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"19600 results found.
- GRB 050410: Swift XRT Position
- GRB 050408: Properties of the Host Galaxy
- GRB 050408: Swift XRT analysis
- GRB 050408, optical observations
- GRB050408: REM NIR and Optical observation
- GRB 050408 Optical Observations
- GRB 050408: Optical afterglow confirmed
- GRB 050408, optical observations
- GRB 050408 optical candidate
- GRB 050408: Swift XRT Position
- Swift-UVOT Optical Counterpart Candidate to XRF 050406
- GRB 050406: early Swift XRT analysis results
- GRB 050406 BAT refined analysis
- GRB 050406: Early observations with Swift-UVOT
- GRB 050406: Swift XRT Position
- Swift-BAT detection of GRB 050406
- Konus-Wind observation of GRB 050401
- GRB050401: Radio observation at 610 MHz with GMRT
- GRB 050401: VLT spectroscopic redshift
- GRB 050401 Optical Observations
- GRB050401: Maidanak optical observation
- GRB 050401 BAT refined analysis
- Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
- GRB 050402A: IR Observations
- GRB 050402: Early observations with Swift-UVOT
- Swift Trigger 113225: P60 Observations
- GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
- GRB 050401: Optical afterglow candidate
- Swift-BAT detection of GRB 050401
- GRB 050401: Prompt XRT position
- Retraction of three Swift GRB triggers
- Swift-BAT detection of GRB 050331b
- GRB 050331: Swift UVOT Source
- Swift-BAT detection of GRB 050331
- GRB 050331: Swift XRT Position
- Swift Data Publicly Available Starting April 5, 2005
- Konus-Wind observation of GRB 050326
- GRB050326: optical limit
- GRB 050326: Early observations with Swift-UVOT
- GRB 050326 XMM-Newton observation
- GRB 050326 : Planned XMM-Newton observation
- GRB 050326: Swift XRT Position
- GRB050326: optical limit 33min before GRB
- GRB 050326 BAT refined analysis
- GRB050326: delayed XRT observation
- Swift-BAT detection of a bright GRB 050326
- GRB050319, optical observations
- GRB050319, color indices
- GRB050319: RTT150 Optical Observations
- Swift-BAT detection of a bright outburst from SGR1806-20
- Swift-BAT trigger 112060 is not a real GRB
- GRB 050319: ROTSE-III Refined Analysis
- GRB 050318: Swift-BAT refined analysis
- Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
- GRB 050319 R band observations
- GRB 050319: Swift-UVOT detection of the afterglow
- GRB 050315: Variability Analysis of Swift BAT Time History
- GRB050319: BR optical photometry
- GRB 050318: SWIFT-UVOT refined analysis
- GRB 050319: Swift-BAT refined analysis
- GRB050319,optical observation
- Swift Detection of GRB 050319
- GRB 050319: Detection of Possible Optical Counterpart
- GRB 050318: Swift/UVOT detection of afterglow emission
- GRB050318: Swift XRT position
- Swift-BAT detection of GRB 050318
- GRB050223: analysis of the XMM-Newton observation
- GRB 050306: ROTSE-III early limits
- GRB 050315: Swift-BAT further refined analysis
- GRB050315: Swift-BAT Refined analysis
- Non-detection of GRB050315 in ATCA Radio Observations
- GRB 050315: Swift XRT Position
- GRB 050315: Early Observations with Swift/UVOT
- Swift-BAT detection of GRB 050315
- GRB050223: No XMM-Newton OM detection of afterglow emission
- GRB050309: CONCAM pre-trigger and trigger coincident optical
- GRB 050126: Redshift determination
- Swift-BAT trigger 107873: No Swift XRT counterpart
- GRB 050306: Confirmation of X-ray afterglow
- GRB 050309, Early optical limits from RAPTOR
- Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
- GRB 050309 : Lulin R-band observation
- Swift 107873: P60 Optical Observations
- GRB 050306: CORRECTION to date of observation
- GRB 050306: No Swift UVOT Optical Counterpart Detected
- GRB 050306: Possible X-ray Afterglow Position from the Swift
- Swift trigger 107518: optical observation
- GRB 050306,optical observation
- GRB 050306: Swift-BAT detection of a long burst
- GRB050215B: Late-Time Swift UVOT Observations
- PROMPT VRcIc Observations of GRB 050223
- GRB 050223: optical observations
- GRB050223 XMM-Newton observation
- INTEGRAL detection of GRB 050223
- GRB050223: No Swift UVOT Detection of Afterglow Emission
- GRB050223: ROTSE-III Optical Observations
- GRB 050223 Swift/BAT detection of a burst
- GRB 050223: Swift XRT Position
- GRB050219b: CORRECTION to time of UVOT observations
- GRB050219b: No Swift UVOT Detection of Afterglow Emission