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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"

21449 results found.

  1. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  2. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  3. GRB 240615A: J-band upper limits from WINTER
  4. GRB 240615A: Fermi GBM Observation
  5. GRB 240615A: Swift-XRT observations
  6. GRB 240615A: GECAM detection
  7. GRB 240615A: FLWO-1.2m optical upper limits
  8. Konus-Wind detection of GRB 240615A (short/hard)
  9. GRB 240615A: GOTO optical upper limits
  10. GRB 240615A: Swift ToO observations
  11. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  12. EXO 0748-676: Swift-BAT refined analysis
  13. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  14. GRB 240529A: LBT optical detection and late temporal decay
  15. GRB 240529A : MITSuME Akeno optical afterglow detection
  16. Trigger 1236151: Swift detection of EXO 0748-676
  17. IPN triangulation of GRB 240607A
  18. Konus-Wind detection of GRB 240606B
  19. GRB 240606B: Fermi GBM Observation
  20. Swift Trigger 1235109: consistent with noise and not astrophysical
  21. GRB 240606B: GECAM-B detection a long burst
  22. GRB 240606B: Swift-XRT afterglow detection
  23. Swift GRB240606.15: Global MASTER-Net observations report
  24. GRB 240606B: Swift ToO observations
  25. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  26. Swift Trigger 1235109: a possible GRB 240606A
  27. IPN triangulation of GRB 240531A (short)
  28. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  29. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  30. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  31. Swift Trigger 1232465: consistent with noise
  32. GRB 240603B: Swift detection of a possible burst
  33. GRB 240529A: MASTER prompt OT detection
  34. GRB 240529A: OSN optical detection
  35. Swift Trigger 1232465 is not a GRB
  36. GRB 240529A: 1.3m DFOT Optical observations
  37. Konus-Wind detection of GRB 240529A
  38. IPN triangulation of the initial episode of GRB 240529A
  39. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  40. GRB 240529A: Insight-HXMT/HE detection
  41. GRB 240529A: GROWTH-India optical follow-up
  42. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  43. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  44. GRB 240529A: Skynet Optical Observations
  45. GRB 240529A: Swift-BAT refined analysis
  46. GRB 240529A: Swift-XRT refined Analysis
  47. GRB240529A: BOOTES-6/DPRT optical detection
  48. GRB 240529A: Swift/UVOT Detection
  49. GRB 240529A: NOT optical observations
  50. GRB 240529A: AstroSat CZTI detection
  51. GRB 240529A: GOTO optical afterglow detection
  52. GRB 240527B: Swift-XRT afterglow detection
  53. GRB 240529A: Enhanced Swift-XRT position
  54. GRB 240529A: Swift detection of a burst with an optical counterpart
  55. Swift GRB240529.12: Global MASTER-Net observations report
  56. GRB 240527B: Fermi-LAT detection
  57. GRB 240523A: Swift-BAT refined analysis
  58. GRB 240523A: Swift-XRT refined Analysis
  59. GRB 240523A: Enhanced Swift-XRT position
  60. GRB 240523A: Swift detection of a burst
  61. GRB 240521B: Fermi GBM Observation
  62. GRB 240513A: Swift-XRT afterglow detection
  63. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  64. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  65. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  66. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  67. GRB 240504A: VZLUSAT-2 detection
  68. GRB 240516A: Swift/UVOT Upper Limits
  69. GRB 240516A: Swift-BAT refined analysis
  70. GRB 240516A ATCA radio observations
  71. IPN triangulation of GRB 240514B (short)
  72. GRB 240513A: Swift ToO observations
  73. GRB 240516A: AstroSat CZTI detection
  74. GRB 240516A: Swift-XRT refined Analysis
  75. GRB 240514E: A possible candidate BD-21 1074
  76. GRB 240516A: Fermi GBM Observation
  77. GRB 240516A: GOTO optical upper limit
  78. GRB 240516A: Swift detection of a burst
  79. Swift GRB240516.15: Global MASTER-Net observations report
  80. GRB 240513A: Swift-XRT observations
  81. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  82. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  83. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  84. GRB 240513A: Tiled Swift observations
  85. GRB 240513A: Fermi-LAT detection
  86. GRB 240511A: Fermi GBM Observation
  87. GRB 240511A: Swift-BAT refined analysis
  88. GRB 240511A: J-band observations with WINTER
  89. GRB 240511A: Enhanced Swift-XRT position
  90. GRB 240511A : MITSuME Akeno optical upper limits
  91. GRB 240511A: Swift-XRT refined Analysis
  92. GRB 240511A: optical afterglow detection from the NOT
  93. Swift GRB 240511A: Global MASTER-Net observations report
  94. GRB 240511A: Prompt enhanced Swift-XRT position
  95. GRB 240511A: Swift detection of a burst
  96. GRB 240504A: Fermi GBM Observation
  97. IPN triangulation of GRB 240504A
  98. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  99. GRB 240415A 1.3m DFOT Optical upper limit
  100. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a

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