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 100401A: Swift/UVOT Upper Limit
- Swift/BAT trigger 417974 (GRB100401A): Swift/XRT observations
- GRB 100401A: Fermi GBM detection
- GRB 100401A Burst, possibly short, detected in ground analysis of BAT data
- GRB 100331B: BOOTES-3 observations
- GRB 100316A: R-band limit
- GRB 100324B: Suzaku WAM observation of the prompt emission
- GRB 100331B: Swift/UVOT Upper Limits
- GRB 100331B: Swift/XRT possible afterglow candidate
- Swift detection of LS V +44 17
- GRB 100331B: SuperAGILE Localization of a Long GRB
- INTEGRAL trigger 5994 (GRB100331A): Swift/XRT observations
- INTEGRAL trigger 5994 / GRB 100331A: GROND detection of a variable source
- GRB 100331A: BOOTES-3 observations
- Konus-Wind observation of GRB 100324B
- GRB 100331A: A long GRB detected by INTEGRAL
- IPN triangulation of GRB100324B
- Konus-Wind observation of GRB 100322A
- Short X-ray Transient detected by MAXI/GSC
- Fermi GBM detection of four Solar Flares
- GRB 100322A: Suzaku WAM observation of the prompt emission
- Fermi/GBM and Swift/BAT detection of a burst from SGR 1806-20
- GRB 100325A: Fermi LAT detection
- GROND observations of GRB100316D/SN2010bh
- GRB 100325A: Fermi GBM detection
- GRB 100324A: GROND observations
- GRB 100324A found in ground analysis of BAT data
- Emerging Supernova in the Afterglow of GRB 100316D
- GRB 100322B or possible Galactic transient detected in ground analysis of BAT data
- GRB 100316D: Spectroscopic Discovery of a Supernova from Magellan
- SGR 1833-0832: Swift/UVOT Upper Limits
- GRB 100322A: Fermi GBM detection
- SGR 1833-0832: Archival Chandra Observations
- SGR 1833-0832 is pulsed at 7.56 seconds
- SGR 1833-0832 is pulsed at 7.56 seconds
- Possible pulsation period in SGR 1833-0832
- Discovery of the Spin Period of SGR 1833-0832
- GRB 100316D: ATCA radio observations
- GRB 100319A: correction to GCN 10527
- Probable SGR 1833-0832: Swift-XRT refined analysis
- Probable SGR 1833-0832: Enhanced Swift-XRT position
- Swift-XRT refined position of the probable new SGR 1833-0832
- Swift-BAT refined analysis of the probable new SGR 1833-0832
- GRB 100219A: MASTER-Net optical alert observations
- GRB 100319A: Swift detection of a burst; possible SGR
- GRB 100316D: Possible Supernova
- GRB 100316D: Pre-burst emission measured by BAT
- GRB 100316D: Further Gemini observations
- GRB 100219A: optical upper limit
- GRB 100316A: optical observations in CrAO
- GRB 100316D: Swift/UVOT Observations
- GRB 100316D: Swift XRT enhanced position and further refined analysis
- GRB 100316B: Swift-XRT refined analysis
- Tentative redshift of GRB100316D from X-ray data
- GRB 100316C: GROND Detection of a Optical/NIR Afterglow Candidate
- Trigger 416226 is probably not a GRB
- GRB 100316D: GROND Detection of the Optical/NIR Afterglow Candidate
- GRB 100316D: Gemini/GMOS and VLT/X-shooter observations
- GRB 100316D: VLT/X-shooter observations
- GRB 100316D: Swift-BAT refined analysis
- GRB100316C: Swift/UVOT Upper Limits
- GRB 100316C: Swift-BAT refined analysis
- GRB 100316B: Swift/UVOT observations
- GRB 100316C: Swift-XRT team refined analysis
- GRB 100316C: Enhanced Swift-XRT position
- GRB 100316D: Swift XRT refined analysis
- GRB 100316A: TAROT Calern observatory optical observations
- GRB 100316A: Swift-XRT refined analysis
- GRB 100316B: Enhanced Swift-XRT position
- GRB 100316A: Swift-BAT refined analysis
- GRB 100316B: Swift-BAT refined analysis
- GRB100316A: Swift/UVOT Upper Limits
- Trigger 416140 is almost certainly not a GRB
- GRB 100316C: BOOTES-3 observations
- GRB 100316D: Swift detection of a burst
- GRB 100316B: VLT/X-shooter redshift
- GRB 100316B: Skynet/PROMPT Observations of Fading
- GRB 100316B: GROND Detection of the Optical/NIR Afterglow Candidate
- XRF 100315A: MAXI/GSC detection of a short X-ray transient
- GRB 100316C: Swift detection of a burst
- GRB 100316A: Enhanced Swift-XRT position
- GRB 100316B: Swift detection of a burst with optical counterpart
- GRB 100316 optical candidate from 1.23m CAHA telescope
- GRB 100316 optical candidate from 1.23m CAHA telescope
- GRB 100316A: Swift/UVOT Observations
- GRB 100316A: Swift-XRT detection
- GRB 100316A: Swift detection of a burst
- IBAS Alert 5992 is not a GRB, but XTE J1855-026
- GRB100305A: Optical upper limits at IAO
- GRB 100305A: Super-LOTIS early observations
- GRB100302A : LOAO observations and Lulin afterglow analysis
- GRB 100305A, Swift-BAT refined analysis
- GRB 100305A: Gemini z'-band observation
- GRB 100305A: Swift/UVOT Upper Limits
- GRB 100305A: Swift-XRT refined analysis
- GRB 100305A Optical Observations
- GRB 100305A: Enhanced Swift-XRT position
- GRB 100305A: Gemini-N OT candidate
- GRB 100305A: PAIRITEL NIR Upper Limits
- GRB 100305A: P60 Observations