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.
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"28059 results found.
- GRB 210323A: Enhanced Swift-XRT position
- GRB 210323A: NOT optical afterglow candidate
- GRB 210323B: Swift/BAT-GUANO detection and possible arcminute localization
- GRB 210323A: Nanshan/NEXT optical upper limit
- GRB 210323A: Swift detection of a short burst
- GRB 210321A: Swift/UVOT Detection
- Konus-Wind detection of GRB 210321A
- GRB 210318B: Swift/UVOT Upper Limits
- GRB 210321A: CrAO optical upper limit
- GRB 210321A: Swift-BAT refined analysis
- IceCube 135113_19489408.amon: Swift-XRT observations
- GRB 210321A: Mondy optical observations
- GRB 210321A: Swift-XRT refined Analysis
- GRB 210321A: Redshift from OSIRIS/GTC
- GRB 210321A: NOT optical afterglow detection and redshift limit
- MAXI GRB210320.89: Global MASTER-Net observations report
- GRB 210321A: Enhanced Swift-XRT position
- GRB 210321A: DDOTI Afterglow Confirmation
- GRB 210321A: Swift/UVOT Detection
- GRB 210321A: Swift-XRT observations
- GRB 210321A: Swift detection of a burst
- GRB 210318B: MITSuME Okayama optical upper limits
- GRB 201216C: VIRT optical observations
- GRB 200524A: Redshift from Gemini-North
- GRB 210318A: Swift-BAT refined analysis
- GRB 210318A: Swift-XRT refined Analysis
- GRB 210318A: Enhanced Swift-XRT position
- GRB 210318B: Fermi GBM detection
- GRB 210318B: Swift-BAT refined analysis
- GRB210318B: Swift detection of a burst
- GRB 210318A: Swift detection of a burst
- GRB 210317A: GECAM detection
- GRB 210306A: GIT optical follow-up
- GRB 210226A: GIT optical upper limit
- GRB 210312B: A long GRB detected by INTEGRAL
- GRB 210306A: LBT observations
- GRB 210306A: Tautenburg observations
- Konus-Wind detection of GRB 210308A
- Konus-Wind detection of GRB 210306A
- Konus-Wind detection of GRB 210305A
- GRB 210306B: Fermi GBM detection
- GRB 210306A: Swift/UVOT Detection
- GRB 210306A: continued Mondy optical observations
- GRB 210308A: Mondy and AbAO optical observations
- GRB 210308A: Swift-BAT refined analysis
- GRB 210307A: Swift-BAT refined analysis
- GRB 210308A: Swift/UVOT Detection
- GRB 210307A: Swift/UVOT Upper Limits
- GRB 210305A: Fermi GBM observation
- GRB 210308A: Fermi GBM detection
- GRB 210305A: Swift-XRT refined Analysis
- GRB 210307A: Swift-XRT refined Analysis
- GRB 210308A: Nanshan/NEXT optical upper limits
- GRB 210306A: Swift-XRT refined Analysis
- GRB 210308A: MITSuME Okayama optical upper limits
- GRB 210306A: continued Mondy optical observations
- GRB 210308A: Swift detection of a burst with an optical counterpart
- GRB 210306A: Swift-BAT refined analysis
- GRB 210306A: Mondy optical observations
- GRB 210305A: Swift/UVOT Upper Limits
- GRB 210307B: GECAM detection
- GRB 210307A: LCO Optical Upper Limits
- GRB 210306B: Swift-BAT refined analysis
- GRB 210305A: Swift-BAT refined analysis
- GRB 210307A: Swift detection of a burst
- GRB 210306A: MITSuME Akeno optical observation
- GRB 210306A: NEXT optical observations
- GRB 210306A: Fermi GBM observation
- GRB 210306A: Tautenburg observations
- GRB 210306A: LCO Optical Afterglow Detection
- GRB 210306A: iTelescope optical afterglow observations
- GRB 210306A: DDOTI Afterglow Confirmation
- GRB 210306A: Swift detection of a burst with a bright optical counterpart
- GRB 210305A: Swift detection of a burst
- GRB 210228B: Insight-HXMT/HE detection
- Trigger 1035744: Swift detection of Sco X-1 due to Star Tracker loss of lock
- GRB 210217A: 3.6m DOT optical observations
- GRB 210226A: Swift/UVOT Upper Limits
- Fermi trigger No 636187116: Global MASTER-Net observations report
- GRB 210228A: GECAM detection
- GRB 210225A: Insight-HXMT/HE detection
- Integral GRB210227.19: Global MASTER-Net OT detection
- GRB 210226A: Swift-BAT refined analysis
- GRB 210226A: Fermi GBM detection
- GRB 210217A: Mondy optical observations
- GRB 210226A: Swift-XRT refined Analysis
- GRB 210218A: Swift-XRT confirmation of afterglow
- GRB 210226A: Burke-Gaffney Observatory optical upper limit
- GRB 210226A: Enhanced Swift-XRT position
- GRB 210222B: 1.3m DFOT Optical upper limit
- GRB 210226A: Swift detection of a burst
- GRB 210222B: REM observations of the optical/NIR afterglow
- GRB 210222B: MITSuME Akeno optical upper limits
- GRB 210222B: Zeiss-1000 of Koshka observatory, optical observations
- GRB 210222B: VIRT optical detection
- GRB 210222B: Swift-BAT refined analysis
- GRB 210222B: Swift-XRT refined Analysis
- GRB 210222B: Swift/UVOT Detection
- GRB 210218A: Swift/UVOT observations
- GRB 210217A: Swift/UVOT Detection