| 1. |
- Güsten, R., et al.
(författare)
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APEX - The Atacama Pathfinder Experiment
- 2006
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 6267 I
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Konferensbidrag (refereegranskat)abstract
- APEX, the Atacama Pathfinder Experiment, has been successfully commissioned and is in operation now. This novel submillimeter telescope is located at 5107 m altitude on Llano de Chajnantor in the Chilean High Andes, on what is considered one of the world's outstanding sites for submillimeter astronomy. The primary reflector with 12 m diameter has been carefully adjusted by means of holography. Its surface smoothness of 17-18 μm makes APEX suitable for observations up to 200 μm, through all atmospheric submm windows accessible from the ground.
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| 2. |
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| 3. |
- Wild, W., et al.
(författare)
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Millimetron—a large Russian-European submillimeter space observatory
- 2009
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:1, s. 221-244
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Tidskriftsartikel (refereegranskat)abstract
- Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution.
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| 4. |
- Schöier, Fredrik, 1969, et al.
(författare)
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An atomic and molecular database for analysis of submillimetre line observations
- 2005
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 432, s. 369-379
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Tidskriftsartikel (refereegranskat)abstract
- Atomic and molecular data for the transitions of a number of astrophysically interesting species are summarized, including energy levels, statistical weights, Einstein A-coefficients and collisional rate coefficients. Available collisional data from quantum chemical calculations and experiments are extrapolated to higher energies (up to $E/k \sim 1000$ K). These data, which are made publically available through the WWW at http://www.strw.leidenuniv.nl/~moldata, are essential input for non-LTE line radiative transfer programs. An online version of a computer program for performing statistical equilibrium calculations is also made available as part of the database. Comparisons of calculated emission lines using different sets of collisional rate coefficients are presented. This database should form an important tool in analyzing observations from current and future (sub)millimetre and infrared telescopes.
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| 5. |
- Pérez-Beaupuits, J.P., et al.
(författare)
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HNC and HCN in Seyfert Galaxies
- 2008
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Ingår i: EAS Publications Series. - : EDP Sciences. - 1633-4760 .- 1638-1963. ; 31, s. 195-196
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Konferensbidrag (refereegranskat)abstract
- What are the physical conditions in the nuclear region of Seyfert galaxies? Can we asses the predominant nuclear source of power starburst or AGN by using high density gas tracers? We have used SEST, JCMT, and IRAM 30 m telescopes to observe the J=1-0, J=3-2, and J=4-3 transition lines of HNC and HCN in the Seyfert 2 galaxies NGC 1068 and NGC 3079. We model the excitatioon conditions of these molecules based on the observed 3–2/1–0 line intensity ratios. In these proceedings we show the line ratios and discuss the excitation conditions modeled. We summarize our results and conclusions as follows: in NGC 1068, the emission of HNC emerges from lower (<10^5 {cm-3}) density gas than HCN (>10^5 {cm-3}). Instead, the emission of HNC and HCN emerges from the same gas in NGC 3079. The observed HCN/HNC line ratios favor a PDR scenario rather than an XDR one. However, the N(HNC)/N(HCN) column density ratios obtained for NGC 3079 can be found only in XDR environments.
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| 6. |
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| 7. |
- 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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| 8. |
- 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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