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- Loenen, A. F., et al.
(författare)
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Extragalactic Chemistry: HCN, HNC, and HCO+ : M. , W. A. Baan, and R.
- 2008
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Ingår i: EAS Publications Series. - : EAS, EDP Sciences. - 1633-4760 .- 1638-1963. ; 31, s. 183-185
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Tidskriftsartikel (refereegranskat)abstract
- High- and low-density tracer molecules have been observed in (Ultra-) Luminous Infrared Galaxies in order to initiate multi-molecule multi-transition studies to evaluate the physical and chemical environment of the nuclear medium and the ongoing nuclear activity. The data, augmented with data available in the literature, are presented in Baan et al. (2007), which also presents a first order analysis. Here, we present the chemical analysis of the J=1–0 transition lines of HCN, HNC, and HCO+.
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- Loenen, A. F., et al.
(författare)
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Mechanical feedback in the molecular ISM of luminous IR galaxies
- 2008
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 488:1, s. L5-L8
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Tidskriftsartikel (refereegranskat)abstract
- Aims. Molecular emission lines originating in the nuclei of luminous infra-red galaxies are used to determine the physical properties of the nuclear ISM in these systems.Methods. A large observational database of molecular emission lines is compared with model predictions that include heating by UV and X-ray radiation, mechanical heating, and the effects of cosmic rays.Results. The observed line ratios and model predictions imply a separation of the observed systems into three groups: XDRs, UV-dominated high-density ( $n \geq 10^5$ cm-3) PDRs, and lower-density ( n = 104.5 cm-3) PDRs that are dominated by mechanical feedback.Conclusions. The division of the two types of PDRs follows naturally from the evolution of the star formation cycle of these sources, which evolves from deeply embedded young stars, resulting in high-density ( $n \geq 10^5$ cm-3) PDRs, to a stage where the gas density has decreased ( n = 104.5 cm-3) and mechanical feedback from supernova shocks dominates the heating budget.
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- Röllig, M., et al.
(författare)
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A photon dominated region code comparison study
- 2007
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 467:No. 1 (May III 2007), s. 187-206
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Tidskriftsartikel (refereegranskat)abstract
- Aims.We present a comparison between independent computer codes, modeling the physics and chemistry of interstellar photon dominated regions (PDRs). Our goal was to understand the mutual differences in the PDR codes and their effects on the physical and chemical structure of the model clouds, and to converge the output of different codes to a common solution.Methods. A number of benchmark models have been created, covering low and high gas densities n = 103,105.5 cm-3 and far ultraviolet intensities $\chi$ = 10, 105 in units of the Draine field (FUV: 6
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- van der Tak, F.F.S., et al.
(författare)
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Detection of extragalactic H3O
- 2008
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Ingår i: Astronomy & Astrophysics. ; 477, s. L5-L8
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Tidskriftsartikel (refereegranskat)
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| 7. |
- van der Tak, F.F.S., et al.
(författare)
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Extragalactic H3O^+: Some Consequences
- 2008
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Ingår i: "Far-Infrared Workshop 2007", EAS Publication Series, eds. C. Kramer, S. Aalto, R. Simon, DOI:10.1051/eas:0831022. ; 31, s. 105-109
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We discuss some implications of our recent detection of extragalactic H{3} O{+}: the location of the gas in M 82, the origin of energetic radiation in M 82, and the possible feedback effects of star formation on the cosmic ray flux in galaxies.
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