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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"

19178 results found.

  1. GRB 240819A: Swift afterglow confirmation
  2. GRB 240824B: Ondrejov D50 optical limit
  3. GRB 240825A: PRIME near-infrared detection
  4. Konus-Wind detection of GRB 240825A (bright/long)
  5. GRB 240825A: Fermi GBM Observation
  6. GRB 240825A: AKO Optical Follow-Up Observations
  7. GRB 240825A: AstroSat CZTI detection of the long bright burst
  8. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  9. GRB 240825A: Swift/UVOT Detection
  10. GRB 240825A: REM detection of the optical/NIR afterglow
  11. GRB 240825A: Swift-XRT refined Analysis
  12. GRB 240825A: VLT/X-shooter redshift
  13. GRB 240825A: SVOM/C-GFT optical observations
  14. GRB 240825A: Montarrenti Observatory optical observations
  15. GRB 240825A: Enhanced Swift-XRT position
  16. GRB 240825A: MASTER optical counterpart observation
  17. GRB 240825A: Fermi-LAT detection
  18. GRB 240825A: LCO optical observations
  19. GRB 240824B: KAIT optical upper limit
  20. GRB 240824B: Fermi GBM Observation
  21. GRB 240825A: GMG Optical Observation
  22. Swift GRB 240825A: Global MASTER-Net observations report
  23. GRB 240825A: 1.6m Mephisto multi-band detection
  24. GRB 240825A: AKO Optical Afterglow Detection
  25. GRB 240825A: Skynet Optical Afterglow observations
  26. GRB 240825A: Nanshan/HMT optical afterglow observations
  27. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  28. GRB 240824A: Swift-BAT refined analysis
  29. GRB 240824A: SVOM/C-GFT optical upper limit
  30. GRB 240824B: Swift-XRT afterglow detection
  31. GRB 240824A: Swift-XRT observations
  32. GRB 240824B: Swift/BAT arcminute localization of a burst
  33. GRB 240824B: Swift ToO observations
  34. GRB 240824A: Swift/UVOT Upper Limits
  35. GRB 240821A: Swift/UVOT observations of the XRT sources.
  36. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  37. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  38. GRB 240824A: KAIT optical upper limit
  39. GRB 240824A: Skynet Optical Afterglow Discovery
  40. GRB 240824A: Swift detection of a burst
  41. Swift GRB240824.04: Global MASTER-Net observations report
  42. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  43. GRB 240821A: Colibri Optical Upper Limit
  44. GRB 240821A: Swift-XRT observations
  45. GRB 240821A: REM optical/NIR upper limits
  46. GRB 240821A: JinShan optical upper limits
  47. GRB 240809A: Mondy and AbAO Optical Observations
  48. GRB 240821A: SVOM/VT follow-up and optical upper limit
  49. GRB 240821A: GMG Optical Upper Limit
  50. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  51. GRB 240821A: Swift ToO observations
  52. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  53. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  54. GRB 240819A: Swift-XRT observations
  55. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  56. GRB 240819A: KAIT optical upper limit
  57. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  58. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  59. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  60. GRB 240819A: Swift ToO observations
  61. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  62. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  63. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  64. Konus-Wind detection of GRB 240811A
  65. GRB 240811A: Swift-BAT refined analysis
  66. GRB 240809A: Swift-BAT refined analysis
  67. GRB 240811A: Bassano Bresciano Observatory upper limit
  68. GRB 240811A: Swift-XRT refined Analysis
  69. GRB 240811A: Swift/UVOT Upper Limits
  70. GRB 240811A: LCOGT Optical Upper Limit
  71. GRB 240811A: Enhanced Swift-XRT position
  72. Konus-Wind detection of GRB 240809A
  73. Swift GRB 240811A: Global MASTER-Net observations report
  74. GRB 240811A: Swift detection of a burst
  75. GRB 240809A: Bassano Bresciano Observatory optical observations
  76. GRB 240809A: KAIT optical observations
  77. GRB 240809A: GIT afterglow observations
  78. GRB 240809A: Swift/UVOT Detection
  79. GRB 240809A: Swift-XRT refined Analysis
  80. IPN triangulation of GRB 240807A / EP 240807a
  81. Swift GRB 240809A: Global MASTER-Net observations report
  82. GRB 240809A: JinShan optical observations
  83. GRB 240809A: Enhanced Swift-XRT position
  84. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  85. GRB 240809A: SVOM/GRM observation
  86. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  87. GRB 240805A: ATCA Radio Upper Limits
  88. GRB 240805B: GIT optical upper limit
  89. GRB 240805B: Swift-BAT refined analysis
  90. GRB 240805A: Swift-BAT refined analysis
  91. Konus-Wind detection of GRB 240805A
  92. GRB 240805B Bassano Bresciano Observatory upper limit
  93. GRB240805A: Fermi GBM Observation
  94. GRB 240805B: JinShan optical afterglow detection
  95. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  96. GRB 240805B: Swift-XRT refined Analysis
  97. GRB 240805B: Swift/UVOT Upper Limits
  98. GRB 240805A: Swift/UVOT Upper Limits
  99. GRB 240805A: SVOM/GRM observation
  100. GRB 240805B: Enhanced Swift-XRT position

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