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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
31191 results found.
- GRB 241229A: EP-FXT afterglow candidates
- GRB 240606B: 7DT Optical upper limits
- GRB 241229B: Swift-BAT refined analysis
- Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB
- GRB241229B: UVOT upper limits
- GRB 241229C: Fermi GBM Final Real-time Localization
- GRB 241228B: D50 optical detection
- GRB 241228B: Fermi GBM Observation
- GRB 241228B: Swift-XRT afterglow detection
- GRB 241229B: Fermi GBM Observation
- GRB 241229A: Swift ToO observations
- GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
- GRB 241228A: Mondy optical afterglow observations
- GRB 241229B: Swift-XRT refined Analysis
- Swift GRB 241229B: Global MASTER-Net observations report
- GRB 241229A: GOTO optical upper limits
- GRB 241228B: VLT/X-shooter redshift of z = 2.674
- GRB 241228A: NOT optical upper limits
- GRB 241228B: LCO optical observation
- GRB 241228A: Swift-BAT refined analysis
- GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
- GRB 241229B: Swift detection of a burst
- GRB 241229B: Fermi GBM Final Real-time Localization
- GRB 241229A: SVOM detection of a long burst
- Fermi GRB 241228B: Global MASTER-Net observations report
- GRB 241228A: Fermi GBM Observation
- GRB241228B: GROWTH-India Telescope optical observations
- Swift GRB 241228A: Global MASTER-Net observations report
- GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
- GRB 241228B: GOTO24jmz optical follow-up observations
- GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
- GRB 241228A: GROWTH-India telescope optical upper limit
- GRB 241228B: Swift ToO observations
- GRB 241228B: TRT optical counterpart confirmation
- GRB 241228A: Swift-XRT refined Analysis
- GRB 241228A: Swift/UVOT Upper Limits
- GRB 241228B: GOTO possible optical counterpart candidate
- GRB 241228A: Enhanced Swift-XRT position
- GRB 241228B: Fermi GBM Final Real-time Localization
- GRB 241228A: Swift detection of a burst
- GRB 241223A: GRBAlpha detection
- GRB 241212A: VZLUSAT-2 detection
- 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