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"21455 results found.
- 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
- Swift GRB230720.30: Global MASTER-Net observations report
- IPN triangulation of GRB 230715D
- Swift Trigger 1180063 is not a GRB
- Swift Trigger 1180060 is not a GRB
- Swift Trigger 1180055 is not a GRB
- IPN triangulation of GRB 230712C (short)
- IPN triangulation of GRB 230712A (short)
- IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
- GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
- IceCube-230708A: Upper limits from Swift/BAT-GUANO
- GRB 230707A: Swift/BAT-GUANO position correction
- GRB 230707B: Fermi GBM Observation
- IceCube-230707A: No candidates detected by Swift-XRT
- Swift Trigger 1178410 is not an astrophysical event
- GRB 230707B: CALET Gamma-Ray Burst Monitor detection
- Swift Trigger 1178410: possible GRB 230709A
- GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 230707A: Swift-XRT observations
- GRB 230707A: Fermi GBM Detection
- GRB 230707A: Swift ToO observations
- GRB 230707A: Swift/BAT-GUANO arcminute localization of a burst
- IBAS trigger number 10311: not a real GRB
- GRB 230328B: LBT detection of the likely host galaxy
- GRB 230628E: Swift/UVOT Detection
- GRB 230628E: Swift-BAT refined analysis
- GRB 230628E: ATCA rapid radio follow-up
- LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
- IPN triangulation of GRB 230625B (ultra-long)
- GRB 230625B: CALET Gamma-Ray Burst Monitor detection
- GRB 230625B: AstroSat CZTI detection
- GRB230628E: VLT optical identification of afterglow candidate
- GRB 230628E: Swift-XRT refined Analysis
- GRB 230628E: Enhanced Swift-XRT position (Correction to name in GCN 34115)
- GRB 230628A: Enhanced Swift-XRT position
- GRB 230628E: LCOGT Optical Upper Limit
- Swift GRB230628.93: Global MASTER-Net observations report
- GRB 230628E: Swift detection of a burst