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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"

36804 results found.

  1. GRB 240529A: GOTO optical afterglow detection
  2. GRB 240527B: Swift-XRT afterglow detection
  3. GRB 240529A: Enhanced Swift-XRT position
  4. GRB 240529A: Swift detection of a burst with an optical counterpart
  5. GRB 240527B: Fermi GBM Observation
  6. Fermi GRB 240527A: Global MASTER-Net observations report
  7. GRB 240527B: Fermi-LAT detection
  8. Fermi GRB 240527B: Global MASTER-Net observations report
  9. GRB 240527B: Fermi GBM Final Localization
  10. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  11. GRB 240527A: Fermi GBM Final Real-time Localization
  12. GRB 240523A: Swift-BAT refined analysis
  13. Fermi trigger No 738348224: Global MASTER-Net observations report
  14. Fermi trigger No 738330463: Global MASTER-Net observations report
  15. GRB 240523A: Swift-XRT refined Analysis
  16. GRB 240523A: Enhanced Swift-XRT position
  17. GRB 240523A: Swift detection of a burst
  18. GRB 240521B: Fermi GBM Observation
  19. Fermi GBM Sub-Threshold Detection of GRB 240516B
  20. GRB 240513A: Swift-XRT afterglow detection
  21. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  22. Fermi trigger No 737996942: Global MASTER-Net observations report
  23. GRB 240521A: GECAM-B detection of a long burst
  24. GRB 240516B: AstroSat CZTI detection
  25. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  26. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  27. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  28. GRB 240514B: VZLUSAT-2 detection
  29. GRB 240504A: VZLUSAT-2 detection
  30. GRB 240502A: VZLUSAT-2 detection
  31. GRB 240519A: GRBAlpha detection
  32. GRB 240516A: Swift/UVOT Upper Limits
  33. GRB 240519A: AstroSat CZTI detection
  34. Fermi trigger No 737788024: Global MASTER-Net observations report
  35. GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
  36. GRB 240516A: Swift-BAT refined analysis
  37. Fermi GRB 240517A: Global MASTER-Net observations report
  38. GRB 240516A ATCA radio observations
  39. IPN triangulation of GRB 240514B (short)
  40. GRB 240513A: Swift ToO observations
  41. GRB 240517A: Fermi GBM Final Real-time Localization
  42. Konus-Wind detection of GRB 240513A
  43. GRB 240516A: AstroSat CZTI detection
  44. GRB 240516A: Swift-XRT refined Analysis
  45. GRB 240514E: A possible candidate BD-21 1074
  46. Fermi trigger No 737559855: Global MASTER-Net observations report
  47. GRB 240516A: Fermi GBM Observation
  48. GRB 240511A: Observations from GTC/OSIRIS+
  49. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  50. GRB 240516A: GOTO optical upper limit
  51. LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
  52. Fermi trigger No 737523389: Global MASTER-Net observations report
  53. GRB 240516A: Swift detection of a burst
  54. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  55. Fermi trigger No 737476171: Global MASTER-Net observations report
  56. GRB 240511A: radio detection of afterglow candidate
  57. GRB 240514B: GOTO candidate optical counterpart
  58. Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
  59. GRB 240514E: MAXI/GSC detection of a probable afterglow
  60. GRB 240514B: GRBAlpha detection
  61. GRB 240514B: Fermi GBM Detection
  62. GRB 240513A: Fermi GBM observation
  63. GRB 240513A: Swift-XRT observations
  64. GRB 240514D: AstroSat CZTI detection
  65. GRB 240514C: Fermi GBM Final Real-time Localization
  66. Fermi GRB 240514B: Global MASTER-Net observations report
  67. Fermi Gamma-ray Burst Monitor triggers 737345659/240514093 and GRB240514A are not GRBs
  68. GRB 240514B: Fermi GBM Final Real-time Localization
  69. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  70. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  71. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  72. GRB 240514A: Fermi GBM Final Real-time Localization
  73. GRB 240513A: Tiled Swift observations
  74. GRB 240513A: Fermi-LAT detection
  75. GRB 240511A: Fermi GBM Observation
  76. GRB 240511A: Swift-BAT refined analysis
  77. Fermi GRB 240513B: Global MASTER-Net observations report
  78. Fermi trigger No 737277727: Global MASTER-Net observations report
  79. GRB 240513B: Fermi GBM Final Real-time Localization
  80. GRB 240513A: AstroSat CZTI detection
  81. Fermi trigger No 737258655: Global MASTER-Net observations report
  82. GRB 240511A: J-band observations with WINTER
  83. Fermi trigger No 737247400: Global MASTER-Net observations report
  84. Fermi trigger No 737244199: Global MASTER-Net observations report
  85. Fermi trigger No 737218721: Global MASTER-Net observations report
  86. Fermi trigger No 737196587: Global MASTER-Net observations report
  87. Fermi trigger No 737168073: Global MASTER-Net observations report
  88. GRB 240511A: Enhanced Swift-XRT position
  89. GRB 240511A : MITSuME Akeno optical upper limits
  90. GRB 240511A: Swift-XRT refined Analysis
  91. GRB 240511A: optical afterglow detection from the NOT
  92. Fermi Gamma-ray Burst Monitor trigger 737102480/240511279 is not a GRB
  93. Fermi Gamma-ray Burst Monitor trigger 737111207/240511380 is not a GRB
  94. Fermi GBM trigger 737105243/240511311 is not a GRB
  95. Fermi trigger No 737173236: Global MASTER-Net observations report
  96. Fermi GRB 240511A: Global MASTER-Net observations report
  97. Swift GRB 240511A: Global MASTER-Net observations report
  98. Fermi trigger No 737105243: Global MASTER-Net observations report
  99. Fermi Gamma-ray Burst Monitor trigger 737133200/240511634 is not a GRB
  100. Fermi trigger No 737152719: Global MASTER-Net observations report

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