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.
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"27941 results found.
- GRB 250522A: Fermi GBM Final Real-time Localization
- EP#01709176612: Swift-XRT counterpart detection of flaring star
- GRB 250521D: GOTO detects LAST counterpart candidate prior to the GRB
- GRB 250521D: LAST tentative optical counterpart candidate
- GRB 250520A: CALET Gamma-Ray Burst Monitor detection
- GRB 250521B: Swift ToO observations
- GRB 250521D: Fermi GBM Final Real-time Localization
- GRB 250521C: Fermi GBM Final Localization
- GRB 250521B: SVOM detection of a burst through offline search
- Konus-Wind detection of GRB 250520A (short/hard)
- GRB 250520A: Swift/UVOT Upper Limits
- GRB 250521A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 250516B
- IPN triangulation of GRB 250516B
- GRB 250520A: J-band observations with WINTER
- GRB 250520A: Swift-XRT refined Analysis
- GRB 250520A: REM optical/NIR early observations
- GRB 250520B: Fermi GBM Final Real-time Localization
- GRB 250520A:SVOM/VT optical candidate
- GRB 250520A: COLIBRÍ optical upper limit
- GRB 250520A: DDOTI Optical Upper Limit
- GRB 250520A: AstroSat CZTI detection of a short burst
- GRB 250516B: GRBAlpha detection
- GRB 250520A: SVOM/GRM observation
- GRB 250520A: Enhanced Swift-XRT position
- GRB 250520A: GOTO optical upper limit
- GRB 250520A: Prompt enhanced Swift-XRT position
- GRB 250520A: Swift detection of a burst
- Swift GRB 250520A: Global MASTER-Net observations report
- GRB 250516B: Insight-HXMT detection
- EP250427a/GRB250427A: VLA Detection of Radio Counterpart
- GRB 250516A: Swift-BAT refined analysis
- Konus-Wind detection of GRB 250516A
- GRB 250516B: NuSTAR Detection of the Prompt Emission
- EP-WXT trigger (ID: 01709176312): a new X-ray outburst of HMXB RX J0111.2-7317
- GRB 250515A: Swift-XRT observations
- Swift GRB 250516A: Global MASTER-Net observations report
- GRB 250515A: 1.6m Mephisto optical detection
- GRB 250516A: AstroSat CZTI detection
- GRB 250516A: Fermi GBM Observation
- GRB 250516A: Swift-XRT refined Analysis
- GRB 250516A: Swift/UVOT Detection
- GRB 250515A: Swift ToO observations
- GRB 250516B: GECAM-B detection of a bright long burst
- GRB 250516A: Enhanced Swift-XRT position
- GRB 250516A: Swift detection of a burst
- GRB 250516A: Fermi GBM Final Real-time Localization
- GRB 250515A: Fermi GBM Final Localization
- GRB 250424A: COLIBRÍ detection of the associated supernova
- Konus-Wind detection of GRB 250512B / EP250512a
- GRB 250502A: TESS observations
- GRB 250511A: GECAM-A detection of a short burst
- GRB 250509A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Final Epochs)
- Konus-Wind detection of GRB 250506A
- GRB 250507B: AstroSat CZTI detection
- GRB 250507B: GRBAlpha detection
- GRB 250506A: GRBAlpha detection
- GRB 250512B: SVOM detection of a burst
- EP250512a: Einstein Probe detection of an X-ray transient
- GRB 250512A: Fermi GBM Final Real-time Localization
- EP250511a: BOOTES-5 optical upper limit
- EP250511a: Einstein Probe detection of an X-ray transient
- GRB 250510B: Fermi GBM Observation
- GRB 250510C: Fermi GBM Final Real-time Localization
- GRB 250510A: Swift-XRT observations
- GRB 250509A: Fermi GBM Observation
- GRB 250510A: follow-up observation with EP-FXT
- GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
- GRB 250510B: Fermi GBM Final Localization
- GRB 250509A: Swift-XRT refined Analysis
- GRB 250510A: SVOM possible detection of a burst
- GRB 250507A: J-band observations with WINTER
- GRB 250509A: Enhanced Swift-XRT position
- GRB 250509A: Prompt enhanced Swift-XRT position
- Swift GRB 250509A: Global MASTER-Net observations report
- GRB 250509A: Swift detection of a burst
- GRB 250509A: Fermi GBM Final Real-time Localization
- GRB 250506A: NOT optical upper limits
- EP250508a: Liverpool Telescope optical upper limits
- EP250508a: follow-up observation with EP-FXT
- GRB 250506A: GECAM detection
- GRB 250506A: Swift-XRT afterglow detection
- EP250508a: Einstein Probe detection of an X-ray transient
- GRB 250507A: Swift-XRT refined Analysis
- GRB 250506A: Swift/UVOT Upper Limits
- GRB 250427B : SVOM detection of a burst through offline search
- GRB 250430A / EP250430a: AstroSat CZTI detection
- EP#01709175213/IGR J19566+0326: Swift-XRT detection
- GRB 250506A: Swift-XRT observations
- EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
- GRB 250507A: SVOM detection of a long burst
- GRB 250504A: EIRSAT-1 GMOD Detection
- GRB 250506A: Swift ToO observations
- IceCube-250506A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 250430A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
- GRB 250506A: SVOM improved position and MXT detection of a fading X-ray afterglow
- GRB 250506A: Swift XRT observations and possible counterpart detection
- GRB 250506A: TRT optical observations
- GRB 250506A: SVOM detection of a burst