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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.

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

868 results found.

  1. LIGO/Virgo/KAGRA S250726ak: Identification of a GW compact binary merger candidate
  2. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  3. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  4. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  5. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  6. IPN triangulation of GRB 250703A
  7. LIGO/Virgo/KAGRA S250704ab: Identification of a GW compact binary merger candidate
  8. IPN triangulation of GRB 250627A (short)
  9. LIGO/Virgo/KAGRA S250702n: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo/KAGRA S250629bs: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo/KAGRA S250629ae: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S250628am: Identification of a GW compact binary merger candidate
  13. EP-WXT trigger 01709179036: a new outburst of GRS 1739-278
  14. IPN triangulation of GRB 250404B
  15. IPN triangulation of GRB 250529A
  16. GRB 250603A: Swift/UVOT Upper Limits
  17. GRB 250421A: AstroSat CZTI detection
  18. IPN triangulation of GRB 250406B (short/hard)
  19. Konus-Wind detection of GRB 250404A / EP250404a
  20. LIGO/Virgo/KAGRA S250331o: Identification of a GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S250328ae: Identification of a GW compact binary merger candidate
  22. GRB 250327B: Las Cumbres optical counterpart detection
  23. IPN triangulation of GRB 250322B
  24. LIGO/Virgo/KAGRA S250326y: Identification of a GW compact binary merger candidate
  25. LIGO/Virgo/KAGRA S250319bu: Identification of a GW compact binary merger candidate
  26. GRB 250312B: Fermi GBM Observation
  27. GRB 250312B: Fermi GBM Final Localization
  28. IPN triangulation of GRB 250308A (short)
  29. IPN triangulation of GRB 250309B
  30. LIGO/Virgo/KAGRA S250226dl: Identification of a GW compact binary merger candidate
  31. IPN triangulation of GRB 250217C (short)
  32. LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
  33. LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
  34. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  36. GRB 250205A: Fermi GBM Observation
  37. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  38. IPN triangulation of GRB 250201A
  39. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  40. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  41. LIGO/Virgo/KAGRA S250202cu: Identification of a GW compact binary merger candidate
  42. IPN triangulation of GRB 250118B
  43. IPN triangulation of GRB 250119B
  44. Improved IPN triangulation of GRB 250107C
  45. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  46. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  51. IPN triangulation of GRB 250113A
  52. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  53. IPN triangulation of GRB 250107D (short/hard)
  54. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  55. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  56. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  57. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  58. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
  60. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  62. IPN triangulation of GRB 241128B
  63. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  64. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  65. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  67. GRB 241127A: Swift detection of a burst with an optical counterpart
  68. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  70. IPN triangulation of GRB 241117A
  71. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  73. Fermi trigger No 753166198: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  75. IPN triangulation of GRB 241107A (short/hard)
  76. S241102cy: Identification of a GW compact binary merger candidate
  77. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  78. GRB 241030A: Swift-BAT refined analysis
  79. IPN triangulation of GRB 241022A (short/hard)
  80. IPN triangulation of GRB 241021A (long)
  81. GRB 241010A: Swift detection of a burst with an optical counterpart
  82. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  83. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  84. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  86. IPN triangulation of GRB 240930B / EP 240930a
  87. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  88. IPN triangulation of GRB 240926A
  89. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  90. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  91. IPN triangulation of GRB 240918B
  92. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  93. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  95. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  96. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  97. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  98. IPN triangulation of GRB 240913C / EP 240913a
  99. LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
  100. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate

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