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"23417 results found.
- GRB 100206A: Optical limit
- GRB 100206A: Enhanced Swift-XRT position
- GRB 100206A: Pre-explosion imaging and host candidate
- GRB 100206A: Swift detection of a short hard burst
- GRB100205A: CFHT z'-band observation
- GRB 100205A: Gemini-N + NIRI photometry
- GRB 100130B: Fermi GBM detection
- GRB 100113A: Fermi GBM detection
- GRB 100205A: Swift UVOT upper limits
- GRB 100203A: Swift XRT and UVOT refined analyses
- GRB 100205A: Enhanced Swift-XRT position
- GRB 100205A Gemini-North IR afterglow candidate
- GRB 100205A: Gemini-South Observations
- GRB 100205A: Super-LOTIS early observations
- GRB 100205A: NOT optical observations
- GRB 100205A: Swift detection of a burst
- GRB 100203A Detected in Ground Analysis of BAT Data
- GRB 100131A: Fermi GBM detection
- GRB 100119A: Suzaku WAM observation of the prompt emission
- GRB 100122A: Fermi GBM detection
- GRB 100122A: MASTER-Net optical observations
- GRB 100116A: Suzaku WAM observation of the prompt emission
- GRB 100115A: Swift-XRT refined analysis
- GRB 100119A: Swift-BAT refined analysis
- GRB 100119A: Swift detection of a burst
- Swift/UVOT refined analysis of GRB100117A
- GRB 100117A: Swift-XRT refined analysis
- GRB 100117A: Gemini-North upper limit
- GRB 100117A: Magellan IMACS imaging
- GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
- GRB100117A: Possible afterglow from NOT observation
- GRB 100117A: Swift detection of a short hard burst
- GRB 100115A: Gemini-N photometry
- GRB 100115A: Enhanced Swift-XRT position
- GRB 100116A: Fermi LAT detection
- GRB 100115A: SARA Astrometry
- GRB 100116A: Fermi GBM detection
- GRB 100115A: SARA Afterglow Candidate
- GRB 100115A: Swift/UVOT Upper Limits
- GRB 100115A: Swift-XRT candidate afterglow
- GRB 100115A detected in ground analysis of Swift-BAT data
- GRB 100111A: PAIRITEL NIR Upper Limits
- GRB 100111A: Swift UVOT Refined Analysis
- GRB 100111A: Enhanced Swift-XRT position
- GRB 100111A: NOT optical observations
- GRB 100111A: Swift detection of a burst with an optical afterglow
- Swift/BAT Detects an Outburst from XTE J1901+014
- GRB 100103A: GROND Upper Limits
- GRB 100103A - UVOT-enhanced XRT position
- GRB 100103A: Swift/UVOT Upper Limits
- GRB 100103A: Swift/XRT position
- Swift Trigger 381591 is probably not a burst
- GRB 091231: GROND NIR observations
- Swift Trigger 381591: Uncatalogued UVOT Source
- GRB 091230: Swift/UVOT Observations
- Trigger 381591: Swift detection of a possible burst
- GRB 091230: Swift-XRT observation
- GRB 091230: GROND optical/NIR afterglow candidate
- Swift Trigger 381434 is not a GRB
- Trigger 381434: Swift detection of a possible burst
- GRB 091221: Skynet/PROMPT Detections
- GRB 091117: Swift-XRT late time observations
- 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: Swift detection of a burst
- Swift trigger 379449 (possible GRB) is not a burst
- GRB 091215: Faulkes Telescope North observations
- Trigger 379449: Swift detection of a possible burst
- GRB 091208A: GAO 150cm telescope Optical Observation
- GRB 091208B: GAO 150cm telescope Optical Observation
- GRB091208A: Swift/UVOT refined analysis
- GRB 091208B: optical observations
- GRB 091208B: GROND observations
- GRB 091208A: Swift-XRT observations
- GRB091208B: NOT optical observations
- GRB091208B: Swift/UVOT refined analysis
- GRB 091208A, RIMOTS optical upper limits
- GRB 091208B: MITSuME Akeno Optical Observation
- GRB 091208B: Enhanced Swift-XRT position
- GRB 091208B: MITSuME Okayama Optical Observation
- 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
- GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
- GRB 091127: GAO 150cm telescope Optical Observation
- GRB 091202: GTC & CAHA optical/nIR afterglow candidate
- GRB 091109A: GROND confirmation of redshift z = 3.5
- GRB 091127, SMARTS optical/IR afterglow observations
- GRB 091202: Swift/UVOT Upper Limits
- GRB 091202: Liverpool Telescope observations
- GRB 091202: Optical and NIR observations
- GRB 091202 - UVOT-enhanced XRT position
- GRB 091127: Zadko Telescope Observations
- GRB 091202: TAROT Calern observatory optical observations
- GRB 091117: Chandra Observations
- Konus-Wind observation of very long GRB 091123