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"23442 results found.
- Skynet/PROMPT Observations of GRB120909A
- GRB 120909A: Swift detection of a burst
- GRB 120907A: Swift/UVOT Detection
- GRB 120907A: Enhanced Swift-XRT position
- GRB 120907A: Swift-BAT refined analysis
- GRB 120907A: NOT optical observations
- GRB 120907A: Swift detection of a burst with optical counterpart
- XMM observations of the short GRB120804A
- GRB 120819A: optical upper limit
- GRB 120802A: optical observations in CrAO
- GRB 120830A: Further Swift Observations
- GRB 120830A: Swift-XRT and UVOT observations
- GRB 120830A: early MASTER optical limit
- IPN Triangulation of short GRB 120830A
- Fermi trigger 368003226 : MASTER optical observations
- GRB 120819A: Swift/UVOT Upper Limits
- GRB 120817A: Swift/UVOT Upper Limits
- GRB 120817B: Deep limit on the optical afterglow from du Pont and Magellan observations
- GRB 120821A: Swift/XRT observations
- GRB 120821A: Swift/UVOT Upper Limits
- GRB 120821A: GROND upper limits
- GRB 120817B - PTF Observations
- GRB 120817A: RAPTOR Limits During Gamma-Ray Emitting Interval
- GRB 120811C: optical observations
- GRB 120819A: Bassano Bresciano Observatory optical observations
- GRB 120819A: GROND afterglow confirmation
- GRB 120819A: MITSuME Ishigakijima upper limits
- GRB 120819A: MITSuME Okayama Optical upper limits
- GRB 120819A: Enhanced Swift-XRT position
- GRB 120819A: afterglow candidate from NOT
- GRB 120819A: Swift detection of a burst
- GRB 120817B: Swift-XRT observations
- GRB 120811C: optical observations
- GRB 120816A: Swift/UVOT Detection of the Optical Afterglow
- GRB 120815A: MASTER-ICATE observations
- IPN Triangulation of GRB 120816B (short/exceptionally intense)
- GRB 120817B: LCO Optical Observations
- IPN Triangulation of GRB 120817B (short/very intense)
- GRB 120816A: optical upper limit
- GRB 120817A: Enhanced Swift-XRT position
- GRB 120815A: Swift/UVOT Detection of the Optical Afterglow
- GRB 120816A: Bassano Bresciano Observatory optical observations
- GRB 120817A: Swift-XRT observations
- GRB 120817A: Swift detection of a burst
- GRB 120816A: Enhanced Swift-XRT position
- GRB 120816A: BOOTES-2 observations
- GRB120816A: OPTIMA discovery of optical counterpart
- GRB 120816A: TAROT Calern observatory optical observations
- GRB 120816A: ROTSE-III Optical Limits
- GRB 120816A: Swift detection of a burst
- GRB 120815A: Enhanced Swift-XRT position
- GRB 120815A: VLT/X-shooter redshift
- GRB 120815A: GROND afterglow candidate
- GRB 120815A: Swift-XRT observations
- GRB 120815A: TAROT La Silla observatory optical observations
- GRB 120815A: Swift detection of a burst
- GCN for GRB 120811C
- GRB 120811A: Swift/XRT-UVOT Obseravations
- GRB120804A: Chandra observations and afterglow detection
- GRB 120805A: optical afterglow confirmation from the NOT
- GRB 120805A: Enhanced Swift-XRT position
- GRB 120811C: RTT150 optical observations
- GRB 120811C: MASTER-Tunka OT observations
- GRB 120811C: Bassano Bresciano Observatory optical observations
- GRB 120811C: Swift/UVOT Detection
- Improved IPN error box for short hard GRB 120811B
- GRB 120811C: RTT150 optical observations
- GRB 120811C: Enhanced Swift-XRT position
- GRB 120811C: TAROT Calern observatory optical observations
- GRB 120811C: Swift detection of a burst with an optical counterpart
- IPN Triangulation of short hard GRB 120811B
- Trigger 530588: Swift detection of XMM J174457-2850.3
- Swift Trigger 530581: GRB 120811A or a galactic transient
- GRB 120803A: optical upper limit
- GRB 120807A: Swift/UVOT Upper Limits
- GRB 120803A: Confirmation of the X-ray afterglow
- GRB 120804A: Konus-Wind and Swift/BAT joint spectral analysis
- GRB 120714B: GROND/FORS2 detection of a supernova
- Swift Trigger 530441 is a false trigger
- GRB 120802A: optical observations
- GRB 120807A: RAPTOR Limits During Gamma-Ray Emitting Interval
- GRB 120807A: TAROT La Silla observatory optical observations
- GRB 120807A: Enhanced Swift-XRT position
- GRB 120807A: Swift detection of a burst
- Fermi/GBM detection of an SGR-like burst
- GRB 120805A: Swift/UVOT Upper Limits
- Swift trigger 530214: uncertain if real or not
- Swift-BAT trigger 529813 is due to noise while entering the SAA
- GRB 120802A: Swift/UVOT Upper Limits
- GRB120805A: Liverpool Telescope observations
- GRB 120805A: TAROT Calern observatory optical observations
- GRB 120805A: Swift detection of a burst
- GRB 120804A: MITSuME Okayama Optical upper limits
- GRB 120804A: Swift/UVOT Upper Limits
- GRB 120804A: GROND upper limits
- GRB 120804A: Enhanced Swift-XRT position
- GRB 120803B: MITSuME Okayama Optical upper limits
- GRB 120803A: MITSuME Okayama Optical upper limits
- GRB 120804A: Swift detection of a short burst
- GRB 120803B: Enhanced Swift-XRT position