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').
10045 results found.
- GRB 231117A: Swift detection of a bright short burst
- GRB 231115A: AGILE/MCAL upper limits
- GRB 231115A : MITSuME Akeno and Okayama optical upper limits
- GRB 231115A: MASTER optical observations
- LIGO/Virgo S231113bw: upper limits from AGILE/MCAL
- SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
- GRB 231110A: CALET Gamma-Ray Burst Monitor detection
- LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
- GRB 231110A: Swift-UVOT Upper Limits
- GRB 231104A: VZLUSAT-2 detection
- GRB 231106B: GRBAlpha detection
- GRB 231110A: Terskol Zeiss-2000 optical upper limit
- GRB 231111A: Mondy optical observations
- GRB 231106A: CALET Gamma-Ray Burst Monitor detection
- GRB 231104A: Fermi-LAT detection
- GRB 231104A: Swift/UVOT Upper Limits
- GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
- GRB 231030B: GRBAlpha detection
- GRB 231028B: VZLUSAT-2 detection
- GRB 231028A: CALET Gamma-Ray Burst Monitor detection
- IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
- LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
- GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
- GRB 231019A: VZLUSAT-2 detection
- GRB 231018A: VZLUSAT-2 detection
- LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
- GRB 231018A: GRBAlpha detection
- GRB 231018A: CALET Gamma-Ray Burst Monitor detection
- GRB 231017A: JinShan optical upper limit
- GRB 231017A: Las Cumbres optical upper limit
- (correction) Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field
- Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field.
- GRB 231004A: CALET Gamma-Ray Burst Monitor detection
- transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
- LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
- LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
- GRB 230911D: GRBAlpha detection
- GRB 230913A: CALET Gamma-Ray Burst Monitor detection
- GRB 230908A: CALET Gamma-Ray Burst Monitor detection
- GRB 230911D: Fermi-LAT detection
- GRB 230911B: GRBAlpha and VZLUSAT-2 joint detection
- GRB 230908A: GRBAlpha detection
- GRB 230818A: radio observation with the VLA
- GRB 230903A: VLT/X-shooter optical observations
- GRB 230827B: CALET Gamma-Ray Burst Monitor detection
- GRB 230828A: GRBAlpha detection
- GRB 230827A: VZLUSAT-2 detection
- GRB 230826A: VZLUSAT-2 detection
- GRB 230827B: VZLUSAT-2 detection
- GRB 230827A: GRBAlpha detection
- GRB 230826A: GRBAlpha detection
- GRB 230826A: Mondy optical observations
- GRB 230818B: CALET Gamma-Ray Burst Monitor detection
- Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
- GRB 230812B: radio detection with the VLA
- MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
- Swift Trigger 1186908 is not a GRB
- GRB 230818B: VZLUSAT-2 detection
- GRB 230812B: Assy optical observations, possible SN rise
- Swift Triggers 1186280 and 1186291 are not GRBs
- GRB 230812B: GIT Confirmation of SN rise
- GRB 230818A: Bassano Bresciano Observatory optical observations
- GRB 230818A: KGO RC-25 optical observations
- GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
- GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
- GRB 230816A: TShAO and Assy optical observations
- GRB230815A: Swift/UVOT upper limits
- GRB 230815A: Fermi GBM detection
- Swift GRB 230815A: Global MASTER-Net observations report
- GRB 230815A: Swift detection of a burst
- GRB 230812B: continued AbAO optical afterglow observations
- GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
- GRB 230812B: CrAO ZTSh optical observations
- GRB 230812B: Koshka Zeiss-1000 optical observations
- GRB 230812B: GIT optical follow-up
- GRB 230812B: Faulkes Telescope North optical afterglow follow-up
- GRB 230812B: OASDG optical observations
- GRB 230812B: AbAO optical observations
- GRB230812B: AGILE/MCAL detection
- GRB 230812B: Fermi-LAT detection
- GRB 230805B : MITSuME Akeno optical upper limits
- GRB 230805B: Swift detection of a burst
- GRB 230802A: Fermi GBM observation
- GRB 230802A: Swift/UVOT Upper Limits
- Swift GRB 230802A: Global MASTER-Net observations report
- LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
- GRB 230802A: Swift detection of a burst
- LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
- GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
- GRB 230723B: MITSuME Ishigaki optical observation
- GRB 230723B: MITSuME Akeno optical afterglow candidate detection
- GRB 230723A: AGILE/MCAL detection
- GRB 230709B: CALET Gamma-Ray Burst Monitor detection
- GRB 230703A: CALET Gamma-Ray Burst Monitor detection
- GRB 230709C: GRBAlpha detection
- GRB 230709B: GRBAlpha detection
- GRB 230707B: CALET Gamma-Ray Burst Monitor detection
- GRB 230626A: VZLUSAT-2 detection