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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"

21525 results found.

  1. GRB 210807C: Fermi GBM detection
  2. GRB 210807C: Swift/UVOT Upper Limits
  3. GRB 210807A: Swift/UVOT Detection
  4. GRB 210807A: Swift-XRT refined Analysis
  5. GRB 210807C: Enhanced Swift-XRT position
  6. Swift GRB210807.74: Global MASTER-Net observations report
  7. Swift GRB210807.96: Global MASTER-Net observations report
  8. GRB 210807C: Swift detection of a burst
  9. Swift GRB 210807A: Global MASTER-Net observations report
  10. Swift GRB210807.79: Global MASTER-Net observations report
  11. Swift GRB210807.78: Global MASTER-Net observations report
  12. GRB 210807A: Enhanced Swift-XRT position
  13. GRB 210807A: BOOTES-5/JGT optical afterglow detection
  14. GRB 210807A: Swift detection of a burst with an optical counterpart
  15. IPN Triangulation of a bright burst from SGR 1935+2154
  16. GRB 210802A: MITSuME Okayama optical upper limits
  17. GRB 210802A: BOOTES-2/TELMA optical upper limit
  18. GRB 210802A: Swift-XRT afterglow detection
  19. GRB 210802A: Fermi-LAT detection
  20. GRB 210802A: Tiled Swift observations
  21. GRB 210731A: continued GROND observations
  22. GRB 210731A: KAIT Optical Detection
  23. GRB 210731A: Swift-BAT refined analysis
  24. GRB 210731A: MASTER optical afterglow detection
  25. GRB 210731A: Swift-XRT refined Analysis
  26. GRB 210731A: GROND observations
  27. GRB 210731A: Fermi GBM Observation
  28. GRB 210731A: Swift/UVOT Detection of an optical afterglow
  29. Swift GRB210731.62: Global MASTER-Net observations report
  30. GRB 210731A: MeerLICHT optical afterglow detection
  31. GRB210731A: Enhanced Swift-XRT position
  32. GRB 210731A: Swift detection of a burst
  33. Swift GRB210731.93: Global MASTER-Net observations report
  34. Trigger 1062273: Swift detection of 4U 1700-377
  35. GRB 210730A: Campo Imperatore optical observations
  36. GRB 210730A: BOOTES-5/JGT and 2.2m CAHA telescopes optical limit
  37. Swift GRB 210730A: Global MASTER-Net observations report
  38. GRB 210730A: TNG optical observations
  39. GRB 210726A: Chandra detection of the X-ray afterglow
  40. GRB 210730A: Fermi GBM observation
  41. GRB 210730A: AstroSat CZTI detection
  42. GRB 210730A: Swift-BAT refined analysis
  43. GRB 210730A: Swift-XRT refined Analysis
  44. GRB 210730A: Swift/UVOT Upper Limits
  45. GRB 210724A: Early CAHA 2.2m limit
  46. GRB 210730A: Enhanced Swift-XRT position
  47. GRB 210730A: Swift detection of a burst near M82
  48. GRB 210724A: Corrected Swift-XRT enhanced position
  49. Fermi GBM Sub-Threshold Detection of GRB 210725B
  50. GRB 210726A: OSIRIS/GTC observations
  51. GRB 210726A: Deep CAHA 2.2m limit
  52. GRB 210726A: 6 GHz VLA radio upper limit
  53. IPN triangulation of GRB 210727A (short)
  54. Fermi GBM Sub-Threshold Detection of GRB 210726A
  55. GRB 210726A: Swift-XRT refined Analysis
  56. GRB 210726A: Swift-BAT refined analysis
  57. GRB 210726A: Likely a short burst
  58. GRB 210726A: RATIR Optical Upper Limits and Candidate Host Galaxy
  59. GRB 210725A: AbAO optical upper limit
  60. GRB 210724A: Swift/UVOT Upper Limits
  61. GRB 210723A: Swift/UVOT Upper Limits
  62. GRB 210725A: Swift/UVOT Upper Limits
  63. GRB 210725B: Swift/UVOT Upper Limits
  64. GRB 210726A: CAHA 2.2m telescope optical limit
  65. GRB 210726A: Enhanced Swift-XRT position
  66. GRB 210726A: Swift detection of a burst
  67. Swift GRB210726.80: Global MASTER-Net observations report
  68. GRB 210725B: Swift-XRT refined Analysis
  69. GRB 210725A: Fermi GBM detection
  70. GRB 210724A: Zeiss-1000 of Koshka observatory, optical upper limit
  71. GRB 210725A: Swift-XRT refined Analysis
  72. GRB 210725B: Swift-BAT refined analysis
  73. GRB 210724A: Swift-XRT refined Analysis
  74. GRB 210725A: Swift-BAT refined analysis
  75. GRB 210724A: Swift-BAT refined analysis
  76. Swift GRB 210725B: Global MASTER-Net observations report
  77. GRB 210724A: Afterglow candidate from OSIRIS/GTC
  78. GRB 210725B: Enhanced Swift-XRT position
  79. GRB 210725A: MITSuME Akeno optical upper limits
  80. GRB 210725B: Swift detection of a burst
  81. GRB 210725A: CALET Gamma-Ray Burst Monitor detection
  82. GRB 210723A: CALET Gamma-Ray Burst Monitor detection
  83. GRB 210725A: KAIT Optical Upper Limit
  84. GRB 210725A: Swift detection of a burst
  85. Swift GRB210725.16: Global MASTER-Net observations report
  86. GRB 210723A: Fermi GBM Observation
  87. GRB210724A: MeerLICHT upper limits
  88. GRB 210724A: Swift detection of a burst
  89. Swift GRB210724.84: Global MASTER-Net observations report
  90. GRB 210723A: Swift-BAT refined analysis
  91. GRB 210723A: Swift-XRT refined Analysis
  92. Swift GRB 210723A: Global MASTER-Net observations report
  93. GRB 210722A: Fermi GBM observation
  94. GRB 210722A: Swift-BAT refined analysis
  95. GRB 210723A: Prompt enhanced Swift-XRT position
  96. GRB 210723A: Swift detection of a burst
  97. GRB 210722A: Swift-XRT refined Analysis
  98. GRB 210722A: Swift/UVOT Detection
  99. GRB 210722A: GIT optical detection and preliminary analysis
  100. Swift GRB 210722A: Global MASTER-Net observations report

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Download all Circulars as a .tar.gz archive (updated once a day):
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