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"- Konus-Wind observation of GRB 141220A
- GRB 141221A: Swift detection of a burst with an optical counterpart
- GRB 141220A: Fermi GBM observation
- GRB 141220A: MITSuME Okayama upper limits
- GRB 141220A: Swift-XRT refined Analysis
- GRB 141220A: Swift-BAT refined analysis
- GRB 141220A: Swift/UVOT Detection
- GRB 141220A: Photometry from OSIRIS/GTC
- GRB 141220A: LT optical afterglow observations
- GRB 141220A: Redshift from OSIRIS at the 10.4m GTC
- GRB141220A: 1.23m CAHA I-band observations
- GRB 141220A: Swift detection of a burst with an optical afterglow
- Fermi Gamma-ray Burst Monitor trigger 440728127 / 141220020 is not a GRB
- IPN Triangulation of GRB 141207A
- GRB 141207A: Suzaku WAM observation of the prompt emission
- GRB 141202A: Suzaku WAM observation of the prompt emission
- GRB 141121A: Keck observations
- GRB 141215A: Swift-XRT observations
- GRB 141215A: Fermi GBM detection
- GRB 141215A Tiled Swift observations
- Konus-Wind observation of GRB 141215A
- IPN Triangulation of GRB 141215A (long/intense)
- GRB 141212A iTelescope observation
- GRB 141212A: Zadko observatory - Gingin optical observations
- GRB 141212B: MITSuME Akeno upper limits
- Konus-Wind observation of GRB 141212B
- GRB 141212B: Swift-XRT refined Analysis
- GRB 141212A: Swift/UVOT Upper Limits
- GRB 141212B: Swift/UVOT Upper Limits
- GRB 141212A: VLA upper limit
- GRB 141212A: Gemini-N spectroscopy and photometry
- GRB 141212B: Swift-BAT refined analysis
- GRB 141212A: Swift-BAT refined analysis
- GRB 141212B: Enhanced Swift-XRT position
- Swift detection of 4U 1700+24 (= V934 Her)
- GRB 141212A: MITSuME Okayama upper limits
- GRB 141212A: Swift-XRT refined Analysis
- GRB 141212A: extended object within the XRT error circle
- GRB141212A: xinglong TNT upper limit
- GRB 141212A: Khureltogot optical upper limit
- GRB 141212A: 1.23m CAHA I-band observations
- GRB 141212B: initial Swift/UVOT observations
- GRB 141212B: Swift/XRT preliminary localization
- GRB 141212A: Enhanced Swift-XRT position
- GRB 141212A: Correction to GCN 17162
- GRB 141212A: MASTER early optical observations
- GRB 141212A: Skynet R-COP Observations
- GRB 141212A: MITSuME Akeno upper limits
- GRB 141212B: Swift detection of a burst
- GRB 141212A: Swift detection of a short burst
- GRB 141207A: Swift-XRT afterglow candidate detection
- GRB 141121A: further VLA observations
- Konus-Wind observation of GRB 141207A
- GRB141208.63: MASTER OT Detection During the Fermi Error Box inspection
- GRB141202A: Discovery Channel Telescope Optical Observations
- GRB141207A: Discovery Channel Telescope Optical Observations
- GRB 141207A: Swift-UVOT Observations
- GRB 141207A: Fermi GBM detection
- GRB 141207A: Swift-XRT observations
- Konus-Wind observation of GRB 141130A
- GRB 141207A Tiled Swift observations
- GRB 141207A: Fermi-LAT Detection
- GRB141121A: Discovery Channel Telescope Optical Observations
- GRB 141205A: Swift/UVOT Upper Limits
- GRB 141205A: Fermi GBM detection
- GRB 141205A: Nanshan optical upper limit
- GRB 141205A: XRT observations
- GRB 141205A Swift-BAT refined analysis
- GRB 141202A: Swift/UVOT Detection of a Variable Source Near the IPN Error Box
- GRB 141121A: Mondy optical observations
- GRB 141205A Short hard GRB found in ground analysis of BAT data
- Konus-Wind observation of GRB 141202A
- GRB 141130A: Mondy optical observations
- GRB 141202A: Swift XRT observations
- GRB 141202A: Fermi GBM Detection
- GRB 141202A Tiled Swift observations
- IPN Triangulation of GRB 141202A (short/hard)
- GRB 141130A: Mondy optical light curve
- GRB 141030A: Nanshan very early optical observations
- GRB 141121A: Continued RATIR Optical Observations
- GRB 141130A: Swift-BAT refined analysis
- GRB 141130A: Swift/UVOT Detection
- GRB 141130A: Swift-XRT refined Analysis
- GRB 141121A: VLA radio detection
- GRB 141130A: Enhanced Swift-XRT position
- GRB 141130A: Nanshan optical observations
- GRB 141130A: Mondy optical observations
- GRB 141130A: Swift detection of a burst with an optical counterpart
- GRB 141121A: Continued RATIR Optical Observations
- GRB 141121A: Mondy optical observations
- GRB 141121A: TSHAO optical observations
- GRB 141121A: Continued RATIR Optical Observations
- GRB 141121A: RATIR Optical Observations - Errata for GCN 17105
- GRB 141121A: MITSuME Ishigakijima Optical Observation after 7 days
- GRB 141121A: Khureltogot optical observations
- IPN Triangulation of GRB 141121A (initial episode)
- GRB 141121A: Mondy optical observations
- GRB 141121A: SPI-ACS/INTEGRAL observations
- GRB 141121A: RATIR Optical and NIR Observations
- Konus-Wind observation of GRB 141121A