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"- Swift-BAT trigger 431756 is not a burst
- Swift/UVOT observations of GRB100814A - title correction to GCN 11097
- GRB 100814A: Fermi GBM observation
- GRB 100814A: Submm observations from APEX
- Swift/UVOT Observations of GRB100814A - a clearer table.
- GRB 100814A: Swift-XRT refined analysis
- Swift/UVOT observations of GRB100814A
- GRB 100814A, Swift-BAT refined analysis
- GRB 100814A: CQUEAN r- and i-band Observation
- GRB 100814A: Enhanced Swift-XRT position
- GRB 100814A: GROND Detection of the Optical/NIR Afterglow
- GRB 100814A: IAC80 R-band observations
- GRB100814A: Magellan Echellette Observations
- GRB 100814A: Swift UVOT observations of the optical afterglow
- GRB 100814A: Swift detection of a burst with an optical afterglow
- GRB 100814A: ROTSE-III Detection of Optical Counterpart
- Swift-BAT trigger 431582 likely is IGR J17464-2811
- GRB 100805A: the 4-th epoch of SAO RAS optical observations
- GRB 100805A: optical observation in CrAO (correction to the GCN 11077 and second epoch)
- GRB 100802A: further NOT observation
- GRB 100805A: Swift/UVOT Observations of a Possible Late-Time Brightening
- GRB 100807A: P200 Infrared Observations
- GRB 100805A: the 3-rd epoch of SAO RAS optical observations
- GRB100807A: optical observation in CrAO
- GRB 100805A: optical observation in CrAO
- GRB 100805A: 2-nd epoch of SAO RAS optical observations
- GRB100807A: MITSuME optical upper limits
- GRB 100807A: Swift XRT refined analysis
- GRB 100807A: P60 Optical Afterglow Discovery
- GRB 100807A: Swift/UVOT Upper Limits
- GRB 100805A: SAO RAS optical observations
- GRB 100807A: Enhanced Swift-XRT position
- GRB 100807A: Swift-BAT refined analysis
- GRB 100807A: ROTSE-III Optical Limits
- GRB 100807A: Swift detection of a burst
- GRB 100805A: IAC80 and 1.5m OSN optical observations
- GRB 100805A: Xinglong TNT optical observation
- GRB 100805A: Early RAPTOR Observations
- GRB 100805A: ROTSE-III Optical detection
- GRB 100805A: Swift/UVOT Observations of the Optical Afterglow
- GRB 100802A: WIYN observations
- GRB 100805A: IAC80 BVR-band observations
- Swift-BAT trigger 430975 is not a burst
- GRB 100805A: Swift-BAT refined analysis
- GRB 100805A: Swift-XRT Refined Analysis
- GRB 100805A: GRAS 002 optical observations
- Trigger 430975: Swift detection of a possible burst
- GRB 100805A: I-band detection from 1.23m CAHA telescope.
- GRB 100805A: Enhanced Swift-XRT position
- GRB 100805A: Liverpool Telescope afterglow observations
- GRB 100805A: Further P60 Monitoring
- GRB 100805A: P60 Optical Afterglow Candidate
- GRB 100805A: Enhanced Swift-XRT position
- GRB 100805A: ROTSE-III Optical Limits
- GRB 100805A: Swift detection of a burst with an optical counterpart
- GRB 100802A: Fermi GBM observation
- GRB 100728B: optical photometry of ISON-NM
- GRB 100713A: second epoch Maidanak optical observation
- GRB 100713A: CrAO optical limits
- GRB 100802A: NOT optical observation
- GRB100802A: MITSuME optical upper limits
- GRB 100802A: P60 Observations
- GRB 100802A: XRT refined analysis
- GRB 100802A: Swift/UVOT Possible Optical Afterglow
- GRB 100728A: Suzaku WAM observation of the prompt emission
- GRB 100802A: Enhanced Swift-XRT position
- GRB 100802A: Swift-BAT refined analysis
- GRB 100802A: Liverpool Telescope observations
- GRB 100802A: ROTSE-III Optical Limits
- GRB 100802A: Possible Swift/UVOT Detection of Optical Afterglow
- GRB 100802A: Swift detection of a burst
- GRB 100725B: TELMA optical observation
- GRB 100728B: Swift/UVOT Observations (correction to GCN 11028)
- GRB 100728B: Swift/UVOT Observations (correction)
- GRB 100728B - NOT optical observation
- GRB 100728B: Swift/UVOT Observations
- GRB 100728B: Lick Observations
- GRB 100728B: Continued KAIT observations
- GRB 100728B, Swift-BAT refined analysis
- GRB 100728B: Swift-XRT Refined Analysis
- Konus-Wind observation of GRB 100728A
- GRB 100728A: GROND Detection of the NIR Afterglow Candidate
- GRB 100727A: Swift/UVOT Upper Limits
- GRB 100728A, Swift-BAT refined analysis
- GRB 100728B: Enhanced Swift-XRT position
- GRB 100728A: Swift/UVOT Upper Limits
- GRB 100728B: Fermi GBM observation
- GRB 100728A: Swift-XRT refined analysis
- GRB 100728B: GROND Detection of the NIR Afterglow
- GRB 100728B: optical detection
- GRB 100728B: Skynet/PROMPT Detections (correction)
- GRB 100728B: KAIT optical afterglow detection (correction)
- GRB 100728B: Swift detection of a burst with an optical counterpart
- GRB 100728A: Skynet/PROMPT Detections
- GRB 100728A: KAIT optical afterglow detection
- GRB 100728A: Fermi GBM observation
- GRB 100728A: Enhanced Swift-XRT position
- GRB 100728A: Swift detection of a burst
- GRB 100727A: Swift XRT refined analysis
- GRB 100727A: Fermi GBM observation