IceCube-210510A: DDOTI Upper Limits

We observed the field of the IceCube bronze event IceCube-210510A (IceCube Collaboration, GCN Circ. 29976) with the DDOTI wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) from 2021-05-10 05:44 to 11:33 UTC (0.9 to 6.7 hours after the trigger) and obtained 4.5 hours of exposure in the w filter. We observed a region covering aproximately 7 degrees in RA and 10 degrees in declination including the entire initial uncertainty region distributed in the GCN Notice and almost the entire updated 90% region (IceCube Collaboration, GCN Circ. 29976) except the small part west of RA = 269.80 degrees. We calibrated our images against the APASS catalog. Comparing to the Pan-STARRS DR1 catalog, we detect no uncataloged point sources to a 10-sigma limiting magnitude of w = 21.44. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.