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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 100807A: Swift XRT refined analysis
  2. GRB 100807A: P60 Optical Afterglow Discovery
  3. GRB 100807A: Swift/UVOT Upper Limits
  4. GRB 100805A: SAO RAS optical observations
  5. GRB 100807A: Enhanced Swift-XRT position
  6. GRB 100807A: Swift-BAT refined analysis
  7. GRB 100807A: ROTSE-III Optical Limits
  8. GRB 100807A: Swift detection of a burst
  9. GRB 100805A: IAC80 and 1.5m OSN optical observations
  10. GRB 100805A: Xinglong TNT optical observation
  11. GRB 100805A: Early RAPTOR Observations
  12. GRB 100805A: ROTSE-III Optical detection
  13. GRB 100805A: Swift/UVOT Observations of the Optical Afterglow
  14. GRB 100802A: WIYN observations
  15. GRB 100805A: IAC80 BVR-band observations
  16. Swift-BAT trigger 430975 is not a burst
  17. GRB 100805A: Swift-BAT refined analysis
  18. GRB 100805A: Swift-XRT Refined Analysis
  19. GRB 100805A: GRAS 002 optical observations
  20. Trigger 430975: Swift detection of a possible burst
  21. GRB 100805A: I-band detection from 1.23m CAHA telescope.
  22. GRB 100805A: Enhanced Swift-XRT position
  23. GRB 100805A: Liverpool Telescope afterglow observations
  24. GRB 100805A: Further P60 Monitoring
  25. GRB 100805A: P60 Optical Afterglow Candidate
  26. GRB 100805A: Enhanced Swift-XRT position
  27. GRB 100805A: ROTSE-III Optical Limits
  28. GRB 100805A: Swift detection of a burst with an optical counterpart
  29. GRB 100802A: Fermi GBM observation
  30. GRB 100728B: optical photometry of ISON-NM
  31. GRB 100713A: second epoch Maidanak optical observation
  32. GRB 100713A: CrAO optical limits
  33. GRB 100802A: NOT optical observation
  34. GRB100802A: MITSuME optical upper limits
  35. GRB 100802A: P60 Observations
  36. GRB 100802A: XRT refined analysis
  37. GRB 100802A: Swift/UVOT Possible Optical Afterglow
  38. GRB 100728A: Suzaku WAM observation of the prompt emission
  39. GRB 100802A: Enhanced Swift-XRT position
  40. GRB 100802A: Swift-BAT refined analysis
  41. GRB 100802A: Liverpool Telescope observations
  42. GRB 100802A: ROTSE-III Optical Limits
  43. GRB 100802A: Possible Swift/UVOT Detection of Optical Afterglow
  44. GRB 100802A: Swift detection of a burst
  45. GRB 100725B: TELMA optical observation
  46. GRB 100728B: Swift/UVOT Observations (correction to GCN 11028)
  47. GRB 100728B: Swift/UVOT Observations (correction)
  48. GRB 100728B - NOT optical observation
  49. GRB 100728B: Swift/UVOT Observations
  50. GRB 100728B: Lick Observations
  51. GRB 100728B: Continued KAIT observations
  52. GRB 100728B, Swift-BAT refined analysis
  53. GRB 100728B: Swift-XRT Refined Analysis
  54. Konus-Wind observation of GRB 100728A
  55. GRB 100728A: GROND Detection of the NIR Afterglow Candidate
  56. GRB 100727A: Swift/UVOT Upper Limits
  57. GRB 100728A, Swift-BAT refined analysis
  58. GRB 100728B: Enhanced Swift-XRT position
  59. GRB 100728A: Swift/UVOT Upper Limits
  60. GRB 100728B: Fermi GBM observation
  61. GRB 100728A: Swift-XRT refined analysis
  62. GRB 100728B: GROND Detection of the NIR Afterglow
  63. GRB 100728B: optical detection
  64. GRB 100728B: Skynet/PROMPT Detections (correction)
  65. GRB 100728B: KAIT optical afterglow detection (correction)
  66. GRB 100728B: Swift detection of a burst with an optical counterpart
  67. GRB 100728A: Skynet/PROMPT Detections
  68. GRB 100728A: KAIT optical afterglow detection
  69. GRB 100728A: Fermi GBM observation
  70. GRB 100728A: Enhanced Swift-XRT position
  71. GRB 100728A: Swift detection of a burst
  72. GRB 100727A: Swift XRT refined analysis
  73. GRB 100727A: Fermi GBM observation
  74. GRB 100727A, Swift-BAT refined analysis
  75. GRB 100727A: Enhanced Swift-XRT position
  76. GRB100727A: MOA optical upper limit
  77. GRB 100727A: Swift detection of a burst
  78. GRB100725B: MITSuME optical upper limits
  79. GRB 100724B: AGILE/GRID analysis
  80. GRB 100724B: Suzaku WAM observation of the prompt emission
  81. GRB 100724B: gamma-ray detection by AGILE
  82. GRB 100725B: Swift-BAT refined analysis
  83. GRB 100725B: refined XRT analysis
  84. GRB 100725A: GROND upper limits
  85. GRB 100725B: Swift/UVOT Upper Limits
  86. GRB 100725A: Swift/UVOT Upper Limits
  87. GRB 100725A: Swift-BAT refined analysis
  88. GRB 100725A: Swift XRT refined analysis
  89. GRB 100725B: Enhanced Swift-XRT position
  90. GRB 100725A: Enhanced Swift-XRT position
  91. GRB100725B: Faulkes Telescope North observations
  92. GRB 100725B: Swift detection of a burst
  93. GRB100725A Faulkes Telescope South observations
  94. Konus-Wind observation of GRB 100724B
  95. GRB 100725A: Prompt enhanced Swift-XRT position
  96. GRB 100725A: Swift detection of a burst
  97. GRB 100724B: Fermi LAT and GBM analysis
  98. GRB 100724B: Fermi GBM detection
  99. GRB 100724A: Swift/BAT spectral lag results
  100. GRB 100724A: Swift XRT refined analysis

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