The DECam Survey of Intermediate Redshift Transients (DESIRT; PIs: Palmese & Wang) is a time domain program using the Dark Energy Camera (DECam) on the Blanco 4m Telescope at the Cerro Tololo Interamerican Observatory as part of the DECam Alliance for Transients (DECAT). We are sharing full nights with the other DECAT programs, including the Deep Drilling Fields Program (see Graham et al. 2021), and DESIRT takes data every ~4 nights between April and the end of July 2022, for a total of 90 hours.
The DESIRT program is designed to observe regions of the sky that the Dark Energy Spectroscopic Instrument (DESI; DESI Collaboration 2016, arXiv:1611.00036) is going to cover around the same time. We have therefore chosen to start the semester with observations of three equatorial regions: one centered on GAMA 15, a second around RA, dec = 224d, +7d , and a third at RA, dec = 193d, +6d (all J2000), for a total of 24 DECam pointings. Using the nominal DECAT cadence during dark and grey time, we cover these regions in grz bands with exposure times of 50, 70, and 110 seconds respectively, plus a second pass in g band with the same exposure time as the first pass. In bright time, we switch to riz exposures. These exposures reach an r-band depth of ~23.2-23.8 (5 sigma).
We promptly process our data on GPUs using the pipeline of Hu, Wang & Chen (2021), and announce new transient discoveries to the TNS using a bot. Public alerts are also being sent to a Kafka broker (public.alerts.ztf.uw.edu:9092 with topic decat_<yyyymmdd>_2022A-388025) following https://decat-webap.lbl.gov/ (Knop et al.)
We welcome all members of the astronomical community to use these data for their own analyses and follow-up observations. Our DECam program has no proprietary period, and we also encourage the community to download our images from the NSF NOIRLab archive under Proposal ID 2022A-388025. Note that no DESI data will be released at this time, but we plan to release interesting DESI observations of transients along with publications at a later time.