GCN Circular 37195
Subject
IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
Event
Date
2024-08-16T20:49:15Z (2 years ago)
From
Jannis Necker at DESY <jannis.necker@desy.de>
Via
Web form
Jannis Necker (DESY), Robert Stein (Caltech), Jesper Sollerman (OKC), Tomas Ahumada (Caltech), Christoffer Fremling (Caltech), Anna Franckowiak (RUB) and Mansi Kasliwal (Caltech) report:
AT2023qqp/ZTF23aaslxmh and AT2024pge/ZTF24aaugpvz were first reported by ZTF (Weimann et al., GCN 36929) as potential counterparts to the high-energy neutrino IceCube-240808A (Zegarelli et. al, GCN 36918), as part of the broader ZTF neutrino follow-up program (Stein et al. 2023).
We obtained spectroscopic observations of AT2024pge/ZTF24aaugpvz at the P200 Hale Telescope with the Double Spectrograph (PI:Fremling) and at Gemini North with GMOS (PI: Stein). Observations took place on 07/24/24 and 07/31/24, respectively. The spectrum shows broad balmer lines at a redshift of z=0.096 which suggests a supernova Type II with a peak g-band magnitude of M=-18.5. This interpretation aligns with the offset from the host center. However, there are no indications for narrow emission lines shich would indicate CSM interaction, so we consider the transient unrelated to the neutrino.
AT2023qqp/ZTF23aaslxmh was observed at Gemini North with GMOS (PI: Stein) on 07/31/24. The spectrum indicates a redshift of z=0.64 which puts the peak g-band magnitude at M=-23.4. There are no supernova-like features and based on the past activity over more than 400 days, AT2023qqp is likely due to AGN activity. The short term flare of around one day with a magnitude increase of 0.5 occuring at neutrino arrival was likely happening by chance.
We conclude that both transient are likely unrelated to IceCube-240721A.
ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; DESY, Germany; TANGO, Taiwan; UW Milwaukee, USA; LANL, USA; TCD, Ireland; IN2P3, France.
Based on observations obtained at the international Gemini Observatory, a program of NSF NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the U.S. National Science Foundation on behalf of the Gemini Observatory partnership: the U.S. National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea).
This work was enabled by observations made from the Gemini North telescope, located within the Maunakea Science Reserve and adjacent to the summit of Maunakea. We are grateful for the privilege of observing the Universe from a place that is unique in both its astronomical quality and its cultural significance.