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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"

36144 results found.

  1. GRB 240529A: AKO Optical Afterglow Detection
  2. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  3. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  4. GRB 240529A: J-band detections with WINTER
  5. GRB 240529A: Skynet Optical Observations
  6. GRB 240529A: Swift-BAT refined analysis
  7. GRB 240529A: Swift-XRT refined Analysis
  8. GRB240529A: BOOTES-6/DPRT optical detection
  9. GRB 240529A: Swift/UVOT Detection
  10. GRB 240529A: NOT optical observations
  11. GRB 240529A: AstroSat CZTI detection
  12. GRB 240529A: GOTO optical afterglow detection
  13. GRB 240527B: Swift-XRT afterglow detection
  14. GRB 240529A: Enhanced Swift-XRT position
  15. GRB 240529A: Swift detection of a burst with an optical counterpart
  16. GRB 240527B: Fermi GBM Observation
  17. Fermi GRB 240527A: Global MASTER-Net observations report
  18. GRB 240527B: Fermi-LAT detection
  19. Fermi GRB 240527B: Global MASTER-Net observations report
  20. GRB 240527B: Fermi GBM Final Localization
  21. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  22. GRB 240527A: Fermi GBM Final Real-time Localization
  23. GRB 240523A: Swift-BAT refined analysis
  24. GRB 240523A: Swift-XRT refined Analysis
  25. GRB 240523A: Enhanced Swift-XRT position
  26. GRB 240523A: Swift detection of a burst
  27. GRB 240521B: Fermi GBM Observation
  28. Fermi GBM Sub-Threshold Detection of GRB 240516B
  29. GRB 240513A: Swift-XRT afterglow detection
  30. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  31. GRB 240521A: GECAM-B detection of a long burst
  32. GRB 240516B: AstroSat CZTI detection
  33. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  34. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  35. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  36. GRB 240514B: VZLUSAT-2 detection
  37. GRB 240504A: VZLUSAT-2 detection
  38. GRB 240502A: VZLUSAT-2 detection
  39. GRB 240519A: GRBAlpha detection
  40. GRB 240516A: Swift/UVOT Upper Limits
  41. GRB 240519A: AstroSat CZTI detection
  42. GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
  43. GRB 240516A: Swift-BAT refined analysis
  44. Fermi GRB 240517A: Global MASTER-Net observations report
  45. GRB 240516A ATCA radio observations
  46. IPN triangulation of GRB 240514B (short)
  47. GRB 240513A: Swift ToO observations
  48. GRB 240517A: Fermi GBM Final Real-time Localization
  49. Konus-Wind detection of GRB 240513A
  50. GRB 240516A: AstroSat CZTI detection
  51. GRB 240516A: Swift-XRT refined Analysis
  52. GRB 240514E: A possible candidate BD-21 1074
  53. GRB 240516A: Fermi GBM Observation
  54. GRB 240511A: Observations from GTC/OSIRIS+
  55. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  56. GRB 240516A: GOTO optical upper limit
  57. LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
  58. GRB 240516A: Swift detection of a burst
  59. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  60. GRB 240511A: radio detection of afterglow candidate
  61. GRB 240514B: GOTO candidate optical counterpart
  62. Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
  63. GRB 240514E: MAXI/GSC detection of a probable afterglow
  64. GRB 240514B: GRBAlpha detection
  65. GRB 240514B: Fermi GBM Detection
  66. GRB 240513A: Fermi GBM observation
  67. GRB 240513A: Swift-XRT observations
  68. GRB 240514D: AstroSat CZTI detection
  69. GRB 240514C: Fermi GBM Final Real-time Localization
  70. Fermi GRB 240514B: Global MASTER-Net observations report
  71. GRB 240514B: Fermi GBM Final Real-time Localization
  72. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  73. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  74. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  75. GRB 240514A: Fermi GBM Final Real-time Localization
  76. GRB 240513A: Tiled Swift observations
  77. GRB 240513A: Fermi-LAT detection
  78. GRB 240511A: Fermi GBM Observation
  79. GRB 240511A: Swift-BAT refined analysis
  80. Fermi GRB 240513B: Global MASTER-Net observations report
  81. GRB 240513B: Fermi GBM Final Real-time Localization
  82. GRB 240513A: AstroSat CZTI detection
  83. GRB 240511A: J-band observations with WINTER
  84. GRB 240511A: Enhanced Swift-XRT position
  85. GRB 240511A : MITSuME Akeno optical upper limits
  86. GRB 240511A: Swift-XRT refined Analysis
  87. GRB 240511A: optical afterglow detection from the NOT
  88. Fermi Gamma-ray Burst Monitor trigger 737102480/240511279 is not a GRB
  89. Fermi Gamma-ray Burst Monitor trigger 737111207/240511380 is not a GRB
  90. Fermi GBM trigger 737105243/240511311 is not a GRB
  91. Fermi GRB 240511A: Global MASTER-Net observations report
  92. Swift GRB 240511A: Global MASTER-Net observations report
  93. Fermi Gamma-ray Burst Monitor trigger 737133200/240511634 is not a GRB
  94. GRB 240511A: Prompt enhanced Swift-XRT position
  95. GRB 240511A: Swift detection of a burst
  96. GRB 240511A: Fermi GBM Final Real-time Localization
  97. Fermi Gamma-ray Burst Monitor trigger 737076431/240510977 is not a GRB
  98. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  99. EP240506a: CrAO ZTSH optical upper limit
  100. GRB 240504A: Fermi GBM Observation

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