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.
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').
15494 results found.
- GRB 240118A: AbAO optical upper limit
- GRB 240117A: Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S240109a: Upper limits from Swift/BAT-GUANO
- GRB 240112D: Glowbug gamma-ray detection
- GRB 240112C: Glowbug gamma-ray detection
- GRB 240112C: Swift/UVOT Detection
- GRB 240112C: Swift-XRT refined Analysis
- GRB 240112C: SAO RAS optical observations
- GRB 240112C: Swift detection of a burst with an optical counterpart
- Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
- GRB 240108A: Glowbug gamma-ray detection
- GRB 240106B: Glowbug gamma-ray detection
- GRB 240106A: Glowbug gamma-ray detection
- GRB 231215A: radio detection with the VLA
- GRB 230818A: further radio observations with the VLA
- GRB 230812B: further radio observations with the VLA
- Swift GRB240109.17: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
- IPN triangulation of GRB 240101C (short)
- GRB 240101A: 1.3m DFOT optical observations
- GRB 240102A: 1.3m DFOT optical upper limit
- GRB 240101B: 1.3m DFOT optical upper limit
- GRB 240102C: AstroSat CZTI detection
- GRB 240102A: Swift-BAT refined analysis
- GRB 240102A: Swift/UVOT Upper Limits
- GRB 240102A: Enhanced Swift-XRT position
- GRB 240102A: Swift-XRT refined Analysis
- GRB 240102A: LCOGT Optical Upper Limits
- GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- GRB 240102A: Swift detection of a burst
- GRB 240101A: Terskol Zeiss-2000 optical observations
- GRB 240101B: Swift/UVOT Upper Limits
- GRB 240101A: Swift/UVOT Upper Limits
- GRB 240101B: Enhanced Swift-XRT position
- GRB 240101A: Enhanced Swift-XRT position
- GRB 240101B: Swift detection of a burst
- GRB 231230A: Swift-XRT refined Analysis
- GRB 231230A: Enhanced Swift-XRT position
- GRB 231230A: Swift/UVOT Upper Limits
- GRB 231230A: NOT optical upper limits
- GRB 231230A: Swift detection of a burst
- GRB 231210B: BOOTES-7 optical upper limit
- LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
- GRB 231222B: Swift-XRT afterglow detection
- GRB 231222A: Tiled Swift observations
- IceCube-231211A: GRANDMA observations of PKS2047+098
- GRB 231220A: Swift ToO observations
- GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
- GRB 231216A: optical upper limits from the INAF Asiago Observatory
- GRB 231215A: AMI-LA radio detection
- GRB 231216A: Nanshan/HMT optical upper limit
- GRB 231216A: LCOGT Optical Upper Limits
- GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 231216A: Swift-XRT refined Analysis
- GRB 231216A: REM NIR upper limits
- GRB 231216A: Swift/UVOT Upper Limits
- GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
- GRB 231216A: GIT optical upper limit
- GRB 231216A: Swift detection of a burst
- GRB 231214A: Swift/UVOT Upper Limits
- GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
- GRB 231215A: Fermi GBM observation
- GRB 231215A : OHP/T193 optical afterglow detection
- GRB 231215A: Swift/UVOT Detection
- GRB 231215A: AKO Optical Upper Limit
- GRB 231215A: Enhanced Swift-XRT position
- GRB 231214A: REM optical/NIR upper limits
- GRB 231215A: GROWTH-India optical follow-up
- GRB 231215A : Nanshan/HMT optical observations
- GRB 231215A : MITSuME Akeno optical afterglow candidate detection
- GRB 231215A: Mondy optical bright afterglow detection
- GRB 231214A: AstroSat CZTI detection
- GRB 231215A: Swift-XRT observations
- GRB 231214A: Enhanced Swift-XRT position
- GRB 231214A: Swift detection of a burst
- GRB 231210B: REM optical/NIR upper limits
- 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
- LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
- Fermi trigger No 724035412: Global MASTER-Net observations report
- GRB 231210B: MeerLICHT afterglow observations
- GRB 231210B: Enhanced Swift-XRT position
- GRB 231210B: VLT/X-shooter redshift
- GRB 231210B: Swift detection of a burst with optical counterpart
- IPN triangulation of GRB 231129C
- GRB231205B: Swift/UVOT Upper Limits
- GRB 231208A: Glowbug gamma-ray detection
- GRB 231205B: 1.3m DFOT Optical upper limit
- GRB 231205B: optical upper limit in TSHAOand AbAO
- GRB231115A: TURBO Pre-Burst Optical Upper Limits
- Fermi-LAT gamma-ray observations of IceCube-231202A
- GRB 231205B: REM optical/NIR upper limits
- GRB 231129C: ASIM MXGS observation and localization
- GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
- GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
- GRB 231205B : MITSuME Akeno optical upper limits
- GRB 231205B: Zadko observatory - Gingin optical observations
- GRB 231205B: Gaoyazi/GOT optical upper limit