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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. GRB100423A : Suzaku WAM observation of the prompt emission
  2. Trigger 421072: Possible Swift detection of a GRB or transient
  3. GRB 100420A: EVLA radio observations
  4. GRB 100420A: Gemini discovery of infrared afterglow
  5. GRB 100423A: xinglong TNT optical upper limit
  6. GRB 100420A: Terskol optical upper limit
  7. GRB 100427A: Swift XRT and UVOT Upper Limits
  8. GRB 100427A: Fermi GBM detection
  9. GRB 100424a. Radio observations
  10. GRB 100418A: RTT150 optical observations
  11. GRB 100427A detected in ground analysis of Swift BAT data
  12. GRB 100414A : EVLA Radio Detection
  13. GRB 100414A : WSRT Radio Detection
  14. Konus-Wind observation of GRB 100423A
  15. GRB 100423A: CrAO optical observations
  16. GRB 100418A: Terskol optical observations
  17. GRB 100424A: CrAO optical observations
  18. GRB 100424A: NIR Afterglow Confirmation
  19. GRB 100425A: Swift XRT refined analysis
  20. GRB 100424A: Gemini/NIRI H-band observations
  21. GRB100425A: Swift/UVOT Upper Limits
  22. GRB 100424A: Swift/UVOT Upper Limits
  23. GRB 100424A: Liverpool Telescope Upper Limits
  24. GRB 100425A: Enhanced Swift-XRT position
  25. GRB 100425A: Swift-BAT refined analysis
  26. GRB 100425A: VLT/X-shooter redshift
  27. GRB 100425A: GROND afterglow observation
  28. GRB 100424A: Gemini/NIRI Candidate Afterglow
  29. GRB 100424A: D50 optical limits
  30. GRB 100425A: candidate optical afterglow from the VLT
  31. GRB100424A: MITSuME optical upper limits
  32. GRB100423A: MITSuME optical upper limits
  33. GRB 100424A : Lulin early z'-band upper limit
  34. GRB 100424A: GROND Upper Limits
  35. GRB 100424A: PAIRITEL NIR Upper Limits
  36. GRB 100424A: Swift-XRT refined analysis
  37. GRB 100425A: Swift detection of a burst
  38. GRB 100424A: WHT z-band observations
  39. GRB 100424A: NOT optical observations
  40. GRB 100424A, Swift-BAT refined analysis
  41. GRB 100424A: Enhanced Swift-XRT position
  42. GRB 100424A: Prompt enhanced Swift-XRT position.
  43. GRB 100424A: Swift detection of a burst
  44. GRB 100420A: GRT Optical Observation
  45. GRB 100418A: ROVOR optical measurements at 35 hours
  46. Swift-BAT refined analysis of trigger 420256
  47. Swift Trigger 420256: D50 optical limits
  48. GRB 100418A: Possible Evidence for a Supernova
  49. GRB 100420A: Swift-BAT refined analysis
  50. GRB 100423B: Fermi GBM detection
  51. GRB 100423A: Swift-BAT refined analysis
  52. Swift Trigger 420256: IAC80 R-band observations
  53. Swift Trigger 420256: BOOTES-2 observations
  54. Swift Trigger 420256: ROTSE-III Optical Limits
  55. Trigger 420256: Swift detection of a possible GRB
  56. GRB 100423A: Skynet/PROMPT Detections
  57. GRB 100423A: GROND discovery of afterglow
  58. GRB 100423A: Swift detection of a burst
  59. Radio afterglow detection of GRB 100418A with the EVLA
  60. GRB 100414A: Radio Afterglow Detection with the Expanded VLA
  61. GRB 100418A: Continued PAIRITEL NIR Observations
  62. GRB 100418A: WSRT Radio Detection
  63. GRB100418A: REM possible afterglow detection
  64. GRB 100418A: Continuing Swift/UVOT Observations
  65. GRB 100418A: further GROND observations and light curve fit
  66. GRB 100418A: RTT150 optical observations
  67. GRB100420A: MITSuME optical upper limits
  68. GRB 100414A: CFHT optical observations
  69. GRB 100420A: Swift/UVOT Upper Limits
  70. GRB 100420A: XRT refined analysis
  71. GRB 100420A: Enhanced Swift-XRT position
  72. GRB 100418A: SARA second epoch
  73. GRB 100420A: SARA Upper Limits
  74. GRB 100418A: RTT150 observations during the optical afterglow maximum
  75. GRB 100418A: optical observations
  76. GRB 100418A: MASTER-Net optical observations
  77. GRB 100414A: Confirmation of the X-ray afterglow
  78. GRB 100418A: VLT optical observations
  79. GRB 100418A: SMA submm detection
  80. GRB 100420A: ROTSE-III Optical Limits
  81. GRB 100420A: Swift detection of a burst
  82. GRB 100418A PAIRITEL NIR Observations
  83. GRB 100418A: ROVOR optical afterglow detection
  84. GRB 100418A: Swift/UVOT Observations
  85. GRB 100418A: Gemini-N redshift confirmation
  86. GRB 100413A: GMRT observation of radio afterglow
  87. GRB 100418A: Swift-XRT Refined Analysis
  88. GRB 100418A: host galaxy detection in the SDSS
  89. GRB100418A: VLT/X-shooter redshift and photometry
  90. GRB 100418A: SARA observations
  91. GRB100414A: SAO RAS optical observations
  92. GRB 100418A: GROND observations; missing author list added
  93. GRB 100418A: GROND observations
  94. GRB 100418A: Swift-BAT refined analysis
  95. GRB 100418A: Enhanced Swift-XRT position
  96. GRB 100418A: ROTSE-III Optical Limits
  97. GRB 100418A: Swift detection of a burst with a possible optical afterglow
  98. GRB 100413A: Radio Afterglow Detection with the EVLA
  99. GRB 100414A: Suzaku WAM observation of the prompt emission
  100. GRB 100414A: Swift/UVOT Observations

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