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An Hα approach to the evolution
of the galaxy population
of the Universe
Jesús s Gallego
Universidad Complutense Madrid
S. Pascual, V. Villar UCM
P.G. Pérez-González, J. Zamorano UCM
D.C. Koo, K. Noeske
Lick
20/10/08 Jesús Gallego - Astrofísica UCM 1

Galaxy formation and evolution
Jesús Gallego – UCM Granada 2008 2

Observational tests: The cosmic SFR density
Madau et al (1996)
MNRAS 283, 1388
Observational result
Lilly et al 1996
UV for CFRS survey
Epoch of maximum SF at z~1
Combination of surveys
Hα local
UV at intermediate z
UV from the HDF-N
¡¡ 1170 citations !!
More than 3000 papers SFRd
in the abstract
Jesús Gallego – UCM Granada 2008 3

Galaxy evolution: SFR tracers
SFR [M/yr] = K • Luminosity
U band
UV continuum
Hydrogen recombination lines
Forbidden lines
Far-infrared
1.4 GHz Radio
R=Light / SFR
R STANDARD
:
- Salpeter IMF, Z
- Mmax=100M
- A V
=1, dust screen
Charlot et al 98
Local SFR calibrations valid for high
redshift? (see Cardiel+03, Moustakas+06)

Galaxy evolution: SFR tracers
SFR [M/yr] = K • Luminosity
LeFloch&Mirabel 04

The multi-λ Lilly-Madau plot
‣ UV based observed with GALEX
‣ Estimated UV corrected
‣ Far-IR (see Pérez talk !!)
‣ Hα based
Schiminovich et al 05
Transition epoch Zp ~ 1-2
β ~ 2-4
α ~ 0 ??
Jesús Gallego – UCM Granada 2008 6

Downsizing since z

New populations at 1.5

Open questions
How the overall picture depends on SFR tracers?
Why the SFR density is flat for z>1?
Are we missing a significative fraction of objects?
What is the role of the AGNs at different epochs?
Are we really measuring downsizing?
What are the new populations of galaxies?
Jesús Gallego – UCM Granada 2008 9

The Hα approach
Samples of Hα-selected star-forming galaxies
Hα as an excellent CURRENT SFR tracer, AGN sensible
Same rest-frame selection criteria
Narrow-band Total line fluxes. No aperture corrections
Line selected
‣ Well defined volume
‣ Complete and representative samples
‣ Wide coverage in the parameters space
Known fields
Multi-wavelength complementary data
t
m
2
σ( Hα)
L( Hα) = hνHα
φ( m) ψ( t) dmdt N
Lyman( m)
σ ∫∫
B
t−tm m
1
SFR Hα
(M
yr -1 ) = L Hα
/ 1.27 x 10 34 W (Kennicutt 1998)

The Hα approach
Evolution of the Hα-based SFR
Hα to compare with UV, FIR… Universes
Properties of galaxies, quenching masses
Hα complementary to FIR to compute total SFRs

Redshifts considered
z=0.02 6563Å ObjPrism UCM survey Gallego+95
Schmidt 80/120 cm
IIIa-F + RG630 filter
471.4 191 galaxies
z < 0.045 EW (Ha) > 20 Å.
“Little spirals”, M* ~10 10 Mo Gallego 97, Izquierdo et al 08

Redshifts considered
z=0.02 6563Å ObjPrism UCM survey Gallego+95
SFR local density
191 galaxies, z

Narrow-band surveys
• Objects selected by their color excess
m A -m E > µ (m A -m E ) + n σ x σ (m A -m E )
• Several apertures
Jesús Gallego – UCM Granada 2008 14

Redshifts considered
z=0.02 6563Å ObjPrism UCM survey Gallego+95
Jesús Gallego – UCM Granada 2008 15

Redshifts considered
z=0.02 6563Å ObjPrism UCM survey Gallego+95
z=0.24 8200Å NB @ I Cuasi-local Pascual+01,05
Jesús Gallego – UCM Granada 2008 16

Redshifts considered
z=0.02 6563Å ObjPrism UCM survey Gallego+95
z=0.24 8200Å NB @ I Cuasi-local Pascual+01,05
z=0.40 9200Å NB @ z Transition epoch Pascual+07
Jesús Gallego – UCM Granada 2008 17

Redshifts considered
z=0.02 6563Å ObjPrism UCM survey Gallego+95
z=0.24 8200Å NB @ I Cuasi-local Pascual+01,05
z=0.40 9200Å NB @ z Transition epoch Pascual+07
z=0.81 1.19μm NB @ J Most-of-the-fun Villar+08
Jesús Gallego – UCM Granada 2008 18

Redshifts considered
z=0.02 6563Å ObjPrism UCM survey Gallego 95
z=0.24 8200Å NB @ I Cuasi-local Pascual 01,05
z=0.40 9200Å NB @ z Transition epoch Pascual 07
z=0.81 1.19μm NB @ J Most-of-the-fun Villar 07
z=2.20 NB&MOS @ K New populations GOYA
Jesús Gallego – UCM Granada 2008 19

Hα@z=0.24: SFRdensity
Pascual et al 2001; 2007
CAHA 2.2m &
INT 2.5m
~1 sqr deg
8200 Å
0.5% NB
F > 4 10 -16
erg/s/cm2
EW(Hα+[NII])
> 20 Å
Jesús Gallego – UCM Granada 2008 20

Hα@z=0.24: Disk-like objects
Pascual et al 09
WHT 4.2m
~20 objects
Phot-z’s
Jesús Gallego – UCM Granada 2008 21

Hα@z=0.24: Moderately massive disks
Pascual et al 09
[NII]λ6584
Hα
[NII]λ6548
Local
Virial and rotational masses ~10 10 Mo
Small fraction of AGNs or ULIRGs

Hα@z=0.24: Contaminants
• Ugriz for Phot-z’s
• Candidates
‘Contaminants’
Hα ELGs [OIII]5007 [OII]3727
z=0.24 z=0.63 z=0.84
Pascual et al 2005
Jesús Gallego – UCM Granada 2008 23

[OIII]5007 Contaminants @ z=0.6
66 arcsec
r=22.5
g-r=0.02
r=22.3
g-r=0.75

Contaminants
• 2 objects are selected at high redshift by their flux excess
in other lines different than Hα
GSS-1-1249
[OIII]λλ 4959,5007 a z~1.4
GSS-1-1200
[OII] λ3727 a z~2.17
Their selection may imply more luminous objects at high z
Jesús Gallego – UCM Granada 2008 25

Hα @ z=0.40
INT 2.5m
~1 sqr deg
9200 Å
0.5% NB
ELAIS-N1
Sa95, Sa114
z=0, Gallego95
10 1.9 0.2 h 3 Mpc 3
L 10 41.9 0.05 h 2 erg s 1
1.3
z=0.24, Pascual 01
Spectroscopy still pending

Hα @ z=0.40: SFRdensity
Jesús Gallego – UCM Granada 2008 27

Hα @ z=0.8
Villar et al 08
CAHA3.5m / Ω-2000
1,21 μm narrow-band filter, J band
~10 4 s exposures
Groth strip, GOODS-N
0.31 sqr deg
165 objects
J
NB
HST extended
Groth strip
WHT4.2m / INGRID
1,18 μm NB, J band
~10 4 s exposures
Groth strip
32 sqr arcmin
~15 objects
J
NB

Photo-redshifts
Villar et al 08
Sextractor stellarity
BzK criterium (Daddi+04)
IRAC and nIR criteria (Eisenhardt+04)
Photometric redshifts from
Pérez-González+05,08
BRI criteria (Fujita+03)
z < 0.7
B-R C
z > 0.7
R C -I C

Extinction correction
Villar et al 08
F dust /F FUV as a indicator
of the dust obscuration
(Buat+05)
Fdust from SPITZER
FFUV from GALEX
A(FUV) f[ log(F dust /F FUV )]
A(Hα)z=0.02 = 1.0 mag
A(Hα)z=0.84 = 1.5 mag

Hα Luminosity Function @ z=0.8
Villar et al 08
FUV ~ 0.4 M
yr -1
Hα ~ 0.7 M
yr -1
MIPS ~ 8.0 M
yr -1
0.7

Hα@z=0.8: SFR Hα-based excess?
Villar et al 08
The star formation
rate density is
0.17 M
yr -1 Mpc 3 ,
~10-15 times
higher than the
local one.
SFRd Hα
evolution:
∝ (1+z) β
β=3.8±0.5
Jesús Gallego – UCM Granada 2008 32

Hα@z=0.8: Field-to-field variance
Villar et al 08
Field to field
variances ~3x
Jesús Gallego – UCM Granada 2008 33

Hα-based UCM Madau plot
Villar et al 08

Hα-based Madau plot
Villar et al 08

UV,Hα, FIR-based Madau plot
Villar et al 08

On the nature of Hα @ z=0.8
Most of objects disk-like in HST images
LIRGs found by Pérez-González ‘05
5 arcsec
10 kpc
Jesús Gallego – UCM Granada 2008 37

On the nature of Hα @ z=0.8
Small fraction of compacts
Less than expected (~30%) of
Major mergers
ULIRGs
AGNs
5 arcsec
10 kpc
Jesús Gallego – UCM Granada 2008 38

Hα @ z=0.8 IRAC data for stellar masses
Phot-z’s (including Spitzer)
SED fitting, stellar masses
GSS073_4662
B F606W I
NB1,18μ IRAC3,6 μ IRAC4,2 μ
Jesús Gallego – UCM Granada 2008 39

On the nature of Hα @ z=0.8
Keck optical spectroscopy
V. Villar thesis @ UCM
DEEP-2
Keck I y II
LRIS/DEIMOS
[OII]3727, Hβ, [OIII]5007
Jesús Gallego – UCM Granada 2008 40

EW(OII) vs. M B
Disk-like spectroscopic properties
Jesús Gallego – UCM Granada 2008 41

Hα@z=0.8: Massive systems
O Local
M~ K R e σ 2 ~10 11 Mo, Evidence of downsizing

On the nature of Hα @ z=0.8
A. Sánchez thesis @ UCM
WHT/LIRIS near-IR spectroscopy
WHT/LIRIS-MOS
Hβ, [OIII]5007, Hα, [NII]6584
J-band, R∼700, 0”25/pix
Hα for ∼30 NB galaxies
Jesús Gallego – UCM Granada 2008 43

The power of Rainbow (see Pérez-González talk)
Hα
ACS-z
IRAC-45

SFR tot – M* relation
Massive galaxies have higher total SFRs (Hα obs
+TIR)
Jesús Gallego – UCM Granada 2008 45

Pseudo-Metallicities
• N2=[NII]6584/Hα
12+log(O/H)=8.90+0.57 x N2
• SED fitting
Metallicities estimated to be close to solar values
Jesús Gallego – UCM Granada 2008 46

The first quantification of
downsizing using a good SFR tracer
Log Mtr
DEEP-2
Hα
Bundy et al 06
0.24
10.0
Redshift
Jesús Gallego – UCM Granada 2008 47

An overall overview up to z∼1
z=0.24
pseudo local population
Population dominated by disk-like g’s
Moderately massive (~10 10 Mo)
z=0.40
Transition epoch
Mass analysis under way
z=0.84
Enhanced star-forming systems
No major mergers
Massive systems (~10 11 Mo)

Future studies @ z>1.5
Jesús Gallego – UCM Granada 2008 49

Hα @ 1.5

FISIR: a fully criogenic TF in the nIR
Finding “holes” in the night sky
Atmospheric
lines dominate
At higher spectral
resolution,
observe between
them
Jesús Gallego – UCM Granada 2008 51

Future
TFs
JWST TFI
Gemini F2T2
GTC-FISIR
Prototype single etalon IR tunable
filter for JWST. Contributed by the
Canadian Sp Ag.
F2T2 will be inserted into
Flamingos-2 and fed by the
Gemini MCAO system.
First light
~2014
Early 2010
Early 2010
Spec resolution
Wavelength
F.O.V.
100
1.5µm – 3.5µm
~2.5’
800+
30% of the range
1.0µm – 1.35µm
~50”
800+
30% of the range
1.0µm – 2.5µm
~3.5’
Image quality
Diffraction limited
MCAO
Diff. limited
P.I.
R. Doyon (Montreal)
R. Abraham (Toronto)
J. Gallego (UCM)