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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"

27402 results found.

  1. GRB 210409A: GECAM detection
  2. GRB 210410A: Fermi-LAT detection
  3. Swift Triggers 1042031 and 1042032 are not astrophysical events
  4. GRB 210406A: Mondy optical afterglow candidate
  5. GRB 210406B: Fermi GBM detection
  6. Konus-Wind detection of GRB 210406A
  7. GRB 210406A: Fermi GBM detection
  8. GRB 210406A: Mondy optical upper limit
  9. GRB 210406A: Konkoly Obs. optical upper limit
  10. GRB 210406A: A long GRB detected by INTEGRAL
  11. GRB 210402A: MASTER prompt and follow up optical observation
  12. GRB 210402A: Swift/UVOT Upper Limits
  13. GRB 210402A: Fermi GBM detection
  14. GRB 210402A: Further NOT optical observations
  15. GRB 210402A: Swift-BAT refined analysis
  16. GRB 210404.141: DDOTI Upper Limits
  17. GRB 210207B: Prompt and very late time observations with HCT.
  18. GRB 210401A: GECAM detection
  19. GRB 210402A: NOT optical afterglow candidate
  20. GRB 210403A: Swift-BAT refined analysis
  21. GRB 210402A: LBT observations
  22. GRB 210402A: DDOTI Upper Limits
  23. GRB 210402A: Swift-XRT refined Analysis
  24. GRB 210402A: Montarrenti Observatory upper limit
  25. GRB 210402A: NOT optical upper limits
  26. GRB 210402A: Swift detection of a burst
  27. GRB 210401A: Fermi GBM Final Real-time Localization
  28. GRB 210328A: GECAM detection
  29. GRB 210330A: GECAM detection
  30. GRB 210328A: BALROG localization (Fermi Trigger / GRB 210328865)
  31. GRB 210326A: Insight-HXMT/HE detection
  32. GRB 210323A: Insight-HXMT/HE detection
  33. GRB 210323A: MASTER optical observation
  34. GRB 210323A: Swift-BAT refined analysis
  35. GRB 210324C: BALROG localization (Fermi Trigger 638308803 / GRB 210324833)
  36. Short GRB 210323A: GTC Observations
  37. GRB 210323A: Swift/UVOT Upper Limits
  38. GRB 210323A: Classification and redshift estimation
  39. GRB 210323A: Kitab optical upper limit
  40. GRB 210323A: Fermi GBM detection
  41. GRB 210323A: Mondy optical observations, counterpart detection
  42. GRB 210318A: Swift/UVOT Upper Limits
  43. GRB 210323A: Swift-XRT refined Analysis
  44. GRB 210323A: Enhanced Swift-XRT position
  45. GRB 210323A: NOT optical afterglow candidate
  46. GRB 210323B: Swift/BAT-GUANO detection and possible arcminute localization
  47. GRB 210323A: Nanshan/NEXT optical upper limit
  48. GRB 210323A: Swift detection of a short burst
  49. GRB 210321A: Swift/UVOT Detection
  50. Konus-Wind detection of GRB 210321A
  51. GRB 210318B: Swift/UVOT Upper Limits
  52. GRB 210321A: CrAO optical upper limit
  53. GRB 210321A: Swift-BAT refined analysis
  54. IceCube 135113_19489408.amon: Swift-XRT observations
  55. GRB 210321A: Mondy optical observations
  56. GRB 210321A: Swift-XRT refined Analysis
  57. GRB 210321A: Redshift from OSIRIS/GTC
  58. GRB 210321A: NOT optical afterglow detection and redshift limit
  59. MAXI GRB210320.89: Global MASTER-Net observations report
  60. GRB 210321A: Enhanced Swift-XRT position
  61. GRB 210321A: DDOTI Afterglow Confirmation
  62. GRB 210321A: Swift/UVOT Detection
  63. GRB 210321A: Swift-XRT observations
  64. GRB 210321A: Swift detection of a burst
  65. GRB 210318B: MITSuME Okayama optical upper limits
  66. GRB 201216C: VIRT optical observations
  67. GRB 200524A: Redshift from Gemini-North
  68. GRB 210318A: Swift-BAT refined analysis
  69. GRB 210318A: Swift-XRT refined Analysis
  70. GRB 210318A: Enhanced Swift-XRT position
  71. GRB 210318B: Fermi GBM detection
  72. GRB 210318B: Swift-BAT refined analysis
  73. GRB210318B: Swift detection of a burst
  74. GRB 210318A: Swift detection of a burst
  75. GRB 210317A: GECAM detection
  76. GRB 210306A: GIT optical follow-up
  77. GRB 210226A: GIT optical upper limit
  78. GRB 210312B: A long GRB detected by INTEGRAL
  79. GRB 210306A: LBT observations
  80. GRB 210306A: Tautenburg observations
  81. Konus-Wind detection of GRB 210308A
  82. Konus-Wind detection of GRB 210306A
  83. Konus-Wind detection of GRB 210305A
  84. GRB 210306B: Fermi GBM detection
  85. GRB 210306A: Swift/UVOT Detection
  86. GRB 210306A: continued Mondy optical observations
  87. GRB 210308A: Mondy and AbAO optical observations
  88. GRB 210308A: Swift-BAT refined analysis
  89. GRB 210307A: Swift-BAT refined analysis
  90. GRB 210308A: Swift/UVOT Detection
  91. GRB 210307A: Swift/UVOT Upper Limits
  92. GRB 210305A: Fermi GBM observation
  93. GRB 210308A: Fermi GBM detection
  94. GRB 210305A: Swift-XRT refined Analysis
  95. GRB 210307A: Swift-XRT refined Analysis
  96. GRB 210308A: Nanshan/NEXT optical upper limits
  97. GRB 210306A: Swift-XRT refined Analysis
  98. GRB 210308A: MITSuME Okayama optical upper limits
  99. GRB 210306A: continued Mondy optical observations
  100. GRB 210308A: Swift detection of a burst with an optical counterpart

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