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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"

14824 results found.

  1. EP240913A / GRB 240913C: AstroSat CZTI detection
  2. GRB 240914A: SVOM/GRM observation
  3. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  4. EP240913a: EP-WXT detection of a fast X-ray transient
  5. GRB 240913B: Fermi GBM Final Real-time Localization
  6. GRB 240912A: Swift/UVOT Detection
  7. GRB 240912A: SVOM/GRM observation
  8. GRB 240913A: Fermi GBM Final Real-time Localization
  9. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  10. GRB 240912A : INTEGRAL SPI ACS LIGHT CURVE
  11. GRB 240912B: Fermi GBM Final Real-time Localization
  12. GRB 240912A: Swift detection of a burst with an optical counterpart
  13. GRB 240912A: Fermi GBM Final Real-time Localization
  14. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  15. EP240908a: Optical afterglow confirmation
  16. GRB 240710A: SVOM/GRM observation
  17. IPN triangulation of GRB 240905B (short)
  18. GRB 240825A: 7DT Optical Upper Limit
  19. GRB 240910A: GRBAlpha detection
  20. GRB 240910B: Fermi GBM Final Real-time Localization
  21. GRB 240910A: SVOM/GRM observation
  22. EP240908a: Updates on the WXT detection result around the trigger time
  23. GRB 240910A: Fermi GBM Final Real-time Localization
  24. EP240908a: optical afterglow candidate
  25. EP240908a: EP detection of a fast X-ray transient
  26. GRB 240908A: Fermi GBM Final Real-time Localization
  27. GRB 240801A: SVOM/GRM observation
  28. GRB 240905E: GIT optical upper limit
  29. GRB 240905B: Fermi-LAT detection
  30. GRB 240902B: AstroSat CZTI detection of a long burst
  31. GRB 240902A: AstroSat CZTI detection of a long burst
  32. GRB 240905E: SVOM/GRM observation
  33. GRB 240905E: Swift detection of a burst
  34. GRB 240905D: AstroSat CZTI detection
  35. GRB 240905A: SVOM/GRM observation
  36. GRB 240905D: Fermi GBM Final Real-time Localization
  37. GRB 240905B: AstroSat CZTI detection and localization
  38. GRB 240905C: Fermi GBM Final Real-time Localization
  39. GRB 240905B: Fermi GBM Final Real-time Localization
  40. GRB 240825A: ATCA Detection of Radio Counterpart
  41. GRB 240905A: Fermi GBM Final Real-time Localization
  42. GRB 240904A: Swift detection of a burst
  43. GRB 240828A: SVOM/GRM observation
  44. GRB 240828A: GECAM detection
  45. GRB 240831B: Fermi GBM Final Localization
  46. GRB 240825A: MeerLICHT afterglow detection
  47. GRB 240821A: VLT spectroscopic observations
  48. GRB 240829B: GRBAlpha detection
  49. GRB 240831A: Fermi GBM Final Real-time Localization
  50. GRB 240825A: MeerKAT detection
  51. GRB 240829B: Fermi GBM Final Localization
  52. GRB 240825A: SVOM/VT optical detection
  53. GRB 240828A: Swift-XRT afterglow detection
  54. GRB 240828B: Swift-XRT afterglow detection
  55. GRB 240829A: Swift detection of a burst
  56. GRB 240828A: Fermi-LAT detection
  57. GRB 240828A: AstroSat CZTI detection of a long burst
  58. GRB 240819A as a likely X-Ray Flash
  59. GRB 240825A: VLA detection
  60. SVOM GRB 240821A: optical afterglow discovery
  61. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  62. GRB 240828A: Fermi GBM Final Real-time Localization
  63. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  64. GRB 240825A: GECAM detection
  65. GRB 240825A: ALMA detection
  66. GRB 240825A: SAO RAS optical observations
  67. GRB 240825A: PRIME near-infrared detection
  68. Konus-Wind detection of GRB 240825A (bright/long)
  69. GRB 240825A: AstroSat CZTI detection of the long bright burst
  70. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  71. GRB 240825A: Swift/UVOT Detection
  72. GRB 240825A: REM detection of the optical/NIR afterglow
  73. GRB 240825A: VLT/X-shooter redshift
  74. GRB 240825A: Fermi-LAT detection
  75. GRB 240824B: Fermi GBM Observation
  76. GRB 240825A: 1.6m Mephisto multi-band detection
  77. GRB 240825A: AKO Optical Afterglow Detection
  78. GRB 240825A: Skynet Optical Afterglow observations
  79. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  80. GRB 240825A: Fermi GBM Final Real-time Localization
  81. GRB 240824B: Swift-XRT afterglow detection
  82. GRB 240824C: Fermi GBM Final Localization
  83. GRB 240824B: MAXI/GSC detection
  84. GRB 240824B: Fermi GBM Final Real-time Localization
  85. GRB 240824A: Retraction of GCN 37255
  86. GRB 240824A: Swift detection of a burst
  87. EP240820a: PRIME J-band Observations
  88. GRB 240822A: AstroSat CZTI detection of a short burst
  89. GRB 240821A: LCO optical observations
  90. GRB 240821A: SVOM/VT follow-up and optical upper limit
  91. GRB 240821A: GMG Optical Upper Limit
  92. GRB 240821A: Fermi GBM Observation
  93. GRB240821A: EIRSAT-1 GMOD Detection
  94. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  95. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  96. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  97. GRB 240821A: SVOM/GRM observation
  98. GRB 240821A: SVOM/GRM observation
  99. GRB 240821B: Fermi GBM Final Localization
  100. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73

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