- Do, Tuan;
- Hees, Aurelien;
- Ghez, Andrea;
- Martinez, Gregory D;
- Chu, Devin S;
- Jia, Siyao;
- Sakai, Shoko;
- Lu, Jessica R;
- Gautam, Abhimat K;
- O'Neil, Kelly Kosmo;
- Becklin, Eric E;
- Morris, Mark R;
- Matthews, Keith;
- Nishiyama, Shogo;
- Campbell, Randy;
- Chappell, Samantha;
- Chen, Zhuo;
- Ciurlo, Anna;
- Dehghanfar, Arezu;
- Gallego-Cano, Eulalia;
- Kerzendorf, Wolfgang E;
- Lyke, James E;
- Naoz, Smadar;
- Saida, Hiromi;
- Schödel, Rainer;
- Takahashi, Masaaki;
- Takamori, Yohsuke;
- Witzel, Gunther;
- Wizinowich, Peter
The general theory of relativity predicts that a star passing close to a supermassive black hole should exhibit a relativistic redshift. In this study, we used observations of the Galactic Center star S0-2 to test this prediction. We combined existing spectroscopic and astrometric measurements from 1995-2017, which cover S0-2's 16-year orbit, with measurements from March to September 2018, which cover three events during S0-2's closest approach to the black hole. We detected a combination of special relativistic and gravitational redshift, quantified using the redshift parameter ϒ. Our result, ϒ = 0.88 ± 0.17, is consistent with general relativity (ϒ = 1) and excludes a Newtonian model (ϒ = 0) with a statistical significance of 5σ.