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"19533 results found.
- GRB 100111A: PAIRITEL NIR Upper Limits
- GRB 100111A: Swift UVOT Refined Analysis
- GRB 100111A: Swift-BAT refined analysis
- GRB 100111A: Enhanced Swift-XRT position
- GRB100111A: Swift-XRT refined analysis
- GRB 100111A: Fermi GBM observation
- GRB 100111A: Swift detection of a burst with an optical afterglow
- Swift/BAT Detects an Outburst from XTE J1901+014
- Swift Trigger #382159 is due to XTE J1752-223
- GRB 100103A: Swift-XRT team refined analysis
- GRB 100103A - UVOT-enhanced XRT position
- GRB 100103A: Swift/UVOT Upper Limits
- GRB 100103A: Correction to Swift position error
- GRB 100103A: Swift/XRT position
- Swift Trigger 381591: Retraction of Reported UVOT Source
- Swift Trigger 381591 is probably not a burst
- Swift Trigger 381591: Uncatalogued UVOT Source
- GRB 091230: Swift/UVOT Observations
- Trigger 381591: Swift detection of a possible burst
- GRB 091230: Swift-XRT observation
- Swift Trigger 381434 is not a GRB
- Trigger 381434: Swift detection of a possible burst
- GRB 091221 : IRSF NIR upper limit
- GRB 091221: Skynet/PROMPT Detections
- GRB 091221: Fermi GBM Observation
- GRB 091117: Swift-XRT late time observations
- GRB 091221 Swift-BAT refined analysis
- GRB091221: Swift/UVOT refined analysis, correction.
- GRB 091221: Swift/UVOT refined analysis
- GRB 091221: Swift-XRT refined analysis
- GRB 091221: Enhanced Swift-XRT position
- GRB 091221: UVOT Confirmation of an Optical Afterglow
- GRB 091221: ROTSE-III Detection of Optical Counterpart
- GRB 091221: Swift detection of a burst
- Swift trigger 379449 (possible GRB) is not a burst
- Trigger 379449: Swift detection of a possible burst
- GRB 091208A: Suzaku WAM observation of the prompt emission
- Konus-Wind observation of GRB 091208A
- GRB091208A: Swift/UVOT refined analysis
- GRB 091208B: optical observations
- GRB 091208B: GROND observations
- GRB 091208A: Swift-XRT observations
- GRB 091208B: Swift-XRT refined analysis
- GRB091208B: Swift/UVOT refined analysis
- GRB 091208B: Fermi GBM observation
- GRB 091208B, Swift-BAT refined analysis
- GRB 091208A Swift-BAT refined analysis
- GRB 091208B: Faulkes Telescope North and South Optical Afterglow
- GRB 091208A, RIMOTS optical upper limits
- GRB 091208B: Enhanced Swift-XRT position
- GRB 091208B, RIMOTS optical upper limits
- GRB 091208B: Swift detection of a burst with an optical afterglow
- GRB 091208B: BOOTES-3 optical afterglow
- GRB 091208: ROTSE-III Optical Limits
- GRB 091208: Swift detection of a burst
- GRB091127: Continuing Swift/UVOT Observations
- GRB091202: Swift-XRT refined analysis
- GRB 091202: Swift/UVOT Upper Limits
- GRB 091202 - UVOT-enhanced XRT position
- GRB 091127: Zadko Telescope Observations
- GRB 091117: Chandra Observations
- GRB 091127: Suzaku WAM observation of the prompt emission
- GRB 091130B: Swift-XRT team refined analysis
- GRB 091130B: Swift-BAT refined analysis
- GRB 091130B: Swift/UVOT Upper Limits
- GRB 091127: Skynet/PROMPT Observations of Fading
- GRB 091130B: Enhanced Swift-XRT position
- Swift trigger 377436 (possible GRB 091130A) is not a burst
- GRB 091130B: MASTER observations
- GRB 091130B: Swift detection of a burst
- GRB 091130: Swift detection of a possible burst
- GRB 091127: Radio observations
- Konus-Wind observation of GRB 091127
- GRB 091127: TAROT La Silla observatory optical observations
- GRB 091127: optical observations
- GRB 091127: Fermi GBM detection
- GRB 091127: Gemini-N redshift
- GRB 091127: Swift-XRT afterglow detection and analysis
- GRB 091127: TAROT La Silla observatory optical decay
- GRB 091127: Swift/UVOT observations
- GRB 091127: Swift-BAT refined analysis
- GRB 091127 : GROND observations
- GRB 091127: Swift/UVOT Detection of an Optical Afterglow
- GRB 091127: Liverpool Telescope afterglow candidate
- GRB 091127: Swift detection of a burst
- GRB 091117A: Suzaku WAM observation of the prompt emission
- GRB 091117A: Swift/UVOT followup observations
- GRB 091117: Swift-XRT observations
- GRB 091117 BAT refined analysis
- GRB 091117: Evidence for Variability of XRT Source #1
- GRB 091117: Swift XRT refined analysis
- GRB 091117: Gemini-North spectroscopy of DSS galaxy
- Konus-Wind observations of GRB 091117A
- GRB 091117: XRT source coincident with a DSS galaxy
- GRB 091117A Detected in ground analysis of BAT data and IPN triangulation
- GRB 091112: Suzaku WAM observation of the prompt emission
- GRB 091102A: Suzaku WAM observation of the prompt emission
- GRB 091109B: Suzaku WAM observation of the prompt emission
- GRB091111: Swift XRT refined analysis
- GRB 091112: Swift-BAT refined analysis