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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 100728B: Enhanced Swift-XRT position
  2. GRB 100728A: Swift/UVOT Upper Limits
  3. GRB 100728B: Fermi GBM observation
  4. GRB 100728A: Swift-XRT refined analysis
  5. GRB 100728B: GROND Detection of the NIR Afterglow
  6. GRB 100728B: optical detection
  7. GRB 100728B: Skynet/PROMPT Detections (correction)
  8. GRB 100728B: KAIT optical afterglow detection (correction)
  9. GRB 100728B: Swift detection of a burst with an optical counterpart
  10. GRB 100728A: Skynet/PROMPT Detections
  11. GRB 100728A: KAIT optical afterglow detection
  12. GRB 100728A: Fermi GBM observation
  13. GRB 100728A: Enhanced Swift-XRT position
  14. GRB 100728A: Swift detection of a burst
  15. GRB 100727A: Swift XRT refined analysis
  16. GRB 100727A: Fermi GBM observation
  17. GRB 100727A, Swift-BAT refined analysis
  18. GRB 100727A: Enhanced Swift-XRT position
  19. GRB100727A: MOA optical upper limit
  20. GRB 100727A: Swift detection of a burst
  21. GRB100725B: MITSuME optical upper limits
  22. GRB 100724B: AGILE/GRID analysis
  23. GRB 100724B: Suzaku WAM observation of the prompt emission
  24. GRB 100724B: gamma-ray detection by AGILE
  25. GRB 100725B: Swift-BAT refined analysis
  26. GRB 100725B: refined XRT analysis
  27. GRB 100725A: GROND upper limits
  28. GRB 100725B: Swift/UVOT Upper Limits
  29. GRB 100725A: Swift/UVOT Upper Limits
  30. GRB 100725A: Swift-BAT refined analysis
  31. GRB 100725A: Swift XRT refined analysis
  32. GRB 100725B: Enhanced Swift-XRT position
  33. GRB 100725A: Enhanced Swift-XRT position
  34. GRB100725B: Faulkes Telescope North observations
  35. GRB 100725B: Swift detection of a burst
  36. GRB100725A Faulkes Telescope South observations
  37. Konus-Wind observation of GRB 100724B
  38. GRB 100725A: Prompt enhanced Swift-XRT position
  39. GRB 100725A: Swift detection of a burst
  40. GRB 100724B: Fermi LAT and GBM analysis
  41. GRB 100724B: Fermi GBM detection
  42. GRB 100724A: Swift/BAT spectral lag results
  43. GRB 100724A: Swift XRT refined analysis
  44. GRB 100724A: Enhanced Swift-XRT position
  45. GRB 100724A: Swift/UVOT observations
  46. GRB 100724A: Swift-BAT refined analysis
  47. GRB 100724A: X-shooter redshift
  48. GRB 100724A: fading afterglow seen with GROND
  49. GRB 100724A, GROND detection of an afterglow candidate
  50. GRB 100724A: Swift detection of a burst
  51. GRB 100614A: 10.4-m GTC deep-optical limit
  52. GRB 100722A: Fermi GBM detection
  53. GRB 100718A: MASTER-Net optical prompt and alert observations
  54. GRB 100719A: Swift-BAT refined analysis
  55. GRB 100719A: Swift detection of a burst
  56. GRB 100713A: optical observation in Maidanak
  57. GRB 100713A: further inspection of TNG images
  58. GRB 100713A: Swift XRT refined analysis
  59. GRB 100713A : IRSF/SIRIUS NIR upper limits
  60. Fermi GBM trigger 300794561 (100714419) is not a GRB
  61. GRB100713A: Swift/UVOT observations
  62. GRB 100713A: GROND upper limits
  63. GRB 100713A: optical upper limit
  64. GRB 100713A: TNG optical observations
  65. GRB 100713A: TELMA and 1.5m OSN optical observations
  66. GRB100713A: Swift X-ray afterglow detection
  67. GRB 100713A: a long GRB detected by INTEGRAL
  68. GRB 100707A: Suzaku WAM observation of the prompt emission
  69. Fermi GBM trigger 300370702 (100709513) is not a GRB
  70. Konus-Wind observation of GRB 100707A
  71. IPN triangulation of GRB 100707A
  72. GRB 100628A: Keck/LRIS Spectroscopy of Host Galaxy Candidate
  73. GRB 100707A: Fermi LAT detection
  74. GRB 100707A: Fermi GBM detection
  75. GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
  76. GRB 100628A: Chandra observations
  77. GRB 100628A: Swift XRT/UVOT refined analysis
  78. Tentative redshift of GRB100704A from Swift-XRT data
  79. Konus-Wind observation of GRB 100701B
  80. IPN triangulation of GRB 100701B
  81. Konus-Wind observation of GRB 100704A
  82. GRB 100703A: a short GRB detected by INTEGRAL
  83. GRB 100704A: Swift XRT refined analysis
  84. GRB 100704: Swift/UVOT Upper Limits
  85. GRB 100704A: Fermi GBM observation
  86. GRB 100704A: Swift-BAT refined analysis
  87. GRB100704A: MOA optical upper limit
  88. GRB 100704A: Enhanced Swift-XRT position
  89. GRB 100704A: Swift detection of a burst
  90. GRB 100615A: Additional Gemini/NIRI observations
  91. GRB 100526A: Gemini/NIRI afterglow confirmation and host galaxy
  92. GRB 100702A, Swift-BAT refined analysis
  93. Fermi GBM trigger 299767472 (100702531) is not a GRB
  94. GRB 100702A: Swift XRT refined analysis
  95. Swift/UVOT observations of GRB100702A - correction
  96. Swift/UVOT observations of GRB100702A
  97. GRB 100702A: Second epoch of Magellan near-IR observations and afterglow limits
  98. GRB 100701B: Fermi GBM detection
  99. GRB 100702A: Magellan near-IR observations
  100. GRB 100702A: VLT optical observations

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