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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"

19662 results found.

  1. GRB 210731A: MeerLICHT optical afterglow detection
  2. GRB210731A: Enhanced Swift-XRT position
  3. GRB 210731A: Swift detection of a burst
  4. Swift GRB210731.93: Global MASTER-Net observations report
  5. Trigger 1062273: Swift detection of 4U 1700-377
  6. GRB 210730A: BOOTES-5/JGT and 2.2m CAHA telescopes optical limit
  7. Swift GRB 210730A: Global MASTER-Net observations report
  8. GRB 210726A: Chandra detection of the X-ray afterglow
  9. GRB 210730A: Fermi GBM observation
  10. GRB 210730A: AstroSat CZTI detection
  11. GRB 210730A: Swift-BAT refined analysis
  12. GRB 210730A: Swift-XRT refined Analysis
  13. GRB 210730A: Swift/UVOT Upper Limits
  14. GRB 210730A: Enhanced Swift-XRT position
  15. GRB 210730A: Swift detection of a burst near M82
  16. GRB 210724A: Corrected Swift-XRT enhanced position
  17. Fermi GBM Sub-Threshold Detection of GRB 210725B
  18. IPN triangulation of GRB 210727A (short)
  19. Fermi GBM Sub-Threshold Detection of GRB 210726A
  20. GRB 210726A: Swift-XRT refined Analysis
  21. GRB 210726A: Swift-BAT refined analysis
  22. GRB 210726A: Likely a short burst
  23. GRB 210726A: RATIR Optical Upper Limits and Candidate Host Galaxy
  24. GRB 210724A: Swift/UVOT Upper Limits
  25. GRB 210723A: Swift/UVOT Upper Limits
  26. GRB 210725A: Swift/UVOT Upper Limits
  27. GRB 210725B: Swift/UVOT Upper Limits
  28. GRB 210726A: CAHA 2.2m telescope optical limit
  29. GRB 210726A: Enhanced Swift-XRT position
  30. GRB 210726A: Swift detection of a burst
  31. Swift GRB210726.80: Global MASTER-Net observations report
  32. GRB 210725B: Swift-XRT refined Analysis
  33. GRB 210725A: Fermi GBM detection
  34. GRB 210725A: Swift-XRT refined Analysis
  35. GRB 210725B: Swift-BAT refined analysis
  36. GRB 210724A: Swift-XRT refined Analysis
  37. GRB 210725A: Swift-BAT refined analysis
  38. GRB 210724A: Swift-BAT refined analysis
  39. Swift GRB 210725B: Global MASTER-Net observations report
  40. GRB 210725B: Enhanced Swift-XRT position
  41. GRB 210725A: MITSuME Akeno optical upper limits
  42. GRB 210725B: Swift detection of a burst
  43. GRB 210725A: CALET Gamma-Ray Burst Monitor detection
  44. GRB 210723A: CALET Gamma-Ray Burst Monitor detection
  45. GRB 210725A: KAIT Optical Upper Limit
  46. GRB 210725A: Swift detection of a burst
  47. Swift GRB210725.16: Global MASTER-Net observations report
  48. GRB 210723A: Fermi GBM Observation
  49. GRB210724A: MeerLICHT upper limits
  50. GRB 210724A: Swift detection of a burst
  51. Swift GRB210724.84: Global MASTER-Net observations report
  52. GRB 210723A: Swift-BAT refined analysis
  53. GRB 210723A: Swift-XRT refined Analysis
  54. Swift GRB 210723A: Global MASTER-Net observations report
  55. GRB 210722A: Fermi GBM observation
  56. GRB 210722A: Swift-BAT refined analysis
  57. GRB 210723A: Prompt enhanced Swift-XRT position
  58. GRB 210723A: Swift detection of a burst
  59. GRB 210722A: Swift-XRT refined Analysis
  60. GRB 210722A: Swift/UVOT Detection
  61. GRB 210722A: GIT optical detection and preliminary analysis
  62. Swift GRB 210722A: Global MASTER-Net observations report
  63. GRB 210722A: Nanshan/NEXT optical afterglow observations
  64. GRB 210722A: Swift detection of a burst with a bright optical counterpart
  65. GRB 210712A: Swift-BAT refined analysis
  66. GRB 210712A: Swift-XRT refined Analysis
  67. GRB 210712A: Swift/UVOT Upper Limits
  68. GRB 210712A: BOOTES-3/YA optical upper limit
  69. GRB 210712A: Enhanced Swift-XRT position
  70. GRB 210712A: Swift detection of a burst
  71. GRB210704A: Gemini near-infrared upper limits
  72. GRB 210706A: Swift/XRT afterglow confirmation
  73. GRB 210708B: Swift-BAT refined analysis
  74. Swift GRB 210708B: Global MASTER-Net observations report
  75. GRB 210708A: Swift/UVOT Upper Limits
  76. GRB 210708A: Swift-BAT refined analysis
  77. Fermi GBM Sub-Threshold Detection of GRB 210708A
  78. GRB 210708B: Swift detection of a possible burst
  79. GRB 210708A: Swift-XRT refined Analysis
  80. GRB 210708A: Swift detection of a burst
  81. Swift GRB210708.10: Global MASTER-Net observations report
  82. GRB 210704A: CAHA 2.2m telescope optical limit
  83. Fermi GBM Observations of SGR J1935+2154
  84. Swift-BAT detection of a burst from SGR 1935+2154
  85. GRB 210706A: Fermi GBM observation
  86. GRB 210706A: optical upper limit of Sintesz-Newton/CrAO and AS-32/AbAO
  87. Konus-Wind detection of GRB 210706A
  88. GRB 210706A: GIT optical upper limits
  89. GRB 210704A: OAJ T80 multi-color detections
  90. GRB 210706A: Swift-XRT afterglow detection
  91. GRB 210706A: Swift ToO observations
  92. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  93. GRB 210704A: OSIRIS/GTC spectroscopy
  94. GRB 210704A: CAHA 2.2m Afterglow Detection
  95. GRB 210704A: Swift/UVOT Upper Limits
  96. GRB 210704A: Assy optical afterglow candidate
  97. GRB 210704A: possible local hosts
  98. GRB 210704A: Fermi GBM detection
  99. GRB 210704A: Swift-XRT afterglow detection
  100. GRB 210704A: Swift ToO observations

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