Galaxy destruction and diffuse light in clusters

Deep images of the Centaurus and Coma clusters reveal two spectacular arcs of diffuse light that stretch for over 100 kpc, yet are just a few kpc wide. At a surface brightness of m_b \sim 27-28th arcsec^-2, the Centaurus arc is the most striking example known of structure in the diffuse light component of a rich galaxy cluster. We use numerical simulations to show that the Centaurus feature can be reproduced by the tidal debris of a spiral galaxy that has been tidally disrupted by the gravitational potential of NGC 4709. The surface brightness and narrow dimensions of the diffuse light suggest that the disk was co-rotating with its orbital path past pericentre. Features this prominent in clusters will be relatively rare, although at fainter surface brightness levels the diffuse light will reveal a wealth of structure. Deeper imaging surveys may be able to trace this feature for several times its presently observed extent and somewhere along the tidal debris, a fraction of the original stellar component of the disk will remain bound, but transformed into a faint spheroidal galaxy. It should be possible to confirm the galactic origin of the Centaurus arc by observing planetary nebulae along its length with redshifts close to that of NGC 4709.Comment: Replaced with version accepted by MNRAS (Dec. 1999): Added missing reference (to pg. 4 & reference list). Section 3 shortened; removed three figures. Now 8 pages long, with 8 figures. Low resolution images included, high resolution version available at http://star-www.dur.ac.uk:80/~calcaneo/cenarc.htm

3-烷基，3-二氢-1H-异吲哚-1-酮的不对称合成

3-烷基-2，3-二氢-1H-异吲哚-1-酮(I)类化合物存在于许多天然有机物和生理活性物质的核心结构中,具有广阔的医学和生化应用前景。此外,这类化合物还可作为不对称合成的手性辅助剂,还原后可作为手性配体,在不对称合成中具有潜在的应用前景。本论文的目的是在本实验室以往研究工作的基础上，开发手性异吲哚酮合成子的合成路线，建立一种灵活多用的合成方法，以期为不对称合成提供新型手性辅助剂,用于不对称合成反应。首先，从邻苯二甲酸酐(II)和（R）-（-）-苯基甘氨醇(III)出发,合成了N–取代邻苯二甲酰亚胺(V)。把V的羟基用苄基保护后的产物VI进行还原烷基化反应,即格氏试剂加成—三氟化硼合乙醚催化下...The 3-substituted-2,3-dihydro-1H-isoindol-1-ones (I) are found as core units in many natural and/or bioactive compounds, they have broad prospect in fields of medicine and biochemistry. After amide carbonyl reduction, they can serve as a group of promising chiral auxiliaries in asymmetric synthesis. Our laboratory has developed a general method for the asymmetric synthesis of pyrrolidines, 2-pyrro...学位：理学硕士院系专业：化学化工学院化学系_有机化学学号：19972501