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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"

21459 results found.

  1. GRB 240829A: Swift detection of a burst
  2. Swift GRB240829.16: Global MASTER-Net observations report
  3. GRB 240828A: Fermi-LAT detection
  4. GRB 240828A: Tiled Swift observations
  5. GRB 240825A: Upper limits from a neutrino search with IceCube
  6. GRB 240819A as a likely X-Ray Flash
  7. GRB 240828B: Swift ToO observations
  8. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  9. GRB 240825A: GECAM detection
  10. GRB 240824A: GIT optical upper limit
  11. GRB 240819A: Swift afterglow confirmation
  12. GRB 240824B: Ondrejov D50 optical limit
  13. GRB 240825A: PRIME near-infrared detection
  14. Konus-Wind detection of GRB 240825A (bright/long)
  15. GRB 240825A: Fermi GBM Observation
  16. GRB 240825A: AKO Optical Follow-Up Observations
  17. GRB 240825A: AstroSat CZTI detection of the long bright burst
  18. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  19. GRB 240825A: Swift/UVOT Detection
  20. GRB 240825A: REM detection of the optical/NIR afterglow
  21. GRB 240825A: Swift-XRT refined Analysis
  22. GRB 240825A: VLT/X-shooter redshift
  23. GRB 240825A: SVOM/C-GFT optical observations
  24. GRB 240825A: Montarrenti Observatory optical observations
  25. GRB 240825A: Enhanced Swift-XRT position
  26. GRB 240825A: MASTER optical counterpart observation
  27. GRB 240825A: Fermi-LAT detection
  28. GRB 240825A: LCO optical observations
  29. GRB 240824B: KAIT optical upper limit
  30. GRB 240824B: Fermi GBM Observation
  31. GRB 240825A: GMG Optical Observation
  32. Swift GRB 240825A: Global MASTER-Net observations report
  33. GRB 240825A: 1.6m Mephisto multi-band detection
  34. GRB 240825A: AKO Optical Afterglow Detection
  35. GRB 240825A: Skynet Optical Afterglow observations
  36. GRB 240825A: Nanshan/HMT optical afterglow observations
  37. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  38. GRB 240824A: Swift-BAT refined analysis
  39. GRB 240824A: SVOM/C-GFT optical upper limit
  40. GRB 240824B: Swift-XRT afterglow detection
  41. GRB 240824A: Swift-XRT observations
  42. GRB 240824B: Swift/BAT arcminute localization of a burst
  43. GRB 240824B: Swift ToO observations
  44. GRB 240824A: Swift/UVOT Upper Limits
  45. GRB 240821A: Swift/UVOT observations of the XRT sources.
  46. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  47. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  48. GRB 240824A: KAIT optical upper limit
  49. GRB 240824A: Skynet Optical Afterglow Discovery
  50. GRB 240824A: Swift detection of a burst
  51. Swift GRB240824.04: Global MASTER-Net observations report
  52. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  53. GRB 240821A: Colibri Optical Upper Limit
  54. GRB 240821A: Swift-XRT observations
  55. GRB 240821A: REM optical/NIR upper limits
  56. GRB 240821A: JinShan optical upper limits
  57. GRB 240809A: Mondy and AbAO Optical Observations
  58. GRB 240821A: SVOM/VT follow-up and optical upper limit
  59. GRB 240821A: GMG Optical Upper Limit
  60. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  61. GRB 240821A: Swift ToO observations
  62. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  63. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  64. GRB 240819A: Swift-XRT observations
  65. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  66. GRB 240819A: KAIT optical upper limit
  67. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  68. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  69. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  70. GRB 240819A: Swift ToO observations
  71. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  72. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  73. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  74. Konus-Wind detection of GRB 240811A
  75. GRB 240811A: Swift-BAT refined analysis
  76. GRB 240809A: Swift-BAT refined analysis
  77. GRB 240811A: Bassano Bresciano Observatory upper limit
  78. GRB 240811A: Swift-XRT refined Analysis
  79. GRB 240811A: Swift/UVOT Upper Limits
  80. GRB 240811A: LCOGT Optical Upper Limit
  81. GRB 240811A: Enhanced Swift-XRT position
  82. Konus-Wind detection of GRB 240809A
  83. Swift GRB 240811A: Global MASTER-Net observations report
  84. GRB 240811A: Swift detection of a burst
  85. GRB 240809A: Bassano Bresciano Observatory optical observations
  86. GRB 240809A: KAIT optical observations
  87. GRB 240809A: GIT afterglow observations
  88. GRB 240809A: Swift/UVOT Detection
  89. GRB 240809A: Swift-XRT refined Analysis
  90. IPN triangulation of GRB 240807A / EP 240807a
  91. Swift GRB 240809A: Global MASTER-Net observations report
  92. GRB 240809A: JinShan optical observations
  93. GRB 240809A: Enhanced Swift-XRT position
  94. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  95. GRB 240809A: SVOM/GRM observation
  96. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  97. GRB 240805A: ATCA Radio Upper Limits
  98. GRB 240805B: GIT optical upper limit
  99. GRB 240805B: Swift-BAT refined analysis
  100. GRB 240805A: Swift-BAT refined analysis

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