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').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"25891 results found.
- IPN triangulation of GRB 240123C (short)
- Swift trigger 1210856 is not astrophysical
- GRB 240123A: Swift-BAT refined analysis
- GRB 240123A: Mondy continued optical observations and the PL decay index
- GRB 240123A : MITSuME Akeno optical afterglow candidate detection
- GRB 240123A: Enhanced Swift-XRT position
- GRB 240122A: Swift/UVOT Upper Limits
- GRB 240123A: Swift-XRT refined Analysis
- GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
- Fermi GBM Sub-Threshold Detection of GRB 240123A
- GRB 240123A: Mondy continued optical observations + correction of the GRB name in GCN 35605
- GRB 240118A: Swift/UVOT Upper Limits
- GRB 240123A: Mondy optical afterglow observations
- GRB 240123A: Swift detection of a burst with a possible optical counterpart
- Swift GRB240123.46: Global MASTER-Net observations report
- GRB 240122A: Swift-XRT afterglow detection
- GRB 240122A: Redshift from OSIRIS+/GTC
- GRB 240122A: Tiled Swift observations
- IPN triangulation of GRB 240119A (short)
- GRB 240118C: GECAM-B detection of a long burst
- GRB 240118A: Mondy optical observations
- GRB 240118A: Swift-XRT afterglow detection
- GRB 240118C: Fermi GBM Observation
- GRB 240118C: Swift/BAT-GUANO detection of a burst
- GRB 240118A: GRBAlpha detection
- GRB 240115A: Fermi GBM Observation
- Swift triggers 1209631, 1209632, 1209635 and 1209644 are not interesting astrophysical events
- GRB 240118A: Swift ToO observations
- GRB 240118A: AbAO optical upper limit
- GRB 240118A: NuSTAR Offline Analysis of the GRB
- GRB 240118A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 240118A: Fermi-LAT detection
- GRID detection of GRB 231230A
- GRB 240115A: Swift/BAT-GUANO detection of a short burst
- Swift Trigger 1209406 is not an astrophysical event
- Swift Triggers 1209401 and 1209403 are not astrophysical events
- Swift Triggers 1209371 through 1209374 are not astrophysical events
- Swift Triggers 1209369 and 1209370 are not astrophysical events
- LIGO/Virgo/KAGRA S240109a: Upper limits from Swift/BAT-GUANO
- GRB 240112C: Glowbug gamma-ray detection
- GRB 240112C: VZLUSAT-2 detection
- Konus-Wind detection of GRB 240112C
- GRB 240112C: GRBAlpha detection
- GRB 240112C: Swift/UVOT Detection
- GRB 240112C: Fermi GBM Detection
- GRB 240112C: Swift-XRT refined Analysis
- GRB 240112C: SAO RAS optical observations
- Swift GRB 240112C: Global MASTER-Net observations report
- GRB 240109A: Swift-BAT refined analysis
- GRB 240112C: Swift detection of a burst with an optical counterpart
- GRB 240109A: Fermi GBM Observation
- GRB 231214A: ATCA Radio Upper Limits
- Konus-Wind detection of GRB 240101C
- Swift GRB240109.17: Global MASTER-Net observations report
- GRB 240109A: Swift detection of a short burst
- LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
- IPN triangulation of GRB 240101C (short)
- GRB GRB240101C: Fermi GBM observation
- GRB 240101A: 1.3m DFOT optical observations
- GRB 240102A: 1.3m DFOT optical upper limit
- GRB 240101B: 1.3m DFOT optical upper limit
- GRB 240101C: Swift/BAT-GUANO detection of a short burst
- GRB 231220A: Swift-UVOT upper limit
- GRB 240102A: Swift-BAT refined analysis
- GRB 240102A: Swift/UVOT Upper Limits
- GRB 231230A: Swift-BAT refined analysis
- GRB 240101A: Swift-BAT refined analysis
- GRB 240101B: Swift-BAT refined analysis
- GRB 240102A: Enhanced Swift-XRT position
- GRB 240101B: Swift-XRT refined Analysis
- GRB 240102A: Swift-XRT refined Analysis
- GRB 240102A: LCOGT Optical Upper Limits
- GRB240102A: BOOTES-6/DPRT optical upper limit
- GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- GRB 240102A: Swift detection of a burst
- GRB 240101A: Terskol Zeiss-2000 optical observations
- GRB 240101B: Swift/UVOT Upper Limits
- GRB 240101A: Swift/UVOT Upper Limits
- GRB 240101A: Swift-XRT refined Analysis
- GRB 240101B: Enhanced Swift-XRT position
- GRB 240101B: KAIT Optical Upper Limit
- GRB 240101A: KAIT Optical Upper Limit
- GRB 240101A: Enhanced Swift-XRT position
- Swift GRB240101.85: Global MASTER-Net observations report
- GRB 240101B: Swift detection of a burst
- GRB 240101A: Swift detection of a burst
- GRB231230A: Fermi GBM Observation
- GRB 231230A: Swift-XRT refined Analysis
- GRB 231230A: GOTO optical upper limits
- GRB 231230A: Enhanced Swift-XRT position
- GRB 231230A: Swift/UVOT Upper Limits
- GRB 231230A: NOT optical upper limits
- GRB 231230A: Prompt enhanced Swift-XRT position
- GRB 231230A: Swift detection of a burst
- Swift GRB231230.06: Global MASTER-Net observations report
- GRB 231210B: BOOTES-7 optical upper limit
- Swift Triggers 1205103, 1205104, 1205107 and 1205110 are not astrophysical events
- LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
- GRB 231222B: Swift-XRT afterglow detection
- GRB 231222B: Fermi-LAT detection