TITLE:   GCN CIRCULAR
NUMBER:  29941
SUBJECT: RATIR Observations of ZTF21aayokph (AT2021lfa) 
DATE:    21/05/05 04:31:03 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H.
Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska
(UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen
Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos
Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou
(U. Wash.), and Vicki Toy (UMD) report:

We observed  ZTF21aayokph (AT2021lfa) (Yao, Perley, and Ho, GCN Circ. 29938)
with the Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold
Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro
Mártir from 2021/05 5.15 to 2021/05 5.18 UTC, obtaining a total of 0.21 hours
exposure in the g, r, Z, Y, J, and H bands and 0.39 hours exposure in the i
band.

We detect the source reported by Yao, Perley, & Ho (GCN Circ. 29938)  In
comparison with the SDSS DR9 and 2MASS catalogs, we obtain:

  g	= 20.85 +/- 0.07
  r	= 20.48 +/- 0.06
  i	= 20.06 +/- 0.03
  Z	= 19.97 +/- 0.07
  Y	= 20.28 +/- 0.16
  J	= 20.16 +/- 0.20
  H	= 18.39 +/- 0.31

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the source.

Observations are continuing.

We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.