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').
23953 results found.
- GRB 241228A: Mondy optical afterglow observations
- 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 241228A: Fermi GBM Observation
- GRB241228B: GROWTH-India Telescope optical observations
- GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
- GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
- GRB 241228A: GROWTH-India telescope optical upper limit
- GRB 241228B: TRT optical counterpart confirmation
- GRB 241228A: Swift-XRT refined Analysis
- GRB 241228A: Swift/UVOT Upper Limits
- GRB 241228A: Enhanced Swift-XRT position
- GRB 241228A: Swift detection of a burst
- IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
- GRB 241212A: VZLUSAT-2 detection
- EP241223a: Mondy AZT-33IK optical observations
- GRB 241029A: LCO optical observation
- GRB 241223A: Swift-XRT observations
- LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
- GRB 241029A: AbAO AS-32 optical observations
- GRB 241223A: Fermi GBM Detection
- Fermi trigger No 756678579: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
- EP241223a
- EP241223a: EP-WXT detection of a fast X-ray transient
- EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
- GRB241113A: 7DT Optical upper limits
- GRB 241223A: GOTO optical observations summary
- GRB 241105A: JWST photometric observations of the host galaxy
- EP241217a: e-MERLIN radio observations
- GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
- The EP-WXT trigger 01709129287 is likely a flaring star
- EP241217a: Liverpool Telescope optical upper limit
- EP241021a: VLA radio 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
- EP241217a: 1.6m Mephisto multi-band optical observations
- GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
- GRB 241218A: Swift/UVOT Upper Limits
- EP241217a: optical upper limit with the Liverpool Telescope
- GRB 241209B: EP-FXT afterglow detection
- GRB 241218A: NOT optical upper limits
- GRB 241218A: Swift-BAT refined analysis
- GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
- EP 241217a: NIR detection with P200/WIRC
- EP 241217a: Possible J-band detection with WINTER
- GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
- EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
- GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
- GRB 241217A / EP241217b: NOT optical upper limits
- GRB 241218A: REM optical upper limit
- GRB 241217A/EP241217b: REM optical/NIR upper limits
- EP241217a: REM optical/NIR upper limits
- GRB 241217a: Liverpool Telescope optical follow-up
- EP241217a: Liverpool Telescope optical follow-up
- GRB 241218A: Swift-XRT refined Analysis
- EP241217a: NOT optical observations
- EP241217a: GROWTH-India Telescope optical observations
- GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
- EP241119a: 7DT Optical upper limits
- EP241217a: Xinglong optical 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: Swift-XRT Detection
- 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
- EP241217a: Kinder optical follow-up observations
- EP241217A: LCO optical observations
- EP241217a: Gemini-North detection of the likely optical counterpart
- EP241217a: EP detection of an X-ray transient
- EP241107a: VLA Radio Observation
- GRB 241213A: Swift-BAT refined analysis
- GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
- GRB 241215A: Mondy AZT-33IK optical observations
- GRB 241212A: Swift-XRT observations
- 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
- Integral GRB241215.58: Global MASTER-Net observations report
- GRB 241213B: Swift-XRT observations
- GRB 241213A: Swift/UVOT Upper Limits
- GRB 241213A: Swift-XRT refined Analysis
- GRB 241212A: Fermi GBM detection
- EP241208a: NOT optical upper limits
- GRB 241213A: LCOGT Optical Upper Limits
- GRB 241213B: MAXI/GSC detection