The density, the cosmic microwave background, and the proton-to-electron mass ratio in a cloud at redshift 0.9
文献类型：期刊论文
| 作者 | Henkel, C.1; Menten, K. M.1; Murphy, M. T.2; Jethava, N.3; Flambaum, V. V.4; Braatz, J. A.5; Muller, S.6,7; Ott, J.5,8; Mao, R. Q.9 |
| 刊名 | ASTRONOMY & ASTROPHYSICS
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| 出版日期 | 2009-06-01 |
| 卷号 | 500期号:2页码:725-734 |
| ISSN号 | 0004-6361 |
| 关键词 | galaxies: abundances galaxies: ISM galaxies: individual: PKS 1830-211 gravitational lensing radio lines: galaxies elementary particles |
| 英文摘要 | Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the gravitational lens system PKS 1830-211, which is by far the best known target to study dense cool gas in absorption at intermediate redshift. Determining average radial velocities and performing Large Velocity Gradient radiative transfer calculations, the aims of this study are (1) to determine the density of the gas, (2) to constrain the temperature of the cosmic microwave background (CMB), and (3) to evaluate the proton-to-electron mass ratio at redshift z similar to 0.89. Analyzing data from six rotational HC(3)N transitions (this includes the J = 7 <- 6 line, which is likely detected for the first time in the interstellar medium) we obtain n(H(2)) similar to 2600 cm(-3) for the gas density of the south-western absorption component, assuming a background source covering factor, which is independent of frequency. With a possibly more realistic frequency dependence proportional to nu(0.5) (the maximal exponent permitted by observational boundary conditions), n(H(2)) similar to 1700 cm(-3). Again toward the south-western source, excitation temperatures of molecular species with optically thin lines and higher rotational constants are, on average, consistent with the expected temperature of the cosmic microwave background, T(CMB) = 5.14 K. However, individually, there is a surprisingly large scatter which far surpasses expected uncertainties. A comparison of CS J = 1 <- 0 and 4 <- 3 optical depths toward the weaker north-western absorption component results in T(ex) = 11 K and a 1-sigma error of 3 K. For the main component, a comparison of velocities determined from ten optically thin NH(3) inversion lines with those from five optically thin rotational transitions of HC(3)N, observed at similar frequencies, constrains potential variations of the proton-to-electron mass ratio mu to Delta mu/mu < 1.4 x 10(-6) with 3-sigma confidence. Also including optically thin rotational lines from other molecular species, it is emphasized that systematic errors are Delta V < 1 km s(-1), corresponding to Delta mu/mu < 1.0 x 10(-6). |
| 学科主题 | Astronomy & Astrophysics |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 类目[WOS] | Astronomy & Astrophysics |
| 研究领域[WOS] | Astronomy & Astrophysics |
| 关键词[WOS] | FINE-STRUCTURE CONSTANT ; GRAVITATIONAL LENS B0218+357 ; EINSTEIN RING PKS-1830-211 ; RADIO-SOURCE PKS1830-211 ; PROBE WMAP OBSERVATIONS ; MOLECULAR ABSORPTION ; PKS 1830-211 ; RADIATION TEMPERATURE ; FUNDAMENTAL CONSTANTS ; PHYSICAL CONSTANTS |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000267363100020 |
| 公开日期 | 2011-12-08 |
| 源URL | [http://159.226.72.40/handle/332002/1441]  |
| 专题 | 紫金山天文台_分子云与恒星形成研究团组 |
| 作者单位 | 1.Max Planck Inst Radioastron, D-53121 Bonn, Germany 2.Swinburne Univ Technol, Ctr Astrophys & Supercomp, Hawthorn, Vic 3122, Australia 3.Natl Inst Stand & Technol, Boulder, CO 80305 USA 4.Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia 5.Natl Radio Astron Observ, Charlottesville, VA 22903 USA 6.Acad Sinica, Inst Astron & Astrophys, Taipei 106, Taiwan 7.Onsala Space Observ, S-43992 Onsala, Sweden 8.CALTECH, Pasadena, CA 91125 USA 9.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China |
| 推荐引用方式 GB/T 7714 | Henkel, C.,Menten, K. M.,Murphy, M. T.,et al. The density, the cosmic microwave background, and the proton-to-electron mass ratio in a cloud at redshift 0.9[J]. ASTRONOMY & ASTROPHYSICS,2009,500(2):725-734. |
| APA | Henkel, C..,Menten, K. M..,Murphy, M. T..,Jethava, N..,Flambaum, V. V..,...&Mao, R. Q..(2009).The density, the cosmic microwave background, and the proton-to-electron mass ratio in a cloud at redshift 0.9.ASTRONOMY & ASTROPHYSICS,500(2),725-734. |
| MLA | Henkel, C.,et al."The density, the cosmic microwave background, and the proton-to-electron mass ratio in a cloud at redshift 0.9".ASTRONOMY & ASTROPHYSICS 500.2(2009):725-734. |
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来源：紫金山天文台
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