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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"

28092 results found.

  1. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  2. GRB 210820A: Swift/UVOT Detection
  3. GRB 210822A: Nanshan/NEXT optical observations
  4. GRB 210822A: Enhanced Swift-XRT position
  5. GRB 210822A: RATIR Optical Detections
  6. GRB 210822A: Swift detection of a burst with an optical afterglow
  7. GRB 210820A: Swift-BAT refined analysis
  8. GRB 210820A: LCO Optical Upper Limit
  9. GRB 210820A: RATIR Optical Detections
  10. GRB 210820A: NOT optical upper limit
  11. GRB 210820A: Nanshan/NEXT optical upper limit
  12. GRB 210820A: Swift-XRT refined Analysis
  13. GRB 210820A: Enhanced Swift-XRT position
  14. GRB 210820A: Swift detection of a burst with an optical counterpart
  15. GRB 210818A: Swift-XRT refined Analysis
  16. GRB 210818A: Swift-BAT refined analysis
  17. Swift Trigger 1069242 is Cyg X-1
  18. GRB 210818A: AstroSat CZTI detection
  19. GRB 210818A: Enhanced Swift-XRT position
  20. GRB 210818A: Swift detection of a burst with an optical counterpart
  21. IceCube-210811A: Upper limits from a search for additional neutrino events in IceCube
  22. GRB 210815A: BALROG localization (Fermi Trigger 650687034 / GRB 210815100)
  23. GRB 210712A: Fermi GBM observation
  24. GRB 210813A: BALROG localization (Fermi Trigger 650508868 / GRB 210813038)
  25. Fermi-LAT Gamma-ray Observations of IceCube-210811A
  26. GRB 210812A: BALROG localization (Fermi Trigger 650479626 / GRB 210812699)
  27. GRB 080101A: Fermi GBM Final Real-time Localization
  28. GRB 210730A: Tautenburg observations
  29. GRB 210807A: Tautenburg observations
  30. GRB 210807C: Swift-BAT refined analysis
  31. GRB 210807A: Swift-BAT refined analysis
  32. GRB 210807C: Swift-XRT refined Analysis
  33. GRB 210807C: Fermi GBM detection
  34. GRB 210807C: Swift/UVOT Upper Limits
  35. GRB 210807A: Swift/UVOT Detection
  36. GRB 210807A: Swift-XRT refined Analysis
  37. GRB 210807C: Enhanced Swift-XRT position
  38. GRB 210610B: Assy optical observations
  39. GRB 210807C: Swift detection of a burst
  40. GRB 210807A: Enhanced Swift-XRT position
  41. GRB 210807A: Swift detection of a burst with an optical counterpart
  42. IPN Triangulation of a bright burst from SGR 1935+2154
  43. GRB 210802A: MITSuME Okayama optical upper limits
  44. GRB 210803A: Fermi GBM observation
  45. Fermi trigger No 649684549: Global MASTER-Net observations report
  46. GRB 210802A: DDOTI Upper Limits
  47. GRB 210802A: BOOTES-2/TELMA optical upper limit
  48. GRB 210802A: Swift-XRT afterglow detection
  49. GRB 210802A: Fermi GBM detection
  50. GRB 210803A: BALROG localization (Fermi Trigger 649684549 / GRB 210803497)
  51. Fermi trigger No 649627691: Global MASTER-Net observations report
  52. GRB 210801A: Fermi GBM detection
  53. GRB 210731A: VLT/X-shooter redshift
  54. IceCube-210730A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  55. GRB 210731A: Swift-BAT refined analysis
  56. GRB 210801A: BALROG localization (Fermi Trigger 649519043 / GRB 210801581)
  57. GRB 210731A: Swift-XRT refined Analysis
  58. Fermi trigger No 649519043: Global MASTER-Net observations report
  59. GRB 210731A: GROND observations
  60. GRB 210731A: Fermi GBM Observation
  61. GRB 210731A: Swift/UVOT Detection of an optical afterglow
  62. GRB 210731A: MeerLICHT optical afterglow detection
  63. GRB210731A: Enhanced Swift-XRT position
  64. GRB 210731A: Swift detection of a burst
  65. Fermi-LAT Gamma-ray Observations of IceCube-210730A
  66. GRB 210730A: Campo Imperatore optical observations
  67. GRB 210730A: BOOTES-5/JGT and 2.2m CAHA telescopes optical limit
  68. GRB 210730A: TNG optical observations
  69. GRB 210730A: Fermi GBM observation
  70. GRB 210730A: AstroSat CZTI detection
  71. GRB 210730A: Swift-BAT refined analysis
  72. GRB 210730A: Swift-XRT refined Analysis
  73. GRB 210730A: Swift/UVOT Upper Limits
  74. GRB 210730A: Enhanced Swift-XRT position
  75. GRB 210730A: Swift detection of a burst near M82
  76. Fermi GBM Sub-Threshold Detection of GRB 210725B
  77. GRB 210726A: 6 GHz VLA radio upper limit
  78. IPN triangulation of GRB 210727A (short)
  79. Fermi GBM Sub-Threshold Detection of GRB 210726A
  80. GRB 210714A: Fermi GBM observation
  81. GRB 210726A: Swift-XRT refined Analysis
  82. GRB 210726A: Swift-BAT refined analysis
  83. GRB 210726A: RATIR Optical Upper Limits and Candidate Host Galaxy
  84. GRB 210727A: BALROG localization (Fermi Trigger 649072251 / GRB 210727410)
  85. GRB 210725A: AbAO optical upper limit
  86. GRB 210724A: Swift/UVOT Upper Limits
  87. GRB 210723A: Swift/UVOT Upper Limits
  88. GRB 210725A: Swift/UVOT Upper Limits
  89. GRB 210725B: Swift/UVOT Upper Limits
  90. GRB 210726A: Enhanced Swift-XRT position
  91. GRB 210726A: Swift detection of a burst
  92. GRB 210725B: Swift-XRT refined Analysis
  93. GRB 210725A: Fermi GBM detection
  94. GRB 210724A: Zeiss-1000 of Koshka observatory, optical upper limit
  95. GRB 210725A: Swift-XRT refined Analysis
  96. GRB 210725B: Swift-BAT refined analysis
  97. GRB 210724A: Swift-XRT refined Analysis
  98. GRB 210725A: Swift-BAT refined analysis
  99. GRB 210724A: Swift-BAT refined analysis
  100. GRB 210724A: Afterglow candidate from OSIRIS/GTC

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