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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"

19694 results found.

  1. GRB 210419A: Swift/UVOT Upper Limits
  2. GRB 210419C: Enhanced Swift-XRT position
  3. GRB 210419C: Swift detection of a burst
  4. GRB 210419A: Enhanced Swift-XRT position
  5. GRB 210419A: Swift detection of a burst
  6. GRB 210413B: LOAO optical upper limit
  7. GRB 210413B: Swift ToO observations
  8. GRB 210413A: GECAM detection
  9. GRB 210411C: Swift/UVOT Detection
  10. GRB 210410A: MITSuME Akeno optical upper limits
  11. GRB 210411C: Enhanced Swift-XRT position
  12. GRB 210406A: 10.4m GTC follow-up observation
  13. GRB 210411C: Swift detection of a burst with an optical counterpart
  14. GRB 210410A: Swift-XRT refined Analysis
  15. GRB 210410A: Swift/UVOT Upper Limits
  16. GRB 210410A: RATIR Optical and NIR Observations
  17. GRB 210409A: GECAM detection
  18. GRB 210406A: Mondy optical afterglow candidate
  19. GRB 210406A: Swift ToO observations
  20. GRB 210406A: Mondy optical upper limit
  21. GRB 210406A: Konkoly Obs. optical upper limit
  22. GRB 210402A: MASTER prompt and follow up optical observation
  23. GRB 210402A: Swift/UVOT Upper Limits
  24. GRB 210402A: Further NOT optical observations
  25. GRB 210404.141: DDOTI Upper Limits
  26. GRB 210207B: Prompt and very late time observations with HCT.
  27. GRB 210402A: NOT optical afterglow candidate
  28. GRB 210402A: LBT observations
  29. GRB 210402A: DDOTI Upper Limits
  30. GRB 210402A: Swift-XRT refined Analysis
  31. GRB 210402A: Montarrenti Observatory upper limit
  32. GRB 210402A: NOT optical upper limits
  33. GRB 210323A: MASTER optical observation
  34. Short GRB 210323A: GTC Observations
  35. GRB 210323B: Swift ToO observations
  36. GRB 210323A: Swift/UVOT Upper Limits
  37. GRB 210323A: Kitab optical upper limit
  38. GRB 210323A: Mondy optical observations, counterpart detection
  39. GRB 210318A: Swift/UVOT Upper Limits
  40. GRB 210323A: Enhanced Swift-XRT position
  41. GRB 210323A: NOT optical afterglow candidate
  42. GRB 210323B: Swift/BAT-GUANO detection and possible arcminute localization
  43. GRB 210323A: Nanshan/NEXT optical upper limit
  44. GRB 210323A: Swift detection of a short burst
  45. GRB 210321A: Swift/UVOT Detection
  46. GRB 210318B: Swift/UVOT Upper Limits
  47. GRB 210321A: CrAO optical upper limit
  48. GRB 210321A: Swift-BAT refined analysis
  49. IceCube 135113_19489408.amon: Swift-XRT observations
  50. GRB 210321A: Mondy optical observations
  51. GRB 210321A: Redshift from OSIRIS/GTC
  52. GRB 210321A: NOT optical afterglow detection and redshift limit
  53. GRB 210321A: Enhanced Swift-XRT position
  54. GRB 210321A: DDOTI Afterglow Confirmation
  55. GRB 210321A: Swift/UVOT Detection
  56. GRB 210321A: Swift-XRT observations
  57. GRB 210318B: MITSuME Okayama optical upper limits
  58. GRB 201216C: VIRT optical observations
  59. GRB 210318A: Enhanced Swift-XRT position
  60. GRB 210318A: Swift detection of a burst
  61. GRB 210306A: GIT optical follow-up
  62. GRB 210226A: GIT optical upper limit
  63. INTEGRAL SPI-ACS on 2021-03-12 (04)11-08:15) are due to calibration activity
  64. GRB 210306A: LBT observations
  65. GRB 210306A: Tautenburg observations
  66. GRB 210306B: Fermi GBM detection
  67. GRB 210306A: Swift/UVOT Detection
  68. GRB 210306A: continued Mondy optical observations
  69. GRB 210308A: Mondy and AbAO optical observations
  70. GRB 210308A: Swift/UVOT Detection
  71. GRB 210307A: Swift/UVOT Upper Limits
  72. GRB 210305A: Swift-XRT refined Analysis
  73. GRB 210307A: Swift-XRT refined Analysis
  74. GRB 210308A: Nanshan/NEXT optical upper limits
  75. GRB 210306A: Swift-XRT refined Analysis
  76. GRB 210308A: MITSuME Okayama optical upper limits
  77. GRB 210306A: continued Mondy optical observations
  78. GRB 210308A: Swift detection of a burst with an optical counterpart
  79. GRB 210306A: Mondy optical observations
  80. GRB 210305A: Swift/UVOT Upper Limits
  81. GRB 210307A: Swift detection of a burst
  82. GRB 210306A: MITSuME Akeno optical observation
  83. GRB 210306A: NEXT optical observations
  84. GRB 210306A: Tautenburg observations
  85. GRB 210306A: iTelescope optical afterglow observations
  86. GRB 210306A: DDOTI Afterglow Confirmation
  87. GRB 210306A: Swift detection of a burst with a bright optical counterpart
  88. GRB 210305A: Swift detection of a burst
  89. GRB 210217A: 3.6m DOT optical observations
  90. GRB 210226A: Swift/UVOT Upper Limits
  91. GRB 210217A: Mondy optical observations
  92. GRB 210218A: Swift-XRT confirmation of afterglow
  93. GRB 210226A: Burke-Gaffney Observatory optical upper limit
  94. GRB 210226A: Enhanced Swift-XRT position
  95. GRB 210222B: 1.3m DFOT Optical upper limit
  96. GRB 210226A: Swift detection of a burst
  97. GRB 210222B: REM observations of the optical/NIR afterglow
  98. GRB 210222B: MITSuME Akeno optical upper limits
  99. GRB 210222B: Zeiss-1000 of Koshka observatory, optical observations
  100. GRB 210222B: VIRT optical detection

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