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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. Sébastien Muller (ASIAA, Taiwan) M. Guélin (IRAM) M. Dumke (ESO) R. Lucas (IRAM). IAU Colloquium 199 Probing galaxies through quasar absorption lines, ShangHai, China, 2005 March 14-19.

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Sébastien Muller (ASIAA, Taiwan) M. Guélin (IRAM) M. Dumke (ESO) R. Lucas (IRAM)

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  1. Probing isotopic ratios at z=0.89 Molecular line absorptions in front of the quasar PKS 1830-211 Sébastien Muller (ASIAA, Taiwan) M. Guélin (IRAM) M. Dumke (ESO) R. Lucas (IRAM) IAU Colloquium 199 Probing galaxies through quasar absorption lines, ShangHai, China, 2005 March 14-19

  2. Absorption systems • Lyman  forest •  gas filaments in extragalactic medium • 1012 - 1019 cm-2 • Damped Lyman  & HI 21 cm absorption •  outer parts of spiral galaxies • 1019 - 1021 cm-2 • Molecular absorption •  central parts of galaxies • 1020 - 1024 cm-2

  3. 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

  4. Molecular absorption systems in the mm

  5. PKS 1830-211 Intervening galaxy : z=0.89 Typical spiral Photometry from HST (Winn et al 2002) I = 22 V > 24.7 SW position I > 24.9 V > 26.3 1st case of QSR lensed by a face-on spiral Mass within 3 kpc: (Wiklind & Combes 1998) 6 – 9 1010 M MERLIN 6cm HST WFPC2 I band image NE 1’’ SW 2–4 kpc Patnaik et al 1994

  6. Plateau de Bure Interferometer observations 12C/13C 14N/15N 16O/18O 18O/17O 32S/34S • Observations :  Summer time between 1999 – 2002 • Compact configuration • Self calibration

  7. Main isotopomers  2 components NE and SW SW : complete absorption for HCO+ non symetric profiles  = sum of velocity components with widths similar to MW clouds (~10 km/s)

  8. Iabs = IO (1-exp-)

  9. 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 ???

  10. 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

  11. 14N : secondary, enhanced in CNO cycle at equilibrium 15N : secondary, destroyed in CNO, produced in explosive H or He burning 14N / 15N : increases with metallicity (gradient in the MW)

  12. 16O : primary, produced in massive stars 18O : secondary, produced in He burning from 14N

  13. 18O / 17O : constant value through the disk of the MW 17O : secondary, produced in low mass stars

  14. Sulfur : product of explosive O burning in MASSIVE stars Ratio 32S / 34S ???

  15. Summary 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 stars to release the processed materials Nearby SB : because of time scale, outputs from massive stars dominate  Different from LMC (O) (metallicity ?)

  16. Conclusion 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

  17. Backgroundsource Absorption And even 2 lensed images !

  18. Lucas & Liszt 1998 Cernicharo et al 2000 Wang et al 2004 Chin 1999

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