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"5050 results found.
- GRB 100925A / MAXI J1659-152: Optical observation with the Kottamia 188cm telescope
- GRB 100924A: GROND detection of an optical/NIR afterglow
- GRB 100915A: Swift-XRT refined analysis
- GRB 100909A: Swift-XRT refined analysis
- GRB 100901A: CrAO optical observations
- GRB 100906A: GRAS-007 optical observations
- GRB 100906A: Swift-XRT refined analysis
- GRB 100905A: Swift-XRT refined analysis.
- Optical observations of GRB 100901A
- GRB 100902A: UKIRT JK Observation
- GRB10901A: Optical observations at IAO
- GRB 100902A: Swift XRT refined analysis
- GRB 100901A: Kanata Telescope observation of the optical afterglow
- GRB 100901A: SARA-N observations
- GRB100901A: MITSuME Okayama Optical Observation
- GRB 100901A: Swift-XRT Team refined analysis
- GRB100823A : MOA optical observation
- GRB 100823A: VLT/X-Shooter spectroscopy
- GRB100816A Swift-XRT refined analysis
- GRB 100814A: Swift-XRT refined analysis
- GRB 100814A: CQUEAN r- and i-band Observation
- GRB 100805A: Swift-XRT Refined Analysis
- GRB 100802A: XRT refined analysis
- GRB 100728B: Swift-XRT Refined Analysis
- GRB 100728A: GROND Detection of the NIR Afterglow Candidate
- GRB 100728A: Swift-XRT refined analysis
- GRB 100728B: optical detection
- GRB 100728A: Swift detection of a burst
- GRB 100727A: Swift XRT refined analysis
- GRB 100727A: Fermi GBM observation
- GRB 100724B: gamma-ray detection by AGILE
- GRB 100725A: Swift XRT refined analysis
- GRB 100725B: Swift detection of a burst
- GRB 100724B: Fermi LAT and GBM analysis
- GRB 100724B: Fermi GBM detection
- GRB 100724A: Swift XRT refined analysis
- GRB 100724A: X-shooter redshift
- GRB 100724A, GROND detection of an afterglow candidate
- GRB 100707A: Fermi GBM detection
- Konus-Wind observation of GRB 100704A
- GRB 100704A: Swift XRT refined analysis
- GRB 100615A: Additional Gemini/NIRI observations
- GRB 100526A: Gemini/NIRI afterglow confirmation and host galaxy
- GRB 100702: ROTSE-III Optical Limits
- GRB 100702A: Swift detection of a short burst
- GRB 100628A: GROND optical/NIR observations of the host candidate
- GRB 100628A: Gemini North Observations
- Swift-BAT trigger 426048 is not a burst
- GRB 100625A: Swift-XRT Team refined analysis
- GRB 100621A: Swift XRT refined analysis
- GRB 100619A: Swift-XRT refind analysis
- XRF 100616a : MAXI/GSC detection of a probable XRF
- GRB 100615A: Swift-XRT refined analysis
- GRB 100614A: Swift-XRT refined analysis
- GRB 100615A: NTT/Ultracam imaging
- GRB 100614A: WHT I-band observations
- GRB 100606A Swift-XRT refined analysis
- Swift detection of outburst from the SFXT IGR J18410-0535
- GRB 100526A: Swift XRT refined analysis
- GRB 100522A: Swift XRT refined analysis
- GRB 100522A: Enhanced Swift-XRT position
- GRB 100522A: Swift detection of a burst
- GRB 100518A: Faulkes Telescope North Afterglow Candidate
- GRB 100517A: MASTER-Net wide field camera prompt optical observations
- GRB 100514A: Swift XRT refined analysis
- GRB 100513A: Swift XRT refined analysis
- GRB100504A: Optical upper limits at IAO
- GRB 100508A: Swift-XRT Refined analysis
- GRB 100504A: Swift-XRT refined analysis
- GRB 100504A: GROND Upper limits
- GRB 100420A: Gemini discovery of infrared afterglow
- GRB 100427A: Fermi GBM detection
- GRB 100418A: RTT150 optical observations
- GRB 100424A: CrAO optical observations
- GRB 100424A: Liverpool Telescope Upper Limits
- GRB 100425A: GROND afterglow observation
- GRB100424A: MITSuME optical upper limits
- GRB 100424A : Lulin early z'-band upper limit
- GRB 100424A: GROND Upper Limits
- GRB 100424A: Swift-XRT refined analysis
- GRB 100424A: NOT optical observations
- GRB 100423A: Swift detection of a burst
- GRB 100420A: XRT refined analysis
- GRB 100420A: ROTSE-III Optical Limits
- GRB 100420A: Swift detection of a burst
- GRB 100418A: Swift-XRT Refined Analysis
- GRB 100418A: host galaxy detection in the SDSS
- GRB 100413A: Swift-XRT Refined Analysis
- IPN triangulation of GRB100324B
- Short X-ray Transient detected by MAXI/GSC
- GRB 100322A: Suzaku WAM observation of the prompt emission
- GRB 100324A: GROND observations
- GRB 100324A found in ground analysis of BAT data
- GRB 100316D: Further Gemini observations
- GRB 100316C: Swift-XRT team refined analysis
- GRB 100316A: Swift-XRT refined analysis
- GRB 100305A: Swift-XRT refined analysis
- GRB 100305A: Enhanced Swift-XRT position
- GRB 100305A: Gemini-N OT candidate
- GRB 100305A: Swift detection of a burst