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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"

7413 results found.

  1. Fermi416242156: possible iPTF counterpart
  2. GRB 140311A: Nanshan afterglow decay
  3. GRB 140304A: Swift detection of a burst
  4. GRB 140302A: GROND afterglow candidate
  5. GRB 140302A: Swift detection of a burst
  6. GRB 140301A: NOT afterglow candidate
  7. GRB 140301A: Swift detection of a burst
  8. GRB 140219A: Mondy optical observations of XRT source #5
  9. GRB 140219A: Retraction of X-ray afterglow
  10. GRB 140219A: iPTF optical observations
  11. GRB 140219A: optical observations of XRT source #5
  12. GRB 140219A: XRT afterglow candidate
  13. GRB 140219A: Xuyi and Nanshan upper limits
  14. GRB 140221A Tiled Swift observations
  15. GRB 140219A Tiled Swift observations
  16. GRB 140215A: Swift detection of a burst with optical counterpart
  17. GRB 140213A: Swift/UVOT Detection
  18. GRB 140206A: Swift/UVOT optical detection
  19. GRB140206A - Optical afterglow candidate
  20. GRB 140129B: Swift detection of a burst with an optical afterglow
  21. GRB 140129A: ROTSE-III Detection of Optical Counterpart
  22. GRB 140129A: Swift detection of a burst with an optical afterglow
  23. Fermi412093190: iPTF optical counterpart search
  24. GRB 140103A: optical upper limit
  25. GRB 140103A: AAO optical afterglow candidate
  26. GRB 140114A: Swift detection of a burst
  27. GRB 140110A: Swift/UVOT retraction of UVOT candidates
  28. GRB 140110A Tiled Swift observations
  29. GRB 140108A: D50+BART optical candidate detection
  30. GRB 140108A: 1.23m CAHA observations
  31. GRB 140108A: MASTER-Net OT detection
  32. GRB 140108A: Swift detection of a burst
  33. GRB 140105A/Fermi410578384: MASTER-Net early optical observations
  34. Fermi410578384: iPTF optical afterglow candidates for a possible short GRB
  35. GRB 140102A, Optical Observations
  36. GRB 140102A: Fermi-LAT detection of a burst
  37. GRB 140103A: Swift detection of a burst
  38. GRB 140102A: Swift detection of a burst with optical counterpart
  39. GRB 131231A: iPTF optical afterglow candidate coincident with Nanshan detection
  40. GRB 131231A: afterglow confirmation from the NOT
  41. GRB 131231A: Nanshan afterglow candidate
  42. GRB 131229A: Swift detection of a burst
  43. GRB 131227A: OT candidate from KAIT Optical observations
  44. GRB 131227A: Swift detection of a burst
  45. GRB 131218A: Zadko observatory - Gingin optical candidate
  46. Trigger 581129: Swift-BAT triggered on noise
  47. GRB 131209A: Swift XRT and UVOT observations
  48. GRB 131209A Tiled Swift observations
  49. GRB 131205A: Swift detection of a burst
  50. GRB 131126A: iPTF upper limits on the afterglow of a short GRB
  51. GRB 131202A: Swift detection of a burst
  52. GRB 131127B: Bassano Bresciano Observatory optical observations of iPTF13ecv
  53. GRB 131127A: RATIR Rejection of High-z Candidate
  54. GRB 131128A: Swift/UVOT Detection
  55. GRB 131127B: Bassano Bresciano Observatory optical observations
  56. GRB 131128A: Nanshan afterglow confirmation
  57. GRB 131128A: MASTER-Net optical observations
  58. GRB 131128A: Nanshan afterglow candidate
  59. GRB 131128A: Swift detection of a burst
  60. GRB 131127A: RATIR Optical and NIR Observations, High-z Candidate
  61. Fermi407254341: iPTF optical afterglow candidates
  62. GRB 131127A: Swift detection of a burst
  63. GRB 131117A: Swift detection of a burst
  64. GRB 130925A: HST imaging
  65. GRB 131108A: Fermi GBM observation
  66. GRB 131108A: Fermi-LAT refined analysis
  67. GRB 131108A: 1.23m CAHA optical candidate
  68. GRB 131108A Tiled Swift observations
  69. GRB 131105A: TAROT La Silla observatory optical observations
  70. GRB 131105A: VLT/X-shooter optical afterglow candidate
  71. GRB 131105A: Swift detection of a burst
  72. GRB 131103A: Swift detection of a burst
  73. GRB 131031A: Swift/UVOT Upper Limits
  74. GRB 131031A: 1.23m CAHA afterglow candidate
  75. GRB 131030A: Swift detection of a burst with an optical counterpart
  76. GRB 131029A Tiled Swift observations
  77. Swift Trigger 575905: a possible GRB
  78. GRB 131024B: Swift detection of a burst
  79. GRB 131024A: Swift detection of a burst
  80. GRB 131014A: RATIR Optical/NIR Afterglow Retraction
  81. GRB 131018B: Swift/UVOT Upper Limits
  82. GRB 131018A: Swift detection of a burst
  83. GRB 131014A: Swift/UVOT Upper Limits
  84. GRB 131014A: RATIR Optical and NIR Observations
  85. GRB 131014A: NOT afterglow candidate
  86. GRB 131014A Tiled Swift observations
  87. GRB 131011A: Fermi GBM detection
  88. iPTF 13dsw/Fermi403206457: X-Shooter redshift
  89. Swift-XRT detection of iPTF 13dsw/Fermi403206457
  90. GRB 131011A: GROND afterglow observations
  91. Fermi403206457: continued P60 observations and fading behavior
  92. Fermi403206457: Weihai optical upper limit
  93. Fermi403206457: NOT optical observations
  94. Fermi403206457: iPTF detection of a possible optical afterglow
  95. Trigger 574266 is not a Swift detection of a known source
  96. GRB 130925A: Possible signatures of binary nature in the afterglow - Request for observations
  97. GRB 131004A: TNG optical afterglow confirmation
  98. GRB 131004A: Swift detection of a burst (may be short)
  99. GRB 130925A/Sw J0244-2609: mm observations at PdBI
  100. NuSTAR observations of GRB 130925A

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