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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"

35949 results found.

  1. GRB 221009A: Fermi GBM detection of an extraordinarily bright GRB
  2. GRB 221009A: Swift detected transient may be GRB
  3. GRB 221008A: Swift-XRT observations
  4. GRB 221008A: Tiled Swift observations
  5. GRB 221008A: MAXI/GSC detection
  6. GRB 220915A: Detection by GRBAlpha
  7. GRB 221006A: Swift-XRT observations
  8. GRB 221006A: Tiled Swift observations
  9. GRB 221006A: MAXI/GSC detection
  10. GRB 220930A: MITSuME Akeno optical upper limits
  11. GRB 220912A: Detection by VZLUSAT-2
  12. GRB220927A: Detection by GRBAlpha
  13. Fermi GBM trigger 686565116/221004355 is not a GRB
  14. Fermi GBM trigger 686435254/221002852 is not a GRB
  15. Fermi GBM trigger 686350260/221001869 is not a GRB
  16. GRB 220921A: ATCA detection of radio counterpart
  17. GRB 220930A: AbAO Optical Upper Limit
  18. Konus-Wind detection of GRB 220930A
  19. GRB 220930A: AstroSat CZTI detection
  20. GRB 220930A: Swift-BAT refined analysis
  21. GRB 220930A: Swift-XRT refined Analysis
  22. GRB 220930A: LCOGT Optical Upper Limits
  23. GRB 220930A: Swift/UVOT Upper Limits
  24. GRB 220930A: Enhanced Swift-XRT position
  25. Swift GRB 220930A: Global MASTER-Net observations report
  26. GRB 220930A: BOOTES-5/JGT early optical upper limit
  27. GRB 220930A: Prompt enhanced Swift-XRT position
  28. GRB 220930A: COATLI Upper Limits
  29. GRB 220930A: Swift detection of a burst
  30. Konus-Wind detection of GRB 220927A
  31. Fermi GRB 220927A: Global MASTER-Net observations report
  32. IPN triangulation of GRB 220927A (long)
  33. GRB 220921A: LCOGT Optical Observations
  34. GRB 220611A: Host galaxy redshift from VLT/X-shooter
  35. GRB 220927A: Fermi GBM Final Localization
  36. GRB 220924A: Fermi GBM detection
  37. Ultra-long GRB 220525B: Konus-Wind and Fermi-GBM detection
  38. Swift Trigger 1125354 (GRB 220926A) is not a GRB
  39. Swift GRB 220926A: Global MASTER-Net observations report
  40. Analysis of long GRB 220926B detected by INTEGRAL
  41. GRB 220926B
  42. GRB 220926A: Swift detection of a burst
  43. Fermi GRB 220925A: Global MASTER-Net observations report
  44. GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
  45. GRB 220921A: further MeerLICHT observations
  46. GRB 220925A: Fermi GBM Final Real-time Localization
  47. GRB 220924A: Fermi GBM Final Real-time Localization
  48. GRB 220921A: ALMA detection
  49. GRB 220921A: DDOTI Detection of the Afterglow
  50. Konus-Wind detection of GRB 220921A
  51. GRB 220921A: Fermi GBM detection
  52. GRB 220921A: MeerLICHT afterglow observations
  53. GRB 220921A: Swift-XRT Observations
  54. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  55. GRB 220921A: Fermi-LAT detection
  56. GRB 220921A: Tiled Swift observations
  57. Improved IPN error box for GRB 220910A
  58. GRB 220909A: Fermi GBM observation
  59. Konus-Wind detection of GRB 220910A
  60. GRB 220910B: Fermi GBM Final Localization
  61. Fermi GRB 220912A: Global MASTER-Net observations report
  62. GRB 220910A: Fermi GBM observation
  63. IPN triangulation of GRB 220910A (bright/long)
  64. GRB 220912A: AstroSat CZTI detection
  65. GRB 220831A: DECam optical counterpart follow-up
  66. GRB 220909A: Swift-XRT observations
  67. GRB 220912A: Fermi GBM Final Real-time Localization
  68. IPN triangulation of GRB 220905A
  69. GRB 220909A: Swift ToO observations
  70. GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
  71. GRB 220831A: Gemini-South Infrared Observations
  72. GRB 220910A: AstroSat CZTI detection
  73. GRB 220910A: AGILE detection
  74. GRB 220909A: Fermi GBM Final Real-time Localization
  75. GRB 220907A: Swift-BAT refined analysis
  76. GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
  77. IPN triangulation of GRB 220903A (long)
  78. GRB 220907A: Fermi GBM observation
  79. GRB 220907A: Nanshan/NEXT optical upper limits
  80. GRB 220907A: Swift/UVOT Upper Limits
  81. GRB 220907A: Swift-XRT refined Analysis
  82. GRB 220831A: ATCA 5/9 GHz radio observations
  83. GRB 220907A: Swift-XRT position
  84. GRB 220907A: Swift detection of a burst
  85. GRB 220907A: Fermi GBM Final Real-time Localization
  86. GRB 220831A: Swift-UVOT Upper Limits
  87. Fermi GRB 220905A: Global MASTER-Net observations report
  88. GRB 220905A: BALROG localization (Fermi Trigger 684070128 / GRB 220905478)
  89. GRB 220905A: Fermi GBM Final Real-time Localization
  90. GRB 220831A: DECam detection of a possible optical counterpart
  91. Fermi GRB 220902A: Global MASTER-Net observations report
  92. GRB 220902A: Fermi GBM Final Real-time Localization
  93. GRB 220831A, VLT/HAWK-I near-infrared observations
  94. GRB 220831C: Fermi GBM Final Localization
  95. GRB 220831A: Fermi GBM observation
  96. GRB 220831A: Swift-XRT observations
  97. GRB 220831B: Fermi GBM Final Localization
  98. GRB 220831A: Swift ToO observations
  99. GRB 220831A: Swift/BAT-GUANO localization of a short burst
  100. Fermi GBM trigger 683571622/220830709 is not a GRB

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