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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"

19592 results found.

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

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