GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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 131014A
- GRB 131014A: NOT afterglow candidate
- GRB 131014A: Nanshan optical observations
- GRB 131014A: Swift detection of a possible X-ray afterglow
- GRB 131014A Tiled Swift observations
- GRB 131014A: Fermi-LAT detection
- GRB 131014A: Fermi GBM detection
- GRB 131011A: Fermi GBM detection
- iPTF 13dsw/Fermi403206457: X-Shooter redshift
- Swift-XRT detection of iPTF 13dsw/Fermi403206457
- GRB 131011A: GROND afterglow observations
- Fermi403206457: continued P60 observations and fading behavior
- Fermi403206457: Weihai optical upper limit
- Fermi403206457: NOT optical observations
- Fermi403206457: iPTF detection of a possible optical afterglow
- Trigger 574266 is not a Swift detection of a known source
- GRB 130925A: Possible signatures of binary nature in the afterglow - Request for observations
- GRB 130831A: Continued RATIR Optical and NIR Observations
- GRB 130831A: VLT/FORS2 spectroscopic detection of a supernova
- GRB 131004A: MOSFIRE NIR imaging
- GRB 131004A: Correction to XRT refined analysis
- GRB 131004A: Skynet PROMPT/DSO-14 upper limits
- GRB 131004A, Swift-BAT refined analysis
- GRB 131004A: Fermi GBM observation
- GRB 131004A: CARMA 93 GHz upper limit
- GRB 131004A: Swift/UVOT Detection
- GRB 131004A: RATIR Optical and NIR Upper Limits
- GRB 131004A: Swift-XRT refined Analysis
- GRB131004A: TNG Redshift confirmation
- GRB 131004A: GROND observations of the afterglow
- GRB 131004A: Enhanced Swift-XRT position
- GRB131004A: Magellan Redshift
- GRB 131004A: Liverpool Telescope optical afterglow observations
- GRB 131004A: TNG optical afterglow confirmation
- GRB 131004A: optical afterglow from the NOT
- GRB 131004A: Swift detection of a burst (may be short)
- GRB 131002A, Swift-BAT refined analysis
- GRB 130925A: 3mm observations with CARMA
- GRB 131002A: Fermi GBM observation
- GRB 130925A/Sw J0244-2609: mm observations at PdBI
- GRB 131002B, Swift-BAT refined analysis
- GRB 131002B: GROND upper limits
- GRB 131002B: Swift-XRT Refined Analysis
- GRB 131002B: Swift/UVOT Upper Limits
- GRB 131002A: Swift/UVOT Detection
- GRB 131001A, Swift-BAT refined analysis
- GRB 131002A: Swift-XRT refined Analysis
- GRB 131002B: Enhanced Swift-XRT position
- GRB 131002A: ISON-NM optical observations
- Swift J1242.9-3530, Swift-BAT refined analysis
- GRB 131001A: Swift UVOT and XRT Upper Limits
- GRB 131002A: Enhanced Swift-XRT position
- NuSTAR observations of GRB 130925A
- Fermi Gamma-ray Burst Monitor trigger 402405063 / 131002466 is not a GRB
- GRB 131002B: Swift detection of a burst
- GRB 131002A: Swift detection of a burst
- GRB 131002A: Faulkes Telescope North optical afterglow
- GRB 131001A detected in ground analysis of Swift-BAT data
- GRB 130925A: continuing Swift/XRT monitoring
- Swift Operations in the event of a US Government shutdown
- IPN Observations of GRB 130925A
- US Government shutdown may impact GRB operation of GCN
- GRB 130930A: Swift detection of a burst
- GRB 130929A: Swift/UVOT Upper Limits
- GRB 130831A: Continued RATIR Optical and NIR Observations
- GRB 130929A: Swift-XRT refined Analysis
- GRB 130929A, Swift-BAT refined analysis
- GRB 130929A: Enhanced Swift-XRT position
- GRB 130929A: TAROT La Silla observatory optical observations
- GRB 130929A: Swift detection of a burst
- Fermi LAT Upper Limits on GRB 130925A
- GRB 130925A: Swift/UVOT Detection of the Host Galaxy
- GRB 130925A: Swift/UVOT Upper Limits
- GRB 130925A: sub-mm non-detection with SMA
- GRB 130925A: optical upper limit
- GRB 130925A: Continued RATIR Optical and NIR Observations
- GRB 130925A: Fermi GBM Detection
- Konus-Wind observation of GRB 130925A
- Observation of possible GRB/TDE 130925A by INTEGRAL/SPI-ACS: three activity episodes
- GRB 130925A: RATIR Optical and NIR Observations
- GRB 130925A Swift-BAT refined analysis
- GRB 130925A: Historical non-detection from Rosat-HRI
- Fermi GBM detection of GRB 130925A and a possible precursor
- GRB 130925A: Swift-XRT refined Analysis
- GRB 130925A: Initial Similarities to Swift J1644+57
- GRB 130925A: TAROT La Silla observatory optical observations
- GRB 130925A: Enhanced Swift-XRT position
- GRB 130925A: VLT/X-shooter redshift
- GRB 130925A: VLT/UVES observations
- GRB 130925A: MAXI/GSC detection
- GRB 130925A: GROND afterglow candidate
- GRB 130925A: Swift detection of a burst
- IPN Triangulation of SGR-like burst 130913 - probable association with SGR/AXP 1E1841-045
- GRB 130831A: RTT150 optical observations
- GRB 130702A: RTT150 optical observations
- GRB 130831A: RATIR Confirmation of NIR/Optical Afterglow Flattening
- GRB 130903A: optical observations
- GRB 130907A: Maidanak optical observations
- GRB 130912A: AAO optical upper limit
- Fermi Trigger 401326696: MASTER prompt optical observations