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"5544 results found.
- GRB 100418A: Swift detection of a burst with a possible optical afterglow
- GRB 100414A: IPN Localization
- GRB 100414A: Fermi GBM detection
- GRB 100413A: Swift detection of a burst
- GRB100401A: GROND Upper Limits
- GRB 100331B: GROND Upper limits
- GRB 100316A: R-band limit
- Swift detection of LS V +44 17
- INTEGRAL trigger 5994 / GRB 100331A: GROND detection of a variable source
- Fermi GBM detection of four Solar Flares
- GRB 100316C: GROND Detection of a Optical/NIR Afterglow Candidate
- GRB 100316D: Swift detection of a burst
- GRB 100305A: P60 Observations
- GRB 100305A: Swift detection of a burst
- GRB 100302A: Swift detection of a burst
- GRB 100206A: optical observations in CrAO
- GRB 100206A: optical observations in Terskol
- GRB 100213B: Swift detection of a burst
- GRB 100212A: Swift detection of a burst
- GRB 100205A: Keck limits on an underlying host galaxy
- GRB 100206A: WHT candidate afterglow
- GRB 100206A: Enhanced Swift-XRT position
- GRB 100206A: Pre-explosion imaging and host candidate
- GRB 100206A: Swift detection of a short hard burst
- GRB 100113A: Fermi GBM detection
- GRB 100205A Gemini-North IR afterglow candidate
- GRB 100205A: Gemini-South Observations
- GRB 100205A: NOT optical observations
- Short X-ray Transient detected by MAXI/GSC
- GRB 100119A: Swift detection of a burst
- GRB 100117A: Swift detection of a short hard burst
- GRB 091221: Swift detection of a burst
- GRB 091208A: GAO 150cm telescope Optical Observation
- GRB 091208B: GAO 150cm telescope Optical Observation
- GRB 091208B: GROND observations
- GRB 091208B: Fermi GBM observation
- GRB 091208A, RIMOTS optical upper limits
- GRB 091208B: MITSuME Akeno Optical Observation
- GRB 091208B: MITSuME Okayama Optical Observation
- GRB 091208B, RIMOTS optical upper limits
- GRB 091208B: Swift detection of a burst with an optical afterglow
- GRB 091208B: BOOTES-3 optical afterglow
- GRB 091208: ROTSE-III Optical Limits
- GRB 091202: GTC & CAHA optical/nIR afterglow candidate
- GRB 091202 - UVOT-enhanced XRT position
- GRB 091126B: Fermi GBM detection
- GRB 091130B: Swift detection of a burst
- GRB 091127: NOT observations
- GRB 091109B: Suzaku WAM observation of the prompt emission
- GRB 091109: Faulkes Telescope South observations
- GRB 091109: Enhanced Swift-XRT position
- GRB091109: REM detection of the NIR afterglow
- GRB 091109: Swift detection of a burst with optical afterglow
- GRB 091104: Swift detection of a burst
- GRB 091029: Swift detection of a burst with an optical counterpart
- A mistake in testing a new function in Swift
- GRB 091026: Swift detection of a Gamma Ray Burst
- GRB 091024: Fermi GBM Observations
- GRB 091024: Swift-XRT team refined analysis
- GRB 091024: GRAS004 optical observations
- GRB 091020: Swift detection of a burst with an optical afterglow
- GRB 091018: miniTAO/ANIR Observations
- GRB 091010: optical obsevation
- GRB 091010: optical afterglow candidate rejection
- GRB 091010: RXTE detection
- GRB 090910: SuperAGILE Localization of a Long GRB
- GRB 090929B: Suzaku WAM observation of the prompt emission
- Konus-Wind observation of GRB 090929B
- GRB 090929B: Swift detection of a burst
- GRB 090926B: Swift detection of a burst
- GRB 090925: Fermi GBM detection
- GRB 090915: Swift-XRT detection of a fading X-ray counterpart
- GRB 090823: Swift XRT confirmation of the X-ray afterglow
- GRB 090904A: ROTSE-III Optical Limits
- GRB 090904: Swift detection of a burst
- GRB 090902B: GROND NIR Afterglow Observations
- GRB 090902: Fermi GBM detection
- GRB 090831B: MITSuME optical upper limits
- GRB 090831: MAXI GSC detection
- GRB 090831: Fermi GBM detection
- GRB 090826: Fermi GBM detection
- GRB 090817: No host galaxy, no supernova
- GRB 090817: aphotometry of USNO-B1.0 341-0096763
- Fermi Gamma-ray Burst Monitor trigger 271934815 is not a GRB
- GRB 090814A, RIMOTS optical upper limits
- GRB 090814: Swift detection of a burst
- GRB 090812: P60 Confirmation of Optical Afterglow
- GRB 090812: Swift detection of a burst with an optical counterpart
- GRB 090809 X-shooter redshift
- GRB 090807: Swift detection of a burst
- GRB 090709A : Quick look analysis of the Suzaku observation
- GRB 090711: Fermi GBM detection
- Fermi Gamma-ray Burst Monitor triggers 269935914 through 270021937 are not GRBs
- GRB 090715B: break in the optical afterglow decay
- GRB 090709B: Fermi GBM detection
- GRB 090709A: Wyoming Infrared Observatory NIR upper limits
- GRB 090626: Suzaku WAM observation of the prompt emission
- GRB 090709: PAIRITEL NIR Upper Limits
- GRB 090529: CrAO optical upper limit
- GRB 090529: Mt.Terskol optical observations