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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"

233 results found.

  1. XRF040916, BVRcIc field calibration
  2. GRB040827 optical observations
  3. GRB040825B, BVRcIc field photometry
  4. GRB040825A, BVRcIc field photometry
  5. GRB040825B: Correction to GCN 2657
  6. GRB040422, BVRcIc field calibration
  7. INTEGRAL-SPI/ACS GRB data: timing correction
  8. GRB030913, candidate afterglow observations
  9. GRB030913: AAVSO optical observations
  10. XRF030723, BVRcIc field photometry update
  11. GRB030725, optical transient observations
  12. GRB030725, possible optical transient
  13. XRF030723, BVRcIc field photometry correction
  14. XRF030723, BVRcIc field photometry
  15. GRB030723, optical observations
  16. GRB030528, BVRI field photometry
  17. GRB030418, BVRcIc field photometry
  18. GRB030429, BVRcIc field photometry
  19. GRB030429, possible optical counterpart
  20. GRB030329, optical position
  21. GRB030328, UBVRcIc field photometry
  22. GRB030329, fading resumes
  23. GRB030329, cessation of fading
  24. GRB030329, new UBVRcIc field photometry
  25. GRB030329, BVRcIc field photometry
  26. GRB030131, BVRcIc field photometry
  27. GRB030324, BVRcIc field photometry
  28. GRB030323, possible optical counterpart
  29. GRB030323, BVRcIc field calibration
  30. GRB030227, BVRcIc field photometry
  31. GRB030226, BVRcIc field calibration
  32. GRB030204 field photometry
  33. GRB030115, afterglow candidate
  34. GRB021219, optical observations
  35. GRB021211, BVRI field photometry
  36. GRB021201, BVRcIc field photometry
  37. GRB021113, SPI ACS observation
  38. GRB021112, BVRI field photometry
  39. GRB021016, optical observations
  40. GRB021004, UBVRcIc field photometry update
  41. GRB021004, astrometric position
  42. GRB021004, Optical Observations
  43. GRB021004, BVRcIc field photometry
  44. XRF020903, BVRI field photometry
  45. GRB020812: negative optical observations
  46. GRB020813, UBVRI field calibration
  47. GRB020813, optical observations
  48. GRB020813, astrometric position
  49. GRB020801, optical afterglow candidate
  50. GRB020604, optical observations
  51. GRB020604, BVRcIc field photometry
  52. GRB020603, BVRcIc field observations
  53. GRB020531, BVRcIc field photometry
  54. GRB020531, optical observations
  55. GRB020525, optical observations
  56. GRB020406(?), optical observations
  57. GRB020410, optical observations
  58. GRB020406(?), optical observations
  59. GRB020331 field photometry
  60. GRB020317 BVRI field photometry
  61. GRB011211 revised BVRI field photometry
  62. GRB020305 BVRI field photometry
  63. GRB020322 BVRI field photometry
  64. GRB020321 optical observations
  65. GRB020124 BVRI field photometry
  66. SN2002ap (SN/GRB?) UBVRI Field Photometry
  67. GRB011212, BVRI field photometry
  68. GRB011211, BVRI field photometry
  69. GRB011130 (XRF011130) optical observations
  70. GRB011019, optical observations -- correction
  71. GRB011019, optical observations
  72. GRB010921, negative optical observations
  73. GRB010921 field photometry
  74. GRB010629, optical observations
  75. GRB010412, field photometry
  76. GRB010324, revised field photometry
  77. GRB010324, field photometry
  78. GRB010326B, field photometry
  79. GRB010326, field photometry
  80. GRB010220, field photometry
  81. GRB010324, optical observations
  82. GRB 010222, Optical Observations
  83. GRB010214, field photometry
  84. GRB010222, field photometry
  85. GRB010222, optical observations
  86. GRB010222
  87. GRB010222
  88. GRB010213, Near-IR observations
  89. GRB 010119, optical observations
  90. GRB010103, optical observations
  91. GRB001120, optical observations
  92. GRB001105 BVRI field photometry correction
  93. GRB001105, BVRI field photometry
  94. GRB001019, Optical Observations
  95. GRB 000911, BVRI field photometry
  96. GRB000830, BVRI field photometry
  97. GRB 000727, optical observations
  98. GRB000630, Revised BVRI Field Photometry
  99. GRB000630, BVRI Field Photometry
  100. GRB000519, BVRI field photometry

Advanced

Download all Circulars as a .tar.gz archive:
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