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"
913 results found.
- GRB 221009A BOOTES-2/TELMA and OSN optical detections
- GRB 221008A: Swift-XRT observations
- GRB 221008A: Tiled Swift observations
- GRB 221008A: MAXI/GSC detection
- GRB 221006A: Swift-XRT observations
- GRB 221006A: Tiled Swift observations
- GRB 221006A: MAXI/GSC detection
- GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
- MAXI GRB220706.73: Global MASTER-Net observations report
- Trigger 1113743: Swift detection of MAXI J0655-013
- GRB 220624A: Fermi GBM Detection
- Swift Detection of MAXI J0655-013
- MAXI GRB220607.31: Global MASTER-Net observations report
- MAXI GRB220607.41: Global MASTER-Net observations report
- Konus-Wind detection of GRB 220506A
- Konus-Wind detection of GRB 220514B
- GRB 220514B: Swift-XRT observations
- GRB 220514B: Tiled Swift observations
- GRB 220514B: MAXI/GSC detection
- MAXI GRB220514.98: Global MASTER-Net observations report
- GRB 220506A: MITSuME Akeno optical upper limits
- GRB 220506A: GIT optical upper limit.
- GRB 220506A: BOOTES-5/JGT optical upper limit
- GRB 220506A: Swift-XRT afterglow detection
- GRB 220506A: Tiled Swift observations
- GRB 220506A/MAXI J1558-266: MAXI/GSC detection
- MAXI GRB220506.27: Global MASTER-Net observations report
- IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
- GRB 220310A: MITSuME Akeno optical observation
- IPN triangulation of GRB 220310A
- GRB 220310A: [KAO-Egypt] SDSS r, i observation
- Konus-Wind detection of GRB 220310A
- GRB 220310A: GIT confirmation of optical afterglow.
- GRB 220310A: MASTER optical counterpart detection
- GRB 220310A: Swift ToO observations
- GRB 220310A: CALET Gamma-Ray Burst Monitor detection
- GRB 220310A: MAXI/GSC detection
- MAXI GRB220310.02: Global MASTER-Net observations report
- GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
- GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
- GRB 211227A: CALET Gamma-Ray Burst Monitor detection
- GRB 211227A: MAXI/GSC detection
- GRB 211225A: MITSuME Akeno optical upper limits
- MAXI GRB211225.14: Global MASTER-Net observations report
- GRB 211225A/MAXI J0827-071: MAXI/GSC detection
- GRB 211218A: MITSuME Akeno optical upper limits
- GRB 211218A, MAXI J0909-041: MAXI/GSC detection
- MAXI GRB211218.04: Global MASTER-Net observations report
- GRB 211115A: CALET Gamma-Ray Burst Monitor detection
- GRB 211115A: MAXI/GSC detection
- Fermi GRB 210812A: Global MASTER-Net observations report
- MAXI GRB210709.93: Global MASTER-Net observations report
- GRB 210704A: AstroSat CZTI detection
- Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
- GRB 210607A/MAXI J1733-222: MAXI/GSC detection
- MAXI GRB210607.82: Global MASTER-Net observations report
- Konus-Wind detection of GRB 210602A
- MAXI GRB210602.50: Global MASTER-Net observations report
- GRB 210602A: CALET Gamma-Ray Burst Monitor detection
- GRB 210602A: MAXI/GSC detection
- GRB 210528B: DDOTI Upper Limits on the Afterglow
- MAXI GRB210528.95: Global MASTER-Net observations report
- GRB 210528B: MAXI/GSC detection
- MAXI GRB210521.54: Global MASTER-Net observations report
- GRB 210521A: MAXI/GSC detection
- Swift Detection of MAXI J1803-298 including an optical counterpart
- MAXI GRB210501.83: Global MASTER-Net observations report
- MAXI GRB210320.89: Global MASTER-Net observations report
- GRB 210320A: MAXI/GSC detection
- Konus-Wind detection of GRB 210222A
- GRB 210222A: CALET Gamma-Ray Burst Monitor detection
- GRB 210222A: MAXI/GSC detection
- SGR 1935+2154: MAXI/GSC detection
- NuEm-210111A: MAXI/GSC upper limit
- MAXI GRB210110.64: Global MASTER-Net observations report
- GRB 210110A: MAXI/GSC detection
- GRB 210109A: MAXI/GSC detection
- GRB 210102B: further Swift-XRT observations
- GRB 210102B: Assy optical afterglow identification
- GRB 210102B: Tiled Swift observations
- GRB 210102B: Assy optical observations
- GRB 210102B: Swift-XRT observations
- MAXI GRB210102.38: Global MASTER-Net observations report
- GRB 210102B: Tiled Swift observations
- GRB 210102B: MAXI/GSC detection
- IceCube-201209A : MAXI/GSC upper limit
- IceCube Alert 201130.85: Global MASTER-Net observations report
- MAXI GRB201021.68: Global MASTER-Net observations report
- GRB 201021B MAXI/GSC detection
- Swift GRB 201017A: Global MASTER-Net observations report
- GRB 201014A: BOOTES-1 and -2 early optical upper limits
- Fermi GRB 200916A: Global MASTER-Net observations report
- GRB 200903D: MAXI/GSC detection
- GRB 200809B: Fermi GBM detection
- GRB 200809B: Swift-XRT afterglow detection
- GRB 200809B: MAXI/GSC detection
- GRB 200615B: CALET Gamma-Ray Burst Monitor detection
- GRB 200615B: MAXI/GSC detection
- IceCube-200615A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200517A: Swift-XRT Confirmation of afterglow