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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"

6200 results found.

  1. GRB 130425: MASTER-Net optical observations
  2. GRB 130427A: Nishi-Harima NIR Observations
  3. GRB 130427B: Tentative VLT/X-shooter redshift
  4. GRB 130427A, Optical Observations
  5. GRB 130427A: Swift-XRT refined Analysis
  6. GRB 130427B: Swift-XRT refined Analysis
  7. GRB 130427A: Fermi GBM observation
  8. GRB 130427A: Fermi-LAT detection of a burst
  9. GRB 130427A: PAIRITEL NIR Detections
  10. GRB 130425A: Fermi GBM detection
  11. GRB 130420A: ROTSE-III data analysis
  12. GRB 130420B: Fermi GBM observation
  13. GRB 130420B: Swift-XRT refined Analysis
  14. GRB 130420A: Fermi GBM observation
  15. GRB 130420A: ISON-NM optical observations
  16. GRB 130420A: Swift-XRT refined Analysis
  17. GRB 130420A: PAIRITEL NIR detections
  18. GRB 130418A: Swift-XRT refined Analysis
  19. GRB 130418A: T18 and T21 optical observations
  20. GRB 130418A, Swift-BAT refined analysis
  21. GRB 130418A: REM NIR observations
  22. GRB 130418A: Swift detection of a burst with an optical counterpart
  23. GRB 130408A: Swift-XRT refined Analysis
  24. Swift/XRT observation of GRB 130327B
  25. GRB 130306A: Confirmation of the X-ray Afterglow
  26. Swift Trigger 552142 is a noise event
  27. GRB 130327B: Fermi-LAT detection of a burst
  28. GRB 130327B: Fermi GBM detection
  29. Swift Trigger 552142: a possible GRB
  30. GRB 130327A: Swift-XRT refined Analysis
  31. GRB 130327A: PAIRITEL NIR Afterglow Candidate
  32. GRB 130325A: Fermi LAT detection
  33. GRB 130325A: Fermi GBM detection
  34. GRB 130315A: Swift-XRT refined Analysis
  35. Swift XRT observations of GRB 130310A
  36. GRB 130313A: Fading X-ray Afterglow
  37. GRB 130313A: Swift-XRT refined Analysis
  38. Swift XRT observations of GRB 130310A
  39. GRB 130306A: Swift Detection of a Possible Afterglow
  40. GRB 130310A: Fermi GBM detection
  41. GRB 130305A: Further Swift-XRT Observations
  42. GRB 130307A: Fermi GBM detection
  43. GRB 130305A: Swift/XRT detection of the afterglow
  44. GRB 130305A: Fermi GBM observation
  45. GRB 130216A: Swift/XRT observations
  46. GRB 130219A: Fermi GBM detection
  47. GRB 130216B: Swift/XRT observations
  48. GRB 130216A: Fermi GBM observation
  49. GRB 130216B: Fermi GBM observation
  50. GRB 130216B: P200 NIR Observations
  51. GRB 130216A: P200 NIR Observations
  52. GRB 130215A: Additional P200 NIR observations
  53. GRB 130215A: P200 NIR observations
  54. GRB 130215A: Fermi GBM detection
  55. GRB 130215A: iTelescope T11 observations
  56. GRB 130215A: REM NIR observations
  57. Swift GRB130206A: late XRT observations.
  58. GRB 121128A: optical observations
  59. GRB 130211A: Swift-XRT refined Analysis
  60. GRB 130206A: Fermi LAT Observations
  61. GRB 130206A: Fermi GBM observation
  62. GRB 130206A: XRT and UVOT follow-up observations.
  63. GRB 130206A: Swift-XRT observations
  64. GRB 130131B: Swift-XRT refined Analysis
  65. GRB 130131A: Swift-XRT refined Analysis
  66. GRB 130127A: Fermi GBM detection
  67. GRB 130122A: Swift-XRT refined Analysis
  68. GRB 130102A: Swift-XRT refined Analysis
  69. GRB 121229A: Swift-XRT refined Analysis
  70. GRB 121226A: Swift-XRT refined Analysis
  71. GRB 121226A: Optical Observations
  72. GRB 121225B: Fermi GBM observation
  73. GRB 121225B: Fermi LAT Detection
  74. GRB 121217A theoretical estimate of redshift and of supernova occurrence
  75. GRB 121217A: Fermi GBM observation
  76. GRB 121217A: Swift-XRT refined Analysis
  77. GRB 121209A: LOAO Observation
  78. GRB121212A: NOT optical imaging
  79. GRB 121211A: Fermi GBM observation
  80. GRB 121212A: PAIRITEL NIR Observations
  81. GRB 121212A: Swift-XRT refined Analysis
  82. GRB 121211A: Swift-XRT refined Analysis
  83. GRB 121209A: Swift-XRT refined Analysis
  84. GRB 121209A: GROND optical afterglow candidate
  85. GRB 121209A: PAIRITEL NIR Observations
  86. GRB 121202A: Swift-XRT refined Analysis
  87. GRB 121202A: Fermi GBM observation
  88. GRB 121201A: GROND afterglow observations and photometric redshift
  89. GRB 121201A: Swift-XRT refined Analysis
  90. GRB 121128A: Swift-XRT refined Analysis
  91. GRB 121122A: Fermi GBM observation
  92. GRB 121128A: Fermi GBM observation
  93. GRB 121117A: Terskol obseravtions
  94. GRB 121123A: Swift/UVOT Observations
  95. GRB 121125A: Swift-XRT refined Analysis
  96. GRB 121125A: Fermi GBM Observation
  97. GRB 121123A: Swift-XRT refined Analysis
  98. GRB 121123A: Fermi GBM observation
  99. GRB 121117A: Optical observations
  100. GRB 121117A: Swift-XRT refined Analysis

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