Sébastien Muller
(ASIAA, Taiwan)
M. Guélin (IRAM)M. Dumke (ESO)R. Lucas (IRAM)
Probing isotopic ratios at z=0.89
Molecular line absorptions
in front of the quasar PKS 1830-211
IAU Colloquium 199 Probing galaxies through quasar absorption lines, ShangHai, China, 2005 March 14-19
Absorption systems
- Lyman forest
gas filaments in extragalactic medium
1012 - 1019 cm-2
- Damped Lyman & HI 21 cm absorption
outer parts of spiral galaxies1019 - 1021 cm-2
- Molecular absorption
central parts of galaxies1020 - 1024 cm-2
Background quasars & molecular absorption
Need a background continuum source …
mm flux of quasars weaker than in the radio cm (SNR depending on the background continuum source)
And an absorption system !
Dense gas, closer to the center of the intervening
galaxy(small impact parameter)
Highly probable association with gravitational lensing
Molecular absorption systems in the mm
Zabs N H2 (cm-
2)
Cen A 0.002 2. 10 20 Host galaxy
3C293 0.04 > 6. 10 20 Host galaxy
PKS 1413+135
0.25 5. 10 20 Host galaxy
B3 1504+377
0.67 1.2 10 21 Host galaxy
B 0218+357 0.68 4. 10 23 Background QSR
PKS 1830-211
0.89 4. 10 22 Background QSR
HST WFPC2I band imageNE
SW
MERLIN 6cm
2–4 kpc
Intervening galaxy :
z=0.89Typical spiral
Photometry from HST(Winn et al 2002)I = 22V > 24.7
SW positionI > 24.9V > 26.3
1st case of QSR lensedby a face-on spiral
Mass within 3 kpc:(Wiklind & Combes 1998) 6 – 9 1010 M
1’’
PKS 1830-211
Patnaik et al 1994
Plateau de Bure Interferometer observations
Observations :
Summer time between 1999 – 2002
Compact configuration
Self calibration
HCO+ (1-2) 94.6 GHz
H13CO+ (1-2) 92.0 GHz
HC18O+ (1-2) 90.3 GHz
HC17O+ (1-2) 92.3 GHz
HCN (1-2) 94.0 GHz
H13CN (1-2) 91.6 GHz
HC15N (1-2) 91.3 GHz
HNC (1-2) 96.2 GHz
HN13C (1-2) 92.4 GHz
H15NC (1-2) 94.2 GHz
CS (3-4) 103.9 GHz
C34S (3-4) 102.2 GHz
12C/13C14N/15N16O/18O18O/17O32S/34S
Main isotopomers
2 componentsNE and SW
SW : complete absorption for HCO+
non symetric profiles
= sum of velocity components with widths similar to MW clouds
(~10 km/s)
Iabs = IO (1-exp-)
Let’s compare the isotopic ratios in:
One beam pencil in a galaxy at z = 0.89 6.4 Gyr ago
Solar System 4.5 Gyr ago
Local ISM (Lucas & Liszt 1998) now !
Galactic Center
IRC +10216 (Cernicharo et al 2000) archetype of AGB star
LMC (Chin 1999) low metallicity galaxy
NGC 4945 (Wanf et al 2004) nucleus of a nearby SB galaxy
Is there a clear chemical evolution ???
12C : produced directly from He in massive stars (primary)13C : produced from 12C and 16O in H burning (secondary)
Problems : selected photodissociation, chemical fractionation, optically thin lines for 12C
14N : secondary, enhanced in CNO cycle at equilibrium15N : secondary, destroyed in CNO,
produced in explosive H or He burning14N / 15N : increases with metallicity (gradient in the MW)
16O : primary, produced in massive stars18O : secondary, produced in He burning from 14N
18O / 17O : constant value through the disk of the MW17O : secondary, produced in low mass stars
Sulfur : product of explosive O burning in MASSIVE stars
Ratio 32S / 34S ???
Isotopic ratios in the z=0.89 galaxy are :
Different from SS, local ISM, GC
Very different from IRC+10216 !
Closer to SBs
no time for the low and intermediate mass starsto release the processed materials
Nearby SB : because of time scale, outputs from massive stars dominate
Different from LMC (O) (metallicity ?)
Summary
Isotopic ratios = signature of the chemical evolution and nuclear processing (???)
Molecular absorption measurements
Galaxy at z = 0.89 : look back time of 6.4 Gyr
But only one beam pencil
STATISTICS and chemical evolution : MORE SOURCES !!!
Need to observe more absorption systems at different z !
ALMA
Conclusion
Backgroundsource
AbsorptionAnd even 2 lensed images !
PKS 1830Solar
SystemLocal ISM
IRC+1021
6
Nuclei of nearby SBNGC 4945
LMC
12C / 13C 32 10 89 40 - 70
45 50 62
14N / 15N 140 -50+130
270 240 > 4400
100 114
16O / 18O 67 24 490 600 1300 200 > 2000
18O / 17O 13 3 5.5 3.5 0.7 6 2
32S / 34S 10 1 20 19 22 13.5 18
Chin 1999Wang et al 2004
Lucas &Liszt 1998
Cernicharoet al2000
