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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"

21140 results found.

  1. Fermi GRB 210411B: Global MASTER-Net observations report
  2. GRB 210406A: 10.4m GTC follow-up observation
  3. Fermi GRB 210411A: Global MASTER-Net observations report
  4. GRB 210410A: Swift/UVOT Upper Limits
  5. GRB 210406A: Swift-XRT observations
  6. GRB 210410A: RATIR Optical and NIR Observations
  7. Fermi GRB 210410A: Global MASTER-Net observations report
  8. GRB 210406A: Swift ToO observations
  9. GRB 210406A: Mondy optical upper limit
  10. Integral GRB210406.72: Global MASTER-Net observations report
  11. GRB 210402A: Swift/UVOT Upper Limits
  12. GRB 210402A: Further NOT optical observations
  13. GRB 210207B: Prompt and very late time observations with HCT.
  14. GRB 210402A: NOT optical afterglow candidate
  15. Fermi trigger No 639199407: Global MASTER-Net observations report
  16. GRB 210402A: LBT observations
  17. Swift GRB210403.35: Global MASTER-Net observations report
  18. GRB 210402A: Montarrenti Observatory upper limit
  19. GRB 210402A: NOT optical upper limits
  20. GRB 210402A: Swift detection of a burst
  21. Fermi trigger No 639093861: Global MASTER-Net observations report
  22. Swift GRB210402.92: Global MASTER-Net observations report
  23. Fermi GRB 210401A: Global MASTER-Net observations report
  24. GRB 210330A: MASTER optical observation
  25. Fermi trigger No 638414549: Global MASTER-Net observations report
  26. GRB 210321A: OSN Upper Limit
  27. GRB 210323A: MASTER optical observation
  28. Fermi GRB 210324C: Global MASTER-Net observations report
  29. Fermi GRB 210324B: Global MASTER-Net observations report
  30. GRB 210323A: Gemini-North Optical Source Detection
  31. Short GRB 210323A: GTC Observations
  32. GRB 210312B: OSN Afterglow Observations
  33. GRB 210323B: Swift ToO observations
  34. GRB 210323A: Swift/UVOT Upper Limits
  35. GRB 210323A: Mondy optical observations, counterpart detection
  36. GRB 210318A: Swift/UVOT Upper Limits
  37. GRB 210323A: NOT optical afterglow candidate
  38. Swift GRB 210323A: Global MASTER-Net observations report
  39. GRB 210323B: Swift/BAT-GUANO detection and possible arcminute localization
  40. GRB 210323A: Nanshan/NEXT optical upper limit
  41. GRB 210321A: Swift/UVOT Detection
  42. GRB 210318B: Swift/UVOT Upper Limits
  43. IceCube Alert 210322.11: Global MASTER-Net observations report
  44. IceCube 135113_19489408.amon: Swift-XRT observations
  45. GRB 210321A: Mondy optical observations
  46. GRB 210321A: NOT optical afterglow detection and redshift limit
  47. GRB 210321A: MASTER optical observation
  48. MAXI GRB210320.89: Global MASTER-Net observations report
  49. GRB 210321A: DDOTI Afterglow Confirmation
  50. GRB 210321A: Swift/UVOT Detection
  51. GRB 210321A: Swift-XRT observations
  52. GRB 201216C: VIRT optical observations
  53. Swift GRB210318.13: Global MASTER-Net observations report
  54. Fermi trigger No 637729731: Global MASTER-Net observations report
  55. Swift GRB 210318A: Global MASTER-Net observations report
  56. Fermi GRB 210317A: Global MASTER-Net observations report
  57. Fermi trigger No 637521056: Global MASTER-Net observations report
  58. GRB 210312B: Redshift from OSIRIS/GTC
  59. GRB 210306A: HCT optical upper limit
  60. GRB 210312B: MASTER OT confirmation
  61. Integral GRB210312.87: Global MASTER-Net observations report
  62. Fermi GRB 210312A: Global MASTER-Net observations report
  63. GRB 210306A: LBT observations
  64. GRB 210306A: Tautenburg observations
  65. GRB 171205A: Continued ATCA observations
  66. Fermi trigger No 637027080: Global MASTER-Net observations report
  67. GRB 210306A: Early Spectroscopy of the Optical Afterglow
  68. GRB 210306A: Swift/UVOT Detection
  69. GRB 210306A: continued Mondy optical observations
  70. GRB 210308A: Mondy and AbAO optical observations
  71. Fermi trigger No 636926765: Global MASTER-Net observations report
  72. GRB 210308A: Swift/UVOT Detection
  73. GRB 210307A: Swift/UVOT Upper Limits
  74. Swift GRB 210308A: Global MASTER-Net observations report
  75. GRB 210308A: Nanshan/NEXT optical upper limits
  76. GRB 210306A: continued Mondy optical observations
  77. GRB 210306A: 1.3m DFOT observations
  78. GRB 210306A: Mondy optical observations
  79. GRB 210305A: Swift/UVOT Upper Limits
  80. Swift GRB210307.36: Global MASTER-Net observations report
  81. GRB 210306A: NEXT optical observations
  82. Swift GRB 210306A: Global MASTER-Net observations report
  83. GRB 210306A: Tautenburg observations
  84. GRB 210306A: iTelescope T24 optical observations
  85. GRB 210306A: iTelescope optical afterglow observations
  86. GRB 210306A: DDOTI Afterglow Confirmation
  87. Swift GRB 210305A: Global MASTER-Net observations report
  88. Fermi trigger No 636459103: Global MASTER-Net observations report
  89. GRB 210217A: 3.6m DOT optical observations
  90. GRB 210226A: Swift/UVOT Upper Limits
  91. Fermi trigger No 636187116: Global MASTER-Net observations report
  92. Fermi trigger No 636168178: Global MASTER-Net observations report
  93. Integral GRB210227.20: Global MASTER-Net observations report
  94. Integral GRB210227.20: Global MASTER-Net observations report
  95. Integral GRB210227.19: Global MASTER-Net observations report
  96. GRB 210217A: Mondy optical observations
  97. GRB 210226A: KAIT Optical Upper Limit
  98. Swift GRB 210226A: Global MASTER-Net observations report
  99. GRB 210218A: Swift-XRT confirmation of afterglow
  100. GRB 210222B: 1.3m DFOT Optical upper limit

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