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"25904 results found.
- GRB 240414A: AbAO optical upprer limit
- GRB 240415A: Swift/UVOT Detection
- GRB 240415A: Fermi GBM Observation
- GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
- GRB 240415A: Earliest optical followup with the Kinder observations
- GRB 240415A: Enhanced Swift-XRT position
- GRB 240415B: Swift ToO observations
- GRB 240415B: Swift/BAT-GUANO Correction
- GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 240415A: OHP/T193 optical observations
- GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
- GRB 240414A: Fermi GBM Observation
- GRB 240414A: Photometric observation from 2.2m CAHA
- GRB 240414A: Swift/UVOT Detection
- LXT 240402A/GRB 240402B: Swift follow-up observations
- GRB 240414A: Mondy optical observations
- GRB 240414A: AKO Optical Upper Limit
- GRB 240415A: Prompt Swift-XRT observations
- GRB 240415A: Swift detection of a burst
- GRB 240414A: Swift-XRT refined Analysis
- GRB 240414A: Enhanced Swift-XRT position
- GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
- GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- GRB 240414A: Skynet Optical Afterglow Observations
- Swift GRB 240414A: Global MASTER-Net observations report
- IPN triangulation of GRB 240410A
- IPN triangulation of GRB 240411A
- GRB 240414A : MITSuME Akeno optical upper limits
- GRB 240414A: Redshift confirmation from GTC/OSIRIS+
- GRB 240414A : OHP/T193 redshift determination
- GRB 240414A : OHP/T193 optical counterpart detection
- GRB 240414A: Swift detection of a burst
- GRB 240411B: CrAO/ZTSh optical observations
- GRB 240411B: Kinder observations with Lulin observatory
- GRB 240411B: HiPERCAM/GTC observation
- GRB 240411B: Swift-BAT refined analysis
- GRB 240411B: Swift-XRT refined Analysis
- GRB 240411B: 1.3m DFOT Optical observations
- GRB 240411B: OHP/T193 optical observations
- GRB 240411B: Enhanced Swift-XRT position
- GRB 240411B: LCO optical afterglow detection
- GRB 240411B: Swift detection of a burst
- EP240408A: MASTER optical observations
- EP240408a: GROND detection of a candidate counterpart
- EP240408a: Swift follow-up observation
- Swift Trigger 1220736: detection of 4U 1543-62.
- Swift satellite resumes pointed science observations
- X-ray transient LXT 240402A: WFST optical upper limits
- GRB/FXT 240402B: Kinder optical counterpart candidate
- GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
- LXT 240402A: EP-FXT detection of the X-ray afterglow
- X-ray transient EP 240315a: Second epoch Chandra observations
- GRB 240318A: Fermi GBM Observation
- Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
- GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
- GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
- GRB 240317B: Swift/BAT-GUANO Angular Error Correction
- GRB 240317B: Fermi GBM Observation
- Swift satellite in safe mode
- X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
- GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
- X-ray transient EP240315a: Kitab observatory optical upper limitns
- Einstein Probe detected of a fast X-ray transient EP240315a
- GRID detection of GRB 240306A
- Swift Triggers 1220155, 1220156, 1220157, 1220158, 1220160 and 1220161 were not astrophysical
- Swift Triggers 1220093, 1220094, 1220095 and 1220096 are not astrophysical
- Swift Triggers 1220090, 1220091 and 1220092 are not astrophysical
- GRB240204A: VIRT optical upper limit
- Swift triggers 1219917, 1219917 and 1219922 were not astrophysical
- Swift Trigger 1219909 and 1219910 are not a astrophysical
- Swift Trigger 1219905 is not a GRB
- Swift Trigger 1219874 is not astrophysical
- Swift GRB240309.61: Global MASTER-Net observations report
- Swift Trigger 1219325 is not a GRB
- GRB 240306A: Fermi GBM observation
- Konus-Wind detection of GRB 231118A
- GRB 240306A: AstroSat CZTI detection
- GRB 240306A: Swift/BAT-GUANO detection of a burst
- GRB 240305A: Fermi GBM observation
- Swift GRB240305.18: Global MASTER-Net observations report
- Swift GRB240305.16: Global MASTER-Net observations report
- GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 240218A: Chandra Detection and Jet Break Confirmation
- Swift Trigger 1218701: Yes, we triggered on Swift J151857.0-572147 again
- Swift Trigger 1218696: Another trigger on Swift J151857.0-572147
- GRB240218A: ATCA observation of the radio counterpart
- Swift Trigger 1218645: Another detection of Swift J151857.0-572147
- Swift J151857.0-572147: Swift-BAT refined analysis
- GRB 240225B: Swift-XRT afterglow detection
- Swift detection of Swift J151857.0-572147
- Swift GRB 240303A: Global MASTER-Net observations report
- Swift J151857.0-572147: Confirmation of a new galactic transient
- GRB 240215A: Swift-XRT afterglow detection
- GRB 240303A: Swift detection of a burst
- GRB 240225A (short): Glowbug gamma-ray detection
- GRB 240229A: DDOTI Upper Limits on the Afterglow
- GRB 240218A: NOEMA upper limit
- Swift BAT Triggers 1218081 and 1218082 are not astrophysical
- GRB 240225B: Swift ToO observations