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"- GRB 140927A: Swift detection of a burst
- Swift Trigger 613581 is not an astrophysical event
- Swift Trigger 613516 is not an astrophysical event
- GRB 140919A, Swift-BAT refined analysis
- GRB 140919A: Swift-XRT refined Analysis
- GRB 140919A: Swift/UVOT Detection
- GRB 140919A: GROND afterglow candidate
- GRB 140919A: Fermi GBM observation
- GRB 140919A: Enhanced Swift-XRT position
- GRB 140919A: Swift/UVOT observations
- GRB 140919A: Swift-XRT observations
- GRB 140919A: Swift detection of a burst
- GRB 140916B: LOT and iPTF follow-up of optical afterglow candidates
- Swift detection of outburst from 4U 1700+24
- GRB 140916A: Swift/UVOT Upper Limits
- GRB 140916A: Swift-BAT refined analysis
- GRB 140916A: UKIRT J-band observations
- GRB 140916A: Swift-XRT refined Analysis
- GRB 140916A: Enhanced Swift-XRT position
- GRB 140916A: MITSuME Okayama upper limits
- GRB 140916B: iPTF Optical Observations
- GRB 140916A: FTS observations
- GRB 140916A: Prompt enhanced Swift-XRT position
- GRB 140916A: Swift detection of a burst
- GRB 140907A: Continued DCT Observations
- Fermi GBM trigger 140913075 is not a GRB
- GRB 140909A: Confirmation of the Swift-XRT afterglow
- Possible radio detection of GRB 140903A with the GMRT
- GRB 140907A: Mondy optical observations
- GRB 140903A: Chandra detection of the afterglow
- GRB 140909A: Swift/UVOT Upper Limits
- GRB 140909A: Swift-XRT observations
- GRB 140907A: 1.23m CAHA optical observations
- GRB 140907A: TShAO observations
- GRB 140909A: Swift detection of a GRB
- Konus-Wind observation of GRB 140906C
- GRB 140907A: MASTER optical observations
- Refined IPN Triangulation of GRB 140906C
- GRB 140907A: Nishi-Harima NIR Observations
- GRB 140907A: MITSuME Akeno Optical Observation
- GRB 140907A: Discovery Channel Telescope observations
- IPN Triangulation of GRB 140906C (short/hard)
- GRB 140907A: T100 observations
- GRB 140907A: Swift-BAT refined analysis
- GRB 140907A: Fermi GBM Detection
- GRB 140907A: redshift from the 10.4m GTC telescope
- GRB 140907A: Swift-XRT refined Analysis
- GRB 140907A: Enhanced Swift-XRT position
- GRB 140907A: MITSuME Ishigakijima Optical Observation
- GRB140907A: MITSuME Okayama Optical Observation
- GRB 140907A : Virtual Telescope optical observations
- GRB140907A: Swift UVOT detection
- GRB 140906B: Fermi GBM Detection of a Long GRB
- GRB 140907A : Optical observations from Nanshan
- GRB 140907A: Swift detection of a burst with an optical counterpart
- GRB 140906A - Fermi GBM Detection
- GRB 140906A: iPTF optical transient candidates
- GRB 140903A: Confirmation of Optical Fading from Discovery Channel Telescope
- GRB 140903A: Possible optical variability
- GRB 140903A: NOT optical and NIR observations
- GRB 140901B: Swift XRT observation
- GRB 140903A: FTN observations
- GRB 140818B: TShAO optical upper limit
- GRB 140903A: ISON-Kislovodsk observations
- GRB 140903A: MAXI/GSC upper limit
- GRB 140903A: 6 GHz VLA detection
- GRB 140903A: Pan STARRS images of the field
- GRB 140901B: Fermi GBM detection
- GRB 140903A: tentative spectroscopic redshift
- GRB 140901B found in ground analysis of BAT data
- GRB 140903A: Swift/UVOT Upper Limits
- GRB 140903A: Swift-BAT Spectral lag analysis
- GRB 140903A: P60 Optical Observations
- GRB140903A: Discovery Channel Telescope Optical Detection
- GRB 140903A: Swift-BAT refined analysis
- GRB 140903A: Swift-XRT refined Analysis
- GRB 140903A: Coincident galaxy cluster in archival images
- GRB 140903A: Confirmed Swift detection of a short burst
- GRB 140903A: Preliminary Swift/XRT localization
- GRB 140903A: Swift detection of a possible burst
- GRB 140901A: Fermi GBM detection
- IPN Triangulation of GRB 140901A (short/hard/very intense)
- GRB 140831A: iPTF observations of a possible short burst detected by Fermi GBM
- GRB 140829A: Fermi GBM Detection
- GRB 140829A: iPTF optical observations
- GRB140818B, the review of the sky area in plate archives
- GRB 140828A, Swift-BAT refined analysis
- Konus-Wind observation of GRB 140825A
- GRB 140828A: Fermi GBM observation
- Swift Mission Operations Center Fully Operational
- IPN Triangulation of GRB 140825A (very intense/long)
- GRB 140828A: Swift detection of a burst
- IPN Triangulation of GRB 140824B
- Swift Burst Response Reenabled
- GRB 140818B: TLS observations
- GRB 140824A: optical upper limit in CrAO
- GRB 140824B: Swift observations
- Fermi TRIGGER_NUM 430645968: MASTER OT inside error box
- Swift Mission Operations Center Moving Tomorrow
- GRB 140824B: Fermi GBM Detection