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"
24595 results found.
- GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
- GRB 231129A: Swift-BAT refined analysis
- GRB 231129A: JinShan optical upper limit
- GRB 231129C: Glowbug gamma-ray detection
- GRB 231129C: Swift-XRT observations
- GRB 231129A: Swift/UVOT Upper Limits
- GRB 231129A: optical upper limit in Mondy observatory
- GRB 231129C: Fermi GBM Observation of a very bright GRB
- GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
- GRB 231129C: MAXI/GSC detection
- GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)
- GRB 231129C: Fermi GBM detection of a very bright burst
- GRB 231129A: Enhanced Swift-XRT position
- LIGO/Virgo/KAGRA S231129ac: Updated Sky localization
- GRB 231129A: Swift-XRT refined Analysis
- Fermi trigger No 722977823: Global MASTER-Net observations report
- GRB 231129B: MAXI/GSC detection
- Fermi-LAT gamma-ray observations of IceCube-231125A
- LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
- GRB 231129A: INTEGRAL detection of a long GRB
- GRB 231129A: Swift detection of a burst
- LIGO/Virgo/KAGRA S231127cg: Updated Sky localization
- GRB 231123C: Fermi GBM Observation
- GRB 231123B: Fermi GBM Observation
- IceCube-231125A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S231127cg: Identification of a GW compact binary merger candidate
- GRB 231117A: MeerKAT 1.3GHz detection
- GRB 231127A: AstroSat CZTI detection
- GRB 231125A (short): Glowbug gamma-ray detection
- GRB 231123B: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 231125A: AstroSat CZTI detection of a short burst
- GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
- GRB 231123C: Insight-HXMT/HE detection
- Fermi trigger No 722460326: Global MASTER-Net observations report
- GRB 231123C (short): Glowbug gamma-ray detection
- GRB 231124A: Glowbug gamma-ray detection
- GRB230728A: VIRT optical upper limit
- GRB230506C: VIRT optical upper limit
- GRB230506B: VIRT optical upper limit
- GRB 231123C: Swift/BAT-GUANO detection of a short burst likely outside the coded FOV
- LIGO/Virgo/KAGRA S231118an: Updated Sky localization and EM Bright Classification
- GRB 231117A: Mondy optical observations
- LIGO/Virgo/KAGRA S231123cg: Identification of a GW compact binary merger candidate
- GRB 231118A: REM optical afterglow detection
- GRB 231122B: AstroSat CZTI detection
- GRB 231122B: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- GRB 231122B: Glowbug gamma-ray detection
- GRB 231117A: Continued GTC Observations
- GRB 231122A: GECAM detection
- GRB 231122B: GECAM detection
- GRB 231117A: Swift/UVOT late time observations
- GRB 231117A: GTC Near-Infrared Observations
- GRB 231117A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231119u: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S231118ab: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S231118d: Updated Sky localization and Source Classification
- GRB 231118A: VZLUSAT-2 detection
- GRB 231117A: AMI-LA radio observations
- GRB 231118A: Swift-BAT refined analysis
- 231118A: Swift-UVOT Detection
- GRB231117A: Swift-UVOT detection
- GRB 231117A : MITSuME Akeno optical afterglow candidate detection
- GRB 231118B: Fermi GBM observation
- GRB 231118A: Fermi GBM observation
- LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
- GRB 231117A: Swift-XRT refined Analysis
- GRB 231118A: Swift-XRT refined Analysis
- GRB 231118A: MeerLICHT afterglow detection
- LIGO/Virgo/KAGRA S231119u: One counterpart neutrino candidate from IceCube neutrino searches
- GRB 231117A: OHP/T120 optical observations
- GRB 231118A: VLT/X-shooter redshift
- Fermi trigger No 722039659: Global MASTER-Net observations report
- GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
- LIGO/Virgo/KAGRA S231119u: Identification of a GW compact binary merger candidate
- GRB 231117A: AKO Follow-Up Observation
- GRB 231118A: Las Cumbres optical detection
- GRB 231118B: BALROG localization (Fermi Trigger 722039659 / GRB 231118940)
- GRB 231118A: LCOGT Optical Observations
- GRB 231118A: Enhanced Swift-XRT position
- GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
- GRB 231118A: Skynet Optical Afterglow Discovery
- LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate
- GRB 231117A: GRBAlpha detection
- LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
- GRB 231115A: Wendelstein Optical/Infrared Observations
- GRB 231115A: JinShan optical upper limits
- LIGO/Virgo/KAGRA S231118d: Identification of a GW compact binary merger candidate
- GRB 231117A: GIT optical follow-up
- GRB 231117A: LT observations consistent with fading
- GRB 231117A: REM optical and NIR early-time observations
- GRB 231117A: AKO Optical Upper Limit
- GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
- GRB 231117A (short): Glowbug gamma-ray detection
- GRB 231117A: ATLAS non-detection of an optical counterpart
- GRB 231115A : OHP/T120 optical upper limit
- GRB 231117A : MITSuME Akeno optical upper limits