GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"24153 results found.
- IceCube Alert 260825A: Global MASTER-Net observations report
- IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260825A: Fermi GBM Final Real-time Localization
- IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260822A: PRIME near-infrared upper limits from multiple epochs
- GRB 260822A: EP/FXT follow-up observations
- GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
- GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
- GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
- GRB 260822A: LCO optical upper limits
- The EP-WXT trigger 01709287395 is likely a flaring star
- GRB260822B: Fermi GBM Final Localization
- GRB 260822A: GROWTH-India Telescope Upper Limits
- GRB 260822A: GOTO optical upper limit
- GRB 260822A: SVOM detection of a short burst
- Fermi-LAT Gamma-ray Observations of IceCube-260821A
- Fermi-LAT Gamma-ray Observations of IceCube-260807A
- IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260818B: SVOM/C-GFT optical upper limit
- EP260731a: SVOM/ECLAIRs detection through offline targeted search
- IceCube Alert 260821A: Global MASTER-Net observations report
- The EP-WXT trigger 01709286204 is likely a flaring star
- IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260818B: SVOM/GRM observation
- EP detected a brightening of LMXB 1ES 1735-26.9
- GRB260820A: Fermi GBM Final Real-Time Localization
- GRB 260818B: EP-FXT follow-up observation
- GRB 260818B: SVOM/ECLAIRs refined analysis
- GRB 260818A: SVOM/ECLAIRs refined analysis
- GRB 260810A: SVOM/GRM observation
- GRB260818A: EP-FXT follow-up observation
- GRB 260818B: LCO optical upper limits
- GRB 260818B: SVOM detection of a short burst
- GRB 260818A: LCO optical upper limits
- GRB 260818A: SVOM possible detection of a long and faint GRB
- EP260806a: SVOM/ECLAIRs detection through targeted search
- The EP-WXT trigger 01709281429 is likely a flaring star
- The EP-WXT trigger 01709280562 is likely a flaring star
- The EP-WXT trigger 01709279838 is likely a flaring star
- GRB 260805D: SVOM/GRM detection of a possible magnetar burst
- GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
- GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
- GRB 260813A: Fermi GBM Final Real-time Localization
- EP260812a: NOT and Liverpool Telescope upper limits:
- EP260812b: Liverpool Telescope observations
- EP260812b: GOTO detection of the optical counterpart
- EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
- EP260812a: SVOM/C-GFT optical upper limit
- EP260812b: SVOM/VT optical observation
- GRB 260808A: SVOM/GRM observation
- Fermi GBM Sub-Threshold Detection of GRB 260809A
- GRB 260808B: SVOM/VT optical re-brightening at day 3
- GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
- GRB 260806A: CALET Gamma-Ray Burst Monitor detection
- GRB 260807A: SVOM/ECLAIRs refined analysis
- IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
- GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
- EP260809a: VLT/X-shooter spectroscopic redshift z = 3.07
- GRB 260808A: CALET Gamma-Ray Burst Monitor detection
- GRB 260805C: CALET Gamma-Ray Burst Monitor detection
- GRB 260804A: CALET Gamma-Ray Burst Monitor detection
- GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
- The EP-WXT trigger 01709278015 is likely a flaring star
- IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260809A: SVOM/VT optical counterpart
- GRB 260808B: SVOM/ECLAIRs refined analysis
- EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
- GRB 260809A: SVOM detection of a faint burst
- GRB 260808B: NOT optical observations
- GRB 260808B: LCO optical observations
- GRB 260808A: NuSTAR detection of prompt emission
- EP260809a: LCO optical observation
- GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
- GRB 260808B: SVOM/VT optical afterglow confirmation
- GRB 260808C: Fermi GBM Final Real-time Localization
- GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
- GRB 260808B: SVOM/VT optical candidate from VHF data
- GRB 260808B: SVOM detection of a faint burst
- GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119)
- Fermi GRB 260808A: Global MASTER-Net observations report
- GRB 260808A: Fermi GBM Final Real-time Localization
- IceCube Alert 260807A: Global MASTER-Net observations report
- IceCube-260805A: One candidate from the Zwicky Transient Facility
- GRB 260807A: SVOM possible detection of a faint burst
- IceCube-260807A - IceCube observation of a high-energy neutrino candidate track-like event
- EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260806a: LCO likely optical counterpart
- GRB 260715A: cubesat Avion detection
- GRB 260709A: cubesat Avion detection
- GRB 260708A: cubesat Avion detection
- IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event
- Fermi GRB 260805A: Global MASTER-Net observations report
- GRB 260805B: Fermi GBM Final Localization
- GRB 260805B: BALROG localization (Fermi Trigger 807622617 / GRB 260805484)
- GRB 260805A: Fermi GBM Final Localization
- AT 2026wki: EP/FXT follow-up observations
- GRB 260730B: CALET Gamma-Ray Burst Monitor detection
- IceCube-Cascade 260801A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260804A: Fermi GBM Final Real-time Localization