XAO OpenIR  > 研究生学位论文
Alternative TitleThe H2O Maser Survey towards BGPS Sources
Thesis Advisor周建军
Degree Grantor中国科学院大学
Place of Conferral中国科学院新疆天文台
Degree Discipline理学
Keyword脉泽 分子谱线 恒星形成
Abstract恒星形成过程中,会伴随着吸积、喷流及外向流等恒星形成活动。这些活动会激发脉泽。其中水脉泽是最常见的一种脉泽。普遍认为水脉泽为碰撞激发,并且高分辨的研究发现水脉泽与恒星形成时所产生的外向流成协。对水脉泽的各种属性的研究对认识和了解恒星,特别是大质量恒星的形成过程有着重要的作用。 BGPS源是1.1mm连续谱巡天的点源表。经过前人的研究发现,BGPS源中包含了大质量恒星形成的各个演化阶段样本。这也为我们提供了一个搜寻水脉泽的很好的样本。我们从BGPS v1.0列表中选取了两批BGPS源,并利用新疆天文台南山25米射电望远镜其进行了水脉泽的搜寻工作。1)1.1mm流量大于5 Jy,共选出221个源,探测到107个水脉泽。2)银经大于85度,共选出274个源,探测到24个水脉泽。 在对数据处理的过程中,我们发现强脉泽的影响范围要远大于射电望远镜的HPBW。对于南山射电望远镜,我们拟合出了影响半径与脉泽强度之间的关系。在影响半径内,脉泽可通过射电望远镜的旁瓣被观测到。这非常有益于我们排除单点观测中的假的脉泽信号。也对我们以后观测中源的选取及数据处理有非常大的帮助。 对这两批源进行分析、研究后发现:水脉泽的探测率与60, 100, 450, 850和1100 μm长波段的流量表现出较好的相关性。但与12, 24 μm短波段流量相关性较差。随着激发源的演化,水脉泽的峰值流量、积分流量、光度均表现出增加的趋势。并且水脉泽的速度分布也会变得更宽。相对于只与水脉泽成协或只与甲醇脉泽成协的源相比,同时与水脉泽和甲醇脉泽成协的源处在相对较晚的演化阶段。
Other AbstractThe activities of star formation, such as accretion, jet, and outflow, are companied with star forming process. These activities could excite masers. The most common maser is H2O maser. It is generally accepted that H2O masers are pumped by collision. High resolution observations show that H2O masers are associated with outflow in star formation region. Researching the properties of H2O masers is very important for investigating the mechanism of star formation, especially massive star formation. BGPS sources are the 1.1mm emission point sources catalogue. Previous works show that BGPS sources comprise whole sample of massive star formation region in different evolutionary stage. This provides us a good sample for searching H2O masers. We performed observations by Nanshan 25m radio telescope of Xinjiang Astronomical Observatory. Our sample consists of two portions of BGPS sources from v1.0 BGPS catalogue. 1) BGPS sources with flux density exceeding 5 Jy. As a result, we selected 221 BGPS sources. We detected 107 H2O masers. 2) BGPS sources with longitude greater than 85°. We selected 274 BGPS sources. We detected 24 H2O masers. When we process the data of observation, we find that the influential radius of intensive maser is much large than HPBW of radio telescope. We give the relation between influential radius and intensity of maser. The maser could be detected through side lobes in the influential radius. This relation is very helpful to eliminate the fake detection in the observation mode of single point. This is also useful for the source selection and the procedure of processing the data in future observation. We find that the detection rate of H2O masers has close relation with long wavelength (60, 100, 450, 850, 1100 μm), but less correlation is shown with short wavelength (12,24μm). As the exciting sources evolve, the peak flux density, integral flux density, and luminosity of H2O masers show increment. The velocity range of H2O masers becomes wider as well. The sources associated with both H2O and CH3OH masers are more evolved than those sources associated with only H2O maser or only with CH3OH masers.
Subject Area天体物理
Document Type学位论文
Recommended Citation
GB/T 7714
席宏伟. BGPS源的水脉泽搜寻[D]. 中国科学院新疆天文台. 中国科学院大学,2015.
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