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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"

28094 results found.

  1. GRB 210406A: Konkoly Obs. optical upper limit
  2. GRB 210406A: A long GRB detected by INTEGRAL
  3. GRB 210402A: MASTER prompt and follow up optical observation
  4. GRB 210402A: Swift/UVOT Upper Limits
  5. GRB 210402A: Fermi GBM detection
  6. GRB 210402A: Further NOT optical observations
  7. GRB 210402A: Swift-BAT refined analysis
  8. GRB 210404.141: DDOTI Upper Limits
  9. GRB 210207B: Prompt and very late time observations with HCT.
  10. GRB 210401A: GECAM detection
  11. GRB 210402A: NOT optical afterglow candidate
  12. GRB 210403A: Swift-BAT refined analysis
  13. GRB 210402A: LBT observations
  14. GRB 210402A: DDOTI Upper Limits
  15. GRB 210402A: Swift-XRT refined Analysis
  16. GRB 210402A: Montarrenti Observatory upper limit
  17. GRB 210402A: NOT optical upper limits
  18. GRB 210402A: Swift detection of a burst
  19. GRB 210401A: Fermi GBM Final Real-time Localization
  20. GRB 210328A: GECAM detection
  21. GRB 210330A: GECAM detection
  22. GRB 210328A: BALROG localization (Fermi Trigger / GRB 210328865)
  23. GRB 210326A: Insight-HXMT/HE detection
  24. GRB 210323A: Insight-HXMT/HE detection
  25. GRB 210323A: MASTER optical observation
  26. GRB 210323A: Swift-BAT refined analysis
  27. GRB 210324C: BALROG localization (Fermi Trigger 638308803 / GRB 210324833)
  28. Short GRB 210323A: GTC Observations
  29. GRB 210323A: Swift/UVOT Upper Limits
  30. GRB 210323A: Classification and redshift estimation
  31. GRB 210323A: Kitab optical upper limit
  32. GRB 210323A: Fermi GBM detection
  33. GRB 210323A: Mondy optical observations, counterpart detection
  34. GRB 210318A: Swift/UVOT Upper Limits
  35. GRB 210323A: Swift-XRT refined Analysis
  36. GRB 210323A: Enhanced Swift-XRT position
  37. GRB 210323A: NOT optical afterglow candidate
  38. GRB 210323B: Swift/BAT-GUANO detection and possible arcminute localization
  39. GRB 210323A: Nanshan/NEXT optical upper limit
  40. GRB 210323A: Swift detection of a short burst
  41. GRB 210321A: Swift/UVOT Detection
  42. Konus-Wind detection of GRB 210321A
  43. GRB 210318B: Swift/UVOT Upper Limits
  44. GRB 210321A: CrAO optical upper limit
  45. GRB 210321A: Swift-BAT refined analysis
  46. IceCube 135113_19489408.amon: Swift-XRT observations
  47. GRB 210321A: Mondy optical observations
  48. GRB 210321A: Swift-XRT refined Analysis
  49. GRB 210321A: Redshift from OSIRIS/GTC
  50. GRB 210321A: NOT optical afterglow detection and redshift limit
  51. MAXI GRB210320.89: Global MASTER-Net observations report
  52. GRB 210321A: Enhanced Swift-XRT position
  53. GRB 210321A: DDOTI Afterglow Confirmation
  54. GRB 210321A: Swift/UVOT Detection
  55. GRB 210321A: Swift-XRT observations
  56. GRB 210321A: Swift detection of a burst
  57. GRB 210318B: MITSuME Okayama optical upper limits
  58. GRB 201216C: VIRT optical observations
  59. GRB 200524A: Redshift from Gemini-North
  60. GRB 210318A: Swift-BAT refined analysis
  61. GRB 210318A: Swift-XRT refined Analysis
  62. GRB 210318A: Enhanced Swift-XRT position
  63. GRB 210318B: Fermi GBM detection
  64. GRB 210318B: Swift-BAT refined analysis
  65. GRB210318B: Swift detection of a burst
  66. GRB 210318A: Swift detection of a burst
  67. GRB 210317A: GECAM detection
  68. GRB 210306A: GIT optical follow-up
  69. GRB 210226A: GIT optical upper limit
  70. GRB 210312B: A long GRB detected by INTEGRAL
  71. GRB 210306A: LBT observations
  72. GRB 210306A: Tautenburg observations
  73. Konus-Wind detection of GRB 210308A
  74. Konus-Wind detection of GRB 210306A
  75. Konus-Wind detection of GRB 210305A
  76. GRB 210306B: Fermi GBM detection
  77. GRB 210306A: Swift/UVOT Detection
  78. GRB 210306A: continued Mondy optical observations
  79. GRB 210308A: Mondy and AbAO optical observations
  80. GRB 210308A: Swift-BAT refined analysis
  81. GRB 210307A: Swift-BAT refined analysis
  82. GRB 210308A: Swift/UVOT Detection
  83. GRB 210307A: Swift/UVOT Upper Limits
  84. GRB 210305A: Fermi GBM observation
  85. GRB 210308A: Fermi GBM detection
  86. GRB 210305A: Swift-XRT refined Analysis
  87. GRB 210307A: Swift-XRT refined Analysis
  88. GRB 210308A: Nanshan/NEXT optical upper limits
  89. GRB 210306A: Swift-XRT refined Analysis
  90. GRB 210308A: MITSuME Okayama optical upper limits
  91. GRB 210306A: continued Mondy optical observations
  92. GRB 210308A: Swift detection of a burst with an optical counterpart
  93. GRB 210306A: Swift-BAT refined analysis
  94. GRB 210306A: Mondy optical observations
  95. GRB 210305A: Swift/UVOT Upper Limits
  96. GRB 210307B: GECAM detection
  97. GRB 210307A: LCO Optical Upper Limits
  98. GRB 210306B: Swift-BAT refined analysis
  99. GRB 210305A: Swift-BAT refined analysis
  100. GRB 210307A: Swift detection of a burst

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