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"37304 results found.
- GRB 080503: Chandra Observation of X-ray Rebrightening or Flattening
- GRB080507: Swift/UVOT followup observations
- GRB 080506:Optical observations from HCT
- GRB 080507: Swift-XRT position of a possible afterglow
- GRB 080506: VLA radio upper limit
- GRB 080507: GRB localization by SuperAGILE
- GRB 080503: Fading in continued Gemini imaging
- GRB080506: Swift/UVOT observations
- GRB 080506, Swift-BAT refined analysis
- GRB080503, RIMOTS optical upper limit
- GRB 080506: Observations from NOT
- GRB 080506: TLS afterglow detection in VRIZ
- GRB 080506: Enhanced Swift-XRT position
- GRB 080506: Optical observation with KANATA/TRISPEC
- GRB 080506: Swift detection of a burst with optical afterglow
- GRB 080503: VLA radio upper limit
- GRB 080503: Observations from NOT
- GRB 080430: TLS imaging one day after the GRB
- GRB 080503: No further optical rebrightening
- GRB 080503: Late-time Optical rebrightening (possible mini-SN)
- GRB 080503, Swift-BAT lag and time-resolved spectral analysis
- GRB 080503: MITSuME Ishigakijima optical upper limits
- GRB080503: Swift/UVOT Upper Limits
- GRB080503 XRT refined analysis
- GRB 080503, Swift-BAT refined analysis
- GRB 080430
- GRB 080503: Enhanced Swift-XRT position
- GRB 080503: MITSuME Akeno optical upper limits
- GRB 080503: New candidate afterglow/host in Gemini imaging
- GRB 080503: Swift detection of a short burst
- GRB 080411: Continued Swift Monitoring
- GRB 080430: Optical observations
- GRB 080430: Shallow decay
- GRB080430: RTT150 Optical Observations
- GRB080430: Swift/UVOT observations
- VLA radio upper limit on GRB 080430
- GRB 080430 - multicolor observations of the afterglow
- GRB080430: optical observations
- GRB 080430: Hobby-Eberly Telescope Absorption Redshift
- GRB 080430: Swift-XRT refined analysis
- GRB 080430: Enhanced Swift-XRT position
- GRB 080430: Spectroscopy from CAHA
- GRB 080430 - SDSS Pre-Burst Observations
- GRB 080430: Bootes observation
- GRB 080430: Swift detection of a burst with optical afterglow
- GRB960202B - on the association with SN 1996cr
- GRB080426: Observations from CAHA
- GRB 080426: Swift-XRT refined analysis
- GRB080426: Swift/UVOT upper limits
- GRB 080426: Enhanced Swift-XRT position
- GRB 080426: Swift detection of a possibly short burst
- Possible GRB 080315: XRT non-detection of afterglow
- GRB 080320 : Faulkes Telescope North Observations
- GRB 080319A : Liverpool and Faulkes Telescopes Observations
- GRB080319A: MAGIC telescope GeV observation
- Swift-BAT trigger 309665 is not a GRB
- GRB 080420A: ROTSE-III Optical Limits on a possible short burst
- GRB 080420?: Swift detection of a possible short burst
- GRB080310, BVRcIc field calibration
- GRB 080413A: Suzaku/WAM and Swift/BAT joint spectral analysis
- Swift XRT and UVOT observations of GRB080414
- GRB 080319B: Jet Break, Energetics, Supernova
- GRB 080413B: Faulkes Telescope South optical afterglow observations
- GRB 080413A: Liverpool Telescope and Faulkes Telescope South optical observations
- GRB 080413A: Suzaku WAM observation of the prompt emission
- GRB 080413B: Suzaku WAM observation of the prompt emission
- GRB 080413A: MOA-II optical afterglow observations
- GRB 080319B: Continued Gemini-N monitoring
- GRB 080414 Watcher observations
- GRB 080414: A long GRB detected by INTEGRAL
- VLA radio observations of GRB 080413B
- GRB 080413A: Gemini-South Spectroscopy
- GRB 080413B: Gemini-South Spectroscopy
- VLA radio observations of GRB 080413A
- IBAS Alert n. 5257 : not a GRB
- GRB080413B
- Swift-BAT spectral lag analysis of GRB 080413B
- GRB 080413a, SMARTS optical/IR afterglow observations
- GRB 080413B: Swift XRT refined analysis
- GRB080413A: Swift/UVOT observations
- GRB 080413A: Swift-XRT refined analysis
- GRB 080413A Bootes observation
- GRB 080413A: VLT/UVES redshift
- GRB 080413B: VLT redshift
- GRB080413B: REM NIR & Optical Observation
- GRB 080413B: GROND detection of afterglow in all bands
- GRB 080413B: Swift detection of a possibly short burst with optical counterpart
- GRB 080413A: REM detection of the NIR Afterglow
- GRB 080413: Enhanced Swift-XRT position
- GRB 080413: Swift detection of a burst with an optical afterglow
- GRB 080413: ROTSE-III Detection of Optical Counterpart
- GRB 080411: Swift/UVOT refined analysis
- GRB 080411, Swift-BAT refined analysis
- GRB 080411: Swift-XRT Refined Analysis
- Konus-Wind observation of GRB 080411
- GRB 080411: Enhanced Swift-XRT position
- GRB 080411: VLT redshift
- GRB 080411: GROND detection of optical afterglow candidate
- GRB080330: MAGIC telescope GeV observation
- GRB 080411: Swift detection of a bright burst