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"28047 results found.
- GRB231111A: Optical follow-up observations with Mephisto
- GRB 231111A: GMG observation (correction)
- GRB 231111A: GMG observation upper limit
- GRB 231106B: GRBAlpha detection
- GRB 231110A: Terskol Zeiss-2000 optical upper limit
- GRB 231111A: Swift-XRT refined Analysis
- GRB 231111A: Mondy optical observations
- GRB 231111A: Enhanced Swift-XRT position
- GRB 231110A: SAO RAS optical observations
- GRB231111A: GIT confirmation of the optical afterglow
- GRB 231111A: Nanshan/HMT optical observations
- GRB 231111A: Swift detection of a burst with an optical counterpart
- Swift GRB231111.60: Global MASTER-Net observations report
- GRB231110A: WFST Observation and upper limits
- GRB 231110A: Swift detection of a burst
- LIGO/Virgo/KAGRA S231110g: Updated Sky localization
- LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S231108u: Updated Sky localization
- LIGO/Virgo/KAGRA O4 Landscape
- LIGO/Virgo/KAGRA S231108u: Identification of a GW compact binary merger candidate
- GRB 231104A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
- GRB 231104A: NuSTAR Observation of the prompt emission
- GRB 231104A: 3.6m DOT optical upper limit
- IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S231106y: one counterpart neutrino candidate from IceCube neutrino searches
- Fermi-LAT gamma-ray observations of IceCube-231103A
- GRB 231104A: NOT upper limit
- GRB 231104A: Fermi GBM Observation
- Fermi GRB 231103A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231104ac: Updated Sky localization
- GRB 231104A: AKO Upper Limit
- GRB 231104A: AstroSat CZTI detection
- GRB 231104A: Swift-XRT refined Analysis
- GRB 231104A: Fermi-LAT detection
- LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
- GRB 231104A: Swift/UVOT Upper Limits
- GRB 231104A: Enhanced Swift-XRT position
- GRB231104A: LCOGT Optical Upper Limits
- GRB 231104A: Swift detection of a bright burst
- Fermi-LAT gamma-ray observations of IceCube-231027A
- LIGO/Virgo/KAGRA S231102w: Updated Sky localization
- GRB 231101A: Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S231102w: Identification of a GW compact binary merger candidate
- New Swift-BAT/GUANO and IceCube Notices Available via GCN Kafka
- GRB 231101A: Fermi GBM Final Real-time Localization
- GRB 231028B: VZLUSAT-2 detection
- GRB 231030B: Fermi GBM Detection
- IPN triangulation of GRB 231020A
- GRB 231030B: BALROG localization (Fermi Trigger 720388704 / GRB 231030832)
- GRB 231028A: Swift-BAT refined analysis
- IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
- GRB 231024A: AKO Optical Counterpart Candidate
- LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
- GRB 231028A: AstroSat CZTI detection
- GRB 231028A: Glowbug gamma-ray detection
- GRB 231028A: Fermi GBM Detection
- LIGO/Virgo/KAGRA S231028bg: Updated Sky localization
- LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate
- GRB 231028A: Swift detection of a burst
- GRB 231019A: Glowbug gamma-ray detection
- GRB 231025A: Fermi GBM Observation
- GRB 231024A: Fermi GBM Observation
- GRB 231025A: Swift/BAT-GUANO detection of a likely short burst
- GRB 231020B: AstroSat CZTI detection
- GRB 231024A: GOTO optical counterpart candidate
- LIGO/Virgo/KAGRA S231025a: two counterpart neutrino candidates from IceCube neutrino searches
- The photometry of the transient in Messier 31 field: GMG observation
- GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231020bw: Updated Sky localization
- GRB 231020A: Fermi GBM Detection
- GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
- GRB 231019A: VZLUSAT-2 detection
- GRB 231018A: VZLUSAT-2 detection
- GRB 231020B: BALROG localization (Fermi Trigger 719530557 / GRB 231020900)
- LIGO/Virgo/KAGRA S231020ba: Updated Sky localization and EM Bright Classification
- GRB 231020A: BALROG localization (Fermi Trigger / GRB 231020790)
- LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
- GRB 231015A: NuSTAR Detection of Prompt Emission
- LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
- GRB 231017A: 1.3m DFOT Optical upper limit
- LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
- IceCube-231004A: Upper limits from Fermi-GBM Observations
- GRB 231018A: Glowbug gamma-ray detection
- IPN triangulation of GRB 231018A
- GRB 231017A: Swift/UVOT Upper Limit
- GRB 230911C: ATCA detection of possible radio counterpart
- GRB 231017A: JinShan optical upper limit
- GRB 231018A: GROWTH-India Follow-Up of a Fermi Long GRB
- LIGO/Virgo/KAGRA S231018cb: One counterpart neutrino candidate event from an IceCube neutrino search
- IC231004A: Classification of AT2023uqf/ZTF23abidzvf as a rapidly-evolving supernova with CSM interaction
- GRB 231017A: Las Cumbres optical upper limit
- GRB 231015A: Glowbug gamma-ray detection
- GRB 231017A: LCOGT Optical Upper Limits