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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"

5559 results found.

  1. GRB 210210A: MASTER afterglow observation
  2. ZTF21aahifke/AT2021clk: ZTF discovery of an optical fast transient (possible afterglow)
  3. Fermi GRB 210202A: Global MASTER-Net observations report
  4. Fermi trigger No 633963272: Global MASTER-Net observations report
  5. Recent activity of SGR 1935+2154 as observed by CGBM
  6. Fermi trigger No 633879387: Global MASTER-Net observations report
  7. Fermi trigger No 633348010: Global MASTER-Net observations report
  8. GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
  9. GRB 210112A: Deep CAHA 2.2m detection
  10. GRB 210112A: Swift/UVOT Detection
  11. GRB 210112A: Swift-BAT refined analysis
  12. GRB 210112A: OSN Reddened Afterglow Detection
  13. GRB 210112A: Kitab a optical upper limit
  14. GRB 210112A: Enhanced Swift-XRT position
  15. GRB 210112A: Swift detection of a burst with an optical counterpart
  16. GRB 210109A: MAXI/GSC detection
  17. GRB 210105A: Fermi GBM Final Real-time Localization
  18. GRB 210102B: Assy optical observations
  19. Fermi GRB 210102C: Global MASTER-Net observations report
  20. Swift GRB 210102C: Global MASTER-Net observations report
  21. GRB 210102B: MAXI/GSC detection
  22. Fermi GRB 210101A: Global MASTER-Net observations report
  23. Fermi trigger No 631119348: Global MASTER-Net observations report
  24. Fermi trigger No 631113166: Global MASTER-Net observations report
  25. Fermi trigger No 631104264: Global MASTER-Net observations report
  26. GRB 201229A: SAO RAS optical observations
  27. IPN triangulation of GRB 201227A (short)
  28. ZTF20acozryr/AT2020yxz (GRB 201103B): Maidanak optical observations
  29. Fermi trigger No 630681391: Global MASTER-Net observations report
  30. Baksan Neutrino Observatory Alert 201225.54: Global MASTER-Net observations report
  31. IceCube-201221A: No significant detection in HAWC
  32. Fermi GRB 201222B: Global MASTER-Net observations report
  33. GRB 201222B: BALROG localization (Fermi Trigger / GRB 201222461)
  34. GRB 201222B: Fermi GBM Final Real-time Localization
  35. GRB 201209A: Mondy optical observations, afterglow confirmation
  36. Fermi GRB 201218A: Global MASTER-Net observations report
  37. Fermi GRB 201216A: Global MASTER-Net observations report
  38. Fermi GRB 201214B: Global MASTER-Net observations report
  39. IceCube-201209: No significant detection in HAWC
  40. GRB 201203A: Zeiss-1000 (Koshka observatory) optical upper limit
  41. IceCube-201209A: No Candidate Counterparts from the Zwicky Transient Facility
  42. GRB 201203A: 1.3m DFOT, optical upper limits
  43. IceCube Alert 201209.43: Global MASTER-Net observations report
  44. GRB 201208A: Fermi GBM observation
  45. GRB 201208A: Fermi-LAT detection
  46. GRB 201208A: AstroSat CZTI detection
  47. GRB 201208A: Fermi GBM Final Real-time Localization
  48. Swift GRB 201203A: Global MASTER-Net observations report
  49. IceCube-201130A: No Candidate Counterparts from the Zwicky Transient Facility
  50. GRB 201203A: DDOTI Observations
  51. GRB 201201A: DDOTI Observations
  52. Fermi trigger No 628278856: Global MASTER-Net observations report
  53. GRB 201121B: Fermi GBM Final Real-time Localization
  54. Fermi GRB 201120B: Global MASTER-Net observations report
  55. Baksan Neutrino Observatory Alert 201120.43: Global MASTER-Net observations report
  56. GRB 201116A: OSN Afterglow Candidate
  57. Fermi trigger No 627198169: Global MASTER-Net observations report
  58. IceCube-201114A: No significant detection in HAWC
  59. GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
  60. ZTF20acozryr/AT2020yxz: Zwicky Transient Facility discovery of a fast optical transient with no associated GRB
  61. Swift Trigger 1004219: Detection of SGR 1830-0645
  62. GRB 201103B: AGILE detection
  63. Fermi GRB 201104A: Global MASTER-Net observations report
  64. Fermi GRB 201103A: Global MASTER-Net observations report
  65. Swift GRB 201031A: Global MASTER-Net observations report
  66. Fermi GRB 201031B: Global MASTER-Net observations report
  67. GRB 201029A: Swift-XRT refined Analysis
  68. Fermi trigger No 625695596: Global MASTER-Net observations report
  69. GRB 201024A: 1.3m DFOT optical observations
  70. GRB 201024A: Redshift from GTC/OSIRIS
  71. GRB 201024A: BOOTES-2/TELMA early optical observation and 1.5m OSN follow-up
  72. GRB 201024A: Swift detection of a burst with an optical afterglow
  73. IceCube-201021A: No significant detection in HAWC
  74. Baksan Neutrino Observatory Alert 201022.66: Global MASTER-Net observations report
  75. Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
  76. GRB 201021C: VLT/X-shooter redshift
  77. IceCube-201014A: No significant detection in HAWC
  78. Konus-Wind observation of GRB 201013A
  79. Fermi GRB 201016B: Global MASTER-Net observations report
  80. GRB 201016B: BALROG localization (Fermi Trigger 624510986 / GRB 201016136)
  81. GRB 201016B: Fermi GBM Final Real-time Localization
  82. GRB 201013A: AstroSat CZTI detection
  83. GRB 201013A: CALET Gamma-Ray Burst Monitor detection
  84. GRB 201013A: FRAM-ORM possible afterglow candidate
  85. GRB 201013A: Swift detection of a burst
  86. Fermi trigger No 624139481: Global MASTER-Net observations report
  87. IceCube-200929A: JCMT/SCUBA2 observations
  88. GRB 201009A: AstroSat CZTI detection
  89. GRB 201009A: AGILE detection of a burst
  90. Fermi GRB 201007A: Global MASTER-Net observations report
  91. Fermi trigger No 623470566: Global MASTER-Net observations report
  92. Fermi trigger No 623493962: Global MASTER-Net observations report
  93. Swift-XRT observations of IceCube 200929A
  94. IceCube-200926B: No significant detection in HAWC
  95. Swift-XRT observations of IceCube 200926A
  96. GRB 200925B: Swift-XRT refined analysis update
  97. Fermi GRB 200925A: Global MASTER-Net observations report
  98. Fermi GRB 200924A: Global MASTER-Net observations report
  99. Fermi GRB 200923A: Global MASTER-Net observations report
  100. Fermi GRB 200922B: Global MASTER-Net observations report

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