Evaluation Of Accuracy Of SED Fitting Photo-z Based On CSST Analog Catalog

With the continuous advancement of technical conditions,human beings have a wider and wider understanding of galaxies and celestial bodies in the universe,and more and more methods have emerged to help humans explore the physical properties hidden in the information of cosmic celestial bodies obtained from telescopes.In this paper,we mainly use the method of photometric redshift spectral fitting to explore the CSST simulation data based on the COSMOS sky survey,and analyze the obtained results to evaluate the accuracy of photometric redshift.First,we give a brief introduction to the catalog data used,and give a detailed introduction to the data processing process and data distribution,as well as the main research methods of this article;Secondly,we explored the photometric redshift accuracy of SED fitting using the same software and different spectral templates,as well as using the same template and different photometric software,and carried out a comprehensive analysis.When fitting the photometric redshift,the accuracy of the photometric redshift obtained by using the HYPERZ photometric software and using the EAZY template(seven emission line templates and a dusty starburst galaxy template)is the best;Next,we found in Outlier's test that~2 sometimes leads to wrong estimation due to the high spectral similarity between different templates and some redshift regions of the template itself,thus causing misjudgment of redshift;In exploring the influence of photometric error on photometric redshift accuracy,we found that the i-band photometric error has the greatest impact,followed by the NUV-band;Then,we found that the photometric redshift accuracy is affected by the flux of galaxies in the NUV-band(especially in the"redshift desert"range),and when the flux of galaxies in this range is absent,the photometric redshift accuracy will change significantly;Finally,we found that by adding constraints—prior probability(especially the r-band prior)and performing SED fitting,the photometric redshift accuracy will be significantly improved.