Download Massive quiescent galaxies at cosmic noon Robert Feldmann UC Berkeley

Massive quiescent galaxies at
cosmic noon
Robert Feldmann
UC Berkeley
R. Feldmann, SnowPAC, March 2016
1
nt redshifts, finding good agreement between the semi-analytic
mented in the literature (e.g. Damen et al. 2009). Further, in the
Bimodality of nearby galaxies
Star forming
The Astrophysical Journal, 735:86 (21pp), 2011 July 10
•
•
•
high SFR per unit mass
young ages
dominate the low mass end
•
•
•
Quiescent
low SFR per unit mass
old ages, red colors
dominate the massive end
U-V
color (u-r)
The Astrophysical Journal, 735:86 (21pp), 2011 July 10
V-J
Figure 17. Rest-frame UVJ diagram for NMBS galaxies with S/N > 8 in the K band out to a redshift of 3.5. The gray scale rep
lines indicating the separation between quiescent “red sequence” galaxies and star-forming galaxies (both blue and red). The qu
highest redshift interval
2.5 < z < 3.5. Apparently,
the first quiescent
galaxiesOesch
stopped forming stars by that redshift (see also M
e.g. Kauffmann+03,
Baldry+04,06,
Scarlata+07,
+2010, Peng+10, Wong+12, Ciambur+2013, Kelvin+2014 ...
Additionally, we modify the limits in U − V and V – J such
that
R. Feldmann, SnowPAC, March 2016
galaxies is therefore ideal for ch
NIR medium-band filters relative
2
filters.
Galaxies at Cosmic Noon (z~1.5-3)
• the
two populations exist already at peak of cosmic SF history
The Astrophysical Journal, 739:24
The Astrophysical
(14pp), 2011 September
Journal,20
739:24 (14pp), 2011 S
10 M
•
~equal
number
of
SF
and
quiescent
galaxies
at
M*≳few
10
☉
The
Astrophysical
Journal,
739:24
(14pp),
2011
September
20
The Astrophysical Journal, 739:24 (14pp), 2011 September 20
Brammer
et al.
The Astrophysical Journal, 739:24 (14pp), 2011 September 20
• =>
factors aside from mass likely
important in “quenching” of SF
The Astrophysical Journal, 739:24 (14pp), 2011 September 20
Magnelli+2014
z ~ 0.6
z~2
Figure
Stellar
mass
functions
sample
(top
panels)
split
using
thesaq
Figure 4. Stellar mass functions for the full NMBS sample (top panels) Figure
and
split4.4.
using
themass
quiescent/star-forming
selection
shown
infunctions
Figure
2panels)
(middle
panels).
The
Stellar
functionsfor
Figure
forthe
thefull
full
4. NMBS
Stellar
NMBS
mass
sample
(top
forand
theand
full
split
NMBS
using
Brammer+2011
points
shown
are
simple
redshift
histograms
divided
byby
thethe
volume
ofhistograms
the
NMBS,
with
Pois
points shown are simple redshift histograms divided by the volume of the
NMBS,
Poisson
error
bars. for
Representative
Schechter
(1976)
function
fitssplit
aredivided
shown,
points
shown
are
simple
redshift
points
histograms
shown
divided
are
simple
redshift
volume
ofand
the
NMBS,
with
b
Figure
4.with
Stellar
mass
functions
the full
NMBS
sample
(top
panels)
using
the
with
the
rest-frame
slope
fixed
to
α
=
−0.99,
−1.4,
and
−0.7
for
the
full,
star-forming,
and
with the rest-frame slope fixed to α = −0.99, −1.4, and −0.7 for the full,
star-forming,
and
quiescent
samples,
The
dotted
lines
show
the
local
stellarPoi
points
are
simple
divided
byslope
the −0.7
volume
NMBS,
with
with
theshown
rest-frame
sloperedshift
fixed
tohistograms
with
α =respectively.
the
−0.99,
rest-frame
−1.4,
and
fixed
for
toof
the
αthe
=full,
−0.99,
star-forming
−1.4,
a
mass
function
of
all
(black),
early-type
(red),
and
late-type
(blue)
galaxies
(Bell
et
al.
2003),
mass function of all (black), early-type (red), and late-type (blue) galaxies
(Bell
et rest-frame
al. 2003),
as described
the text.
The
light
hatched
regions
the
with
the
slope
fixed
to mass
α = in
−0.99,
−1.4,
and
−0.7
for
the
full, show
star-forming,
an
mass
function
of allscaled
(black),
early-type
function
(red),
and
of
late-type
all
(black),
(blue)
early-type
galaxies
(red),
(Bell
and
et90%
al.
late2
completeness
limit
for
red
galaxies
at
the
high-redshift
end
of
each
bin.
Note
that
we
determin
completeness limit for red galaxies at the high-redshift end of each bin. Note
that
we
determine
number
and
mass
densities
below
by
simply
counting
objects
at
masses
mass
function
of
all
(black),
early-type
(red),
and
late-type
(blue)
galaxies
(Bell
et
al.
2003
completeness limit for red galaxies
completeness
at the high-redshift
limit forend
redofgalaxies
each bin.
at the
Note
high-redshift
that we dete
where
thebottom
NMBS
isforcomplete,
rather
thanhigh-redshift
integrating
the
Schechter
functions.
Thewe
pa
where the NMBS is complete, rather than integrating the Schechter functions.
The
panels
show
the
fraction
of
red,
quiescent
galaxies
as
a
function
ofbottom
stellar
completeness
limit
red
galaxies
at
the
end
of
each
bin.
Note
that
determi
where
the
NMBS
is complete,
rather
where
than
the
integrating
NMBS
issample
complete,
the Schechter
rather
functions.
than
integrating
The
botto
t
3
R. Feldmann,mass
SnowPAC,
March
2016
Figure
4.
Stellar
mass
functions
for
the
full
NMBS
(top
panels)
and
split
using
massand
andearly+late
redshift. The
dottedfunctions,
line showswhile
the ratio
of thelines
Bell show
et al. (2003)
andSchechter
early+latet
and redshift. The dotted line shows the ratio of the Bell et al. (2003) early
Schechter
the solid
the ratioearly
of the
galaxy inferred from photometric data.
ptical galaxies but much
8–13
significant
recent structural
onsiderable attention
, Galaxies
Massive
at Cosmic
Noon and dynamica
galaxies over the past 10 Gyr.
The uncerta
rown in size by a factor of
ALMA: 870μm + CO
Extreme
Star-bursts
(SMGs)
was determined
from simulations~1.4that
i
rs (10 Gyr). A key
test of
Gyr
and template
mismatch. However, w
ellarHighest
kinematics of• one
form of
stars atnoise
rates ~1000
times
possibility
that some subtle systematic effe
objects are as extreme
asour Galaxy,
that of
very dusty
the analysis, given the low signal-to-noise
ed to have much• higher
extremely luminous in sub-mm
laxies of the same mass.
We observed the galaxy, dubbed 1255–0,
• few examples
in today’s
Universe:
1’’ the Gemi
tellar velocity dispersion
Infrared
Spectrograph
(GNIRS) on
all major
5 2.186, corresponding
to galaxy
totalmergers
of 29 h. The de-redshiftedOteo
spectrum
et al. 2016
Star formation activity
The ISM of two interacting distant
Lowest
• ncom ~ 10-5 Mpc-3 (today’s clusters)
Quiescent galaxies
• low star formation, little dust
• often very compact (≲ 1 kpc)
• ncom ~ 10-4 - 10-5 Mpc-3
(today’s groups & clusters)
HST image
~3 Gyr
Fig. 2.— Upper : ALMA 870µm continuum map of SGP38326.
The three detected SMGs are indicated. The grey contours represent the integrated 12 CO(5–4) emission. This line is clearly detected in both SMG1 and SMG2, but there is no 12 CO(5–4) detection in SMG3. The beam sizes of the 12 CO(5–4) (grey ellipse,
1.1!! × 1.0!! ) and dust continuum (white ellipse, 0.16!! × 0.12!! ) observations are shown, and clearly highlight the impressive increase
in spatial resolution. Bottom: Velocity map of SMG1 derived from
the 12 CO(5–4) emission using moment masking (Dame 2011). It
can be seen that, despite the lack of spatial resolution, the 12 CO(5–
4) observations already indicate that SMG1 presents a disk-like
rotation. In both panels, north is up and east is left.
28.6 ± 5.8 mJy, S500µm = 46.2 ± 6.8 mJy. SGP38326
was subsequently observed with SCUBA-2 at 870 µm
(S870µm = 32.5 ± 4.1 mJy) and, by fitting a set of FIR
templates to its SPIRE and SCUBA-2 flux densities, we
determined a best-fit photometric redshift zphot ∼ 4.5.
The ALMA spectral scan in the 3mm window confirmed its redshift to be z = 4.425 ± 0.001 via detection of the 12 CO(4–3) and 12 CO(5–4) emission lines
(Fig. 1). The total IR luminosity of SGP38326, obtained from an SED fit to the Herschel and SCUBA-
0.5″
b
van Dokkum et al. 2009
R. Feldmann, SnowPAC, March 2016
Model
13
4
C.M. Casey et al. / Physics Reports 541 (2014) 45–161
50
C.M. Casey
al. / Physics
Reports
541 (2014)
45–161
Merger
based
paradigm
etReports
al. /etPhysics
Reports
541 (2014)
45–161
C.M. CaseyC.M.
et al. Casey
/ Physics
541 (2014)
45–161
50
C.M. Casey et al. / Physics Reports 541 (2014) 45–161
50
Star-burst
interacting galaxies
B
AGN /Quasar
D
C
Hopkins et al. 2008
quiescent galaxy
isolated disk galaxies
A
A
B
C D
E
E
e.g. Di Matteo+2005,
Springel+2005, ...
also see Mark Brodwin’s
talk yesterday
R. Feldmann, SnowPAC, March 2016
5
Merger based paradigm
Success of this picture
• explains/links origin of star-bursting and quiescent galaxies
• many galaxies in a young Universe show disturbed morphologies
Challenges
• fails to reproduce observed number density of star-bursting galaxies
• short duty cycle of star-bursts
• rate of major mergers between galaxies is too low
• mergers do not produce enough sub-mm flux efficiently
• Unclear whether super-massive black hole regulate/stop star formation
R. Feldmann, SnowPAC, March 2016
6
Basic Questions:
• Why are some massive galaxies at Cosmic Noon quiescent and
others of the same stellar mass are star forming?
• What is the origin of the extreme star-bursting population at
Cosmic Noon?
• How important is the moment/energy injection from supermassive
black holes?
• Which role does the cosmological environment / halo assembly
play?
R. Feldmann, SnowPAC, March 2016
7
Massive
PI: Feldmann in collaboration with:
F RE
Feedback In Realistic Environments
E. Quataert (Berkeley),
P. F. Hopkins (Caltech),
C-A. Faucher Giguere (NorthWestern),
D. Keres (UC San Diego)
Goals:
. Feldmann (Berkeley), E. Quataert (Berkeley), P. F. Hopkins (Caltech),
-A. Faucher Giguere (NorthWestern), D. Keres (UC San Diego)
Farthest observed galaxies
Peak epoch of
galaxy formation
Today
1. Study the peak era
of galaxy formation in the Universe
Specs
SPH / FIRE
with high-resolution cosmological simulations
• 18 zoom-in regions in a (144 Mpc)3 box
http://www.astrophoto.com/M82.htm
(pressure-entropy) SPH
. & improved art. viscosity
• main halos ~ 3×1012 M
(a few billion years
after the Big Bang)
(~14 billion years
after the Big Bang)
– 3×1013 M
(end of re-ionization)
4
• downprocesses
to z=2
2.
Explore
the
physical
that shape the
tional softening
• mSPH ~ 3×104 M
at those times
nergetic FB galaxy
from SNe &population
stellar
•
pressure, metal+mol. cooling
, 100% efficiency per tff
minimal gravitational softening for gas,
stars ~10 pc
• ~1 billion SPH particles
3. Prepare synthetic observations that guide the interpretation
of upcoming galaxy surveys with current and future
instruments
9
• Atacama Large Millimeter/SubMM Array (ALMA)
• James Webb Space Telescope (JWST)
• LSST, TMT, GMT, ESO E-ELT
R. Feldmann, SnowPAC, March 2016
8
MassiveFIRE
• Suite of cosmological, hydrodynamical zoom-in simulations
• Run with GIZMO (pressure-entropy SPH)
• Star formation and stellar feedback modeling based on
Feedback in Realistic Environments (FIRE) approach
(Hopkins et al. 2014)
• star formation not tuned to empirical scaling relations
• stellar feedback physically modeled (no “recipes”):
radiation pressure, stellar winds, supernovae
• no energy / momentum injection from
• High numerical resolution: ~10 pc, ~104 M⊙◉☉
R. Feldmann, SnowPAC, March 2016
credit P .F. Hopkins
supermassive black holes
9
Selection
• 18 individual zoom-in simulations (range of assembly histories)
• ~40 massive galaxies (~50% centrals)
z=2
3 × 10 1 3 M !
1 × 10 1 3 M !
3 × 10 1 2 M !
3 halo mass bins at z=2:
3×1012, 1013, and 3×1013 M☉
• secondary selection based on
environmental density
• Largest sample of simulated massive
galaxies at z~2 with highly resolved
internal structure
]
[ solar
halo mass
M( <
R vi r) [ Mmasses
! ]
• primary selection based on halo mass
14
10
13
10
12
10
11
10
0
13.7
2
3.3
4
1.5
z
6
1
0.68
cosmic time [ Gyr ]
R. Feldmann, SnowPAC, March 2016
10
Validation of the physical model
• properties of galaxies in today’s Universe, e.g., relations between
star formation rate, gas content, mass-metallicity relation
(e.g. Hopkins et al. 2014, Ma et al. 2016)
• properties of outflows driven by stellar energy/momentum injection
(Muratov et al. 2015)
• Variability of the star formation rate in galaxies
(Sparre, Hayward, RF et al. 2016)
• covering fractions of neutral hydrogen in massive halos
(Faucher-Giguère, RF, et al. 2016)
• presence of large star forming clumps in massive, young galaxies
(Oklopčić, Hopkins, RF, et al. submitted)
• Soft X-ray emission, Sunyaev-Zel’dovich signal
(van de Voort, Quataert, RF et al. in prep)
• Properties of dwarf galaxies (see Andrew’s talk)
• ...
R. Feldmann, SnowPAC, March 2016
11
Stellar mass - halo mass relation
10
10
Mstar[Msun]
10
12
MassiveFIRE
11
10
10
10
10
10
10
z=2
z=5
z=9
High resolution
Medium resolution
Centrals
Satellites
9
8
7
Moster et al. 2013
z=2
z=5
z=9
6
5
R. Feldmann, SnowPAC, March 2016
10
9
10
10
11
10
10
Mvir[Msun]
12
10
13
10
14
RF et al. 2016 MNRAS
12
Separating star forming and quiescent galaxies
• physical classification: low star formation rates per unit stellar mass
• observational classification: galaxy colors consistent with low/high SF
(U-V)restframe
t = 3 Gyr
U
V
J
Straatman et al. 2014
Tomczak et al. 2014
R. Feldmann, SnowPAC, March 2016
(V-J)restframe
13
Star forming and quiescent galaxies
star formation rate
/ galaxy
sSFR
[yr-1] mass [ yr-1 ]
10
10
10
10
10
-8
• SF/Quiescent
classification based
on U-V, V-J colors
(from mock images)
-9
MassiveFIRE
Star forming
Quiescent
-10
• matches well the split
of galaxies into those
on and those below
the SF sequence
Centrals
Satellites
High res.
Medium res.
-11
z=2
z=1.7
Schreiber et al. 2015
-12
• Quiescence:
factor of a few below
the SF sequence;
not fully “quenched”
z=2
z=1.7
10
10
10
11
galaxy stellar M
mass
solar
[M[ sun
] masses ]
star
R. Feldmann, SnowPAC, March 2016
14
Star forming
galaxies
• dusty
• disturbed
morphologies
• disky / irregular
Quiescent
galaxies
• dust-poor
• spherical/elliptical
• yellow-ish colors
R. Feldmann, SnowPAC, March 2016
15
Growth history of halos and galaxies
Quiescent galaxy
Star forming galaxy
12
12
10
10
0.05M D M
M b a r≤ 1 . 5 × 1 0 4 K
M star
M g a s≤ 1 . 5 × 1 0 4 K
11
11
10
Mass (< r) [ M
sun
]
Mass (< r) [ Msun ]
10
10
10
9
10
0.05M D M
M b a r≤ 1 . 5 × 1 0 4 K
M star
M g a s≤ 1 . 5 × 1 0 4 K
10
10
9
10
10
fi t t e d gr ow t h r at e s [ X , R ] : d l nM X ( < R ) /d z
[ D M, R v i r] : 0. 54
[ st ar s + gas ≤ 1. 5 × 10 4 K , 0. 1 R v i r] : 0. 14
[ st ar s , 0. 1 R v i r] : 0. 24
ID 9:0
Q
7
10
SF
8
8
10
ID 223:0
fi t t e d gr ow t h r at e s [ X , R ] : d l nM X ( < R ) /d z
[ D M, R v i r] : 1. 49
[ st ar s + gas ≤ 1. 5 × 10 4 K , 0. 1 R v i r] : 1. 67
[ st ar s , 0. 1 R v i r] : 2. 24
2
3
4
5
6
7
7
10
8
M (t) / e
R. Feldmann, SnowPAC, March 2016
3
4
5
6
7
8
z
z
z(t)
2
[1 + z(t)]
“smoothes out” individual mergers
• estimate growth rates at z=2
•
16
1.25
1
Star forming
Quiescent
Centrals
Satellites
log
10
0.75
M
star
10
10.5
11
11.5
0.5
stronger baryon growth
d lnM H I + H 2 + s t a r ( < 0.1R vi r ) /d t [ Gyr − 1 ]
galaxy growth (stellar + gas mass)
1.5
0.25
0
−0.25
stronger DM growth
−0.25
0
0.25
0.5
0.75
1
d lnM D M ( < R vi r ) /d t [ Gyr
1.25
−1
]
1.5
RF et al. 2016 MNRAS,
see also RF & Mayer 2015
dark matter halo growth
• galaxy & halo growth are strongly correlated (similar timescales)
• Low specific growth rates necessary to become quiescent
R. Feldmann, SnowPAC, March 2016
17
log10(S
H
11
10
10
1.0
-1.0
10
0
1
0.5
2
z
3
4
5
Simple Toy Model
6 7 8
• Identify SF/Quiescent with galaxies with increasing/decreasing SFR
shift. The overlaid white lines show average mass accretion histories for halos as
mass of >1015.5 M! at z = 0 and therefore are not expected to exist. Right panel:
or galaxies at z = 0. This figure shows the historical star formation rate for stars
is so low, this is equivalent to the star formation rate traced along the white mass
• What (specific) baryonic growth rate corresponds to dSFR/dt = 0?
10000
10
Time [Gyr]
4
7
11
1
Behroozi+13
Mh(z=0) = 10 MO
•
1000
2
12
•
Mh(z=0) = 10 MO
d ln Mbar
1 R + dtdep /dt
|dSFR/dt=0 =
crit (M⇤ , t) ⌘
dt
tdep + M⇤ /SFR
14
Mh(z=0) = 10 MO
•
•
-1
SFR [MO yr ]
•
10
• Specific growth rates >
crit
=> increasing SFR, increasing gas reservoir
1
0.1
0.01
0
d
R)SFR + SFR tdep
dt
Mh(z=0) = 10 MO
13
100
d
d
Mbar = (Mstar + Mgas ) = (1
dt
dt
0.5
1
2
z
3
4
5
6 7 8
alo mass and redshift (lines). Shaded regions indicate the 1σ posterior distribution.
nes). Shaded regions indicate the 1σ posterior distribution. Histories for 1015 M!
• SFR ~ c SFR
crit
=> decreasing SFR,
limit: SFR ~ net inflow rate onto galaxy
, c determined from dSFR/dt=0 condition, c ~ 0.16 - 0.3
MS in Figure 6.
We show similar plots with 1σ uncertainties
The left-hand panel demonstrates that the SFR at fixed halo
mass has been monotonically decreasing since very early
• ratedep
redshifts. This
of decrease is different for different halo
masses. At moderate to high redshifts (z > 2), larger halo
masses generically have larger average SFRs. However, at lower
redshifts, the highest mass halos (Mh ! 1014 M! ) become so
inefficient that they have lower SFRs than group-scale (1013 M! )
halos or Milky-Way sized (1012 M! ) halos.
From the perspective of individual galaxies, it is more
illuminating to look at the SFH in the right panel of Figure 6.
Because halos continually gain mass over time, and do so
R. Feldmann,
March
more
rapidly atSnowPAC,
early redshifts,
the 2016
SFH for galaxies is not
t
• Specific growth rates <
(Genzel et al. 2015), SFRMS (Schreiber et al. 2015)
crit ~ 0.25, 0.27, 0.4 Gyr-1 for M*~1010, 3×1010, 3×1011 M☉
18
Let’s do the numbers
1
10
10.5
MassiveFIRE (hydro) simulations
N-body simulation + analytic model
fquiescent(>M)
0.7
simulations
0.6
0.4
0.3
Xcrit x1.1
x1.0
0.2
0
1.5
model observations
0.5
x0.9
0.1
M growth
1.25
quiescent fraction
0.8
10
10.5
11
11.5
11.2
z~2
Tomczak et al. 2014
Muzzin et al. 2013
0.9
og10 Mstar
log10Mstar[Msun]
10.8
11
11.1
12
12.5
13
log10Mvir[Msun]
13.5
14
Figure 5. Fraction of quiescent, central galaxies residing in halos
e of baryonic
Model:above
Quiescent
galaxies
are those
with dbylnMassiveFIRE
Mhalo/dt <are
a given mass.
The fractions
predicted
DM masses of
shown
standard deviaR. Feldmann,
SnowPAC, March
2016by filled circles. Error bars indicate 1
how
quiescent
crit
19
Normalize
Normaliz
Normalized
10–1
1
a
1
10–2
100
Normalized quantities
31
2
1012)
2 23
12
10 ) (M
2
3
SFR/1,526 (M yr–1)
Normalized
Normalized
quantities
Normalizedquantities
quantities
10–1
10–2
10–3
star formation rate
6
30 1
10
M /(1.1 ×
)
d
bc
*
10
S850/31.9Dust
(mJy) mass/(1.5 × 10 ) (M ) b
1×
(M )
SFR/1,526
10–1
ass/(1.5
× 1010(M
) (M yr) –1)
Normalized quantities
LETTER RESEARCH
Extreme
star-bursts
LETTER
Time since Big Bang (Gyr) RESEARCH
Time since
Big Time
Bang
since
(Gyr)
Big
Bang
(Gyr)
since
Big Bang
(Gyr)
100Time
b
10
10
d
5
4
z
3
2
sSFR/10.0 (Gyr–1)
10–1
6
100
Time since Big B
3
1
Time Time
since
Big
(Gyr)
since
BigBang
Bang (Gyr)
10–2–2
10
0
10
1000
10
b
1
100ac
2
2
c
sSFR/10.0 (Gyr–1)
12
M
/(1.1
× 10
) (M SFR/1,526
)
/31.9
(mJy)
SS850
(mJy)
850/31.9
* mass/(1.5 × 1010) (M )
Dust
5 mJy = 5 10-29 W m-2 Hz-1
10–1 3
100
3
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22
66
d
Normalized quantities
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10
of physical and observable properties of
the 11| |Evolution
includes
a correction
factor
of 0.7
forTurk,
massof
loss.
major
g
Narayanan,
RF,
etLocations
al. 2015 of
Nature
Figure
Evolution
ofphysical
physical
and observable
observable
properties
of
the
includ
Figure
of
and
properties
the
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100the central galaxy. In each
on region and
panel, the emission
mergers
(.1:3)
arethe
noted
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vertical
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on thethe
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of b. T
submillimetre
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and
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central
galaxy.
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each
panel,
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merge
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and
central
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c star
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are shown
withrate,
thick
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shaded
in c shows
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would
be detectabl
properties
ofthe
thehigh
200
kpc
submillimetre
emission
region
shown
with
thick
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10–1 region
properties
of
200
kpc
submillimetre
emission
region
are
thick
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5 mJy).
pinkdashed
and purple
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e of the central galaxy are S
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dashed
lines.
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those
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solid
while
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are
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850
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be classified
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Stellar
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dustmass;
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predicted
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and
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mm
d
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0 region
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andsSFR
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grey
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d denotes
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M*/SFR). The SFR is averaged on 50 Myrd,d,
/SFR).
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50
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and regim
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sSFR/10.0 (Gyr )
•–1spectrum agrees sSFR/10.0
well
with
observations
10
1.9
(mJy)
density projections of six arbitrarilypresent
chosengas
snapbetween
z<
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outliers.
One consequence
of a model
i
present
gas
surface
density
projections
of
six arbitrarily
arbitrarily
chosen snapsnapbetwe
surface
density
projections
six
chosen
betwe
20
R. Feldmann,ofSnowPAC,
March 2016
evolution
the submillimetre-luminous
phase SMGs typically lie on the main sequence of star formation
z = 2 MS
z (kpc)
50
Lessons for SMG formation
0
–50
• many sub-mm observations confuse multiple sources into one
z = 3.0
NH (g cm–2)
–100
• galaxy is surrounded by smaller (but still luminous) companions1018
z = 2.6
z = 2.8
100
1017
z (kpc)
50
0
–50
1016
–100
z = 2.5
–100
–50
250
kpc
0
50
y (kpc)
100
z = 2.2
–100
–50
0
50
100
z = 2.0
–100
–50
50
x (kpc)
0
50
FWHM of SCUBA
C.M. Casey et al. / Physics Reports 541 (2014) 45–161
100
x (kpc)
sub-mm phase not initiated by subhaloes.
majorSome
merger
(last
finished
~1 Gyr
of the brightest
SMGs
arise from numerous
galaxiesearlier)
within the
e 2 | Surface•density projection maps of the 250 kpc region around
entral submillimetre galaxy for redshifts z < 2–3. The submillimetre
ion region probed in surveys typically encompasses a central galaxy in a
ve halo that •
is undergoing a protracted bombardment phase by numerous
}
beam in a rich environment (bottom right panel). The colour coding denotes
the gas column density (NH), with the colour bar on the right.
star formation is powered by large gas reservoir:
solves problem with
SMG number counts
• inflow
gasdustfrom
web
e from ,1 kpc to 8 kpc, compare
well withof
recent
maps cosmic
can come from
older stars with ages tage . 0.1 Gyr. Using standard
conversions25, the estimated SFR from the integrated infrared SED
rved using the Atacama Large Millimetre Array24.
he stellar masses, gas fractions•and lifetimes are in agreement (3–1,100 mm) can exceed ,3,000M[ yr21 (Extended Data Fig. 6), and
re-accretion of gas expelled via outflows
some previous lower-resolution cosmological efforts10, although hence infrared-based SFR derivations of dusty galaxies at high z may
predicted SFR and luminosity from this model are substantially over-estimate the true SFR by a factor of ,2. Indeed, the contribution
satellitetime
galaxies(~1
to the Gyr)
global SFR, along with the contribution of old
r. The SFR•ofstar
the group
of galaxies remains
in the regionhigh
peaks for
at of
formation
long
21
00M[ yr . Importantly, up to half of the total infrared luminosity stars to the infrared luminosity may relieve some tensions between the
inferred SFRs from submillimetre galaxies and massive galaxies modelled in cosmological hydrodynamic simulations10.
8
R. Feldmann, SnowPAC, March 2016
50
50 50
50
50
C.M. Casey et al. / Physics Reports 541 (2014) 45–161
Casey
al.
Physics
Reports
541 (2014)
C.M. CaseyC.M.
et al.Casey
/C.M.
Physics
541/(2014)
45–161
et Reports
al. /et
Physics
Reports
541 (2014)
45–16145–161
C.M. Casey et al. / Physics Reports 541 (2014) 45–161
Fig. 2. A schematic diagram of the evolution of a galaxyFig.
undergoing
a major
merger
of gas-rich
during
itsdisks
lifetime.
Image
credits:
(a) NOAO/AURA/N
2. A schematic diagram
of the evolution
of a galaxy
undergoing adisks
major merger
of gas-rich
during its lifetime.
Image
credits: (a) NOAO/AURA/NSF;
(b) REU program/NOAO/AURA/NSF; (c) NASA/STScI/ACS Science Team; (d) Optical (left): NASA/STScI/R. P. van der Marel & J. Gerssen; X-ray (right):
(b) REU program/NOAO/AURA/NSF; (c) NASA/STScI/ACS
Science Team; (d) Optical (left): NASA/STScI/R. P. van der Marel & J. Gerssen; X-ray (righ
NASA/CXC/MPE/S. Komossa et al.; (e) Left: J. Bahcall/M. Disney/NASA; Right: Gemini Observatory/NSF/University of Hawaii Institute for Astronomy; (f)
J. Bahcall/M.
Disney/NASA; (g)Right:
F. Schweizer
(CIW/DTM);Observatory/NSF/University
(h) NOAO/AURA/NSF.
NASA/CXC/MPE/S. Komossa et al.; (e) Left: J. Bahcall/M.
Disney/NASA;
Gemini
of Hawaii Institute for Astronomy;
Source: This figure is reproduced from Hopkins et al. (2008) with permission from the authors and AAS.
J. Bahcall/M. Disney/NASA; (g) F. Schweizer (CIW/DTM); (h) NOAO/AURA/NSF.
Source: This figure is reproduced from Hopkins et al. (2008) with permission from the authors and AAS.
21
Summary
• The young Universe hosts galaxies with very different properties than
today’s Universe
• Origin and evolution of quiescent / star-bursting galaxy population at
this epoch is not (fully) understood
• Quiescent galaxies:
• Often assumed to be the result of energy injection from supermassive
black holes
• may become quiescent as a result of a slow down of their cosmic
accretion of gas
• Star-bursting galaxies:
• traditionally associated with major mergers between galaxies, but
• may be driven by gas accretion from cosmological distances & recycling
Properties of galaxies are tightly linked to
the growth history of their halos
R. Feldmann, SnowPAC, March 2016
22