DRAFT
2026-07-10 02:10:58
Type: Object/s-Discovery/Classification
Identification of a Fast and Red Optical Transient in the LSST Alert Stream (170631094842425480 / AT 2026tim)
Authors: Michael Camilo (Cornell), Anna Y. Q. Ho (Cornell), Daniel Perley (LJMU), and Adam Miller (Northwestern)
Source Group: ZTF
Abstract:
We report the identification of a fast and red transient in the LSST alert stream (170631094842425480 / AT 2026tim). It has a peak apparent extinction-corrected magnitude of m_z ~ 22.2 mag.

AT2026tim (LSST ID 170631094842425480) was first detected at a position (J2000) of:

RA = 20:07:41.01  (301.920885 deg)

Dec = -29:34:37.01 (-29.576947 deg)

on 2026 July 06, at 06:42:43.7 (07:49:41.5) UTC by LSST at i (z) = 22.8 (22.4) +/- 0.15 (0.12) mag.

Over the next night, the transient brightened in the i (z) band by 0.32 (0.19) +/- 0.18 (0.18) magnitudes. Over the following two nights, a 0.71 +/- 0.16 magnitude fade was seen in i band. The transient is 0.17 arcseconds from a catalogued source in Legacy Survey Data Release 10, which has an extended morphology. The RMS scatter in the positions of the LSST detections is 0.08 arcsec.

The averaged extinction corrected color is i - z = 0.31 +/- 0.13 magnitudes, indicating that the transient is red.

The transient could potentially be nuclear; given the lack of a detailed light-curve history at this position we caution that an AGN flare origin is possible. However, due to the fast evolution and red colors, and lack of a catalogued AGN or radio source at this position, we encourage follow-up observations.

Show current TNS values
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 2026tim [170631094842425480] 20:07:41.012 -29:34:37.01 Other 20:07:41.012 -29:34:37.01

Comments

Michael
Camilo

Fri, 07/10/2026 - 01:32