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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.

Lucene Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3036 results found.

  1. GRB 220921A: Swift-XRT Observations
  2. GRB 220909A: Swift-XRT observations
  3. GRB 220831A: Gemini-South Infrared Observations
  4. GRB 220907A: Swift-XRT refined Analysis
  5. GRB 220907A: Swift-XRT position
  6. GRB 220831A: Swift-UVOT Upper Limits
  7. GRB 220831A: Swift-XRT observations
  8. GRB 220826A: Swift-XRT refined Analysis
  9. GRB 220810A: Further Swift-XRT observations
  10. GRB 220813A: Swift-XRT refined Analysis
  11. GRB 220810A: Swift-XRT observations
  12. GRB 220730A: Swift-XRT afterglow detection
  13. GRB 220730A: Swift-XRT observations
  14. GRB 220715B: Swift-XRT refined Analysis
  15. GRB 220714B: Swift-XRT refined Analysis
  16. GRB 220711B: 10.4 m GTC(+EMIR) observations
  17. GRB 220711B: 10.4 m GTC(+EMIR) observations
  18. GRB 220710A: Swift-XRT afterglow detection
  19. GRB 220711B: Swift-XRT refined Analysis
  20. GRB 220708A: Swift-XRT refined Analysis
  21. GRB 220708B: Swift-XRT afterglow detection
  22. GRB 220706A: Swift-XRT refined Analysis
  23. GRB 220701A: Swift-XRT refined Analysis
  24. GRB 220627A: Swift-XRT afterglow detection
  25. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  26. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  27. GRB 220623A: Swift-XRT refined Analysis
  28. GRB 220611A: Continued Gemini Infrared Observations
  29. GRB 220618A: Swift-XRT refined Analysis
  30. GRB 220617A: Swift-XRT observations
  31. GRB 220611A: Gemini Ks counterpart detection
  32. GRB 220611A: Gemini South Infrared Detection
  33. GRB 220611A: Swift-XRT refined Analysis
  34. GRB 220606B: Swift follow-up observations
  35. GRB 220527A: Swift/UVOT detection
  36. GRB 220527A: Swift-XRT afterglow detection
  37. Fermi GRB 220523A: Global MASTER-Net observations report
  38. GRB 220521A: Swift-XRT refined Analysis
  39. GRB 220518A: Swift-XRT refined Analysis
  40. Continued Chandra monitoring of GW170817 at ~4.8 yr post-merger
  41. GRB 220514B: Swift-XRT observations
  42. GRB 220511A: Swift-XRT afterglow detection
  43. GRB 220511A: Swift-XRT observations
  44. GRB 220506A: Swift-XRT afterglow detection
  45. GRB 220430A: Swift-XRT refined Analysis
  46. GRB 220426A: Swift-XRT and UVOT observations
  47. GRB 220427A: Swift-XRT refined Analysis
  48. GRB 220418B: Swift-XRT observations
  49. GRB 220403C: Further Swift-XRT observations
  50. GRB 220412B: Swift-XRT observations
  51. GRB 220412A: Swift-XRT refined Analysis
  52. GRB 220403C: Swift-XRT observations
  53. GRB 220408A: Swift-XRT refined Analysis
  54. Chandra upper limit at the location of GRB 220408A
  55. GRB 220403B: Swift-XRT refined Analysis
  56. GRB 220325A: Swift-XRT refined Analysis
  57. GRB 220319A: Swift-XRT refined Analysis
  58. GRB 220310C: Swift-XRT observations
  59. GRB 220306B: Swift-XRT refined Analysis
  60. GRB 220305A: Swift-XRT refined Analysis
  61. GRB 220302A: Swift-XRT refined Analysis
  62. GRB 220219B: Swift-XRT observations
  63. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  64. ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
  65. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  66. GRB 220117B: Swift-XRT refined Analysis
  67. GRB 220117A: Swift-XRT refined Analysis
  68. Confirmation of the X-ray afterglow of GRB 220107B
  69. GRB 220107A: Swift/UVOT Detection
  70. GRB 220107B: Swift-XRT afterglow detection
  71. GRB 220107A: Swift-XRT afterglow detection
  72. GRB 220101A: Swift-XRT refined Analysis
  73. GRB 211229A: Swift-XRT and UVOT observations
  74. Fermi GRB 211229B: Global MASTER-Net observations report
  75. GRB 211227A: Swift-XRT refined Analysis
  76. GRB 211221A: Swift-XRT refined Analysis
  77. GRB 211106A: XMM-Newton monitoring campaign detections
  78. GRB 211211A: Swift-XRT refined Analysis
  79. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  80. GRB 211207A: Swift-XRT refined Analysis
  81. GRB 211129A: Swift-XRT refined Analysis
  82. Chandra observations of GRB 210905A
  83. GRB 211106A: Swift/UVOT upper limits
  84. GRB 211107B: Swift-XRT afterglow detection
  85. GRB 211106A: Swift-XRT afterglow detection
  86. GRB 211107B: Swift-XRT observations
  87. GRB 211106A: Swift-XRT observations
  88. Swift Trigger 1082569 is probably not a GRB
  89. GRB 211024A: Swift-XRT observations
  90. GRB 211018A: Swift-XRT observations
  91. GRB 211025A: Swift-XRT refined Analysis
  92. GRB 211024B: CAHA 2.2m Detection; ultra-long GRB?
  93. GRB 211024B: Swift-XRT refined Analysis
  94. GRB 211023B: Swift-XRT refined Analysis
  95. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  96. GRB 210928A: Swift-XRT refined Analysis
  97. GRB 210930A: Swift/UVOT Upper Limits
  98. GRB 210930A: Swift-XRT refined Analysis
  99. GRB 210919A: Swift-XRT refined Analysis
  100. GRB 210912A: Swift-XRT refined Analysis

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