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"21392 results found.
- GRB 230818A: Enhanced Swift-XRT position
- GRB 230818A: Swift detection of a burst
- Swift GRB230818.98: Global MASTER-Net observations report
- Swift GRB230818.98: Global MASTER-Net OT detection
- GRB 230816A: Swift-BAT refined analysis
- GRB 230816A: SVOM/C-GFT optical detection
- GRB 230816A: Swift-XRT refined Analysis
- GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
- GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
- GRB 230816A: Enhanced Swift-XRT position
- GRB230816A: Possible host and GIT detection of optical counterpart
- Swift GRB230816.80: Global MASTER-Net observations report
- IPN triangulation of GRB 230815B
- GRB 230816A: Nanshan/HMT optical afterglow detection
- GRB 230815A: SOAR/Goodman follow-up imaging
- Swift GRB230816.67: Global MASTER-Net observations report
- GRB 230816A: Swift detection of a burst
- GRB 230815A: Swift-BAT refined analysis
- GRB230815A: Swift/UVOT upper limits
- GRB 230812B: GAD Observatory optical observations (upper limit)
- GRB 230815A: Swift-XRT refined Analysis
- GRB 230812B: iTelescope optical upper limit
- GRB230815A: BOOTES-6/DPRT optical upper limit
- GRB 230815A: Fermi GBM detection
- Swift GRB 230815A: Global MASTER-Net observations report
- GRB 230815A: Enhanced Swift-XRT position
- GRB 230815A: Swift detection of a burst
- GRB 230812B: Upper limits from a neutrino search with IceCube
- GRB 230812B: GIT optical follow-up
- GRB 230812B: Faulkes Telescope North optical afterglow follow-up
- GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
- GRB 230812B: OASDG optical observations
- GRB 230812B: Detected Optical Afterglow Candidate
- GRB230812B: AGILE/MCAL detection
- GRB 230812B: Swift-XRT afterglow detection
- GRB 230812: Swift/UVOT Detection
- GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
- GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
- Fermi GRB 230812B: MASTER optical counterpart
- GRB 230812B: KAIT Optical Afterglow Candidate
- GRB 230812B: Improved Swift/XRT localization
- GRB 230812B: Preliminary Swift/XRT localization
- GRB 230812B: Tiled Swift observations
- GRB 230808A: Fermi GBM Detection
- GRB 230805B: Swift-BAT refined analysis
- GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
- GRB 230805B: AstroSat CZTI detection
- GRB 230808A: Swift/BAT-GUANO detection of a burst
- GRB 230805B : MITSuME Akeno optical upper limits
- LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
- GRB 230805B: Fermi GBM observation
- GRB 230805B: Enhanced Swift-XRT position
- GRB 230805B: Swift/UVOT Upper Limits
- GRB 230805B: Bassano Bresciano observatory upper limit
- GRB 230805B: BOOTES-6/DPRT optical upper limit and 1.5m OSN detection
- GRB 230805B: Swift-XRT refined Analysis
- GRB 230805B: SAO RAS optical observations
- Swift GRB 230805B: Global MASTER-Net observations report
- GRB 230805B: Swift detection of a burst
- GRB 230802A: Fermi GBM observation
- GRB 230802A: Swift-BAT refined analysis
- GRB 230802A: Swift/UVOT Upper Limits
- Swift GRB 230802A: Global MASTER-Net observations report
- GRB 230802A: BOOTES-5/JGT optical upper limit
- GRB 230802A: Swift-XRT refined Analysis
- GRB 230802A: Enhanced Swift-XRT position
- GRB 230802A: Swift detection of a burst
- LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
- GRB 230728A: Swift-BAT refined analysis
- GRB 230723B: Swift-BAT refined analysis
- GRB 230723B: MITSuME Ishigaki optical observation
- GRB 230728A: BOOTES-1 optical upper limit
- GRB 230728A: Fermi GBM Observation
- GRB 230728A: LCOGT Optical Upper Limit
- GRB 230728A: Swift/UVOT Upper Limits
- GRB 230728A: Swift-XRT refined Analysis
- GRB 230728A: Enhanced Swift-XRT position
- GRB 230728A: NOT optical observations and possible host galaxy
- GRB 230727A: AstroSat CZTI detection
- GRB 230728A: Swift detection of a burst
- Swift GRB230728.12: Global MASTER-Net observations report
- GRB 230727A: Swift/BAT-GUANO detection of a burst
- GRB 230723B: MITSuME Akeno optical afterglow candidate detection
- GRB 230723B: ATCA rapid radio follow-up
- IBAS trigger number 10337: not a real GRB
- GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
- GRB 230723B: Leavitt Observatory upper limit
- GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
- GRB 230723B: Montarrenti Observatory upper limit
- GRB 230723B: Optical afterglow candidate from CAHA
- GRB 230723B: Bassano Bresciano Observatory upper limit
- GRB 230723B: Fermi GBM observation
- GRB 230723B: Swift-XRT refined Analysis
- GRB 230723B: non-detections from Observatoire de Haute-Provence
- GRB 230723B: Optical limit from CAHA
- GRB 230723B: Swift/UVOT Upper Limits
- Swift GRB 230723B: Global MASTER-Net observations report
- Swift-XRT position for GRB 230723B
- GRB 230723B: Swift-XRT observations
- GRB 230723B: Swift detection of a burst