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"28050 results found.
- GRB 230911D: Fermi GBM observation
- IPN triangulation of GRB 230911D (long)
- 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 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- GRB 230911C: Enhanced Swift-XRT position
- GRB 230911D: BALROG localization (Fermi Trigger 716111594/ GRB 230911329)
- GRB 230911C: Swift detection of a burst
- GRB 230906A: BlackGEM upper limits
- GRB 230903A: TESS observations of optical emission
- GRB 230906A: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches
- Glowbug gamma-ray detection GRB 230905B
- GRB 230906A: Swift/UVOT Upper Limits
- GRB 230818A: radio observation with the VLA
- GRB 230205A: LBT spectroscopy of two host galaxy candidates
- GRB 230906A: Swift-XRT observations
- GRB 230812B: Chandra late-time detection of the X-ray afterglow
- GRB 230905B: GECAM-C detection of a long burst
- LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification
- 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
- Fermi trigger No 715429986: Global MASTER-Net observations report
- GRB 230903A: Fermi GBM detection
- LIGO/Virgo/KAGRA S230904n: 1 counterpart neutrino candidate from IceCube neutrino searches
- GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
- 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
- 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 S230820bq: Updated Sky localization
- LIGO/Virgo/KAGRA S230814ah: Updated Sky localization
- GRB 230827A: Fermi GBM Observation
- GRB 230826A: Swift-BAT refined analysis
- GRB 230827A: VZLUSAT-2 detection
- GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 230826A: VZLUSAT-2 detection
- GRB 230827B: VZLUSAT-2 detection
- GRB 230827B / GRB 230827256: Fermi GBM Observation
- Subject: GRB230826A: Swift/UVOT upper limits
- GRB 230827A: BALROG localization (Fermi Trigger / GRB 230827762)
- GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
- AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
- Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
- GRB 230826A: Fermi GBM Observation
- Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
- GRB 230826A: Enhanced Swift-XRT position
- GRB 230826A: Swift-XRT refined Analysis
- GRB 230826A: Mondy optical observations
- Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
- GRB 230826A: Swift detection of a burst
- Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
- LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
- Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
- GRB 230812B: radio detection with the VLA
- LIGO/Virgo/KAGRA S230825k: Updated Sky localization
- LIGO/Virgo/KAGRA S230825k: Identification of a GW compact binary merger candidate
- GRB 230824A: AKO Optical Afterglow Candidate
- LIGO/Virgo/KAGRA S230824r: Updated Sky localization
- LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
- GRB 230822A: Swift/BAT-GUANO detection of a burst
- GRB 230818B: VZLUSAT-2 detection
- LIGO/Virgo/KAGRA S230822bm: Updated Sky localization
- LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate
- GRB 230812B: Assy optical observations, possible SN rise
- GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
- GRB 230818A: Swift-BAT refined analysis
- GRB 20230818A: GIT optical upper limit
- GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
- LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
- Swift Triggers 1186280 and 1186291 are not GRBs
- GRB 230818A: Fermi GBM Observation
- GRB 230812B: GIT Confirmation of SN rise
- LIGO/Virgo/KAGRA S230819ax: Updated Sky localization
- GRB 230818A: Nickel and KAIT telescope optical observations
- GRB 230812B: SAO RAS Zeiss-1000 observations
- GRB 230818A: further SAO RAS Zeiss-1000 observations
- LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate
- GRB 230818A: AKO Upper Limit
- GRB 230818A: Tautenburg observations
- GRB 230818A: Leavitt Observatory upper limit
- GRB 230818A: Swift-XRT refined Analysis
- GRB 230818A: Bassano Bresciano Observatory optical observations
- GRB 230818A: KGO RC-25 optical observations
- GRB 230818A: Swift/UVOT Detection
- GRB 230818A: Enhanced Swift-XRT position
- GRB 230818A: SAO RAS Zeiss-1000 observations
- Fermi trigger No 713974668: Global MASTER-Net observations report