It is with great sadness that the journal learned of the passing of our colleague, Associate Editor, Dr. Yu Gao.

Yu’s brilliant career was cut short by his untimely death. After completing his undergraduate studies in China, Yu obtained his PhD at the State University of New York at Stony Brook in 1996. After a number of distinguished postdoctoral fellowships in the USA and Canada, he returned in 2004 to China where he rose to Chief Scientist at the Purple Mountain Observatory (Chinese Academy of Sciences) and most recently Full Professor, Department of Astronomy, Xiamen University. He has over 200 papers to his name with more than 4800 citations. He is perhaps best known for his seminal paper with Phil Solomon, using HCN to trace dense star-forming gas in galaxies (Gao and Solomon, 2004).

Yu joined the journal as Associate Editor in 2008 and served it with great distinction. He contributed to 52 volumes of the journal, or 185 issues. He was utterly professional and dependable in his editorial role.

Although numbers capture some of Yu’s scientific impact, arguably his greatest impact was on his graduate students and postdocs, and through his vast international network of collaborators.

Yu leaves a big gap and will be greatly missed by all.

Editor-in-Chief