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').
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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.
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subject:"Swift"body:"GRB"submitter:"Judith Racusin"- GRB 091003: Swift/UVOT Detection of an Optical Afterglow
- GRB 091003: Skynet/DSO Observations
- GRB 091003: UVOT-enhanced XRT position
- GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
- GRB 091003: Swift XRT analysis
- GRB 091003A: Fermi LAT detection
- GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
- GRB 091003A: Fermi GBM detection
- GRB 090926A: Skynet/PROMPT Observations of Post-Peak Fading
- GRB 090929A: Swift/UVOT Observations
- GRB 090929A, Swift-BAT refined analysis
- GRB 090929B, Swift-BAT refined analysis
- Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
- GRB 090929A: Swift-XRT non-detection
- Konus-Wind observation of GRB 090929A
- Konus-Wind observation of GRB 090929B
- GRB 090927: Fermi GBM observation
- GRB 090929B: Swift-XRT refined analysis
- GRB 090926A: Fermi LAT and GBM refined analysis
- GRB 090929B: Gemini-N upper limits
- GRB 090929B: Skynet/DSO Observations
- GRB 090929B: Swift/UVOT Observations
- Konus-RF observation of GRB 090929A
- GRB 090929B: RAPTOR Discovery of Optical Counterpart
- GRB 090929A BAT location of the Fermi GBM burst
- Correction: GRB 090929B: Enhanced Swift-XRT position
- GRB 090929: Enhanced Swift-XRT position
- GRB 090929B: Swift detection of a burst
- GRB 090929A: Fermi GBM detection
- GRB090926A: Swift-XRT refined analysis
- GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
- Konus-Wind and Konus-RF observations of GRB 090926A
- GRB 090927: VLT redshift
- GRB 090926B: Fermi GBM detection
- GRB 090927: Zadko Telescope observations
- GRB 090927, Swift-BAT refined analysis of the possibly short burst
- Swift/UVOT observations of GRB 090927
- GRB 090926A: Skynet/PROMPT Continued Observations
- GRB 090927: Swift XRT refined analysis
- GRB 090926A: Suzaku WAM observation of the prompt emission
- GRB 090927: Enhanced Swift-XRT position
- GRB090926B: Swift/UVOT Upper Limits
- GRB090926A: Swift/UVOT observations
- GRB 090926B: VLT spectroscopy
- GRB 090927: Swift/UVOT detection of an optical afterglow
- GRB 090927: Swift detection of a short burst
- GRB 090926B: optical object in error circle
- GRB 090926B: MAXI GSC detection
- GRB 090926A: VLT/X-shooter redshift
- GRB 090926B: NOT optical observation
- GRB 090926B: Swift XRT refined analysis
- GRB 090926B: Swift-BAT refined analysis
- GRB 090926A: Swift/UVOT detection of an optical afterglow
- GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
- GRB090926A: UVOT-enhanced XRT position
- GRB 090926B: Swift detection of a burst
- GRB 090926: Fermi LAT detection
- GRB 090926: Fermi GBM detection
- GRB 090925: Fermi GBM detection
- GRB090904B : IRSF NIR upper limit
- GRB090922A: correction to Fermi location
- GRB 090922A: Fermi GBM detection
- Swift returns to normal operations
- GRB 090715B: Skynet/PROMPT Detections
- GRB 090726: Skynet/GORT Observations
- GRB 090916: Swift-XRT upper limit
- GRB 090807: Skynet/DSO Observations
- GRB 090915: GROND upper limits
- Swift-BAT temporarily off-line for a few days
- Short-Duration GRB 090916: Skynet/PROMPT Observations
- GRB 090915: SARA detection of afterglow candidate
- GRB 090912: optical observation
- GRB 090915: Swift/UVOT detection of an optical afterglow candidate
- GRB 090702: Skynet/GORT Observations
- GRB 090902B: Skynet/PROMPT Observations
- GRB 090916, Swift-BAT refined analysis
- GRB 090915: Swift-XRT detection of a fading X-ray counterpart
- GRB 090916: Swift detection of a short burst
- GRB 090915 Swift-BAT detection of a burst in ground analysis
- GRB 090827: Confirmation of the X-ray afterglow
- GRB 090912: Swift-XRT refined analysis
- GRB 090912, Swift-BAT refined analysis
- GRB 090912: Swift/UVOT Upper Limits
- GRB 090912 optical upper limit
- GRB 090912: Enhanced Swift-XRT position
- GRB 090912: Swift detection of a burst
- GRB 090910: Fermi GBM detection
- GRB 090814A: Skynet/DSO & GORT Observations
- GRB 090823: Swift XRT confirmation of the X-ray afterglow
- GRB 090904B: GROND detection of the optical afterglow
- GRB 090831A: Suzaku WAM observation of the prompt emission
- GRB 090904A: Swift/UVOT Refined Analysis
- GRB 090904B: Swift/UVOT Refined Analysis
- GRB 090902B: Suzaku WAM observation of the prompt emission
- GRB 090829A: Suzaku WAM observation of the prompt emission
- GRB 090904B: Fermi GBM detection
- GRB 090904A: Swift-XRT refined analysis
- GRB 090904B: Swift XRT Refined Analysis
- GRB 090904B: MOA-II Optical observation
- GRB 090904A: Enhanced Swift XRT position