Simultaneous multiwavelength observations of sagittarius A | |
An, T![]() | |
刊名 | ASTROPHYSICAL JOURNAL
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2005-11-20 | |
卷号 | 634期号:1页码:L49-L52 |
关键词 | accretion black hole physics Galaxy : center radio continuum : galaxies accretion disks |
通讯作者 | The Astrophysical Journal |
英文摘要 | We observed Sgr A* using the Very Large Array (VLA) and the Giant Metrewave Radio Telescope (GMRT) at multiple centimeter and millimeter wavelengths on 2003 June 17. The measured flux densities of Sgr A*, together with those obtained from the Submillimeter Array (SMA) and the Keck II 10 m telescope on the same date, are used to construct a simultaneous spectrum of Sgr A* from 90 cm to 3.8 mu m. The simultaneous spectrum shows a spectral break at about 3.6 cm, a possible signature of synchrotron self-absorption of the strong radio outburst that occurred near epoch 2003 July 17. At 90 cm, the flux density of Sgr A* is 0.22 +/- 0.06 Jy, suggesting a sharp decrease in flux density at wavelengths longer than 47 cm. The spectrum at long cm wavelengths appears to be consistent with free-free absorption by a screen of ionized gas with a cutoff similar to 100 cm. This cutoff wavelength appears to be three times longer than that of similar to 30 cm suggested by Davies, Walsh, & Booth based on observations in 1974 and 1975. Our analysis suggests that the flux densities of Sgr A* at wavelengths longer than 30 cm could be attenuated and modulated by stellar winds from massive stars close to Sgr A*. |
学科主题 | 射电天文学 |
WOS标题词 | Science & Technology ; Physical Sciences |
类目[WOS] | Astronomy & Astrophysics |
研究领域[WOS] | Astronomy & Astrophysics |
关键词[WOS] | SUPERMASSIVE BLACK-HOLE ; GALACTIC-CENTER ; SUBMILLIMETER ARRAY ; 1 MILLIMETER ; MILKY-WAY ; ASTERISK ; RADIO ; SPECTRUM ; VARIABILITY ; CENTIMETER |
收录类别 | SCI |
语种 | 英语 |
WOS记录号 | WOS:000233348100013 |
公开日期 | 2010-04-29 |
内容类型 | 期刊论文 |
源URL | [http://119.78.226.72//handle/331011/8021] ![]() |
专题 | 上海天文台_VLBI研究室 |
作者单位 | 1.Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China 2.Natl Radio Astron Observ, Socorro, NM 87801 USA 3.Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA 4.Natl Ctr Radio Astrophys, TIFR, Pune 411007, Maharashtra, India |
推荐引用方式 GB/T 7714 | An, T,Goss, WM,Zhao, JH,et al. Simultaneous multiwavelength observations of sagittarius A[J]. ASTROPHYSICAL JOURNAL,2005,634(1):L49-L52. |
APA | An, T.,Goss, WM.,Zhao, JH.,Hong, XY.,Roy, S.,...&Shen, ZQ.(2005).Simultaneous multiwavelength observations of sagittarius A.ASTROPHYSICAL JOURNAL,634(1),L49-L52. |
MLA | An, T,et al."Simultaneous multiwavelength observations of sagittarius A".ASTROPHYSICAL JOURNAL 634.1(2005):L49-L52. |
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