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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

28130 results found.

  1. GRB 240821A: Keck/LRIS spectroscopic observations
  2. EP241021a: Gemini-South detection of optical rebrightening
  3. GRB 241026A: the 100th GRB detected by GRBAlpha
  4. GRB 241026A: TNOT optical counterpart detection
  5. Konus-Wind detection of GRB 241025A
  6. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  7. GRB 241026A: GECAM detection
  8. GRB 241025A: Swift/UVOT Detection
  9. GRB 241026A: GROWTH-India Telescope optical observations
  10. GRB 241026A: BTA redshift identification of z = 2.79
  11. GRB 241026A: J-band observations with WINTER
  12. GRB 241026A: Las Cumbres optical detection
  13. GRB 241025A: Mondy optical observations
  14. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  15. GRB 241026A: Swift-XRT refined Analysis
  16. GRB 241026A: Enhanced Swift-XRT position
  17. GRB 241026A: KAIT optical observations
  18. EP241026b: EP detection of a fast X-ray transient
  19. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  20. GRB 241026A: SAO RAS observations of possible optical afterglow
  21. GRB 241026A: Prompt enhanced Swift-XRT position
  22. GRB 241026A: Swift detection of a burst
  23. GRB 241026A: Fermi GBM Final Real-time Localization
  24. GRB241025A: 1.3m DFOT optical afterglow detection
  25. EP241021a: optical follow-up observations with Xinglong Observatory
  26. ​GRB 241025A: optical photometry from Konkoly
  27. GRB 241025A: GROWTH-India Telescope optical observations
  28. GRB 241025A: COLIBRÍ Detection of the Afterglow
  29. GRB 241025A: Swift-XRT refined Analysis
  30. GRB 241025C: Fermi GBM Detection
  31. GRB 241025C: Fermi GBM Final Localization
  32. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  33. GRB 241025B: Fermi GBM Final Localization
  34. EP 241021a: Swift-XRT observations
  35. EP241025a (GRB 241025A): EP observations update
  36. GRB 241025A : SVOM/VT optical afterglow observations
  37. EP 241021A: Swift ToO observations
  38. EP241021a: Liverpool Telescope optical follow-up observations
  39. GRB 241025A: Enhanced Swift-XRT position
  40. GRB 241025A: DDOTI Afterglow detection
  41. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  42. GRB 241025A: TRT optical afterglow observation
  43. GRB 241025A: Fermi GBM Final Real-time Localization
  44. GRB 241025A: Swift detection of a burst with an optical counterpart
  45. GRB 241001A: ATCA radio observations
  46. GRB 241024B: Fermi GBM Final Localization
  47. EP241021a: No Detection in Fermi-GBM Observation
  48. GRB 241010A: VIRT Optical Upper Limit
  49. GRB 241024A: Fermi GBM Final Localisation
  50. EP241021a: VLT/FORS2 redshift z = 0.75
  51. EP241021a: KAIT optical observations
  52. EP241021a: EP-FXT follow-up observation update
  53. EP241021a: Optical counterpart observations with the Liverpool Telescope
  54. EP241021a: 1.3m DFOT Optical observations
  55. EP241021a: NOT likely optical counterpart
  56. GRB241017A: 1.3m DFOT optical upper limit
  57. GRB 241018A: 1.3m DFOT Optical upper limit
  58. GRB 241018A: EP-FXT afterglow detection
  59. EP241021a: EP detection of a fast X-ray transient
  60. Konus-Wind detection of GRB 241018A
  61. GRB 241018A: BOOTES-4/MET optical upper limit
  62. GRB 241018A: Mondy optical upper limit
  63. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  64. GRB 241018A: GROWTH-India telescope optical upper limit
  65. GRB 241018A: Swift-XRT observations
  66. GRB 241018A: REM optical/NIR upper limits
  67. GRB 241018A: NOT optical observations
  68. GRB 241018A: LCO/0.4m optical upper limits
  69. GRB 241018A: Swift ToO observations
  70. GRB 241006A: VIRT Optical Upper Limit
  71. GRB 240727A: VIRT Optical Upper Limit
  72. GRB 241018A: X-ray afterglow candidate observed by MXT
  73. GRB 241018A: Detection of a bright long GRB by SVOM
  74. GRB 241017A: Swift-XRT observations
  75. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  76. GRB 241001A: EP-FXT afterglow detection
  77. GRB241016C: Fermi GBM Final Localization
  78. GRB 241017A: Swift ToO observations
  79. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  80. GRB 241016B: Fermi GBM Final Localization
  81. GRB 241016A: Fermi GBM Final Real-time Localization
  82. IceCube alert 139977_2910365 retraction
  83. GRB 240916A: radio detection with the VLA
  84. GRB 241009A: LCO optical upper limits
  85. GRB 241013B: Fermi GBM Final Real-time Localization
  86. GRB 241013A: Fermi GBM Final Real-time Localization
  87. GRB 241011A: Fermi GBM Final Real-time Localization
  88. GRB 241009A: GRANDMA optical upper limits
  89. GRB 241009A: Swift-XRT afterglow detection
  90. GRB 241010A: JinShan optical observations and potential host galaxy
  91. GRB 241006A: ATCA Radio Upper Limits
  92. GRB 241010A: Swift-XRT refined Analysis
  93. GRB 241010A: J-band observations with WINTER
  94. GRB 241010B: Fermi GBM Final Real-time Localization
  95. GRB 241010A: Enhanced Swift-XRT position
  96. GRB 241010A: LCO optical observations
  97. GRB 241010A: Swift detection of a burst with an optical counterpart
  98. GRB 241009A: Swift ToO observations
  99. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  100. GRB 241008A: Fermi-LAT detection

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