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"23574 results found.
- GRB 260925A: Swift-BAT refined analysis
- Swift Trigger 1513439: consistent with noise and not astrophysical
- Fermi GRB 260926C: Global MASTER-Net observations report
- Fermi GRB 260926A: Global MASTER-Net observations report
- GRB 260924A: Near-infrared detection with MDM/MIRAGE
- GRB 260924A: COLIBRÍ optical observations
- GRB 260925A: Swift-XRT refined Analysis
- Swift Trigger 1513439 is probably not a GRB
- Konus-Wind detection of GRB 260924A
- GRB 260923A: Glowbug gamma-ray detection
- GRB 260924A: Optical follow-up observations with Kinder
- GRB 260922A: Glowbug gamma-ray detection
- GRB 260925A: COLIBRÍ optical upper limits
- GRB 260924A: Ondrejov D50 optical afterglow detection
- EP260924a: J-band upper limit with WINTER
- GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
- GRB 260925A: Swift detection of a burst
- GRB 260924A: Swift-BAT refined analysis
- GRB 260924A: Swift-XRT refined Analysis
- Konus-Wind detection of GRB 260922A
- GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
- Konus-Wind detection of GRB 260921A (possible merger-origin)
- GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
- GRB 260922A: CALET Gamma-Ray Burst Monitor detection
- The EP-WXT trigger 01709319842 is likely a flaring star
- GRB 260924A: Swift detection of a burst
- Fermi GRB 260923A: Global MASTER-Net observations report
- GRB 260922A: Ondrejov D50 optical limit
- GRB 260922A: Swift-BAT refined analysis
- EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
- GRB 260922A: J-band upper limit with WINTER
- GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
- GRB 260922A: COLIBRÍ optical upper limits
- Konus-Wind detection of GRB 260810A
- GRB 260920A: Glowbug gamma-ray detection
- GRB 260918A: SVOM/ECLAIRs refined analysis
- GRB 260921A: Swift-BAT refined analysis
- EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
- EP Alert 260921.58: Global MASTER-Net observations report
- GRB 260917B:: SVOM/ECLAIRs refined analysis
- EP260920a: VLT/HAWK-I near-infrared candidate
- Swift GRB 260921A: Global MASTER-Net observations report
- GRB 260921A: Swift detection of a burst
- EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
- EP260920b: refined analysis of the EP-WXT and EP-FXT observations
- EP260920b: COLIBRÍ optical observations
- EP Alert 260921.01: Global MASTER-Net observations report
- EP260920b: Global MASTER-Net observations report
- EP Alert 260920.66: Global MASTER-Net observations report
- EP260917a: Global MASTER-Net observations report
- EP260920a: COLIBRÍ optical upper limits
- IceCube Alert 260919A: Global MASTER-Net observations report
- EP Alert 260919.40: Global MASTER-Net observations report
- GRB 260915A: VLT optical and near-infrared upper limits
- EP260917a: refined analysis of the EP-FXT observations
- EP Alert 260918.62: Global MASTER-Net observations report
- EP Alert 260918.24: Global MASTER-Net observations report
- SVOM GRB260918.16: Global MASTER-Net observations report
- Konus-Wind detection of GRB 260916B (short/hard)
- The EP-WXT trigger 01709318279 is likely a flaring star
- GRB 260916B: Glowbug gamma-ray detection of a short burst
- IPN triangulation of GRB 260916B (short)
- EP260917A: J-band upper limit with WINTER
- IPN triangulation of GRB 260810A
- EP Alert 260917.32: Global MASTER-Net observations report
- GRB 260917B: EP-FXT follow-up observation
- EP260917a: COLIBRÍ optical upper limits
- GRB 260915A: Swift-XRT afterglow detection
- GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
- GRB 260917A: Glowbug gamma-ray detection
- GRB 260915A: SVOM/ECLAIRs refined analysis
- GRB 260917B: WINTER J-band observations
- SVOM GRB260917.16: Global MASTER-Net observations report
- GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
- Fermi trigger No 811304653: Global MASTER-Net observations report
- GRB 260915A: J-band upper limit with WINTER
- Fermi trigger No 811264269: Global MASTER-Net observations report
- GRB 260909A: NOEMA detection
- GRB 260914A: SVOM/ECLAIRs refined analysis
- GRB 260909A: Swift-XRT observations
- GRB 260916A: MAXI/GSC detection
- MAXI GRB260916.37: Global MASTER-Net observations report
- GRB 260915A: REM optical/NIR observations
- GRB 260914A: REM optical/NIR observations
- GRB 260914A: VLT/X-shooter observations and redshift confirmation
- GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 260914A: VLT/X-shooter spectroscopic redshift z = 0.778
- GRB 260915A: 10.4m GTC deep optical limits
- SVOM GRB260915.05: Global MASTER-Net observations report
- GRB 260915A: SVOM/VT optical upper limits from VHF data
- EP Alert 260914.53: Global MASTER-Net observations report
- GRB 260914A: EP-FXT follow-up observation
- GRB 260914A: SVOM/VT optical observation from VHF data
- GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
- SVOM GRB260914.47: Global MASTER-Net observations report
- GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
- SVOM GRB260913.32: Global MASTER-Net observations report
- GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
- GRB 260909A: CrAO and AbAO optical upper limits