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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"

36155 results found.

  1. GRB 240825A: Fermi GBM Observation
  2. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  3. GRB 240825A: AKO Optical Follow-Up Observations
  4. GRB 240825A: AstroSat CZTI detection of the long bright burst
  5. GRB 240825A: Swift/UVOT Detection
  6. GRB 240825A: REM detection of the optical/NIR afterglow
  7. GRB 240825A: Swift-XRT refined Analysis
  8. GRB 240825A: VLT/X-shooter redshift
  9. GRB 240825A: SVOM/C-GFT optical observations
  10. GRB 240825A: Montarrenti Observatory optical observations
  11. GRB 240825A: Enhanced Swift-XRT position
  12. GRB 240825A: MASTER optical counterpart observation
  13. GRB 240825A: Fermi-LAT detection
  14. GRB 240825A: LCO optical observations
  15. GRB 240824B: KAIT optical upper limit
  16. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  17. GRB 240824B: Fermi GBM Observation
  18. Fermi GRB 240825A: Global MASTER-Net observations report
  19. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  20. GRB 240824B: NOT optical upper limit
  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 240825A: Fermi GBM Final Real-time Localization
  29. GRB 240824A: Swift-BAT refined analysis
  30. GRB 240824A: SVOM/C-GFT optical upper limit
  31. GRB 240824B: Swift-XRT afterglow detection
  32. GRB 240824A: Swift-XRT observations
  33. GRB 240824B: Swift/BAT arcminute localization of a burst
  34. GRB 240824B: Swift ToO observations
  35. Fermi GRB 240824C: Global MASTER-Net observations report
  36. GRB 240824C: Fermi GBM Final Localization
  37. GRB 240824A: Swift/UVOT Upper Limits
  38. GRB 240821A: Swift/UVOT observations of the XRT sources.
  39. GRB 240824B: MAXI/GSC detection
  40. GRB 240824B: Fermi GBM Final Real-time Localization
  41. GRB 240824A: Retraction of GCN 37255
  42. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  43. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  44. GRB 240824A: KAIT optical upper limit
  45. GRB 240824A: Skynet Optical Afterglow Discovery
  46. GRB 240824A: Swift detection of a burst
  47. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  48. GRB 240821A: Colibri Optical Upper Limit
  49. GRB 240821A: Swift-XRT observations
  50. GRB 240822A: AstroSat CZTI detection of a short burst
  51. GRB 240821A: REM optical/NIR upper limits
  52. GRB 240821A: LCO optical observations
  53. GRB 240821A: JinShan optical upper limits
  54. GRB 240809A: Mondy and AbAO Optical Observations
  55. GRB 240821A: SVOM/VT follow-up and optical upper limit
  56. GRB 240821A: GMG Optical Upper Limit
  57. Fermi GRB 240821A: Global MASTER-Net observations report
  58. GRB 240821A: Fermi GBM Observation
  59. GRB 240821A: Swift ToO observations
  60. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  61. GRB240821A: EIRSAT-1 GMOD Detection
  62. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  63. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  64. Fermi GRB 240821B: Global MASTER-Net observations report
  65. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  66. GRB 240821A: SVOM/GRM observation
  67. GRB 240821A: SVOM/GRM observation
  68. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  69. GRB 240821B: Fermi GBM Final Localization
  70. GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
  71. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  72. GRB 240821A: Fermi GBM Final Real-time Localization
  73. GRB 240819A: Swift-XRT observations
  74. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  75. GRB 240820B: SVOM/GRM observation
  76. GRB 240819A: KAIT optical upper limit
  77. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  78. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  79. GRB 240819A: X-ray follow-up observation with EP-FXT
  80. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  81. GRB 240820A: Fermi GBM Final Real-time Localization
  82. GRB 240819A: Swift ToO observations
  83. GRB 240814A: SVOM/GRM observation
  84. GRB 240814C: SVOM/GRM observation
  85. GRB 240815A: SVOM/GRM observation
  86. GRB 240817A: Fermi GBM Final Real-time Localization
  87. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  88. IBAS Alert n.10856: not a GRB
  89. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  90. EP240816b: KAIT optical upper limit
  91. GRB 240814B: GRBAlpha detection
  92. Fermi GRB 240814A: Global MASTER-Net observations report
  93. Fermi GRB 240814C: Global MASTER-Net observations report
  94. GRB 240814C: Fermi GBM Final Real-time Localization
  95. Fermi GRB 240814B: Global MASTER-Net observations report
  96. GRB 240812B: SVOM/GRM observation
  97. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  98. GRB 240814B: Fermi GBM Final Real-time Localization
  99. GRB 240814A: Fermi GBM Final Real-time Localization
  100. Konus-Wind detection of GRB 240811A

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