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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"

5073 results found.

  1. Fermi trigger No 663658976: Global MASTER-Net observations report
  2. Fermi GRB 220111A: Global MASTER-Net observations report
  3. GRB 220107A: SAO RAS optical observations
  4. GRB 220101A: Additional Liverpool telescope photometry
  5. GRB 220107A: SAO RAS optical observations
  6. Fermi GRB 220107A: Global MASTER-Net observations report
  7. Fermi trigger No 663129379: Global MASTER-Net observations report
  8. GRB 220101A: LCO Continued Optical Observations
  9. Fermi GRB 220103A: Global MASTER-Net observations report
  10. GRB 220103A: Fermi GBM Final Real-time Localization
  11. Alert from the HAWC Burst Monitor HAWC-220103A
  12. GRB 220101A: LCO Optical Observations
  13. GRB 220101A: Asiago spectroscopic and photometric detection
  14. GRB 211229A: Fermi GBM observation
  15. Fermi GRB 211229A: Global MASTER-Net observations report
  16. GRB 211229A: Fermi GBM Final Real-time Localization
  17. Konus-Wind detection of the intermediate flare from SGR 1935+2154
  18. Swift GRB211227.98: Global MASTER-Net observations report
  19. GRB 211225A: MITSuME Akeno optical upper limits
  20. Swift GRB 211225B: Global MASTER-Net observations report
  21. Fermi GRB 211225C: Global MASTER-Net observations report
  22. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  23. AGILE observations of a bright burst from SGR 1935+2154
  24. GRB 211218A: MITSuME Akeno optical upper limits
  25. GRB 211221A: MeerLICHT optical limits
  26. Fermi GRB 211219B: Global MASTER-Net observations report
  27. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  28. MAXI GRB211218.04: Global MASTER-Net observations report
  29. Fermi GRB 211216A: Global MASTER-Net observations report
  30. GRB 211211A: SAO RAS optical observations
  31. Swift GRB 211211A: Global MASTER-Net observations report
  32. GRB 211212A: Fermi GBM Final Real-time Localization
  33. Fermi GRB 211211B: Global MASTER-Net observations report
  34. Fermi trigger No 660868196: Global MASTER-Net observations report
  35. Fermi trigger No 660736561: Global MASTER-Net observations report
  36. Fermi GRB 211204B: Global MASTER-Net observations report
  37. Fermi GRB 211204A: Global MASTER-Net observations report
  38. GRB 211204A: Fermi GBM Final Real-time Localization
  39. Swift GRB 211203A: Global MASTER-Net observations report
  40. GRB 211203A: Swift detection of a burst
  41. Fermi GRB 211130A: Global MASTER-Net observations report
  42. GRB 211120548: Fermi GBM observation
  43. GRB 211118A: Fermi GBM detection
  44. HAWC-211123A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  45. Alert from the HAWC Burst Monitor HAWC-211123A
  46. Fermi trigger No 659106591: Global MASTER-Net observations report
  47. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  48. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  49. Fermi trigger No 658755664: Global MASTER-Net observations report
  50. Fermi GRB 211112A: Global MASTER-Net observations report
  51. GRB 211110A: AstroSat CZTI detection
  52. Fermi trigger No 658214822: Global MASTER-Net observations report
  53. Fermi GRB 211109B: Global MASTER-Net observations report
  54. GRB 211102A: BALROG localization (Fermi Trigger 657533168 / GRB 211102338)
  55. GRB 211102A: Fermi GBM Final Real-time Localization
  56. Fermi GRB 211031A: Global MASTER-Net observations report
  57. GRB 211018A: Swift-XRT observations
  58. GRB 210610B: Sintesz-Newton/CrAO optical observations
  59. GRB 211023B: BOOTES-4/MET and 1.5m OSN optical upper limit
  60. Fermi GRB 211024A: Global MASTER-Net observations report
  61. IPN Triangulation of GRB 210927B
  62. Fermi GRB 211019A: Global MASTER-Net observations report
  63. Fermi trigger No 655673024: Global MASTER-Net observations report
  64. Fermi trigger No 655401471: Global MASTER-Net observations report
  65. Fermi trigger No 654854799: Global MASTER-Net observations report
  66. Fermi GRB 210929B: Global MASTER-Net observations report
  67. GRB 210929A: Fermi GBM Final Real-time Localization
  68. IPN triangulation of GRB 210925B
  69. GRB 210919A OSN 1.5m Source Confirmation
  70. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  71. GRB 210919A: NOT upper limits
  72. GRB 210917A: Fermi GBM Final Real-time Localization
  73. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  74. Fermi trigger No 653066776: Global MASTER-Net observations report
  75. Fermi trigger No 653084584: Global MASTER-Net observations report
  76. Fermi trigger No 653083551: Global MASTER-Net observations report
  77. Fermi trigger No 653072474: Global MASTER-Net observations report
  78. Fermi trigger No 653054042: Global MASTER-Net observations report
  79. Fermi trigger No 653049776: Global MASTER-Net observations report
  80. Fermi trigger No 653022153: Global MASTER-Net observations report
  81. Swift detection of a burst from SGR Swift J1555.2-5402
  82. Fermi trigger No 652927551: Global MASTER-Net observations report
  83. Fermi trigger No 652911693: Global MASTER-Net observations report
  84. Fermi trigger No 652906639: Global MASTER-Net observations report
  85. Fermi GRB 210909A: Global MASTER-Net observations report
  86. Fermi GRB 210904A: Global MASTER-Net observations report
  87. Swift GRB210903.59: Global MASTER-Net observations report
  88. Swift GRB210903.58: Global MASTER-Net observations report
  89. Fermi GRB 210903A: Global MASTER-Net observations report
  90. Fermi GRB 210903B: Global MASTER-Net observations report
  91. Integral GRB210829.14: Global MASTER-Net observations report
  92. Fermi GRB 210827A: Global MASTER-Net observations report
  93. GRB 210826A: Swift-XRT observations
  94. Swift detection of an outburst from SGR Swift J1555.2-5402
  95. GRB 210824A: Fermi GBM Observation
  96. GRB 210822A: GROND observations
  97. GRB 210824A: Fermi GBM Final Real-time Localization
  98. GRB 210820A: GROND observations
  99. Fermi GRB 210822B: Global MASTER-Net observations report
  100. Fermi GRB 210821A: Global MASTER-Net observations report

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