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"- IPN localization of short bright GRB 090227B
- Konus-Wind observation of GRB 090301A
- GRB 090301A: Swift-BAT refined analysis
- GRB 090301B: Fermi GBM detection
- GRB 090227B: Fermi GBM detection
- GRB 090301: Swift detection of a burst
- Swift_BAT_Lightcurve Notice for Trigger Number 344565 is not valid
- GRB 090228: Fermi GBM detection
- GRB 090227: Fermi GBM detection
- GRB 090206: Fermi GBM detection
- SGR J1550-5418
- GRB 081211B: Nearby cluster
- Ongoing activity of AXP/SGR 1E1547.0-5408
- GRB 090222: Fermi GBM detection
- GRB 090219: Fermi GBM detection
- Swift Restored
- Swift Trigger 343319 is not a GRB
- GRB 090217: Suzaku WAM observation of the prompt emission
- GRB090217: XRT analysis
- Konus-Wind observation of GRB 090217
- IPN localization of GRB 090217
- GRB 090213: Fermi GBM detection
- GRB090217: Fermi-LAT Detection
- GRB 090217: Fermi GBM detection
- SGR activity seen by BAT during ICSP Ionospheric Events
- Detailed lightcurves of ICSP VLF Observation of SGR/AXP 1E1547.0-5408
- GRB 090207 - Fermi GBM Observations
- Fermi Gamma-ray Burst Monitor trigger 255729682 is not a GRB
- GRB 090129: Fermi GBM detection
- VLA radio upper limit on GRB 090205
- GRB 090205: VLT optical decay
- Fermi Gamma-ray Burst Monitor trigger 255541748 cannot be classified
- GRB 090205: Swift/UVOT Upper Limits
- GRB 090205: VLT refined redshift
- GRB 090205: Swift-XRT refined analysis
- GRB 090205: Swift burst of interest
- GRB 090205: VLT spectroscopic redshift
- GRB 090205: GROND observations and photometric redshift estimate
- GRB 090205: VLT candidate afterglow
- GRB 090205: Swift-BAT refined analysis
- GRB 090205: Enhanced Swift-XRT position
- GRB 090205: Swift detection of a burst
- GRB 080319B: IceCube upper limit on high-energy neutrino flux
- GRB 090131: Suzaku WAM observation of the prompt emission
- ICSP VLF observation of the signatures of SGR/AXP 1E1547.0-5408 bursts
- GRB 090126A: Swift-XRT afterglow confirmation
- Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
- Konus-Wind observation of GRB 090201
- GRB 090202: Fermi GBM detection
- GRB 090131: Fermi GBM detection
- GRB 090201: Swift-XRT refined analysis
- GRB090201: Swift UVOT upper limits
- GRB 090201: object inside the enhanced XRT error circle
- GRB 090201: Enhanced Swift-XRT position
- GRB 090201: VLT NIR observations
- GRB 090201: Swift-BAT refined analysis
- GRB 090201: VLT afterglow candidate
- GRB 090201: Swift-XRT detection of the possible X-ray afterglow
- GRB090113: MAGIC telescope GeV observation
- GRB 090201: ROTSE-III Optical Limits
- GRB 090201: Swift detection of a burst
- GRB 090126A: Swift/UVOT Upper Limits
- Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29
- GRB 090129: Swift-BAT refined analysis
- GRB 090129: Swift detection of a burst
- IBAS Alert N. 5442 is not a GRB
- Suzaku ToO Observation of AXP 1E 1547.0-5408
- Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
- AXP 1E1547.0-5408: RHESSI observations up to 400 keV
- GRB 090102: HST observations and host galaxy
- GRB 090126C: Fermi GBM detection
- GRB 090126A: Swift-XRT Refined Analysis
- GRB 090126B: Fermi GBM detection
- GRB 090126: SuperAGILE Localization of a Long GRB
- Konus-Wind detection of very bright SGR-like burst on January 25, 2009
- GRB 090118: no afterglow candidate
- GRB 090123: GROND detection
- 1E1547.0-5408: Swift detection of dust halo
- GRB 090123: Swift XRT refined analysis
- GRB 090123: Swift/UVOT Observations
- AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
- GRB 090123: Swift-BAT refined analysis
- GRB090123: Enhanced Swift-XRT position
- GRB 090123: Swift detection of a burst
- AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
- GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
- Swift-BAT trigger 340734 is not a GRB
- AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
- AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
- GRB 090117C: Suzaku WAM observation of the prompt emission
- AXP 1E1547.0-5408: Fermi GBM observations
- Trigger 340734: Swift detection of a possible short burst
- AXP 1E1547.0-5408 activity with SGR bursts
- GRB 090118: Subaru NIR Observation
- GRB 090118: KPNO 4m 2nd Epoch Observations
- GRB 090118 (BATSS): GRT Optical Observation
- GRB 090118: KPNO 4m Detection of Candidate Afterglow
- GRB 090118: Swift-XRT observations
- GRB090118 Swift/UVOT upper limits
- GRB 090118: GROND Upper Limits