A Common Gas‐Phase Chemistry for Diffuse, Translucent, and Dense Clouds?

Turner, B. E.

doi:10.1086/317026

Cited by 48 publications

(36 citation statements)

References 45 publications

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“…Its abundance is low in cold dark clouds (of the order of or less than 10 −12 relative to H 2 ), where it is presumably heavily depleted onto dust grains, but can reach values several orders of magnitude higher in outflows and shocked gas. It is found to have an intermediate abundance (SiO/H 2 ∼ 10 −10 ) in diffuse and translucent clouds (Lucas & Liszt 2000a;Turner 2000). Toward FG0.89SW, we find a SiO abundance of nearly 4 × 10 −10 that is comparable to, though slightly higher than, that in diffuse/translucent clouds.…”

Section: B17 Siomentioning

confidence: 45%

“…We note that CH 3 CN is also observed in dark clouds (Matthews & Sears 1983) and has been detected in NGC253 (Mauersberger et al 1991). On the other hand, CH 3 CN is detected in neither diffuse (Liszt & Lucas 2001) nor translucent clouds (Turner 2000), with upper limits clearly lower than abundances in dark clouds.…”

Section: B14 Ch 3 Cnmentioning

confidence: 85%

“…It is present in translucent clouds with a quite high abundance of a few 10 −8 relative to H 2 (Turner 2000). No extragalactic detection has been reported so far.…”

Section: B23 C 4 Hmentioning

confidence: 99%

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Molecules atz= 0.89

Müller

Beelen

Guèlin

et al. 2011

A&A

163

284

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We present the results of a 7 mm spectral survey of molecular absorption lines originating in the disk of a z = 0.89 spiral galaxy located in front of the quasar PKS 1830−211. Our survey was performed with the Australia Telescope Compact Array and covers the frequency interval 30-50 GHz, corresponding to the rest-frame frequency interval 57-94 GHz. A total of 28 different species, plus 8 isotopic variants, were detected toward the south-west absorption region, located about 2 kpc from the center of the z = 0.89 galaxy, which therefore has the largest number of detected molecular species of any extragalactic object so far. The results of our rotation diagram analysis show that the rotation temperatures are close to the cosmic microwave background temperature of 5.14 K that we expect to measure at z = 0.89, whereas the kinetic temperature is one order of magnitude higher, indicating that the gas is subthermally excited. The molecular fractional abundances are found to be in-between those in typical Galactic diffuse and translucent clouds, and clearly deviate from those observed in the dark cloud TMC 1 or in the Galactic center giant molecular cloud Sgr B2. The isotopic ratios of carbon, nitrogen, oxygen, and silicon deviate significantly from the solar values, which can be linked to the young age of the z = 0.89 galaxy and a release of nucleosynthesis products dominated by massive stars. Toward the north-east absorption region, where the extinction and column density of gas is roughly one order of magnitude lower than toward the SW absorption region, only a handful of molecules are detected. Their relative abundances are comparable to those in Galactic diffuse clouds. We also report the discovery of several new absorption components, with velocities spanning between −300 and +170 km s −1 . Finally, the line centroids of several species (e.g., CH 3 OH, NH 3 ) are found to be significantly offset from the average velocity. If caused by a variation in the proton-to-electron mass ratio μ with redshift, these offsets yield an upper limit | Δμ μ | < 4×10 −6 , which takes into account the kinematical noise produced by the velocity dispersion measured from a large number of molecular species.

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Section: B17 Siomentioning

confidence: 45%

Section: B14 Ch 3 Cnmentioning

confidence: 85%

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Molecules atz= 0.89

Müller

Beelen

Guèlin

et al. 2011

A&A

163

284

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“…For the derived physical parameters, we also calculated the intensities of the HCO + (1-0) line assuming the molecular abundance of HCO + /H 2 = 2 × 10 −9 (Turner 2000). These predicted line intensities are of the order of 10 −5 K, so far below our detection limits.…”

Section: The Models and Resultsmentioning

confidence: 99%

A molecular cloud within the light echo of V838 Monocerotis

Kamiński

Tylenda

Deguchi

2011

A&A

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Context. V838 Mon is an eruptive variable, which exploded in 2002. It displayed the most spectacular light echo ever observed. However, neither the origin of the reflecting matter nor the nature of the 2002 outburst have been firmly constrained. Aims. We investigate the nature of the CO radio emission detected in the field of the light echo. In particular, we explore its connection to the echoing dust around V838 Mon. Methods. We observed the echo region in multiple CO rotational transitions. We present and analyse maps of the region obtained in the 12 CO(1-0) and (3-2) lines. In addition, deep spectra at several positions were acquired in 12 CO(1-0), (2-1), (3-2), and 13 CO(1-0), (2-1). Radiative transfer modelling of line intensities is performed for chosen positions to constrain the kinetic temperatures and densities. We derive global parameters (e.g. mass, distance, total column density) of the emitting cloud. Results. We found that a compact molecular cloud is located within the echo region. The molecular emission is physically connected to the dusty environment seen in the optical echo and they both belong to the same translucent cloud. The interstellar nature of the cloud is confirmed by its high mass of 90-150 M . We propose that the cloud consists of material remaining after the formation of the cluster to which V838 Mon belongs. This indicates that the eruptive star has a young age (3-10 Myr).

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“…Such a comparison is shown in Figure 4, where we include the fractional abundances measured in diffuse clouds (Liszt et al (2008) and references therein) in translucent clouds (Turner (2000)), in the dark cloud TMC 1 (Ohishi et al (1992)), in the Galactic Center molecular cloud Sgr B2(N) (Nummelin et al (2000)) in the the N113 region in the Large Magellanic Cloud (Wang et al (2009)) and in the nuclear region of the nearby starburst galaxies NGC253 (Martín et al (2006)) and NGC4945 (Wang et al (2004)). There is a large scatter of up to nearly two orders of magnitude between the abundances in different sources, reflecting the different Gérin et al (1997) a source covering factor of unity for all species, so that the apparent optical depths and column densities are strictly speaking lower limits.…”

Section: The Atca 7 MM Spectral Survey Toward Pks1830-211mentioning

confidence: 99%

Absorption Line Surveys at Intermediate Redshift

Müller

2011

Proc. IAU

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Abstract. The z=0.89 spiral galaxy located on the line of sight to the quasar PKS1830-211 is right now the extragalactic object with the largest number of detected molecular species (34, plus isotopic variants). This remarkable molecular inventory was recently built after an unbiased spectral survey of molecular absorption lines with the Australia Telescope Compact Array in the 7 mm band. We present the results of this survey, as a showcase of the various interests of molecular absorption studies at intermediate redshift: chemical inventory and gas properties in distant galaxies, chemical enrichment history of the Universe, measurements of the CMB temperature as a function of z, and constraints on the constancy of fundamental constants.

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A Common Gas‐Phase Chemistry for Diffuse, Translucent, and Dense Clouds?

Cited by 48 publications

References 45 publications

Molecules atz= 0.89

Molecules atz= 0.89

A molecular cloud within the light echo of V838 Monocerotis

Absorption Line Surveys at Intermediate Redshift

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