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"- VLA Radio upper limit on GRB 081118
- GRB 081118: VLT redshift
- GRB 081118: Swift-XRT refined analysis
- GRB 081118: GROND detection of afterglow
- GRB 081118: optical afterglow candidate
- GRB 081118: Swift UVOT Upper Limits
- GRB 081118: Swift-BAT refined analysis
- GRB 081118: Enhanced Swift-XRT position
- GRB 081118: Swift detection of a burst
- GRB 081109A: confirmation of possible detection host galaxy
- Further Swift-XRT observations of the probable GRB 081105.
- GRB 081113: Fermi GBM detection
- GRB 081102: RTT150 Optical observations
- GRB 081110: Fermi GBM detection
- GRB 081110: MASTER: first optical observations Fermi GRB
- GRB 081109: TAROT La Silla observatory optical observations
- GRB 081102: MASTER refind and final results
- GRB 081109: GROND redshift limit and host extinction
- GRB 081025: Swift-XRT further analysis
- GRB 081024B: Swift-XRT late-time observations
- Swift-BAT refined analysis of trigger 334129
- GRB 081109B: Swift/UVOT refined analysis
- GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
- GRB 081109A: Possible Swift-UVOT detection
- GRB 081109A: Faulkes Telescope South observations
- GRB 081109A, Swift-BAT refined analysis
- GRB 081109A: Swift-XRT refined analysis
- GRB 081109: Fermi GBM detection
- GRB 081109: Swift/UVOT upper limits
- GRB 081109A optical upper limit
- Swift-BAT Trigger 334129: possible burst
- GRB 081109: REM NIR afterglow detection
- GRB 081109: Swift detection of a burst
- GRB 081028 - PAIRITEL NIR detection
- GRB 081024C: Fermi Gamma-ray Burst Monitor detection
- SGR 1806-20: Fermi GBM detection
- GRB 081102B: Fermi GBM detection
- GRB 081105B: Fermi GBM detection
- GRB 081107: Fermi GBM detection
- GRB 081104: GROND found no Optical/NIR Afterglow
- GRB 081105: GROND Upper Limits
- Radio observation of GRB 080523 with ATCA
- Radio observation of GRB 080520 with ATCA
- GRB 081105: Observations from OSN
- UVOT/Swift observations of GRB081105
- Swift-XRT observations of GRB 081105
- GRB 081101B: Fermi GBM detection
- Radio observation of GRB 080516 with ATCA
- GRB 081105 Swift/BAT and IPN Localization
- GRB 081025: Fermi GBM observation
- GRB 081104: GROND Detection of the Optical/NIR Afterglow Candidate?
- GRB 081104: refined XRT analysis
- GRB 081104: Enhanced Swift-XRT position
- GRB 081104: Swift-BAT refined analysis
- GRB081104: Swift/UVOT Upper Limits
- Fermi-GBM detection of a Solar Flare
- Fermi Detection of GRB 081102
- GRB 081104 : Faulkes Telescope South observations
- GRB 081104: Swift-XRT position
- GRB 081104: Swift detection of a burst
- Radio observation of GRB 080130 with ATCA
- GRB 081102: MASTER prompt optical limit
- GRB 081102: Swift-XRT refined analysis
- GRB 081102: Swift/UVOT refined analysis
- GRB 081102: Swift-BAT refined analysis
- GRB 081102: Enhanced Swift-XRT position
- Radio observation of GRB 080218b with ATCA
- Radio observation of GRB 080229a with ATCA
- GRB 081102: MASTER VWF promt observation
- GRB 081102: OPTIMA-Burst optical upper limit
- GRB 081102: Swift detection of a burst
- SGR 0501+4516: optical observations in August
- GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection
- SGR 0623-0006 or GRB 081101: Swift-XRT refined analysis
- SGR 0623-0006 or GRB 081101: Swift-BAT/-XRT refined analysis
- Swift-BAT triggered on a probable GRB 081101 (trigger=333320)
- GRB 081024B: BTA deep optical observations
- GRB 081028: CrAO optical observations
- GRB 081024B: new Swift-XRT observations
- Radio observation of GRB 080229b with ATCA
- GRB 081029, SMARTS optical/IR afterglow observations
- GRB 081024B: VLA radio observation
- GRB 081029: UVOT Detection of the Optical Afterglow
- GRB 081029: PROMPT Detections
- GRB 081029: Redshift Confirmation from Gemini-South
- GRB 081029: Swift-BAT refined analysis
- GRB081029: Swift XRT refined analysis
- GRB 081025: Suzaku WAM observation of the prompt emission
- GRB 081024B: Suzaku WAM observation of the prompt emission
- GRB 081029: Enhanced Swift-XRT position
- GRB 081028: GROND Confirmation of the Optical/NIR Afterglow
- GRB 081029: REM observations
- Radio observation of GRB 080303 with ATCA
- Radio observation of GRB 080411 with ATCA
- GRB 081029: UVES/VLT Absorption Redshift
- GRB 081029: GROND Detection of the Optical/NIR Afterglow
- GRB 081029: ROTSE-III Detection of Optical Counterpart
- GRB 081029: Swift detection of a burst
- GRB 081028: Magellan redshift
- GRB 081028B: Fermi GBM detection