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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 100728A: Fermi GBM observation
  2. GRB 100728A: Enhanced Swift-XRT position
  3. GRB 100728A: Swift detection of a burst
  4. GRB 100727A: Swift XRT refined analysis
  5. GRB 100727A: Fermi GBM observation
  6. GRB 100727A, Swift-BAT refined analysis
  7. GRB 100727A: Enhanced Swift-XRT position
  8. GRB100727A: MOA optical upper limit
  9. GRB 100727A: Swift detection of a burst
  10. GRB100725B: MITSuME optical upper limits
  11. GRB 100724B: AGILE/GRID analysis
  12. GRB 100724B: Suzaku WAM observation of the prompt emission
  13. GRB 100724B: gamma-ray detection by AGILE
  14. GRB 100725B: Swift-BAT refined analysis
  15. GRB 100725B: refined XRT analysis
  16. GRB 100725A: GROND upper limits
  17. GRB 100725B: Swift/UVOT Upper Limits
  18. GRB 100725A: Swift/UVOT Upper Limits
  19. GRB 100725A: Swift-BAT refined analysis
  20. GRB 100725A: Swift XRT refined analysis
  21. GRB 100725B: Enhanced Swift-XRT position
  22. GRB 100725A: Enhanced Swift-XRT position
  23. GRB100725B: Faulkes Telescope North observations
  24. GRB 100725B: Swift detection of a burst
  25. GRB100725A Faulkes Telescope South observations
  26. Konus-Wind observation of GRB 100724B
  27. GRB 100725A: Prompt enhanced Swift-XRT position
  28. GRB 100725A: Swift detection of a burst
  29. GRB 100724B: Fermi LAT and GBM analysis
  30. GRB 100724B: Fermi GBM detection
  31. GRB 100724A: Swift/BAT spectral lag results
  32. GRB 100724A: Swift XRT refined analysis
  33. GRB 100724A: Enhanced Swift-XRT position
  34. GRB 100724A: Swift/UVOT observations
  35. GRB 100724A: Swift-BAT refined analysis
  36. GRB 100724A: X-shooter redshift
  37. GRB 100724A: fading afterglow seen with GROND
  38. GRB 100724A, GROND detection of an afterglow candidate
  39. GRB 100724A: Swift detection of a burst
  40. GRB 100614A: 10.4-m GTC deep-optical limit
  41. GRB 100722A: Fermi GBM detection
  42. GRB 100718A: MASTER-Net optical prompt and alert observations
  43. GRB 100719A: Swift-BAT refined analysis
  44. GRB 100719A: Swift detection of a burst
  45. GRB 100713A: optical observation in Maidanak
  46. GRB 100713A: further inspection of TNG images
  47. GRB 100713A: Swift XRT refined analysis
  48. GRB 100713A : IRSF/SIRIUS NIR upper limits
  49. Fermi GBM trigger 300794561 (100714419) is not a GRB
  50. GRB100713A: Swift/UVOT observations
  51. GRB 100713A: GROND upper limits
  52. GRB 100713A: optical upper limit
  53. GRB 100713A: TNG optical observations
  54. GRB 100713A: TELMA and 1.5m OSN optical observations
  55. GRB100713A: Swift X-ray afterglow detection
  56. GRB 100713A: a long GRB detected by INTEGRAL
  57. GRB 100707A: Suzaku WAM observation of the prompt emission
  58. Fermi GBM trigger 300370702 (100709513) is not a GRB
  59. Konus-Wind observation of GRB 100707A
  60. IPN triangulation of GRB 100707A
  61. GRB 100628A: Keck/LRIS Spectroscopy of Host Galaxy Candidate
  62. GRB 100707A: Fermi LAT detection
  63. GRB 100707A: Fermi GBM detection
  64. GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
  65. GRB 100628A: Chandra observations
  66. GRB 100628A: Swift XRT/UVOT refined analysis
  67. Tentative redshift of GRB100704A from Swift-XRT data
  68. Konus-Wind observation of GRB 100701B
  69. IPN triangulation of GRB 100701B
  70. Konus-Wind observation of GRB 100704A
  71. GRB 100703A: a short GRB detected by INTEGRAL
  72. GRB 100704A: Swift XRT refined analysis
  73. GRB 100704: Swift/UVOT Upper Limits
  74. GRB 100704A: Fermi GBM observation
  75. GRB 100704A: Swift-BAT refined analysis
  76. GRB100704A: MOA optical upper limit
  77. GRB 100704A: Enhanced Swift-XRT position
  78. GRB 100704A: Swift detection of a burst
  79. GRB 100615A: Additional Gemini/NIRI observations
  80. GRB 100526A: Gemini/NIRI afterglow confirmation and host galaxy
  81. GRB 100702A, Swift-BAT refined analysis
  82. Fermi GBM trigger 299767472 (100702531) is not a GRB
  83. GRB 100702A: Swift XRT refined analysis
  84. Swift/UVOT observations of GRB100702A - correction
  85. Swift/UVOT observations of GRB100702A
  86. GRB 100702A: Second epoch of Magellan near-IR observations and afterglow limits
  87. GRB 100701B: Fermi GBM detection
  88. GRB 100702A: Magellan near-IR observations
  89. GRB 100702A: VLT optical observations
  90. GRB 100702: ROTSE-III Optical Limits
  91. GRB 100702A: Swift detection of a short burst
  92. GRB 100615A: Chandra X-ray ToO Observation
  93. XRF 100701A : MAXI/GSC detection of a probable XRF
  94. GRB 100213B: Detection of Fading Optical Afterglow
  95. GRB 100625A: Fermi GBM detection
  96. GRB 100628A: Second epoch of Magellan near-IR observations
  97. GRB 100628A: GROND optical/NIR observations of the host candidate
  98. GRB 100628A: Gemini North Observations
  99. GRB 100628A: Coincidence of source "G1" with revised XRT error circle
  100. GRB 100628A: Swift XRT refined position

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