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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"

19938 results found.

  1. The EP-WXT source triggered on July 14th is likely a flaring star
  2. GRB 240713A: Tiled Swift observations
  3. GRB 240712A: Swift detection of a burst
  4. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  5. EP240708a: EP-WXT detection of a fast X-ray transient
  6. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  7. IPN triangulation of GRB 240628B (short)
  8. EP240703a and EP240703b: Swift/XRT upper limits
  9. EP240703c: Kinder optical follow-up and Swift XRT observations
  10. EP240703c: EP-WXT detection of an X-ray transient
  11. IPN triangulation of GRB 240627A
  12. EP240703b: EP-WXT detection of a fast X-ray transient
  13. EP240702a: Swift/XRT upper limit
  14. EP240703a: EP-WXT detection of a fast X-ray transient
  15. EP240702a: EP-WXT detection of a fast X-ray transient
  16. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  17. IPN triangulation of GRB 240619C
  18. GRB 240624A: Swift-BAT refined analysis
  19. Konus-Wind detection of GRB 240619A
  20. GRB240624A: Fermi GBM Observation
  21. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  22. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  23. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  24. Swift GRB 240624A: Global MASTER-Net observations report
  25. GRB 240624A: Swift detection of a burst
  26. GRB 240529A: JinShan optical observations
  27. IPN triangulation of GRB 240615A (short)
  28. EP240618a: Swift/XRT upper limit
  29. EP240617a: tentative Swift/XRT detection of the afterglow
  30. GRB 240619A: Swift-XRT probable afterglow detection
  31. GRB 240619A: Swift ToO observations
  32. GRB 240615A: NOT optical observations
  33. GRB 240615A: possible transient detection from Wendelstein observations
  34. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  35. GRB240615A: 1.3m DFOT optical upper limit
  36. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  37. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  38. GRB 240615A: J-band upper limits from WINTER
  39. GRB 240615A: Fermi GBM Observation
  40. GRB 240615A: Swift-XRT observations
  41. GRB 240615A: GECAM detection
  42. GRB 240615A: FLWO-1.2m optical upper limits
  43. Konus-Wind detection of GRB 240615A (short/hard)
  44. GRB 240615A: GOTO optical upper limits
  45. GRB 240615A: Swift ToO observations
  46. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  47. EXO 0748-676: Swift-BAT refined analysis
  48. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  49. GRB 240529A: LBT optical detection and late temporal decay
  50. GRB 240529A : MITSuME Akeno optical afterglow detection
  51. Trigger 1236151: Swift detection of EXO 0748-676
  52. IPN triangulation of GRB 240607A
  53. Konus-Wind detection of GRB 240606B
  54. GRB 240606B: Fermi GBM Observation
  55. Swift Trigger 1235109: consistent with noise and not astrophysical
  56. GRB 240606B: GECAM-B detection a long burst
  57. GRB 240606B: Swift-XRT afterglow detection
  58. Swift GRB240606.15: Global MASTER-Net observations report
  59. GRB 240606B: Swift ToO observations
  60. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  61. Swift Trigger 1235109: a possible GRB 240606A
  62. IPN triangulation of GRB 240531A (short)
  63. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  64. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  65. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  66. Swift Trigger 1232465: consistent with noise
  67. GRB 240603B: Swift detection of a possible burst
  68. GRB 240529A: MASTER prompt OT detection
  69. GRB 240529A: OSN optical detection
  70. Swift Trigger 1232465 is not a GRB
  71. GRB 240529A: 1.3m DFOT Optical observations
  72. Konus-Wind detection of GRB 240529A
  73. IPN triangulation of the initial episode of GRB 240529A
  74. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  75. GRB 240529A: Insight-HXMT/HE detection
  76. GRB 240529A: GROWTH-India optical follow-up
  77. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  78. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  79. GRB 240529A: Skynet Optical Observations
  80. GRB 240529A: Swift-BAT refined analysis
  81. GRB 240529A: Swift-XRT refined Analysis
  82. GRB240529A: BOOTES-6/DPRT optical detection
  83. GRB 240529A: Swift/UVOT Detection
  84. GRB 240529A: NOT optical observations
  85. GRB 240529A: AstroSat CZTI detection
  86. GRB 240529A: GOTO optical afterglow detection
  87. GRB 240527B: Swift-XRT afterglow detection
  88. GRB 240529A: Enhanced Swift-XRT position
  89. GRB 240529A: Swift detection of a burst with an optical counterpart
  90. Swift GRB240529.12: Global MASTER-Net observations report
  91. GRB 240527B: Fermi-LAT detection
  92. GRB 240523A: Swift-BAT refined analysis
  93. GRB 240523A: Swift-XRT refined Analysis
  94. GRB 240523A: Enhanced Swift-XRT position
  95. GRB 240523A: Swift detection of a burst
  96. GRB 240521B: Fermi GBM Observation
  97. GRB 240513A: Swift-XRT afterglow detection
  98. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  99. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  100. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO

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