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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"

27774 results found.

  1. GRB 240819A: Swift ToO observations
  2. EP240816a: BOOTES-6/DPRT optical upper limit
  3. GRB 240817A: Fermi GBM Final Real-time Localization
  4. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  5. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  6. GRB 240814B: GRBAlpha detection
  7. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  8. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  9. GRB 240814C: Fermi GBM Final Real-time Localization
  10. GRB 240812B: SVOM/GRM observation
  11. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  12. GRB 240814B: Fermi GBM Final Real-time Localization
  13. GRB 240814A: Fermi GBM Final Real-time Localization
  14. Konus-Wind detection of GRB 240811A
  15. Konus-Wind detection of GRB 240810A
  16. GRB 240809A: ATA radio non-detection
  17. GRB 240812D: Fermi GBM Final Real-time Localization
  18. GRB 240812C: Fermi GBM Final Real-time Localization
  19. GRB 240809A: VLA detection
  20. GRB 240809A: ALMA detection
  21. IPN triangulation of GRB 240810A (short)
  22. GRB 240811A: Swift-BAT refined analysis
  23. GRB 240809A: Swift-BAT refined analysis
  24. EP240807a: PRIME H-band upper limits
  25. GRB 240812B: AstroSat CZTI detection of a long burst
  26. GRB 240811A: Bassano Bresciano Observatory upper limit
  27. GRB 240811A: Swift-XRT refined Analysis
  28. GRB 240811A: Swift/UVOT Upper Limits
  29. GRB 240812A: Fermi GBM Final Real-time Localization
  30. GRB 240811A: LCOGT Optical Upper Limit
  31. GRB 240811A: Enhanced Swift-XRT position
  32. GRB 240811A: Upper limits with Mephisto
  33. Konus-Wind detection of GRB 240809A
  34. Swift GRB 240811A: Global MASTER-Net observations report
  35. GRB 240811A: Swift detection of a burst
  36. GRB 240810A: Fermi GBM Final Real-time Localization
  37. GRB 240809A: REM detection of the optical afterglow
  38. GRB 240809A: Bassano Bresciano Observatory optical observations
  39. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  40. GRB 240809A: Conclusive redshift from VLT
  41. GRB 240809A: KAIT optical observations
  42. GRB 240808A: AstroSat CZTI detection
  43. GRB 240809A: GIT afterglow observations
  44. GRB 240809B: MAXI/GSC detection
  45. GRB 240809A: Swift/UVOT Detection
  46. GRB 240809A: Swift-XRT refined Analysis
  47. IPN triangulation of GRB 240807A / EP 240807a
  48. X-ray Transient EP240807a: PRIME near-infrared upper limits
  49. Swift GRB 240809A: Global MASTER-Net observations report
  50. GRB 240809A: JinShan optical observations
  51. GRB 240809A: Enhanced Swift-XRT position
  52. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  53. GRB 240809A: SVOM/GRM observation
  54. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  55. GRB 240807B: AstroSat CZTI detection of a short burst
  56. IceCube-240808A - IceCube observation of a high-energy neutrino candidate track-like event
  57. GRB 240801A: GRBAlpha detection
  58. GRB 240807B: Fermi GBM Final Localization
  59. GRB 240710B: VZLUSAT-2 detection
  60. GRB 240805A: ATCA Radio Upper Limits
  61. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  62. GRB 240720B: VZLUSAT-2 detection
  63. GRB 240710A: VZLUSAT-2 detection
  64. EP240806A: Liverpool Telescope optical follow-up observations
  65. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  66. GRB 240807A: Fermi GBM Final Localization
  67. EP240807a: EP-WXT detection of a fast X-ray transient
  68. EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
  69. GRB 240805B: GIT optical upper limit
  70. GRB 240805B: Swift-BAT refined analysis
  71. GRB 240805A: Swift-BAT refined analysis
  72. EP240806a: LCOGT optical counterpart detection
  73. Konus-Wind detection of GRB 240802A (EP240802a)
  74. Konus-Wind detection of GRB 240805A
  75. GRB 240805B Bassano Bresciano Observatory upper limit
  76. GRB240805A: Fermi GBM Observation
  77. GRB 240805B: JinShan optical afterglow detection
  78. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  79. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  80. EP240806a: EP-FXT detection of the X-ray emission
  81. GRB 240626B: VZLUSAT-2 detection
  82. GRB 240624B: VZLUSAT-2 detection
  83. GRB 240619C: VZLUSAT-2 detection
  84. EP240806a: GSP optical counterpart detection
  85. EP240806a: EP-WXT detection of a fast X-ray transient
  86. GRB 240805B: Optical detection with 1.6m Mephisto
  87. EP240804a: BOOTES-6/DPRT optical detection
  88. GRB 240805B: Swift-XRT refined Analysis
  89. GRB 240805B: Swift/UVOT Upper Limits
  90. GRB 240805A: Swift/UVOT Upper Limits
  91. GRB 240805A: SVOM/GRM observation
  92. GRB 240805B: Enhanced Swift-XRT position
  93. GRB 240805B: LCOGT Optical Upper Limits
  94. Swift GRB 240805B: Global MASTER-Net observations report
  95. GRB 240805B: JinShan optical upper limits
  96. Swift GRB 240805A: Global MASTER-Net observations report
  97. GRB 240805A: Swift-XRT refined Analysis
  98. GRB 240805B: Swift detection of a burst
  99. GRB 240805A: Fermi-LAT detection
  100. GRB 240805A: INTEGRAL spectral analysis

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