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').
18148 results found.
- 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
- EP241021a: Swift-UVOT detection
- GRB241030B: GRANDMA/TAROT Upper Limit
- GRB 241030A: Swift-XRT refined Analysis
- GRB 241030B: AKO Optical Afterglow Detection
- GRB 241030B: Nanshan/HMT optical afterglow detection
- GRB 241030B: SVOM/ECLAIRs detection of a burst
- GRB 241030B: Prompt enhanced Swift-XRT position
- Konus-Wind detection of GRB 241030A
- GRB 241030B: Swift detection of a burst
- GRB 241030A: Fermi-LAT detection
- GRB 241030A: AKO Optical Afterglow Detection
- Swift GRB 241030A: Global MASTER-Net observations report
- GRB 241030A: Swift/UVOT Detection
- EP 241021a: further Swift-XRT observations and X-ray counterpart detection
- GRB 241030A: SVOM/GRM observation
- GRB 241026A: Swift-BAT refined analysis
- GRB 241030A: SVOM/C-GFT optical observations
- GRB 241030A: Multiband optical detection with Mephisto
- GRB 241030A: SVOM/VT optical afterglow observations
- GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
- GRB 241030A : MITSuME Akeno optical afterglow detection
- GRB 241030A: Enhanced Swift-XRT position
- GRB 241030A: TRT optical observations
- GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
- GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
- GRB 241030A: Swift detection of a burst with a bright optical counterpart
- GRB 241026A: Swift/UVOT Upper Limits
- GRB 241029A: Swift-XRT observations
- GRB 241029A: Swift ToO observations
- GRB 241026A: the 100th GRB detected by GRBAlpha
- Konus-Wind detection of GRB 241025A
- GRB 241026A: GECAM detection
- GRB 241026A: SVOM/GRM observation
- GRB 241025A: Swift/UVOT Detection
- GRB 241026A: GROWTH-India Telescope optical observations
- GRB 241026A Fermi GBM Analysis
- GRB 241026A: J-band observations with WINTER
- GRB 241025A: SAO RAS optical observations
- GRB 241026A: Las Cumbres optical detection
- GRB 241025A: Mondy optical observations
- GRB 241026A: Swift-XRT refined Analysis
- GRB 241026A: Enhanced Swift-XRT position
- GRB 241026A: KAIT optical observations
- GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
- GRB 241026A: SAO RAS observations of possible optical afterglow
- GRB 241026A: Prompt enhanced Swift-XRT position
- GRB 241026A: Swift detection of a burst
- Swift GRB241026.95: Global MASTER-Net observations report
- GRB241025A: 1.3m DFOT optical afterglow detection
- GRB 241025A: GROWTH-India Telescope optical observations
- GRB 241025A: COLIBRÍ Detection of the Afterglow
- GRB 241025A: Swift-XRT refined Analysis
- GRB 241025A: Fermi GBM Observation
- IPN triangulation of GRB 241022A (short/hard)
- LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
- GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
- EP 241021a: Swift-XRT observations
- Swift GRB 241025A: Global MASTER-Net observations report
- EP241025a (GRB 241025A): EP observations update
- EP 241021A: Swift ToO observations
- GRB 241025A: Enhanced Swift-XRT position
- GRB 241025A: NOT spectroscopic redshift of z = 4.20
- GRB 241025A: DDOTI Afterglow detection
- EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
- GRB 241025A: SVOM/GRM observation
- GRB 241025A: TRT optical afterglow observation
- GRB 241025A: Swift detection of a burst with an optical counterpart