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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"

35950 results found.

  1. GRB 220710A: Swift ToO observations
  2. GRB 220710A: Swift/BAT-GUANO arcminute localization
  3. GRB 220711B: Swift-BAT refined analysis
  4. IPN triangulation of GRB 220711C (short)
  5. GRB 220711B: Swift-XRT refined Analysis
  6. GRB 220711B: Swift/UVOT Upper Limits
  7. GRB 220711B: Enhanced Swift-XRT position
  8. GRB 220711B: Fermi GBM Detection
  9. GRB 220711B: NOT optical observations
  10. GRB 220711B: LCO Optical Upper Limits
  11. GRB 220711B: Swift detection of a burst
  12. GRB 220711B: Fermi GBM Final Real-time Localization
  13. GRB 220707A: AstroSat CZTI detection
  14. GRB 220708B: GIT optical upper limits
  15. GRB 220711A: Fermi GBM Final Real-time Localization
  16. GRB 220708A: Swift-BAT refined analysis
  17. GRB 220708B: T193-OHP optical upper limit
  18. Konus-Wind detection of GRB 220708B (Correction to GCN 32358)
  19. Konus-Wind detection of GRB 220708B
  20. GRB 220708B: CALET Gamma-Ray Burst Monitor detection
  21. GRB 220708B: Nanshan/NEXT optical upper limits
  22. GRB 220708A: Swift/UVOT Upper Limits
  23. GRB 220706A : NICER detection of re-brightening 1 day after the Swift trigger
  24. GRB 220708A: Swift-XRT refined Analysis
  25. GRB 220706A: Swift/UVOT Upper Limits
  26. GRB 220708B: Swift-XRT afterglow detection
  27. GRB 220708A: BOOTES-5/JGT early optical upper limit
  28. GRB 220706A: Swift-BAT refined analysis
  29. GRB 220708A: Enhanced Swift-XRT position
  30. GRB 220708B: Swift ToO observations
  31. GRB 220708B: Swift/BAT-GUANO arcminute localization
  32. GRB 220708A: Swift-XRT observations
  33. GRB 220708A: Swift detection of a burst
  34. GRB 220706A: LCO Optical Upper Limits
  35. GRB 220627A: ATCA detection of radio counterpart
  36. GRB 220706A: Swift-XRT refined Analysis
  37. GRB 220706A, GROND observations
  38. GRB 220706A: Optical observations from NOT
  39. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  40. GRB 220702B: AstroSat CZTI detection
  41. GRB 220706A: Nanshan/NEXT optical upper limits
  42. GRB 220706A: Enhanced Swift-XRT position
  43. Swift GRB 220706A: Global MASTER-Net observations report
  44. GRB 220706A: Zadko observatory - Gingin optical observations
  45. GRB 220706A: Prompt enhanced Swift-XRT position
  46. GRB 220706A: Swift detection of a burst
  47. GRB 220701A: Swift-BAT refined analysis
  48. GRB 220702B: Fermi GBM Final Localization
  49. GRB 220702A: Fermi GBM Final Localization
  50. GRB 220705A: Fermi GBM Final Localization
  51. GRB 220701A: MITSuME Akeno optical upper limits
  52. GRB 220701A: COATLI Optical Upper Limit
  53. GRB 220701A: AbAO optical upper limit
  54. GRB 220627A: AstroSat CZTI detection
  55. GRB 220701A: Keck/LRIS Optical Upper Limit
  56. GRB 220701A: Swift-XRT refined Analysis
  57. GRB 220701A: LCO Optical Upper Limits
  58. GRB 220701A: BOOTES-5/JGT early optical upper limit
  59. GRB 220701A: Swift/UVOT Upper Limits
  60. GRB 220701A: Lowell Discovery Telescope Optical Observations
  61. GRB 220701A: Enhanced Swift-XRT position
  62. GRB 200701A: KAIT Optical Upper Limit
  63. GRB 220701A: Swift detection of a burst
  64. GRB 220627A, GROND observations
  65. GRB 220624A: AGILE/GRID refined analysis
  66. GRB 220627A: Swift/UVOT Upper Limits
  67. GRB 220627A: Swift-XRT afterglow detection
  68. Konus-Wind detection of GRB 220627A
  69. GRB 220627A: VLT MUSE redshift
  70. GRB 220627A: MeerLICHT candidate optical afterglow
  71. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  72. GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
  73. Konus-Wind detection of GRB 220624A
  74. GRB 220627A: Swift ToO observations
  75. GRB 220627A: Fermi-LAT detection
  76. GRB 220627A: MeerLICHT detection of two afterglow candidates
  77. Fermi GRB 220627A: Global MASTER-Net observations report
  78. GRB 220627A: Fermi GBM Final Real-time Localization
  79. GRB 220623A: GIT optical upper limits.
  80. GRB 220624A: CALET Gamma-Ray Burst Monitor detection
  81. GRB 220623A: T193-OHP optical upper limit
  82. GRB 220624A: Fermi GBM Detection
  83. Fermi GRB 220623B: Global MASTER-Net observations report
  84. Fermi GRB 220624A: Global MASTER-Net observations report
  85. IPN triangulation of GRB 220624A
  86. GRB 220623A: Swift-BAT refined analysis
  87. GRB 220624A: Swift/BAT-GUANO detection outside the coded FOV
  88. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  89. GRB 220624A: AGILE/GRID analysis
  90. GRB 220624A: AGILE detection
  91. Konus-Wind detection of GRB 220623A
  92. GRB 220624B: Fermi GBM Final Real-time Localization
  93. GRB 220624A: Fermi GBM Final Real-time Localization
  94. GRB 220623A: AbAO optical upper limit
  95. GRB 220623A: Swift-XRT refined Analysis
  96. GRB 220623A: NOT optical observations
  97. GRB 220623A: Swift/UVOT Upper Limits
  98. GRB 220623A: BOOTES-5/JGT optical afterglow detection
  99. Konus-Wind detection of GRB 220609B
  100. GRB 220623B: Fermi GBM Final Real-time Localization

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