We report the discovery of an infrared transient in NIRCam images of the SMACS-0723 field taken by the James Webb Space Telescope on MJD 60441.82 (GO-4043, PI Callum Witten). We detect a new source at RA=110.834160, Dec=-73.451752 in 3 filters after subtracting JWST images from 2022-06-07, confirming that this is a transient source. The source is detected in the F090W, F115W and F444W filters, and preliminary photometry yields AB magnitudes of 22.60, 22.70 and 25.21 respectively, implying a very blue colour. If the transient is associated with the nearby (13") brightest cluster galaxy at z=0.39, the absolute magnitudes would be -19.02, -18.91 and -16.41 respectively, consistent with a Type Ia supernova around peak at this redshift. The transient location is coincident with a bright diffraction spike in the pre-transient imaging, so we lack further information on the host. Follow-up observations are encouraged.
| Catalog | Name | Reported RA | Reported DEC | Reported Obj-Type | Reported Redshift | Host Name | Host Redshift | Remarks | TNS RA | TNS DEC | TNS Obj-Type | TNS Redshift |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TNS | 2024jfz | 07:23:20.198 | -73:27:06.31 | 07:23:20.198 | -73:27:06.31 |
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