GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"- GRB 231216A: AST3-3 YaoAn Optical Upper Limit
- GRB 231216A: REM NIR upper limits
- GRB 231216A: Swift/UVOT Upper Limits
- GRB 231216A: Swift-BAT refined analysis
- GRB 231215A: Swift-BAT refined analysis
- GRB 231214A: Swift-BAT refined analysis
- GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
- GRB 231216A: GIT optical upper limit
- GRB 231216A: NOT optical upper limits
- GRB 231216A: BOOTES-2/TELMA optical upper limit
- GRB 231215A: GRBAlpha detection
- Swift GRB231216.77: Global MASTER-Net observations report
- GRB 231216A: Swift detection of a burst
- Konus-Wind detection of GRB 231215A
- GRB 231215A: optical afterglow detection from the INAF Asiago Observatory
- GRB 231215A: NOT optical observations
- GRB 231214A: Swift/UVOT Upper Limits
- GRB 231215A: Redshift from OSIRIS+ / GTC
- GRB 231205B: VZLUSAT-2 detection
- GRB 231204A: VZLUSAT-2 detection
- GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
- GRB 231215A: Fermi GBM observation
- GRB 231215A: CALET Gamma-Ray Burst Monitor detection
- GRB 231215A : OHP/T193 optical afterglow detection
- GRB 231215A: Swift/UVOT Detection
- LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search
- GRB 231215A: Swift-XRT refined Analysis
- GRB 231215A: BOOTES-4/MET optical detection
- GRB 231215A: AKO Optical Upper Limit
- GRB 231215A: AGILE detection
- GRB 231214A: Fermi GBM observation
- Konus-Wind detection of GRB 231210B
- ATCA observations of GRB 231210B
- GRB 231215A: Enhanced Swift-XRT position
- Fermi trigger No 724326442: Global MASTER-Net observations report
- GRB 231214A: REM optical/NIR upper limits
- GRB 231215A: GROWTH-India optical follow-up
- GRB 231215A : Nanshan/HMT optical observations
- GRB 231215A: AstroSat CZTI detection
- GRB 231215A : MITSuME Akeno optical afterglow candidate detection
- GRB 231214A: Swift-XRT refined Analysis
- GRB 231215A: Mondy optical bright afterglow detection
- GRB 231214A: AstroSat CZTI detection
- GRB 231215C: MASTER OT detection
- Swift GRB231215.41: Global MASTER-Net observations report
- GRB 231215A: Swift-XRT observations
- GRB 231215B: Fermi GBM Final Real-time Localization
- GRB 231215A: Swift detection of a burst
- GRB 231214A: Fermi-LAT detection
- GRB 231214A: Enhanced Swift-XRT position
- GRB 231214B: Swift/BAT-GUANO detection of a burst
- GRB231214A: BOOTES-6/DPRT optical upper limit
- Fermi trigger No 724278269: Global MASTER-Net observations report
- Fermi trigger No 724233240: Global MASTER-Net observations report
- Swift GRB231214.85: Global MASTER-Net observations report
- GRB 231214A: Swift detection of a burst
- GRB 231214A: Fermi GBM Final Real-time Localization
- GRB 231210B: REM optical/NIR upper limits
- IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S231213ap: Updated Sky localization
- LIGO/Virgo/KAGRA S231213ap: Identification of a GW compact binary merger candidate
- Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
- IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
- GRB 231212A: GECAM-C detection of a likely short burst
- Fermi trigger No 724035412: Global MASTER-Net observations report
- GRB 231210B: MeerLICHT afterglow observations
- GRB 231210B: Swift-BAT refined analysis
- IceCube Alert 231211.03: Global MASTER-Net observations report
- IceCube-231202A: No candidates from the Zwicky Transient Facility
- GRB 231210B: Swift-XRT refined Analysis
- GRB 231210B: Enhanced Swift-XRT position
- GRB 231210B: VLT/X-shooter redshift
- GRB 231210B: detection of the optical counterpart with the LCOGT 40cm telescope at Sutherland Observatory
- Fermi trigger No 723906955: Global MASTER-Net observations report
- GRB 231210B: Swift detection of a burst with optical counterpart
- Swift GRB231210.90: Global MASTER-Net OT detection
- Swift GRB231210.90: Global MASTER-Net observations report
- IPN triangulation of GRB 231129C
- GRB 231210A: Fermi GBM Final Real-time Localization
- GRB 231208A: GRBAlpha detection
- GRB231205B: Swift/UVOT Upper Limits
- GRB 231208A: Glowbug gamma-ray detection
- GRB 231208A: AstroSat CZTI detection of a faint burst
- LIGO/Virgo/KAGRA S231206ca: Updated Sky localization
- IPN triangulation of GRB 231205A
- GRB 231205B: Swift-BAT refined analysis
- GRB 231205B: 1.3m DFOT Optical upper limit
- LIGO/Virgo/KAGRA S231206cc: Updated Sky localization and Source Classification
- GRB 231206A: joint location of multiple instruments by ETJASMIN
- GRB 231205B: optical upper limit in TSHAOand AbAO
- LIGO/Virgo/KAGRA S231206cc: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S231206ca: Identification of a GW compact binary merger candidate
- GRB231115A: TURBO Pre-Burst Optical Upper Limits
- GRB 231205B: AGILE detection
- Fermi trigger No 723581802: Global MASTER-Net observations report
- GRB 231206B: Fermi GBM Final Real-time Localization
- GRB 231205B: Ondrejov D50 optical upper limit
- GRB 231205B: Swift-XRT refined Analysis