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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"

2857 results found.

  1. Fermi GRB 211112A: Global MASTER-Net observations report
  2. GRB 211110A: AstroSat CZTI detection
  3. Fermi trigger No 658214822: Global MASTER-Net observations report
  4. GRB 211109B: Fermi GBM Final Real-time Localization
  5. GRB 211023A: A BdHN of type I
  6. GRB 211024A: MITSuME Akeno optical observation
  7. Fermi GRB 211031A: Global MASTER-Net observations report
  8. GRB 211023B: LDT Optical Afterglow Detection
  9. GRB 211022A: AstroSat CZTI detection
  10. Fermi GRB 211024A: Global MASTER-Net observations report
  11. Fermi trigger No 656506979: Global MASTER-Net observations report
  12. Fermi GRB 211019A: Global MASTER-Net observations report
  13. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  14. Swift Trigger 1078701 is probably not a GRB
  15. Fermi trigger No 654658271: Global MASTER-Net observations report
  16. Fermi GRB 210929B: Global MASTER-Net observations report
  17. GRB 210929B: Fermi GBM Final Real-time Localization
  18. GRB 210925B: AstroSat CZTI detection
  19. GRB 210926A: AstroSat CZTI detection
  20. GRB 210919A: LOAO and LSGT optical upper limits
  21. Konus-Wind observation of the recent SGR 1935+2154 activity
  22. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  23. Fermi trigger No 653022153: Global MASTER-Net observations report
  24. Fermi trigger No 653010039: Global MASTER-Net observations report
  25. GECAM observations of a series of bursts from SGR J1935+2154
  26. Fermi trigger No 652911693: Global MASTER-Net observations report
  27. Fermi trigger No 652906639: Global MASTER-Net observations report
  28. Fermi GRB 210909A: Global MASTER-Net observations report
  29. GRB 210905A: AstroSat CZTI detection
  30. Fermi trigger No 652585475: Global MASTER-Net observations report
  31. GRB 210610A: Maidanak and AbAO optical observations
  32. Fermi GRB 210904A: Global MASTER-Net observations report
  33. Fermi GRB 210903B: Global MASTER-Net observations report
  34. GRB 210827A: Fermi GBM Observation
  35. Fermi GRB 210827A: Global MASTER-Net observations report
  36. Fermi GRB 210827B: Global MASTER-Net observations report
  37. GRB 210826A: Swift-XRT observations
  38. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  39. Fermi GRB 210822B: Global MASTER-Net observations report
  40. GRB 210822A: Nanshan/NEXT optical observations
  41. Fermi trigger No 650046564: Global MASTER-Net observations report
  42. GRB 210807B: Fermi GBM Final Real-time Localization
  43. Fermi trigger No 649814537: Global MASTER-Net observations report
  44. Fermi trigger No 649519043: Global MASTER-Net observations report
  45. Swift GRB210731.62: Global MASTER-Net observations report
  46. GRB 210730A: Swift-BAT refined analysis
  47. GRB 210730A: Swift detection of a burst near M82
  48. GRB 210714A: Fermi GBM observation
  49. Fermi trigger No 648959581: Global MASTER-Net observations report
  50. GRB 210722A: continued Assy optical observations
  51. Fermi trigger No 648868114: Global MASTER-Net observations report
  52. Swift GRB210724.84: Global MASTER-Net observations report
  53. GRB 210722A: Assy optical detection
  54. GRB 210722A: Swift detection of a burst with a bright optical counterpart
  55. Fermi trigger No 648602917: Global MASTER-Net observations report
  56. Recent activity of SGR 1935+2154 as observed by CGBM
  57. Fermi trigger No 647805873: Global MASTER-Net observations report
  58. GRB 210709A: AstroSat CZTI detection
  59. Fermi trigger No 647653174: Global MASTER-Net observations report
  60. Fermi trigger No 647624281: Global MASTER-Net observations report
  61. Swift GRB 210708B: Global MASTER-Net observations report
  62. GRB 210704A: Assy optical afterglow candidate
  63. Fermi trigger No 647108723: Global MASTER-Net observations report
  64. GRB210702A: MeerLICHT multi-colour photometry
  65. IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  66. Fermi trigger No 646443989: Global MASTER-Net observations report
  67. Fermi GRB 210627B: Global MASTER-Net observations report
  68. Fermi GRB 210627A: Global MASTER-Net observations report
  69. Fermi GRB 210625A: Global MASTER-Net observations report
  70. Fermi trigger No 646189108: Global MASTER-Net observations report
  71. GRB 210619B: Abbey Ridge Observatory optical afterglow observation
  72. GRB 210619B: Liverpool telescope imaging of a red afterglow
  73. Swift GRB210619.99: Global MASTER-Net OT detection
  74. Swift GRB210619.99: Global MASTER-Net observations report
  75. GRB 210618A: Swift-XRT observations
  76. Fermi GRB 210615A: Global MASTER-Net observations report
  77. Follow-up on HAWC Transient Monitoring Alert J0020+3108
  78. GRB210610B: SARA-KP 0.9m Optical Afterglow Detection
  79. Fermi trigger No 645047470: Global MASTER-Net observations report
  80. Konus-Wind detection of GRB 210606B
  81. GRB 210606B: Fermi GBM detection
  82. Fermi trigger No 644449593: Global MASTER-Net observations report
  83. MAXI GRB210602.50: Global MASTER-Net observations report
  84. Fermi trigger No 644359567: Global MASTER-Net observations report
  85. GRB210529B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 644025222)
  86. MAXI GRB210528.95: Global MASTER-Net observations report
  87. GRB 210521A: MAXI/GSC detection
  88. Fermi GRB 210519A: Global MASTER-Net observations report
  89. IceCube Alert 210519.86: Global MASTER-Net observations report
  90. Fermi trigger No 643065622: Global MASTER-Net observations report
  91. Fermi trigger No 642991619: Global MASTER-Net observations report
  92. IceCube-210516A: No significant detection in HAWC
  93. Fermi GRB 210516A: Global MASTER-Net observations report
  94. AMON IC_HAWC NuEm-210515A / NuEm-210515B : No neutrino counterpart detected with ANTARES
  95. Fermi GRB 210515B: Global MASTER-Net observations report
  96. Fermi GRB 210515A: Global MASTER-Net observations report
  97. GRB 210515B: Fermi GBM Final Real-time Localization
  98. Fermi GRB 210511A: Global MASTER-Net observations report
  99. GRB 210511B: Fermi GBM Final Real-time Localization
  100. Fermi GRB 210510A: Global MASTER-Net observations report

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