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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"

19600 results found.

  1. GRB240624A: Fermi GBM Observation
  2. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  3. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  4. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  5. Swift GRB 240624A: Global MASTER-Net observations report
  6. GRB 240624A: Swift detection of a burst
  7. GRB 240529A: JinShan optical observations
  8. IPN triangulation of GRB 240615A (short)
  9. EP240618a: Swift/XRT upper limit
  10. EP240617a: tentative Swift/XRT detection of the afterglow
  11. GRB 240619A: Swift-XRT probable afterglow detection
  12. GRB 240619A: Swift ToO observations
  13. GRB 240615A: NOT optical observations
  14. GRB 240615A: possible transient detection from Wendelstein observations
  15. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  16. GRB240615A: 1.3m DFOT optical upper limit
  17. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  18. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  19. GRB 240615A: J-band upper limits from WINTER
  20. GRB 240615A: Fermi GBM Observation
  21. GRB 240615A: Swift-XRT observations
  22. GRB 240615A: GECAM detection
  23. GRB 240615A: FLWO-1.2m optical upper limits
  24. Konus-Wind detection of GRB 240615A (short/hard)
  25. GRB 240615A: GOTO optical upper limits
  26. GRB 240615A: Swift ToO observations
  27. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  28. EXO 0748-676: Swift-BAT refined analysis
  29. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  30. GRB 240529A: LBT optical detection and late temporal decay
  31. GRB 240529A : MITSuME Akeno optical afterglow detection
  32. Trigger 1236151: Swift detection of EXO 0748-676
  33. IPN triangulation of GRB 240607A
  34. Konus-Wind detection of GRB 240606B
  35. GRB 240606B: Fermi GBM Observation
  36. Swift Trigger 1235109: consistent with noise and not astrophysical
  37. GRB 240606B: GECAM-B detection a long burst
  38. GRB 240606B: Swift-XRT afterglow detection
  39. Swift GRB240606.15: Global MASTER-Net observations report
  40. GRB 240606B: Swift ToO observations
  41. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  42. Swift Trigger 1235109: a possible GRB 240606A
  43. IPN triangulation of GRB 240531A (short)
  44. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  45. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  46. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  47. Swift Trigger 1232465: consistent with noise
  48. GRB 240603B: Swift detection of a possible burst
  49. GRB 240529A: MASTER prompt OT detection
  50. GRB 240529A: OSN optical detection
  51. Swift Trigger 1232465 is not a GRB
  52. GRB 240529A: 1.3m DFOT Optical observations
  53. Konus-Wind detection of GRB 240529A
  54. IPN triangulation of the initial episode of GRB 240529A
  55. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  56. GRB 240529A: Insight-HXMT/HE detection
  57. GRB 240529A: GROWTH-India optical follow-up
  58. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  59. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  60. GRB 240529A: Skynet Optical Observations
  61. GRB 240529A: Swift-BAT refined analysis
  62. GRB 240529A: Swift-XRT refined Analysis
  63. GRB240529A: BOOTES-6/DPRT optical detection
  64. GRB 240529A: Swift/UVOT Detection
  65. GRB 240529A: NOT optical observations
  66. GRB 240529A: AstroSat CZTI detection
  67. GRB 240529A: GOTO optical afterglow detection
  68. GRB 240527B: Swift-XRT afterglow detection
  69. GRB 240529A: Enhanced Swift-XRT position
  70. GRB 240529A: Swift detection of a burst with an optical counterpart
  71. Swift GRB240529.12: Global MASTER-Net observations report
  72. GRB 240527B: Fermi-LAT detection
  73. GRB 240523A: Swift-BAT refined analysis
  74. GRB 240523A: Swift-XRT refined Analysis
  75. GRB 240523A: Enhanced Swift-XRT position
  76. GRB 240523A: Swift detection of a burst
  77. GRB 240521B: Fermi GBM Observation
  78. GRB 240513A: Swift-XRT afterglow detection
  79. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  80. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  81. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  82. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  83. GRB 240504A: VZLUSAT-2 detection
  84. GRB 240516A: Swift/UVOT Upper Limits
  85. GRB 240516A: Swift-BAT refined analysis
  86. GRB 240516A ATCA radio observations
  87. IPN triangulation of GRB 240514B (short)
  88. GRB 240513A: Swift ToO observations
  89. GRB 240516A: AstroSat CZTI detection
  90. GRB 240516A: Swift-XRT refined Analysis
  91. GRB 240514E: A possible candidate BD-21 1074
  92. GRB 240516A: Fermi GBM Observation
  93. GRB 240516A: GOTO optical upper limit
  94. GRB 240516A: Swift detection of a burst
  95. Swift GRB240516.15: Global MASTER-Net observations report
  96. GRB 240513A: Swift-XRT observations
  97. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  98. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  99. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  100. GRB 240513A: Tiled Swift observations

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