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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').
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"
  1. GRB 100423A: CrAO optical observations
  2. GRB 100418A: Terskol optical observations
  3. GRB 100424A: CrAO optical observations
  4. GRB 100424A: NIR Afterglow Confirmation
  5. GRB 100425A: Swift XRT refined analysis
  6. GRB 100424A: Gemini/NIRI H-band observations
  7. GRB100425A: Swift/UVOT Upper Limits
  8. GRB 100424A: Swift/UVOT Upper Limits
  9. GRB 100424A: Liverpool Telescope Upper Limits
  10. GRB 100425A: Enhanced Swift-XRT position
  11. GRB 100425A: Swift-BAT refined analysis
  12. GRB 100425A: VLT/X-shooter redshift
  13. GRB 100425A: GROND afterglow observation
  14. GRB 100424A: Gemini/NIRI Candidate Afterglow
  15. GRB 100424A: D50 optical limits
  16. GRB 100425A: candidate optical afterglow from the VLT
  17. GRB100424A: MITSuME optical upper limits
  18. GRB100423A: MITSuME optical upper limits
  19. GRB 100424A : Lulin early z'-band upper limit
  20. GRB 100424A: GROND Upper Limits
  21. GRB 100424A: PAIRITEL NIR Upper Limits
  22. GRB 100424A: Swift-XRT refined analysis
  23. GRB 100425A: Swift detection of a burst
  24. GRB 100424A: WHT z-band observations
  25. GRB 100424A: NOT optical observations
  26. GRB 100424A, Swift-BAT refined analysis
  27. GRB 100424A: Enhanced Swift-XRT position
  28. GRB 100424A: Prompt enhanced Swift-XRT position.
  29. GRB 100424A: Swift detection of a burst
  30. GRB 100420A: GRT Optical Observation
  31. GRB 100418A: ROVOR optical measurements at 35 hours
  32. Swift-BAT refined analysis of trigger 420256
  33. Swift Trigger 420256: D50 optical limits
  34. GRB 100418A: Possible Evidence for a Supernova
  35. GRB 100420A: Swift-BAT refined analysis
  36. GRB 100423B: Fermi GBM detection
  37. GRB 100423A: Swift-BAT refined analysis
  38. Swift Trigger 420256: IAC80 R-band observations
  39. Swift Trigger 420256: BOOTES-2 observations
  40. Swift Trigger 420256: ROTSE-III Optical Limits
  41. Trigger 420256: Swift detection of a possible GRB
  42. GRB 100423A: Skynet/PROMPT Detections
  43. GRB 100423A: GROND discovery of afterglow
  44. GRB 100423A: Swift detection of a burst
  45. Radio afterglow detection of GRB 100418A with the EVLA
  46. GRB 100414A: Radio Afterglow Detection with the Expanded VLA
  47. GRB 100418A: Continued PAIRITEL NIR Observations
  48. GRB 100418A: WSRT Radio Detection
  49. GRB100418A: REM possible afterglow detection
  50. GRB 100418A: Continuing Swift/UVOT Observations
  51. GRB 100418A: further GROND observations and light curve fit
  52. GRB 100418A: RTT150 optical observations
  53. GRB100420A: MITSuME optical upper limits
  54. GRB 100414A: CFHT optical observations
  55. GRB 100420A: Swift/UVOT Upper Limits
  56. GRB 100420A: XRT refined analysis
  57. GRB 100420A: Enhanced Swift-XRT position
  58. GRB 100418A: SARA second epoch
  59. GRB 100420A: SARA Upper Limits
  60. GRB 100418A: RTT150 observations during the optical afterglow maximum
  61. GRB 100418A: optical observations
  62. GRB 100418A: MASTER-Net optical observations
  63. GRB 100414A: Confirmation of the X-ray afterglow
  64. GRB 100418A: VLT optical observations
  65. GRB 100418A: SMA submm detection
  66. GRB 100420A: ROTSE-III Optical Limits
  67. GRB 100420A: Swift detection of a burst
  68. GRB 100418A PAIRITEL NIR Observations
  69. GRB 100418A: ROVOR optical afterglow detection
  70. GRB 100418A: Swift/UVOT Observations
  71. GRB 100418A: Gemini-N redshift confirmation
  72. GRB 100413A: GMRT observation of radio afterglow
  73. GRB 100418A: Swift-XRT Refined Analysis
  74. GRB 100418A: host galaxy detection in the SDSS
  75. GRB100418A: VLT/X-shooter redshift and photometry
  76. GRB 100418A: SARA observations
  77. GRB100414A: SAO RAS optical observations
  78. GRB 100418A: GROND observations; missing author list added
  79. GRB 100418A: GROND observations
  80. GRB 100418A: Swift-BAT refined analysis
  81. GRB 100418A: Enhanced Swift-XRT position
  82. GRB 100418A: ROTSE-III Optical Limits
  83. GRB 100418A: Swift detection of a burst with a possible optical afterglow
  84. GRB 100413A: Radio Afterglow Detection with the EVLA
  85. GRB 100414A: Suzaku WAM observation of the prompt emission
  86. GRB 100414A: Swift/UVOT Observations
  87. GRB 100414A: Gemini-N observation (correction)
  88. GRB 100414A: GROND Detection of the Optical Afterglow
  89. GRB 100414A: Gemini-N candidate and redshift
  90. GRB 100414A: Enhanced Swift-XRT position of candidate afterglow
  91. GRB 100413A: Suzaku WAM observation of the prompt emission
  92. GRB 100414A: Palomar Transient Factory Observations
  93. GRB 100413B: Swift Confirmation of Burst
  94. GRB 100414A: Swift-XRT detection of a possible X-ray afterglow
  95. GRB 100413A: Swift-BAT final refined analysis
  96. GRB 100414A: IPN Localization
  97. Konus-Wind observation of GRB 100414A (correction to GCN 10597)
  98. Konus-Wind observation of GRB 100414B
  99. GRB 100415A: MAXI/GSC detection of a probable GRB
  100. GRB 100414A: Fermi GBM detection

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