A NEAR-INFRARED MULTIPLE-OBJECT
INTEGRAL-FIELD
SPECTROMETER FOR THE VLT
The Science Case
Matt Lehnert, MPE
Distant Galaxy Science Drivers
• Growth and dynamics of intermediate redshift clusters -- How do
cluster galaxies grow and evolve? When was the morphology density put
into place? What’s the role of “dry” vs. “wet” mergers? Can we see
differences between cluster and field galaxies at high redshifts?
• Dynamics of intermediate and high redshift galaxies -- How do galaxies
grow? Why were galaxies “downsized”? Gas accretion quasi-adiabatically
or through merging? What is the source of angular momentum? Does it
grow linearly with time? How did mass surface density evolve?
• Gas phase metal abundances and absorption lines in distant galaxies –
What is the evolution of mass and metallicity? How was the ISM polluted
with metals? Early enrichment? Metal distribution -- Is this consistent
with “inside-out” galaxy formation models?
• Evolution of AGN – What is the relationship between the growth of
BHs and growth of galaxies? Did this happen in “fits, stops, and starts”?
z
Lyα
He II
[OII]
1
2
3
4
5
6
7
Pop III/AGN
SFR, metallicity, density
extinction, metallicity
[OIII]
metallicity, dynamics
4000Å
G Band
Mg B
CaT
>9
Reionization, escape fraction
Hβ
Hα
8
SFR, extinction, dynamics

Iz-bands: 0.80-1.05 µm
J band: 1.05-1.37 µm
Stellar populations
H band: 1.45-1.85µm
K band: 1.95-2.50 µm
Spatially-Resolved Properties
vrot/ =f(M, z)
&
J/M = f(M, z)
Superwinds
&
Self-regulation
V(r,), (r,), v,
Mvirial, fline(r,)
Mergers
vs.
Infall
[O/H]=f(M, r, z)
dM/dt =f(M, r, z)
J/M,vrot/σ etc. – not with photometry or slitlets
Local Universe Science Drivers
• Stellar populations in the MW and other nearby galaxies. When did the
disk form in other galaxies? What is the relationship between metallicity and
dynamics for individual stars and clusters? What is the age and metallicity
distribution of the stars in, for example, the GC.
• The dynamics of merging/interacting and star-bursting galaxies. Do the
compact young clusters have the same ages as the background stars? Are
the clusters long-lived? What fraction of the star-formation is in clusters?
What about metallicity versus age – what is the mixing time scale for
metals?
• The properties of stars embedded in their natal molecular cloud. What is
the initial mass function? What is the impact of the stars on the surrounding
nebula? IFUs are crucial for removing the nebular emission from stellar
recombination lines.
Diagnostic lines in the Near-IR
Ionization: [SiVI] and other highly ionized forbidden lines for
AGN, Bracket and Paschen lines in emission, various HeI lines,
H2 vib-rotational lines for X-ray heating and PDR diagnostics,
etc.
Shocks: H2 vib-rotational lines, FeII lines, etc.
Ages, surface gravities, and temperatures of stars: CObandheads in the H and K bands, SiI, MgI (in the K and zband), CaI, Bracket and Paschen lines in absorption, the Calcium
triplet in the z-band, etc
Galaxy Number Counts
Förster-Schreiber et al. (2004) and (2006)
K Selected Galaxies
… highly efficient way of selecting distant galaxies …
for 20 < K < 22, z>1.4 …
about 4 sources arcmin-2 over 53
arcmin2 … KMOS FOV
Daddi et al. (2004)
z1-3 Star-Forming Galaxies
Populating the “redshift desert”
z=1.5-3.5
SFR20-60 M yr-1
[M/H] 0.8[M/H]
Selects only actively
star-forming
galaxies!
Steidel et al. (2004)
Clustering of z~3 LBGs
3.06<zspec<3.12 (24)
“Narrow band excess” (72)
“Giant Ly blob” (2)
… 162 objects that are likely to be associated …
Steidel et al. (2000)
Likely Sensitivity of KMOS
In 8 hrs integration (1 night):
BX galaxy at z=2.2101
5 limits for compact galaxies and
between OH lines are:
J~22, H~21.2, K~19.4
… but with SINFONI, in 3 hours,
at ~0.5” seeing, for …
FH1.7x10-16 ergs s-1 cm-2
Ks=19.2
5σ in 1 hour for SINFONI of:
K~18.4 & FH4x10-17 ergs s-1 cm-2
µH4x10-17 ergs s-1 arcsec-2
3 hours of total integration time
Sensitivity Comparison in I/z bands
KMOS has better sensitivity, better sampling, 3-D capability,
and comparable or higher multiplex, and is more flexible …
Stoichiometry
for Cd1-yZnyTe
Galaxies in Pieces – Standard Model
Dark matter distribution on
100s kpc scale.
Gill et al. (2004)
Abadi et al. (2002)
Merger Tree
Ultimately:
Spiral
Elliptical
Frenk, Baugh, & Cole (1996)
smooth vs complex … angular momentum …
dissipative vs. non-dissipative collapse
Angular momentum problem
Galaxies have JDisk ≈ JHalo
SPH plus N-body predict J
that is too low
Steinmetz & Navarro (2000)
Formation of Disks in Mergers?
Gas-rich mergers plus vigorous feedback
No BH
BH
Robertson et al. (2005)
Predicts enough angular momentum, but needs robust
feedback to keep disk from collapsing …
Disk formation – accretion?
Early insights:
ELS ‘62, Silk (1977), Binney (1977), Ostriker & Rees (1977)
In highly dissipative accretion/collapse, disks are very unstable …
~Gyr
~6 kpc
Immeli et al. (2004)
forms individual clumps of ~few x 109 M which coalesce to
form a bulge in a few dynamical times …
Disk formation – accretion
Clumpy galaxies in the UDF …
Elmegreen & Elmegreen (2005)
… properties appear similar to model predictions …
but which model …
Velocity fields of z~2 Galaxies
In best cases: 2-D velocity field
is smooth and consistent with
orbital motion – rotating disks?
v
1623-663
FWHM
500
-200
300
200
SSA22-MD41
100
-170
170
0
250
170
2343-610
170
200
400
300
-170
2346-482
-110
200
110
1623-528
60
180
-60
-60
Förster Schreiber, Genzel, Lehnert et al. (2006)
330
60
320
evidence for high
μK, metal-rich
stellar population
at the dynamical
center of BX610
Q2343-BX610 Hα
line-free K-continuum
[NII]
[NII]/Hα
Range 0.25 - 0.55
≈dynamical center
Förster Schreiber et al. (2006)
Mergers
z~2 galaxy
Model “analogued”
Model “original”
Image
Velocity map Dispersion map
Puech et al. (2006)
Dark Matter Mass and Angular
momentum
If rotational support, compared to
dark matter halos implies
(Mo, Mao &White ‘98):
z~2
Mhalo1011.7 (vc/180 kms-1)3 (1+z/3.2)-1.5 M
jhalo102.8 0.05(vc/180 kms-1)2 (1+z/3.2)-1.5
km s-1 kpc
• jdisk problem persists
• vcircularvvirial since dynamical and
clustering estimates are in rough
agreement
Abadi et al. (2003)
Förster Schreiber, Genzel, Lehnert et al. (2006)
Summary of z~2-3 Galaxy Results
•
•
•
•
•
<Mdyn> ~ few x 1010 M
vcircular  vvirial
Σdyn ~ few x 109 M kpc-2 (Mdyn/Area½)
Jz~2 ~ Jspirallocal, angular momentum “in place”
v/σ and angular momentum may imply rapid
accretion
“inside-out” galaxy formation scenario
Emphasizing the role of gas accretion
… and larger samples!!!!
LBGs at z>5
8191.8Ǻ
BDF1:10 z=5.774
BDF2:19 z=5.645
BDF1:18 z=5.017
BDF1:19 z=5.870
BDF1:26 z=5.056
8083.0Ǻ
7315.5Ǻ
8351.4Ǻ
7362.0Ǻ
HST VIz images of V-band “dropouts”
S/N(Z)>5 S/N(I)>3 S/N(B)<3 I>26.3 V-I>1.7 (contaminants included)
Median UV half-light-radii:
1kpc
Night Sky Problem
… gaps in the night sky are used for narrow band searches …
… KMOS not a particularly good redshift machine …
R=3200
… KMOS can be used to investigate their complex morphologies
…
R>3000 important
for both night sky
subtraction, HeII,
and identifying
source as Ly
emission
Stars in the
Galactic Center
4
IRS3 (WC 5/6)
IRS10 EE (K5 Ia/b)
0.2
3
0.1
2
1
0
0
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.0
2.4
2.1
2.2
2.3
2.4
wavelength (m)
wavelength (m)
1 .3
IRS16SE2 (WN5/6)
0.1
S2 (O8/9 V)
1 .2
1 .1
0
1 .0
-0.1
2.05
2.10
2.15
2.20
2.25
2.30
2.35
0 .9
2.40
2 .1 2
2 .1 4
2 .1 6
2 .1 8
wavelength (m)
7.5
IRS10 EE (M7/8 III)
IRS16 SW (Ofpe/LBV)
6.0
1
10”(0.39 pc)
4.5
0
3.0
1.5
1.6
1.7
1.8
1.9
2.0
2.1
wavelength (m)
2.2
2.3
2.4
2.04 2.06 2.08 2.10 2.12 2.14 2.16 2.18 2.20
wavelength (m)
3D spectroscopy critical
in removing nebular
emission and absorption
from stellar resonance
and recombination lines
KMOS
3-D spectroscopy is crucial for studying in situ
galaxy evolution;
While emphasizing the distant galaxy science
case, KMOS is flexible and can do a wide
range of studies;
The combination of large FOV, 2 dozen IFUs,
and a flexible arm placement means that
KMOS will be highly efficient at getting the
most important targets in any science field;
Will provide robust statistical samples w/ 3-D
data.