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"- Swift GRB230913.70: Global MASTER-Net observations report
- GRB 230913A: Fermi GBM Observation
- LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
- Swift Trigger 1191904 is not a GRB
- Swift GRB230913.70: Global MASTER-Net observations report
- Swift Trigger 1191903 is not an astrophysical event
- GRB 230911A: Swift ToO observations
- GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
- Fermi GRB 230913A: Global MASTER-Net observations report
- GRB 230911A: GOTO optical counterpart candidate
- GRB 230913A: Fermi GBM Final Real-time Localization
- GRB 230908A: CALET Gamma-Ray Burst Monitor detection
- GRB 230911D: NuSTAR Detection of Prompt Emission
- GRB 230911B: AstroSat CZTI detection
- GRB 230911C: Swift-XRT refined Analysis
- GRB 230911C: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S230911ae: Updated Sky localization
- GRB230911C: BOOTES-6/DPRT optical upper limit
- GRB 230906A: Chandra detection of the X-ray afterglow
- Swift GRB 230911C: Global MASTER-Net observations report
- GRB 230911D: Fermi GBM observation
- IPN triangulation of GRB 230911D (long)
- GRB 230911D: Fermi-LAT detection
- GRB230911C: LCOGT Optical Upper Limits
- LIGO/Virgo/KAGRA S230911ae: Identification of a GW compact binary merger candidate
- GRB 230911C: Swift/UVOT Upper Limits
- GRB 230911B: GRBAlpha and VZLUSAT-2 joint detection
- Fermi trigger No 716145795: Global MASTER-Net observations report
- GRB 230911C: GOTO optical upper limits
- GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- GRB 230911B: correction to the KW GCN 34659
- Konus-Wind detection of GRB 230811D
- GRB 230911C: Enhanced Swift-XRT position
- GRB 230911D: BALROG localization (Fermi Trigger 716111594/ GRB 230911329)
- GRB 230911D: Fermi GBM Final Localization
- GRB 230911C: Swift detection of a burst
- Fermi GRB 230911B: Global MASTER-Net observations report
- GRB 230911B: Fermi GBM Final Real-time Localization
- GRB 230911A: Fermi GBM Final Real-time Localization
- GRB 230906A: BlackGEM upper limits
- GRB 230903A: TESS observations of optical emission
- GRB 230906A: AstroSat CZTI detection
- GRB 230910A: Fermi GBM Final Real-time Localization
- GRB 230908A: GRBAlpha detection
- LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches
- GRB 230908A: AstroSat CZTI detection
- Glowbug gamma-ray detection GRB 230905B
- GRB 230906A: Swift/UVOT Upper Limits
- GRID detection of GRB 230827A
- GRB 230818A: radio observation with the VLA
- GRB 230205A: LBT spectroscopy of two host galaxy candidates
- GRB 230906A: Swift-XRT observations
- Konus-Wind detection of GRB 230906A (short)
- IPN triangulation of GRB 230906A (short)
- GRB 230906A: Swift ToO observations
- GRB 230905B: AstroSat CZTI detection
- Fermi GRB 230906A: Global MASTER-Net observations report
- Swift Attitude Control Affecting Some UVOT Images
- GRB 230812B: Chandra late-time detection of the X-ray afterglow
- GRB 230906A: Fermi GBM Final Localizationn
- GRB 230905B: GECAM-C detection of a long burst
- LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification
- GRB 230905A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S230819ax: Correction to PROB_BBH and PROB_TERRES probabilities
- GRB 230903A: Swift-XRT refined Analysis
- GRB 230903A: Enhanced Swift-XRT position
- GRB 230903A: VLT/X-shooter optical observations
- GRB 230903A: Swift-BAT refined analysis
- GRB 230904C: Fermi GBM Final Localization
- Fermi trigger No 715552087: Global MASTER-Net observations report
- Fermi trigger No 715429986: Global MASTER-Net observations report
- Fermi GRB 230903A: Global MASTER-Net observations report
- GRB 230903A: Fermi GBM detection
- GRB 230904B is not a GRB
- LIGO/Virgo/KAGRA S230904n: 1 counterpart neutrino candidate from IceCube neutrino searches
- GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
- Fermi GRB 230904A: Global MASTER-Net observations report
- GRB 230904A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S230904n: Identification of a GW compact binary merger candidate
- GRB 230903A: LCOGT Optical Upper Limits
- GRB 230903A: Swift detection of a burst
- Swift GRB230903.72: Global MASTER-Net observations report
- GRB 230903A: Fermi GBM Final Real-time Localization
- Integral GRB230902.00: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230831e: Updated Sky localization
- LIGO/Virgo/KAGRA S230831e: Identification of a GW compact binary merger candidate
- GRB 230827B: Glowbug gamma-ray detection
- GRB 230827A: Glowbug gamma-ray detection
- GRB 230826A: Glowbug gamma-ray detection
- GRB 230827B: Swift-XRT afterglow detection
- LIGO/Virgo/KAGRA S230715bw: Reissue of Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230830b: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230820bq: Updated Sky localization
- GRB 230812B: Spectroscopic detection of the associated SN 2023pel.
- GRB 230827B: Swift ToO observations
- LIGO/Virgo/KAGRA S230814ah: Updated Sky localization
- GRB 230827A: Fermi GBM Observation
- GRB 230827B: CALET Gamma-Ray Burst Monitor detection
- GRB 230826A: Swift-BAT refined analysis
- GRB 230828A: AstroSat CZTI detection