The Astronomer's Telegram: Top ATels

For reporting and commenting upon new observations of astronomical transients by the professional astrophysics community.

ATel 18081: Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PKS 1743+173

The Large Area Telescope (LAT), one of the two instruments onboard the Fermi Gamma-ray Space Telescope, has observed enhanced gamma-ray activity from a source positionally consistent with the flat-spectrum radio quasar PKS 1743+173, also known as FL16Y J1745.7+1720 (Ballet et al. ...
https://www.astronomerstelegram.org/?read=18081
date: 2026-09-24T20:11:58-00:00
creator: P. Monti-Guarnieri, C. C. Cheung, P. Van Zyl, on behalf of the Fermi Large Area Telescope Collaboration

ATel 18080: Erratum for Atel #18076

The pulsar position is derived from snapshot observations using the FAST 19-beam receiver, with the 1.5' positional uncertainty dominated by the beam size as it far exceeds the telescope's absolute pointing uncertainty. ...
https://www.astronomerstelegram.org/?read=18080
date: 2026-09-24T11:53:04-00:00
creator: Hang Gong, Shaoqiang Xi, Caisong Liu, Pei Wang, Lingqi Meng, Chenchen Miao, Jifeng Liu, Zhen Cao

ATel 18079: NGC 1275: Upper limits from a neutrino search with IceCube

The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search for track-like muon neutrino events arriving from the direction of the radio galaxy NGC 1275 following reports of an exceptionally bright very-high-energy gamma-ray flare by MAGIC, LST-1 (ATel #18060), and MACE (ATel #18064). ...
https://www.astronomerstelegram.org/?read=18079
date: 2026-09-23T21:44:32-00:00
creator: Alicia Mand, Justin Vandenbroucke

ATel 18078: Fermi-LAT Gamma-ray Observations of IceCube-260916A

We report an analysis of observations of the vicinity of the high-energy IC260916A neutrino event (GCN 45598) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. ...
https://www.astronomerstelegram.org/?read=18078
date: 2026-09-23T21:14:59-00:00
creator: L. Pfeiffer, S. Buson, S. Garrappa on behalf of the Fermi-LAT collaboration

ATel 18077: SVOM/ECLAIRs detection of the blazar 1ES 1959+650

We report the detection of the blazar 1ES 1959+650 with the ECLAIRs telescope onboard the SVOM mission on September 18, between 14:26:39.898 and 17:12:50.386 UTC, with a signal-to-noise ratio of 15.79 in the 4-20 keV energy band, while the source was within the ECLAIRs field of view. ...
https://www.astronomerstelegram.org/?read=18077
date: 2026-09-23T15:48:53-00:00
creator: F. Cangemi, S. Le Stum, A. Coleiro, P.-O. Petrucci, L. Tao, L. Zhang

ATel 18076: FAST Discovery of a New Millisecond Pulsar Binary

We report the discovery of a new millisecond pulsar binary using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) & #91;1 & #93;. The system was identified at a beam center of R.A. ...
https://www.astronomerstelegram.org/?read=18076
date: 2026-09-23T13:52:13-00:00
creator: Hang Gong, Shaoqiang Xi, Caisong Liu, Pei Wang, Lingqi Meng, Chenchen Miao, Jifeng Liu, Zhen Cao

ATel 18075: Swift/XRT observation of the Be/X-ray binary pulsar GS 0834-430 during its 2026 outburst

We report on a Swift/XRT observation of GS 0834-430, currently in outburst following the onset of X-ray activity seen by MAXI/GSC on 2026 August 29 (ATel #18031). ...
https://www.astronomerstelegram.org/?read=18075
date: 2026-09-23T13:23:03-00:00
creator: G. K. Jaisawal

ATel 18074: Spectroscopic Classification of Astrophysical Transients with the Lick Shane Telescope

We report the classifications of astrophysical transients from spectroscopic observations with the Kast spectrograph on the Shane telescope obtained on 2026 September 21 UT. ...
https://www.astronomerstelegram.org/?read=18074
date: 2026-09-23T00:08:26-00:00
creator: R. Kaur, R. J. Foley, K. C. Patra

ATel 18073: Swift Observations of V1452 Tau - Emission from Beryllium (7Be II) Revealed ?

The galactic nova V1452 Tau (TCP J05210763+2338194) was discovered on 2026-Aug-06 (ATel# 17947; day 0) and subsequently spectroscopically classified as FeII-type nova (ATel# 17950). ...
https://www.astronomerstelegram.org/?read=18073
date: 2026-09-22T23:38:12-00:00
creator: C. E. Woodward, P. Kuin, K. L. Page, L. Izzo, P. Molaro, S. Starrfield

ATel 18072: LHAASO-WCDA Detection of TeV Flaring Activity from the Blazar 1ES 1959+650

Recent observation with the SST-1M has unveiled bright gamma-ray flaring activity from the blazar 1ES 1959+650 (ATel #18065). Corresponding very-high-energy (VHE) flaring emission from this source has been independently detected by the real-time alert system of LHAASO-WCDA. ...
https://www.astronomerstelegram.org/?read=18072
date: 2026-09-22T15:29:32-00:00
creator: Guangman Xiang, Min Zha, Zhiguo Yao, Jianeng Zhou and Yi Xing report on behalf of the LHAASO Collaboration