Measurement of isotopic ratiosat z=0.89 through molecular 

absorption lines

Sébastien Muller Onsala Space Observatory, Sweden

Observational Constraints on Nucleosynthesis SourcesGarching, 2013 March 25

- Chemical inventory and gas properties in distant galaxies

- No distance dilution

- Spatial resolution (continuum illumination ~ few mas)

Interests of molecular absorption studies at z>0

As cosmological probes

- CMB temperature as a function of redshift

- Test of variations of fundamental constants (, μ=mp/m

e)

- Chemical enrichment of the Universe (isotopic ratios)

  

Source z(abs)Background continuum 

flux(Jy @3mm)

N(H2)

(cm­2)

Molecules detected

Cen A 0.002 6 2 x 1020  CO, OH, NH3, CN, HCO+, HCN, N2H+, CS, H2CO, C3H2

3C293 0.045 2 x 1019 CO, HCO+, HCN

4C31.04 0.060 1 x 1019 CO, HCO+, HCN

PKS 1413+135 0.247 0.5 5 x 1020 CO, CN, HCO+, HCN, HNC

B 1504+377 0.673 0.4 5 x 1020 CO, HCO+, HCN, HNC

B 0218+357 0.685 0.5lensed

4 x 1021 CO, NH3, H20, HCO+, HCN, HNC, CS, H2S, H2CO

PKS 0132­097 0.765 0.4 OH (only)

PKS 1830­211 0.886 2­3lensed

2 x 1022 > 40 ! species (not incl. isotopic variants)

Extragalactic radio­mm molecular absorbers

e.g. see review by Combes 2008

PKS1830-211 is the most notableradio molecular absorber at z>0

Of the only 5 distant radio molecular absorbers known to date(0.24 < z < 0.89)

PKS1830-211 has:

- highest redshift: z=0.89

- brightest mm continuum

- largest amount of absorbing material

- gravitational lens

- molecular absorption toward the SW and NEimages of the quasar

- time variations (continuum & molecular profile)

PKS1830-211

Foreground z=0.19 galaxy

Lensed images of the quasar

z=0.89 absorber

HST, Courbin et al

ALMA Early Science (Cycle 0) data

Muller et al in prep

H2O

1 atom 2 atoms 3 atoms 4 atoms 5 atoms 6 atoms 7 atoms

H CH NH2

NH3

CH2NH CH

3OH CH

3NH

2

C OH H2O H

2CO c-C

3H

2CH

3CN CH

3CCH

CO C2H l-C

3H l-C

3H

2NH

2CHO CH

3CHO

CS HCN HNCO H2CCN

SiO HNC HOCO+ H2CCO

NS N2H+ H

2CS C

4H

SO HCO+ HC3N

SO+ HCO

HOC+

H2S

H2Cl+

HCS+

C2S

Chemical inventory toward the SW LOS

42 species+ 14 isotopic variants

See Muller et al 2011, 2013 + in prep

@ z=0.89 !

Carbon

Difficult to measure 12C/13C

Chemical fractionation-> Need measure ratios of many molecules

Saturation and opacity effectsHCO+HCNHNCCO

12C/13C ~ 50 @z=0.89

CH detected with ALMA13CH in future observations ?

Nitrogen

14N/15N also difficult to measure (bcs large)

Saturation and opacity effectsHCNHNC

But easy to measure the double ratio 14N/15N / 12C/13C ~ 5 (+-1) H13CN / HC15NHN13C / H15NC

NH3 and 15NH

3 with ALMA ?

Oxygen

16O/18O also difficult to measure

HCO+

But easy to measure the double ratio 16O/18O / 12C/13C = 2 (+- ~0.1)H13CO+ HC18O+

18O/17O measurement “free” of opacity effectsHC18O+ / HC17O+

18O/17O = 13 (+-3) @z=0.89

ALMAH

2O heavily saturated

H2

17O detected

Future observations of H2

18O / H2

17O ?

Sulfur

PdBI (Muller et al 2006)

C32S / C34S H

232S / H

234S 

­> 32S/34S = 10.5 +­ 0.6   @z=0.89

32S/34S = 22 Earth = 19 +-8 Local ISM (Lucas & Liszt 1998)

Silicon

ATCA, Muller et al 2011, 2013, and in prep

ATCA 2009 ­> 28Si/29Si = 11 ­2+4ATCA 2011 ­>  28Si/29Si = 6.5 +­ 0.5 @ z=0.89

­>  29Si/30Si = 1.8 +­ 0.3

Earth and local ISM: 28Si/29Si = 2229Si/30Si = 1.5

Slide from Peter Hoppe

Comparison to silicon carbide grainsfrom the Murchinson meteorite

*

Chlorine

­>  35Cl/37Cl ~ 3   @z=0.89

Detection of chloronium H2

35Cl+ and H2

37Cl+ at z=0.89ALMA Early Science Cycle 0 – Muller et al in prep

35Cl/37Cl  =  3.1  Earth = 3.1 +- 0.6 IRC+10216 (Cernicharo et al 2000)

= 1 – 5 in various Galactic sources (Cernicharo et al 2010, Peng et al 2010)

Isotopic ratios

Ratio @z=0.89 Note Earth 

D/H < 7e­4 Upper limit Cosmic 2.5e­5

12C/13C ~50 ? Difficult to measure due to opacity / fractionation effects 89

14N/15N ~200 ~<  (Uncertainty from 12C/13C) 272

16O/18O ~100 <<     (Uncertainty from 12C/13C) 499

18O/17O 13  ± 3 >> 5.5

28Si/29Si 7 ± 0.5(preliminary)

<< 22

29Si/30Si 1.8 ± 0.3(preliminary)

~ 1.5

32S/34S 10.5 ± 0.5 << 22.5

35Cl/37Cl ~3(preliminary)

~ 3.1

  

Molecular absorption at high-redshift = powerful technique

-> Basic gas properties and interstellar chemistry in high-z galaxies

-> Measurements of isotopic ratios

-> Constraints on nucleosynthesis models ?

z=0.89 <-> ~ lookback time of ~half the age of the Universe

Stars with M <~ 1.5 Mo have no time to contribute

Some similarities with isotopic ratios measured in starburst galaxiesWhere enrichment is dominated by massive stars on short time scales

Summary