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"27391 results found.
- GRB 090515: ROVOR Upper Limit
- GRB 090515: MMT/MMIRS NIR Upper Limit
- GRB 090515: Swift/UVOT Observations
- GRB 090515: Swift-XRT refined analysis
- GRB 090515: Enhanced Swift-XRT position
- GRB 090509: Fermi GBM observation
- GRB 090515: Swift-BAT refined spectral analysis
- GRB 090515: Swift-BAT refined analysis
- GRB 090509 - Zadko Telescope observations
- GRB 090515: Gemini-N upper limit
- GRB 090515: WIYN NIR Upper Limit
- GRB 090515: PAIRITEL Upper Limits
- GRB 090515: Swift detection of a short burst
- GRB 090510, Radio limits
- GRB090510: VLT/FORS2 spectroscopic redshift
- GRB 090510: GROND observations
- GRB 090510: Swift/UVOT host galaxy candidates
- GRB 090510: Fermi-LAT follow-up analysis
- GRB 090509, further Swift-BAT refined analysis
- GRB 090510B: Fermi GBM detection
- GRB 090502: Fermi GBM detection
- AGILE detection of GRB 090510
- GRB 090510: UVOT refined analysis
- GRB 090510: Swift XRT refined analysis
- GRB 090510: Enhanced Swift-XRT position
- GRB 090510: NOT afterglow confirmation
- GRB 090510: Swift-BAT refined analysis
- GRB 090510: Fermi GBM detection
- GRB 090509: Swift-BAT refined analysis
- GRB 090509, SMARTS optical/IR afterglow observations
- GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
- GRB 090510: Swift detection of a short hard burst
- GRB 090509: GROND further analysis and redshift limit
- GRB 090509: REM NIR afterglow
- GRB 090509: GROND afterglow candidate
- GRB 090423: 250 GHz upper limit for a z=8.2 GRB with MAMBO-2 at the IRAM 30m
- GRB 080913: 250 GHz upper limit for a z=6.7 GRB with MAMBO-2 at the IRAM 30m
- GRB 090427: GROND observations
- GRB 090429A: ROVOR magnitude limit
- ICSP VLF observation of GRB090427 from two receivers
- ICSP VLF observation of GRB090424 from four receivers
- GRB 090428B: Suzaku WAM observation of the prompt emission
- GRB 090424, SMARTS optical/IR afterglow monitoring
- GRB 090429D: Fermi GBM detection
- GRB 090429C: Fermi GBM detection
- GRB 090429B: Swift/UVOT Upper Limits
- GRB 090429A: Swift/UVOT Upper Limits
- GRB 090429B: Gemini-N further nIR observations
- GRB 090429A: Swift-XRT refined analysis
- GRB 090429A: GROND upper limits
- GRB 090427C: Fermi GBM detection
- GRB 090427B: Fermi GBM detection
- GRB 090426C: Fermi GBM detection
- GRB 090426B: Fermi GBM detection/observation
- GRB 090429B: Swift XRT refined analysis
- GRB 090429A: Enhanced Swift-XRT position
- GRB 090428B: Fermi GBM detection
- GRB 090428: Fermi GBM detection
- GRB 090418A BVRcIc field calibration
- GRB 090429B: RIMOTS optical upper limits
- GRB 090429B: Swift-BAT refined analysis
- GRB 090429A: Swift-BAT refined analysis
- GRB 090429B: Enhanced Swift-XRT position
- GRB090429B: Gemini-N infrared IR candidate
- GRB 090429B: VLT upper limits
- GRB 090429B: GROND Observations
- GRB 090429B: Super-LOTIS early observations
- GRB 090429B: Swift detection of a burst
- GRB 090429: Swift detection of a burst
- GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
- GRB 090424 : Multiband Optical observation from Nainital
- IPN triangulation of very bright GRB 090427
- GRB 090423: CARMA mm observations
- GRB 090426: Swift/BAT spectral lag results
- GRB 090425: Fermi GBM detection
- GRB 090424: Suzaku WAM observation of the prompt emission
- GRB 090426: VLT spectroscopy
- GRB 090426: GROND Observations of the Optical/NIR Afterglow
- GRB 090426: Okayama MITSuME optical observation
- GRB 090426: Swift-BAT refined analysis
- GRB 090426: Swift-XRT refined analysis
- GRB 090423: GROND second epoch imaging and refined SED
- Detection of bright radio afterglow of GRB 090424 with the VLA
- GRB 090426: Enhanced Swift-XRT position
- GRB090426: Observation for Optical counterpart from MIRO
- GRB 090426, RIMOTS optical upper limits
- GRB 090426: Swift detection of a burst with an optical counterpart
- GRB 090424: MASTER-Net prompt optical limit
- GRB 090424: WHT ISIS spectroscopy
- VLA radio observation of high-z GRB 090423
- GRB 090424: THO optical observations
- GRB 090424: GROND Observations of the Optical/NIR Afterglow
- GRB 090423: Y-band field calibration update/correction
- GRB 090423: Swift/BAT spectral lag results
- GRB 090424 : TAOS optical detection
- GRB 090424: Liverpool Telescope observations
- GRB 090424: Swift-XRT refined analysis
- GRB 090424: Optical observations from 1.23m CAHA
- GRB 090423: energetic, luminosity and jet break
- GRB 090424: MASTER-Net prompt optical observations