Low-mass galaxies with extremely active star-formation at z<1.5

• Main Authors: Lim, Chen-Fatt, 林征發
• Other Authors: Yasuhiro Hashimoto
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/34565340766801600360

碩士 === 國立臺灣師範大學 === 地球科學系 === 103 === We have recently developed a method based on broad-band photometry to isolate a sample of galaxies with relatively low stellar mass but extremely active star-formation at redshift up to z$\sim$1.5. We extend our method to select those galaxies from several deep photometry archive datasets which are the UKIRT infrared deep sky survey - Ultra Deep Survey (UKIDSS-UDS), Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) and COSMOS-UltraVISTA survey. The spectroscopic data for each of the catalogs give us a good chance to look at the properties of our samples. These galaxies have low stellar mass (M$_{*}$$\sim$10$^{9}$M$_{\bigodot}$) and low metallicity (12+log(O/H)$\sim$8.0); however, they display high star formation rate per stellar mass (SSFR$\sim$10$^{-9}$M$_{\bigodot}$yr$^{-1}$/M$_{\bigodot}$). Interaction-induced infall of gas could be consistent with these galaxies that high specific star formation rates. These galxies may allow to study in great detail processes, such as starburst activity and chemical enrichment, which are common in the early universe. The properties of low metallicity for these galaxies are similar with Blue Compact Dwarfs (BCDs) in the local Universe, luminous metal-poor star forming galaxies at intermediate redshifts at z$\sim$0.8 and Ly$\alpha$ Emitters (LAEs) at high redshifts. We will discuss more details about our photometic selection and the properties of these young galaxies.