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