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').
18310 results found.
- LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
- LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
- LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
- EP241125a: EP detection of an X-ray transient
- LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
- LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
- LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
- LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
- LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
- LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
- LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
- Konus-Wind detection of GRB 241117A
- IPN triangulation of GRB 241117A
- GRB 241025A: VIRT Optical Upper Limit
- GRB 241115A: CALET Gamma-Ray Burst Monitor detection
- GRB 241115a: PRIME near-infrared upper limits
- GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
- LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
- GRB 241115B: Fermi GBM Observation
- GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
- GRB 241115C: Fermi GBM Observation
- GRB 241115A: Swift-XRT afterglow detection
- EP241115a/GRB 241115D: Optical upper limits with Kinder observations
- EP241115a/GRB 241115D: Swift/XRT follow-up observation
- EP241113a: Swift XRT weak detection
- GRB 241115A: Fermi GBM Observation
- GRB 241115A: LCOGT Optical Upper Limits
- GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
- Swift GRB 241115A: Global MASTER-Net observations report
- GRB 241115A: Swift detection of a burst
- GRB 241113A: Swift-BAT refined analysis
- GRB 241113A: PRIME near-infrared upper limits
- GRB 241113A: J-band observations with WINTER
- GRB 241113B: Swift-XRT observations
- GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
- GRB 241113A: KAIT optical observations
- GRB 241113A: Swift-XRT refined Analysis
- GRB 241113A: Swift/UVOT Detection
- GRB 241113A: REM detection of the optical/NIR afterglow
- Konus-Wind detection of GRB 241107A (short/hard)
- GRB 241113B: Swift ToO observations
- GRB 241113A: LCO optical observations
- GRB 241113A: Enhanced Swift-XRT position
- GRB241113A: LCOGT (40-cm) optical counterpart detection
- GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
- GRB 241113A: Swift detection of a burst with an optical counterpart
- Swift GRB241113.33: Global MASTER-Net observations report
- GRB 241107A: GROWTH-India telescope optical upper limit
- GRB 241112B: Swift-XRT afterglow detection
- GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
- GRB 241112B: Swift ToO observations
- GRB 241107A: INTEGRAL IBIS localization
- IPN triangulation of GRB 241107A (short/hard)
- GRB 241025A: VZLUSAT-2 detection
- GRB 241108A: Swift-XRT observations
- GRB 241108A: Swift ToO observations
- GRB 241030A: TESS observations
- GRB 241105A: EP-FXT follow-up observations
- GRB 241105A: SVOM/GRM observation
- GRB 241105a: PRIME near-infrared upper limits
- GRB 241105A: Swift/UVOT Detection
- GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
- GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
- GRB 241105A: BOOTES-7 optical detection
- GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
- GRB 241105A: Swift-XRT afterglow detection
- GRB 241104A: Swift-XRT observations
- GRB 241105A: Swift ToO observations
- GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 241104A: Swift ToO observations
- GRB 241030A: GRBAlpha detection
- EP241103a: GIT optical upper limit
- EP241103a: GOTO optical upper limit
- EP241103a: Swift XRT detection and improved X-ray position
- GRB 241030A: Swift-UVOT observations of the optical prompt flare
- GRB 241030A: Rapid release of TESS data.
- Swift GRB 241101A: Global MASTER-Net observations report
- GRB 241101A: FRAM-ORM optical limit
- GRB 241101A: Swift-BAT refined analysis
- GRB 241030B: Swift-XRT refined Analysis
- GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
- GRB 241101A: Swift detection of a burst
- GRB 241030B: Montarrenti Observatory optical upper limit
- GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
- GRB 241030A: Fermi GBM Observation
- GRB 241030B: LCOGT Optical Upper Limits
- GRB 241030B: Swift-BAT refined analysis
- GRB 241030A: Swift-BAT refined analysis
- GRB 241030B: Swift/UVOT Detection
- GRB 241029A: LCO optical detection
- Swift GRB241030.77: Global MASTER-Net observations report
- GRB 241030B: SVOM/GRM observation
- GRB 241030B : MITSuME Akeno optical upper limits
- GRB 241030A: COLIBRI Continuing Detection of the Afterglow
- GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
- GRB241030B: Fermi GBM Observation
- GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
- GRB 241030B: Enhanced Swift-XRT position
- GRB 241030B: optical observations from the INAF Asiago Observatory