Download implication on the mass and

The Luminosity-Metallicity
and Mass-Metallicity Relations
of 0.4<z<1 Luminous Infrared Galaxies :
---implication on the mass and metal assembly
of galaxies
Yanchun Liang (NAOC, China)
2005-08, Lijiang
Collaboration with
Francois Hammer, Hector Flores, Francois Assemat
at Paris-Meudon Observatory;
David Elbaz, Delphine Marcillac at Saclay-Service
d’Astrophysique;
Nicolas Gruel at Florid University;
Xianzhong Zheng at MPIE;
Licai Deng at NAOC;
Catherine J. Cesarsky at ESO.
How much star formation was hidden by dust
over the history of the universe ?
(1) IRAS (z<0.3):
detected tens of thousands
of galaxies with the FIR radiation luminosities
From 106Lsun to ~1013Lsun, but only ~2% of
the local bolometric luminosity density
is due to the luminous IR galaxies
(Soifer et al. 1987, ARA&A, 25, 187;
Sanders & Mirabel 1996, ARA&A, 34, 749)
240 mm
(2) COBE (DIRBE) detected a diffuse
background at l > 140 mm
(3) Surveys at 15,90,170,450,850mm
(ISO, SCUBA)

strong evolution
(Elbaz et al. 2002, A&A 384, 848)
ISOCAM 15 mm MIR source counts
(1) ISO 15 mm source
counts show strong
evolution
(2) The comoving density
of infrared light due to
the luminous galaxies
(LIR>1011Lsun) was more
than 40 times larger at
z~1 than today
(3) The main responsibility:
the luminous Infrared
starburst galaxies seen
by ISO at z>0.4,
SFRs > 50 Msunyr-1
(Elbaz et al. 1999, A&A Lett., 351, L37)
(Elbaz et al. 2002, A&A 384, 848; Elbaz & Cesarsky, 2003, Science, 300, 270; Flores et al. 1999, ApJ 517, 148
(4) Most of ISOCAM (>75%)galaxies are Starbursts, AGN only contribute ~20%
(Elbaz et al. 2002 A&A 384 848; Fadda et al. 2002, A&A, 383, 838; Flores et al. 1999;
Franceschini et al. 2003, A&A, 403, 501; Liang et al. 2003b, A&A, submitted)
The Spitzer view on the history of dusty star formation at 0<z<1
Evolution of the comoving IR energy density up to z=1 (green-filled region)
and the respective contributions from low luminosity galaxies (i.e.,
LIR<1011Lsun, blue-filled area),
``infrared luminous'' sources (i.e., LIR>1011Lsun, orange-filled region) and
ULIRGs (i.e., LIR>1012Lsun, red-filled region).
The solid line evolves as (1+z)3.9 and represents the best fit of the total IR
luminosity density at 0<z<1.
Estimates are translated into an ``IR-equivalent SFR'‘ density given on the
right vertical axis, where an absolute additional uncertainty of
$\sim$\,0.3\,dex should be added to reflect the dispersion in the conversion
between luminosities and SFR.
(Le Flo’ch et al. 2005, ApJ, astro-ph/0506462 )
Spectroscopy (VLT/FORS2)
follow-up
for a large sample of ISOCAMselected sources
(Extinction, Metallicities,
L-Z, Mass-Z)
(Liang et al. 2004, A&A, 423, 867)
1. The ISO-selected sample : 105 in 3 fields



CFRS 3h,
UDSR (Ultra-Deep-Survey-Rosat, Marano field),
UDSF (Ultra-Deep-Survey-Firback, Marano field)
(Flores et al. 2004, Elbaz et al. 2004, in preparation )
2. The Optical Observations
using VLT/FORS2 with R600 and I600
spectrograph with a resolution of 5 Å, R=1200
5000 - 9000 Å, slit width 1.2" slit length 10"
3. Redshift identifation
92
zmedian=0.587
(64 with z>0.4)
4. Infrared luminosities
Log(LIR/Lsun)med=11.26
( LIRGs with Log(LIR/Lsun)>11)
5. Emission Line Galaxies (ELG)
85% EL galaxies in the ISO-detected objects , 81% EL galaxies in the total
IR luminosity
Log(LIR/Lsun)med
=11.26
Similar to
Veilleux et al.1995,
Kim et al. 1995:
11.34 for BGSs
11.38 for WGSs
H0=70 km/s/Mpc
M=0.3, L=0.7
9
10
11
12
13
Examples in UDSF
Deblending…
z=0.7094
Log(LIR/Lsun)=11.38
Estimate dust extinction
Stellar absorption correction
Jacoby et al. (1984)
1) Using Hb/Hg ratio :
A V(Balmer)
2) Using energy balance between Hbetra and IR :
A V(IR)
Diagnostic diagram: Starbursts
Most of them (>77%) are HII-region-like galaxies
Consistent with other fields:>70% of ISOCAM/15mm galaxies, “starbursts”
Oxygen abundances in ISM
R23 and calibration from Kobulnicky et al. 1999
12+log(O/H) = 8.35 – 8.93, median 8.67

Luminosity-Metallicity relation (L-Z)
& Mass-Metallicity relation (Mass-Z)
L-Z relation:
z> 0.4 LIRGs are metal deficient
03.0035
! z> 0.4 LIRGs are 0.3 dex
metal-poor from local disks
(at a constant MB): ~ 50%
(12+log(O/H) = 8.35 – 8.93,
median 8.67)
! They can reach local disks
locus assuming an infall time
of ~ 1 Gyr
(PEGASE2, Fioc and RoccaVolmerange, 1999,astroph/9912179: Mtot=1011Msun ,
(Liang et al. 2004, A&A, 423, 867)
also see Kobulnicky et al. 2003, ApJ,
599, 1006)
Are massive spirals already formed at z~ 1 ?
! Connection between LIRGs and disks (z>0.4) (HST morphologies and
color maps) : 40% of LIRGs are large disks (Zheng et al, 2004, A&A)
! Lilly et al (1998) large disk sample (rdisk > 4 h50-1 kpc) at 0.5 < z < 1:
32 (+/-13)% of them are LIRGs
! LIRGs have large stellar masses: 1.4 1010MO <MK < 2.9 1011MO
(see also Franceschini et al. 2003, A&A, 403, 501)
! LIRGs have high
SFRs:
>50 Msunyr-1 ,
TSF(M/SFR)=0.1-1 Gyr
(Mass double time scale: 0.1-1 Gyr)
Time (Gyr)
(Hammer et al. 2005,A&A,430,115)
The Mass-Metallicity relation of
0.4<z<1 galaxies
30% to 50% of the mass locked in stars in
present day galaxies actually condensed
into stars at z<1 (Dickinson et al. 2003;
Pozzetti et al. 2003; Drory et al. 2004; Bell
2004)
Which kinds of galaxies are mainly
responsible for such star formation fraction?
The near-IR K-band luminosity is more directly
related to the stellar mass of galaxies since it
is less affected by star formation and by dust
(Charlot 1998; Bell & de Jong 2000):
We compare the MK-metallicity (mass-Z)
relations of these intermediate-z galaxies
with those of local star-forming galaxies.
(Liang, Hammer, Flores 2005, A&A, submitted)
The 3 local sample galaxies to compare:
NFGS (Nearby Field Galaxy Survey) by
Jansen et al. 2000a,b
KISS ( Salzer et al. 2005)
SDSS (Tremondi et al. 2004; Bell et al. 2003)
NFGS
from Jansen et al. 2000a,b
Such z> 0.4
galaxies are
0.3 dex more
metal-poor
from local disks
(at a given MK):
~ 50%
KISS
from Salzer et al. 2005
SDSS
Tremonti et al.
2004,
Bell et al. 2003;
The 7 galaxies
at z~2.3 from
Shapley et al.
2004
Summary

Spectroscopy follow-up for a ISO-selected sample
galaxies with 0.4<z<1

We study their metallicities on the basic of VLT/ FORS2
spectra, the median oxygen abundance of them is
12+log(O/H)~8.67: ~0.3dex more metal deficient than
the local star forming galaxies at the given magnitude
or stellar mass

By comparing with the local galaxies (e.g. NFGS, KISS,
SDSS) and the high-z (z~2.3) galaxies, we can get a
basic understanding on the assembly of the metals of
galaxies: ~ 50% of metals of these intermediate-z
galaxies was formed since z ~ 1