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').
777 results found.
- GRB 241229B: SAO RAS optical upper limit
- GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
- GRB 241229A: SAO RAS optical observations
- GRB 241229B: SVOM/VT optical candidate
- GRB 241229A: Swift-XRT observations
- GRB 241229A: EP-FXT afterglow candidates
- GRB 241229A: Swift ToO observations
- GRB 241229A: GOTO optical upper limits
- GRB 241229A: SVOM detection of a long burst
- GRB 241212A: VZLUSAT-2 detection
- GRB 241217A/EP241217b: continued SOAR observations
- GRB 241219A: SVOM/GRM observation
- GRB 241105A: JWST photometric observations of the host galaxy
- GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
- GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
- GRB 241217A/EP241217b: SOAR afterglow detection
- GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
- GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
- GRB 241209B: EP-FXT afterglow detection
- 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 241217A/EP241217b: REM optical/NIR upper limits
- GRB 241217a: Liverpool Telescope optical follow-up
- GRB 241217A: GMG Optical Upper Limit
- 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
- GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
- GRB 241214A: GRBAlpha detection
- GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
- GRB 241212A: Swift-XRT observations
- GRB 241214A: SVOM/GRM observation
- GRB 241209B: SVOM/VT optical continuous fading
- GRB 241213A: SVOM/VT optical candidate
- GRB 241212A: Fermi GBM detection
- EP241208a: NOT optical upper limits
- GRB 241212A: Swift ToO observations
- EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
- GRB241212A: OHP/T193 optical observations
- 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 241212A: SVOM detection of a bright long burst
- Konus-Wind detection of GRB 241209B
- GRB 241209B: GRBAlpha detection
- GRB 241206C: GRBAlpha detection
- GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
- GRB 241209B: Swift-XRT afterglow detection
- GRB 241209B: SVOM/VT afterglow detection
- GRB 241209D: COLIBRÍ detection of the afterglow
- GRB 241209A: COLIBRÍ Optical Upper Limit
- GRB 241209B: BOOTES-5 optical upper limit
- GRB 241209B: Swift ToO observations
- GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
- GRB 241206C: SVOM/GRM observation of a likely short burst
- GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
- GRB 241206B: GWAC-F50A optical upper limit
- GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
- GRB 241204A: COLIBRÍ Optical Upper Limit
- GRB 241127B: detection of a long GRB by SVOM/ECLAIRs
- IPN triangulation of GRB 241128B
- SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
- GRB 241128C: SVOM/GRM observation
- GRB 241128B: SVOM/GRM observation
- EP241126a: SVOM/VT observations
- GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
- GRB 241127A: SVOM/GRM observation
- SVOM/GRM observation of GRB 241126B or a short burst from magnetar
- GRB 241126A: SVOM/GRM observation
- LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
- GRB 241113B: EP-FXT afterglow detection
- SVOM/GRM detection of a short burst from SGR 1830
- Konus-Wind detection of GRB 241115D / EP 241115a
- GRB 241026A: radio detection with the VLA
- LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
- GRB 241113B: SVOM/VT optical afterglow observations
- Konus-Wind detection of GRB 241117A
- GRB 241105A: ATCA radio detection
- IPN triangulation of GRB 241117A
- GRB 241025A: VIRT Optical Upper Limit
- GRB 241112B: Mephisto further optical observations
- GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
- GRB 241117A: SVOM/GRM observation of a short burst with extended emission
- EP241115a/GRB 241115D: Optical upper limits with Kinder observations
- GRB 241113B: Mephisto upper limits
- GRB 241115D / EP 241115a: SVOM/GRM observation
- GRB 241113B: KAIT Optical Afterglow Candidate
- GRB 241113B: J-band upper limit from WINTER
- GRB 241113B: Swift-XRT observations
- EP241113b/GRB 241113B: EP detection of GRB 241113B
- GRB 241113B: SVOM/GRM observation
- EP241107a: SOAR upper limits
- Konus-Wind detection of GRB 241107A (short/hard)
- GRB 241113B: Swift ToO observations
- GRB 241112B: GMG Optical Upper Limit