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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"

4738 results found.

  1. Fermi GRB 210101A: Global MASTER-Net observations report
  2. Fermi trigger No 631119348: Global MASTER-Net observations report
  3. Fermi trigger No 631113166: Global MASTER-Net observations report
  4. Fermi trigger No 631104264: Global MASTER-Net observations report
  5. GRB 201229A: SAO RAS optical observations
  6. IPN triangulation of GRB 201227A (short)
  7. ZTF20acozryr/AT2020yxz (GRB 201103B): Maidanak optical observations
  8. Fermi trigger No 630681391: Global MASTER-Net observations report
  9. Baksan Neutrino Observatory Alert 201225.54: Global MASTER-Net observations report
  10. IceCube-201221A: No significant detection in HAWC
  11. Fermi GRB 201222B: Global MASTER-Net observations report
  12. GRB 201222B: BALROG localization (Fermi Trigger / GRB 201222461)
  13. GRB 201222B: Fermi GBM Final Real-time Localization
  14. GRB 201209A: Mondy optical observations, afterglow confirmation
  15. Fermi GRB 201218A: Global MASTER-Net observations report
  16. Fermi GRB 201216A: Global MASTER-Net observations report
  17. Fermi GRB 201214B: Global MASTER-Net observations report
  18. IceCube-201209: No significant detection in HAWC
  19. GRB 201203A: Zeiss-1000 (Koshka observatory) optical upper limit
  20. IceCube-201209A: No Candidate Counterparts from the Zwicky Transient Facility
  21. GRB 201203A: 1.3m DFOT, optical upper limits
  22. IceCube Alert 201209.43: Global MASTER-Net observations report
  23. GRB 201208A: Fermi GBM observation
  24. GRB 201208A: Fermi-LAT detection
  25. GRB 201208A: AstroSat CZTI detection
  26. GRB 201208A: Fermi GBM Final Real-time Localization
  27. Swift GRB 201203A: Global MASTER-Net observations report
  28. IceCube-201130A: No Candidate Counterparts from the Zwicky Transient Facility
  29. GRB 201203A: DDOTI Observations
  30. GRB 201201A: DDOTI Observations
  31. Fermi trigger No 628278856: Global MASTER-Net observations report
  32. GRB 201121B: Fermi GBM Final Real-time Localization
  33. Fermi GRB 201120B: Global MASTER-Net observations report
  34. Baksan Neutrino Observatory Alert 201120.43: Global MASTER-Net observations report
  35. GRB 201116A: OSN Afterglow Candidate
  36. Fermi trigger No 627198169: Global MASTER-Net observations report
  37. IceCube-201114A: No significant detection in HAWC
  38. GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
  39. ZTF20acozryr/AT2020yxz: Zwicky Transient Facility discovery of a fast optical transient with no associated GRB
  40. Swift Trigger 1004219: Detection of SGR 1830-0645
  41. GRB 201103B: AGILE detection
  42. Fermi GRB 201104A: Global MASTER-Net observations report
  43. Fermi GRB 201103A: Global MASTER-Net observations report
  44. Swift GRB 201031A: Global MASTER-Net observations report
  45. Fermi GRB 201031B: Global MASTER-Net observations report
  46. GRB 201029A: Swift-XRT refined Analysis
  47. Fermi trigger No 625695596: Global MASTER-Net observations report
  48. GRB 201024A: 1.3m DFOT optical observations
  49. GRB 201024A: Redshift from GTC/OSIRIS
  50. GRB 201024A: BOOTES-2/TELMA early optical observation and 1.5m OSN follow-up
  51. GRB 201024A: Swift detection of a burst with an optical afterglow
  52. IceCube-201021A: No significant detection in HAWC
  53. Baksan Neutrino Observatory Alert 201022.66: Global MASTER-Net observations report
  54. Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
  55. GRB 201021C: VLT/X-shooter redshift
  56. IceCube-201014A: No significant detection in HAWC
  57. Konus-Wind observation of GRB 201013A
  58. Fermi GRB 201016B: Global MASTER-Net observations report
  59. GRB 201016B: BALROG localization (Fermi Trigger 624510986 / GRB 201016136)
  60. GRB 201016B: Fermi GBM Final Real-time Localization
  61. GRB 201013A: AstroSat CZTI detection
  62. GRB 201013A: CALET Gamma-Ray Burst Monitor detection
  63. GRB 201013A: FRAM-ORM possible afterglow candidate
  64. GRB 201013A: Swift detection of a burst
  65. Fermi trigger No 624139481: Global MASTER-Net observations report
  66. IceCube-200929A: JCMT/SCUBA2 observations
  67. GRB 201009A: AstroSat CZTI detection
  68. GRB 201009A: AGILE detection of a burst
  69. Fermi GRB 201007A: Global MASTER-Net observations report
  70. Fermi trigger No 623470566: Global MASTER-Net observations report
  71. Fermi trigger No 623493962: Global MASTER-Net observations report
  72. Swift-XRT observations of IceCube 200929A
  73. IceCube-200926B: No significant detection in HAWC
  74. Swift-XRT observations of IceCube 200926A
  75. GRB 200925B: Swift-XRT refined analysis update
  76. Fermi GRB 200925A: Global MASTER-Net observations report
  77. Fermi GRB 200924A: Global MASTER-Net observations report
  78. Fermi GRB 200923A: Global MASTER-Net observations report
  79. Fermi GRB 200922B: Global MASTER-Net observations report
  80. Fermi GRB 200919B: Global MASTER-Net observations report
  81. GRB 200916B: MASTER optical observation
  82. Fermi-GBM Sub-Threshold Detection of GRB 200917A
  83. GRB 200917A: Swift detection of a burst
  84. Fermi trigger No 621893860: Global MASTER-Net observations report
  85. IceCube Alert 200914.00: Global MASTER-Net observations report
  86. IceCube-200911A: No significant detection in HAWC
  87. IPN triangulation of GRB 200907A (short)
  88. GRB 200909B: Swift detection of a burst
  89. Fermi GRB 200909A: Global MASTER-Net observations report
  90. Fermi GRB 200907C: Global MASTER-Net observations report
  91. Fermi GRB 200906A: Global MASTER-Net observations report
  92. GRB 200906A: LBT near-infrared upper limit
  93. GRB 200906A: Nanshan/NEXT optical upper limit
  94. GRB 200903E: AstroSat CZTI detection
  95. Fermi GRB 200903C: Global MASTER-Net observations report
  96. AGILE detection of a burst (AGILE trigger no. 526185273)
  97. GRB200817B: AstroSat CZTI detection
  98. Fermi GRB 200903B: Global MASTER-Net observations report
  99. Swift GRB200903.03: Global MASTER-Net observations report
  100. GRB 200901A: MASTER OT early detection

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