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"7300 results found.
- GRB 141207A Tiled Swift observations
- GRB 141202A Tiled Swift observations
- GRB 141121A: Continued RATIR Optical Observations
- GRB 141130A: Mondy optical observations
- GRB 141130A: Swift detection of a burst with an optical counterpart
- GRB 141124A: iPTF upper limits
- GRB 141118A: Fermi GBM Detection
- GRB 141118A: iPTF Optical Observations
- GRB 141121A: GROND Afterglow candidate
- GRB 141121A: Swift detection of a burst
- GRB 141104A: further Swift-XRT observations and afterglow candidate
- Swift Trigger 618673: probable noise event
- Swift Trigger 618402: probable noise event
- GRB 141109A: REM NIR candidate afterglow
- GRB 141109B: Swift detection of a burst
- GRB 141109A: Swift detection of a burst
- GRB 141104A: Swift-XRT observations
- GRB 141104A Tiled Swift observations
- GRB 141031B: Swift detection of a burst
- GRB 141031A: GROND detection of a possible optical afterglow candidate
- GRB 141031A: Swift detection of a burst
- GRB 141029A Tiled Swift observations
- GRB 141028A: Swift/XRT detection of the X-ray afterglow
- GRB 141028A: GROND Afterglow confirmation (MASTER source)
- GRB 141028A Tiled Swift observations
- GRB 141028A: MASTER OT candidate detection
- GRB 141026A: GROND observations
- GRB 141026A: Swift detection of a burst
- GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate
- GRB 141022A: Swift detection of a burst
- GRB 141020A: Swift detection of a burst with an optical counterpart
- GRB 141017A: Swift detection of a burst
- GRB 141015A: Swift/XRT localization
- GRB 141005A: Additional P60 imaging and afterglow confirmation
- GRB 141005A: Swift detection of a burst
- GRB 141004A: Swift detection of a burst with an optical counterpart
- Swift observations of HD 305560
- GRB 140930B: GROND observations
- GRB 140930B: MMT confirmation of the optical afterglow
- GRB 140930B: ISON-Kislovodsk observations
- GRB 140930B: WHT detection of candidate afterglow
- GRB 140930B: Swift detection of a short burst
- GRB 140930A/MAXI J2259+524: MAXI-GSC detection
- GRB 140928A: GROND Afterglow Candidate
- GRB 140927A: Swift detection of a burst
- GRB 140919A: GROND afterglow candidate
- GRB 140919A: Swift/UVOT observations
- GRB 140916B: iPTF Optical Observations
- GRB 140916A: Swift detection of a burst
- GRB 140903A: Chandra detection of the afterglow
- GRB140907A: Swift UVOT detection
- GRB 140906A: iPTF optical transient candidates
- GRB 140903A: Confirmation of Optical Fading from Discovery Channel Telescope
- GRB 140903A: tentative spectroscopic redshift
- GRB140903A: Discovery Channel Telescope Optical Detection
- GRB 140831A: iPTF observations of a possible short burst detected by Fermi GBM
- GRB 140829A: iPTF optical observations
- GRB 140824B: Swift observations
- GRB 140824A: Swift detection of a burst
- GRB 140817A: Khureltogot optical upper limit
- GRB 140818B: ISON-Kislovodsk and ISON-Burakan optical upper limit
- GRB 140818A: GROND confirmation of afterglow candidate
- GRB140819A: Deep GROND Upper Limits
- Fermi 430148973/MASTER candidate: LCO-Sutherland observations
- Fermi trigg_num 430148973: OSN I-band observations
- GRB 140818B : Correction to GCN 16713
- GRB 140818B: Swift/UVOT Upper Limits
- GRB140818B : GROND afterglow candidate
- GRB 140818B: OSN I-band afterglow candidate
- GRB 140818B: Swift detection of a burst
- Swift detection of SAX J1712.6-3739
- GRB 140818A Tiled Swift observations
- GRB 140817A: Swift detection of a burst
- GRB 140808A / PTFeag: VLA K-band observations
- GRB 140815A: GROND afterglow candidate
- Swift Trigger 609694 is probably not an astrophysical source
- Swift trigger 609139 is probably 4U 1850-03
- Swift observations of possible GRB 140809A candidate
- GRB 140808A: Swift/UVOT Upper Limits
- GRB 140808A: Redshift from the 10.4m GTC telescope
- GRB 140808A: Swift-XRT observations
- GRB 140808A: optical afterglow candidate iPTF14eag
- GRB 140801A: Swift/UVOT Upper Limits
- GRB 140730A: Swift detection of a burst
- Swift Trigger 607506 is probably noise
- GRB 140729A Tiled Swift observations
- Trigger 607399: Swift detection of SGR1806-20
- GRB 140723A: LCO-Sutherland optical candidate retraction
- GRB 140723A: LCO-Sutherland optical candidate
- GRB 140723A Tiled Swift observations
- GRB 140716A: Confirmation of the Swift-XRT afterglow
- GRB 140716A: GROND confirmation of the afterglow
- GRB 140719A: FTS observations
- GRB 140719A: GROND Afterglow candidate
- GRB 140719A: Swift detection of a burst
- GRB 140716A: Swift/UVOT Upper Limits
- GRB 140716A: GROND afterglow candidate
- GRB 140716A: Swift-XRT detection of an afterglow candidate
- GRB 140713A: Swift detection of a burst
- GRB 140709A: Continued RATIR Optical and NIR Observations