Clusters of galaxies have a huge mass which can act as gravitational lenses.Galaxies behind clusters can be distorted by the lenses to form arcs in images.Herein a search was done for giant lensed arcs using the SDSS ...Clusters of galaxies have a huge mass which can act as gravitational lenses.Galaxies behind clusters can be distorted by the lenses to form arcs in images.Herein a search was done for giant lensed arcs using the SDSS data.By visually inspecting SDSS images of newly identified clusters in the SDSS DR8 and Stripe 82 data,we discover 8 strong lensing clusters together with additional 3probable and 6 possible cases.The lensed arcs show bluer colors than the member galaxies of clusters.The masses and optical luminosities of galaxy clusters interior to the arcs are calculated.The mass-to-light ratios are found to be in the range of a few tens of M⊙/L⊙,consistent with the distribution of previously known lensing clusters.展开更多
Brightest Cluster Galaxies （BCGs） are mostly elliptical galaxies and very rarely have prominent star formations. We found that five out of 8,812 BCGs are E＋A （i.e., post-starburst） galaxies, having an Hd absorpti...Brightest Cluster Galaxies （BCGs） are mostly elliptical galaxies and very rarely have prominent star formations. We found that five out of 8,812 BCGs are E＋A （i.e., post-starburst） galaxies, having an Hd absorption line with an equivalent width 〉2.5 A and no distinct emission lines in [O II] and Ha-. The E＋A features we identified from the BCGs for the first time are not as significant as those in general galaxies, indicating that historically the star formations were not very violent.展开更多
The survey data of Wide-field Infrared Survey Explorer(WISE)provide an opportunity for the identification of galaxy clusters.We present an efficient method for detecting galaxy clusters by combining the WISE data with...The survey data of Wide-field Infrared Survey Explorer(WISE)provide an opportunity for the identification of galaxy clusters.We present an efficient method for detecting galaxy clusters by combining the WISE data with SuperCOSMOS and 2MASS data.After performing star-galaxy separation,we calculate the number of companion galaxies around the galaxies with photometric redshifts previously estimated by the SuperCOSMOS,2MASS and WISE data.A scaled richness Rscal 30 is set as a criterion to identify clusters.From a sky area of 275 deg2of the Sloan Digital Sky Survey Stripe 82 region,we identify 302 clusters in the redshift range of 0.1<z<0.35,247(82%)of which are previously known SDSS clusters.The results suggest that our method is efficient for identifying galaxy clusters by using the all sky data of the SuperCOSMOS,2MASS and WISE.展开更多
基金supportedby the National Natural Science Foundation of China(Grant Nos.11103032and 11261140641)the China Ministry of Science and Technology(GrantNo.2013CB837900)the Young Researcher Grant of National Astronomical Observatories,Chinese Academy of Sciences
文摘Clusters of galaxies have a huge mass which can act as gravitational lenses.Galaxies behind clusters can be distorted by the lenses to form arcs in images.Herein a search was done for giant lensed arcs using the SDSS data.By visually inspecting SDSS images of newly identified clusters in the SDSS DR8 and Stripe 82 data,we discover 8 strong lensing clusters together with additional 3probable and 6 possible cases.The lensed arcs show bluer colors than the member galaxies of clusters.The masses and optical luminosities of galaxy clusters interior to the arcs are calculated.The mass-to-light ratios are found to be in the range of a few tens of M⊙/L⊙,consistent with the distribution of previously known lensing clusters.
基金supported by the Liaoning Educational Foundation of China (Grant No.2009A646)the National Natural Science Foundation of China (Grant Nos.10773016,10821061 and 1083303)+1 种基金the National Key Basic Research Science Foundation of China (Grant No.2007CB815403)Funding for the creation and distribution of the SDSS Archive has been provided by the Alfred P.Sloan Foundation
文摘Brightest Cluster Galaxies （BCGs） are mostly elliptical galaxies and very rarely have prominent star formations. We found that five out of 8,812 BCGs are E＋A （i.e., post-starburst） galaxies, having an Hd absorption line with an equivalent width 〉2.5 A and no distinct emission lines in [O II] and Ha-. The E＋A features we identified from the BCGs for the first time are not as significant as those in general galaxies, indicating that historically the star formations were not very violent.
基金supported by the National Natural Science Foundation of China (Grant No.11103032)the Young Researcher Grant of National Astronomical Observatories,Chinese Academy of Sciences+3 种基金This publication makes use of data products from the Wide-field Infrared Survey Explorer,which is a joint project of the University of California,Los Angeles,and the Jet Propulsion Laboratory/California Institute of Technology,funded by the National Aeronautics and Space AdministrationFunding for the SDSS and SDSS-Ⅱ has been provided by the Alfred P.Sloan Foundation,the Participating Institutionsthe National Science Foundationthe U.S.Department of Energy,the National Aeronautics and Space Administration,the Japanese Monbukagakusho,the Max Planck Society,and the Higher Education Funding Council for England
文摘The survey data of Wide-field Infrared Survey Explorer(WISE)provide an opportunity for the identification of galaxy clusters.We present an efficient method for detecting galaxy clusters by combining the WISE data with SuperCOSMOS and 2MASS data.After performing star-galaxy separation,we calculate the number of companion galaxies around the galaxies with photometric redshifts previously estimated by the SuperCOSMOS,2MASS and WISE data.A scaled richness Rscal 30 is set as a criterion to identify clusters.From a sky area of 275 deg2of the Sloan Digital Sky Survey Stripe 82 region,we identify 302 clusters in the redshift range of 0.1<z<0.35,247(82%)of which are previously known SDSS clusters.The results suggest that our method is efficient for identifying galaxy clusters by using the all sky data of the SuperCOSMOS,2MASS and WISE.
