions
・M★-MUV relations x Ishigaki+18 luminosity functions
Low-mass end is ＞1dex
fainter than everConsistentThisWork~106M⦿

・Fit to Schechter function

Galaxy Stellar Mass Density Evolutions
・Integrate stellar mass functions (Schechter)✓χ2 smaller by ~2.8 for slow one

Support slow evolution✓Star-formation efficiency
was higher at z＞8＋DMH evolution？

This Work
Madau+18, +14,
McLeod+16, Ellis+13

Oesch+18, +14, Harikane+18

②
Early Globular Cluster (GC)
Candidates

Why Early GCs?
・GCs ＝ dense stellar systems✓Formation？

✓Stellar population？

✓Formed w/ single burst at z＞5

tlb＝12.5Gyr( zform＜5)

HR diagramof M92:©http://www.ing.iac.es/PR/science/m92̲high.html

Model prediction fromsingle star burst at tlb

Need to directly observe formation epochReーM★ Relations of Local GCs
10✓ωCen

4E/S0・＜40pc

Effective Radius [pc]

©ESO

1000

✓Pal5

✓Pal14・＜107M⦿
100
©SDSS

@z＝0101061081010
Stellar Mass [M ]1012

Early GC candidatesz＞6 LBGs w/Re＜40pc & M★＜107M⦿

ReーM★ Relations of High-z Galaxies
・Re ← Sersic profile fitting(Kawamata+18)

E/S0

Effective Radius [pc]・M★ ← MUV x
M★ーMUV relation

104

1000100log µ1001061081010
Stellar Mass [M ]121012

ReーM★ Relations of High-z Galaxies
104

HFF5C-4260-1364
HFF5C-4039-1566

Effective Radius [pc]E/S0

HFF2C-1156-3446
1000

100log µ10✓In Abell S1063(first to analyze)✓First to identify as
early GC candidates

01061081010
Stellar Mass [M ]12✓M0416I-6115434445
in Bouwens+171012✓GC1 in Vanzella+17a(Lya detected w/MUSE)✓Re & M★ consistentSummary

deep HST・Identify 357 LBGs at z~6-9 w/ full data sets of HFF
・Galaxy stellar mass functions extend to M★~106M⦿
✓＞1dex lower mass than ever

deepSpitzer

・Galaxy stellar mass densities at z＞8 support
slow evolution of SFRD
・Find early GC candidates w/ Re＜40pc & M★＜107M⦿
✓Progenitors to local GCs？

Magnificationby lensing