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"
32190 results found.
- GRB 241217A/EP241217b: continued SOAR observations
- Fermi GRB 241226A: Global MASTER-Net observations report
- GRB 241226A: Fermi GBM Final Real-time Localization
- EP241223a: Mondy AZT-33IK optical observations
- GRB 241029A: LCO optical observation
- GRB 241223A: Swift-XRT observations
- GRB 241029A: AbAO AS-32 optical observations
- GRB 241223A: Fermi GBM Detection
- GRB 241219A: SVOM/GRM observation
- GRB241113A: 7DT Optical upper limits
- Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
- Fermi GRB 241223A: Global MASTER-Net observations report
- GRB 241223A: GOTO optical observations summary
- GRB 241105A: JWST photometric observations of the host galaxy
- GRB 241223A: Swift ToO observations
- GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
- GRB 241223A: Fermi GBM Final Real-time Localization
- GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
- GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
- Fermi Gamma-ray Burst Monitor trigger 756447119/241221175 is not a GRB
- Fermi GRB 241221A: Global MASTER-Net observations report
- GRB 241221A: Fermi GBM Final Real-time Localization
- GRB 241217A/EP241217b: SOAR afterglow detection
- GRB 241218A: Mondy AZT-33IK optical upper limit
- EP241217a : Leavitt Observatory optical upper limit
- GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
- GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
- GRB 241218A: Swift/UVOT Upper Limits
- GRB 241209B: EP-FXT afterglow detection
- Konus-Wind detection of GRB 241204A (short/hard)
- GRB 241218A: NOT optical upper limits
- GRB 241218A: Swift-BAT refined analysis
- GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
- GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
- GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
- GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
- GRB 241217A / EP241217b: NOT optical upper limits
- GRB 241218A: REM optical upper limit
- GRB 241217A/EP241217b: REM optical/NIR upper limits
- GRB 241218a: Liverpool Telescope optical follow-up
- GRB 241217a: Liverpool Telescope optical follow-up
- GRB 241218A: Swift-XRT refined Analysis
- GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
- GRB 241209A: ATCA radio follow-up observations
- EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
- GRB 241218A: LCOGT Optical Upper Limit
- GRB 241218A: Enhanced Swift-XRT position
- GRB 241217A: GMG Optical Upper Limit
- GRB 241218A: Swift detection of a burst
- GRB 241217A : SVOM/VT optical afterglow detection
- GRB 241217A: Swift-XRT afterglow detection
- GRB 241217A: LCO optical upper limit
- GRB 241217A: GRANDMA/TAROT optical upperlimits
- EP241217A: Non-detection from Fermi-GBM Observations
- GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
- GRB 241214A: GRBAlpha detection
- GRB 241213A (EP241213a): GRBAlpha detection
- GRB 241209D: GRBAlpha detection
- GRB 241213A: Swift-BAT refined analysis
- GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
- Konus-Wind detection of GRB 241213A (EP 241213a)
- GRB 241215A: Mondy AZT-33IK optical observations
- GRB 241212A: Swift-XRT observations
- GRB 241214A: SVOM/GRM observation
- GRB 241215A: Nanshan/HMT optical upper limit
- GRB 241215A: Montarrenti Observatory optical upper limit
- GRB 241215A: GROWTH-India telescope optical upper limit
- GRB 241215A: A long GRB detected by INTEGRAL
- GRB 241213B: Swift-XRT observations
- GRB 241209D: CALET Gamma-Ray Burst Monitor detection
- GRB 241209B: SVOM/VT optical continuous fading
- GRB 241213A: SVOM/VT optical candidate
- GRB 241213B: Tiled Swift observations
- GRB 241213A: Swift/UVOT Upper Limits
- GRB 241213B: CALET Gamma-Ray Burst Monitor detection
- GRB 241213A: Swift-XRT refined Analysis
- GRB 241212A: Fermi GBM detection
- GRB 241212A: Swift ToO observations
- GRB 241213A: LCOGT Optical Upper Limits
- EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
- GRB 241213B: MAXI/GSC detection
- GRB 241213A: REM optical/NIR upper limits
- GRB 241213A: Enhanced Swift-XRT position
- GRB241212A: OHP/T193 optical observations
- GRB 241213A: SAO RAS optical upper limit
- Swift GRB 241213A: Global MASTER-Net observations report
- GRB 241213A: Swift detection of a burst
- GRB 241212A : SVOM/C-GFT optical upper limit at early phase
- GRB 241212A : SVOM/VT bright optical afterglow
- GRB 241212A: AstroSat CZTI detection
- GRB 241209B: GRANDMA/TRT upper limit
- GRB 241207A: TSHAO Zeiss-1000 optical observations
- GRB 241212A: SVOM detection of a bright long burst
- GRB 241212A: Fermi GBM Final Real-time Localization
- GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
- GRB 241209A: Chandra X-ray Detection
- Konus-Wind detection of GRB 241209B
- GRB 241207A: EIRSAT-1 GMOD Detection
- GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
- GRB 241209B: GRBAlpha detection