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').
17300 results found.
- GRB 240118A: Swift-XRT afterglow detection
- IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER
- GRB 240118A: GRBAlpha detection
- GRB 240118A: AbAO optical upper limit
- GRB 240117A: Glowbug gamma-ray detection
- Konus-Wind detection of GRB 240118A
- LAT GRB240118.08: Global MASTER-Net observations report
- GRB 240115B: AstroSat CZTI 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: VZLUSAT-2 detection
- GRB 240107A: VZLUSAT-2 detection
- GRB 240112C: GRBAlpha 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
- GRB 240110A: AstroSat CZTI detection
- 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
- Konus-Wind detection of GRB 240101C
- 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 S240109a: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
- IceCube-240105A: JCMT SCUBA2 Detection of Two Bright Submillimeter Sources
- GRB 240106A: GRBAlpha detection
- LIGO/Virgo/KAGRA S240107b: Identification of a GW compact binary merger candidate
- 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
- LIGO/Virgo/KAGRA S240104bl: Identification of a GW compact binary merger candidate
- GRB 240102A: Swift/UVOT Upper Limits
- GRB 240101A: Swift-BAT refined analysis
- GRB 240102A: Enhanced Swift-XRT position
- GRB 240102A: Swift-XRT refined Analysis
- GRB 240102A: LCOGT Optical Upper Limits
- Fermi trigger No 725857207: Global MASTER-Net observations report
- GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- GRB 240102A: Swift detection of a burst
- GRB 240101C: GRBAlpha detection
- 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
- LIGO/Virgo/KAGRA S231231ag: Identification of a GW compact binary merger candidate
- GRB231230A: Fermi GBM Observation
- GRB 231230A: GOTO optical upper limits
- 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
- LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231226av: Identification of a GW compact binary merger candidate
- GRB 231222B: GRBAlpha detection
- LIGO/Virgo/KAGRA S231224e: Identification of a GW compact binary merger candidate
- GRB 231222B: Swift-XRT afterglow detection
- LIGO/Virgo/KAGRA S231223j: Identification of a GW compact binary merger candidate
- IceCube-231211A: GRANDMA observations of PKS2047+098
- GRB 231220A: Swift/BAT-GUANO arcminute localization of a long burst
- GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
- 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: 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 231215A: GRBAlpha detection
- GRB 231216A: Swift detection of a burst
- Konus-Wind detection of GRB 231215A
- GRB 231214A: Swift/UVOT Upper Limits
- 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 : OHP/T193 optical afterglow detection
- GRB 231215A: Swift/UVOT Detection
- GRB 231215A: AKO Optical Upper Limit
- GRB 231214A: Fermi GBM observation
- 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