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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"

3051 results found.

  1. Fermi GRB 211031A: Global MASTER-Net observations report
  2. GRB 211023B: LDT Optical Afterglow Detection
  3. GRB 211022A: AstroSat CZTI detection
  4. Fermi GRB 211024A: Global MASTER-Net observations report
  5. Fermi trigger No 656506979: Global MASTER-Net observations report
  6. Fermi GRB 211019A: Global MASTER-Net observations report
  7. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  8. Swift Trigger 1078701 is probably not a GRB
  9. Fermi trigger No 654658271: Global MASTER-Net observations report
  10. Fermi GRB 210929B: Global MASTER-Net observations report
  11. GRB 210929B: Fermi GBM Final Real-time Localization
  12. GRB 210925B: AstroSat CZTI detection
  13. GRB 210926A: AstroSat CZTI detection
  14. GRB 210919A: LOAO and LSGT optical upper limits
  15. Konus-Wind observation of the recent SGR 1935+2154 activity
  16. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  17. Fermi trigger No 653022153: Global MASTER-Net observations report
  18. Fermi trigger No 653010039: Global MASTER-Net observations report
  19. GECAM observations of a series of bursts from SGR J1935+2154
  20. Fermi trigger No 652911693: Global MASTER-Net observations report
  21. Fermi trigger No 652906639: Global MASTER-Net observations report
  22. Fermi GRB 210909A: Global MASTER-Net observations report
  23. GRB 210905A: AstroSat CZTI detection
  24. Fermi trigger No 652585475: Global MASTER-Net observations report
  25. GRB 210610A: Maidanak and AbAO optical observations
  26. Fermi GRB 210904A: Global MASTER-Net observations report
  27. Fermi GRB 210903B: Global MASTER-Net observations report
  28. GRB 210827A: Fermi GBM Observation
  29. Fermi GRB 210827A: Global MASTER-Net observations report
  30. Fermi GRB 210827B: Global MASTER-Net observations report
  31. GRB 210826A: Swift-XRT observations
  32. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  33. Fermi GRB 210822B: Global MASTER-Net observations report
  34. GRB 210822A: Nanshan/NEXT optical observations
  35. Fermi trigger No 650046564: Global MASTER-Net observations report
  36. GRB 210807B: Fermi GBM Final Real-time Localization
  37. Fermi trigger No 649814537: Global MASTER-Net observations report
  38. Fermi trigger No 649519043: Global MASTER-Net observations report
  39. Swift GRB210731.62: Global MASTER-Net observations report
  40. GRB 210730A: Swift-BAT refined analysis
  41. GRB 210730A: Swift detection of a burst near M82
  42. GRB 210714A: Fermi GBM observation
  43. Fermi trigger No 648959581: Global MASTER-Net observations report
  44. GRB 210722A: continued Assy optical observations
  45. Fermi trigger No 648868114: Global MASTER-Net observations report
  46. Swift GRB210724.84: Global MASTER-Net observations report
  47. GRB 210722A: Assy optical detection
  48. GRB 210722A: Swift detection of a burst with a bright optical counterpart
  49. Fermi trigger No 648602917: Global MASTER-Net observations report
  50. Recent activity of SGR 1935+2154 as observed by CGBM
  51. Fermi trigger No 647805873: Global MASTER-Net observations report
  52. GRB 210709A: AstroSat CZTI detection
  53. Fermi trigger No 647653174: Global MASTER-Net observations report
  54. Fermi trigger No 647624281: Global MASTER-Net observations report
  55. Swift GRB 210708B: Global MASTER-Net observations report
  56. GRB 210704A: Assy optical afterglow candidate
  57. Fermi trigger No 647108723: Global MASTER-Net observations report
  58. GRB210702A: MeerLICHT multi-colour photometry
  59. IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  60. Fermi trigger No 646443989: Global MASTER-Net observations report
  61. Fermi GRB 210627B: Global MASTER-Net observations report
  62. Fermi GRB 210627A: Global MASTER-Net observations report
  63. Fermi GRB 210625A: Global MASTER-Net observations report
  64. Fermi trigger No 646189108: Global MASTER-Net observations report
  65. GRB 210619B: Abbey Ridge Observatory optical afterglow observation
  66. GRB 210619B: Liverpool telescope imaging of a red afterglow
  67. Swift GRB210619.99: Global MASTER-Net OT detection
  68. Swift GRB210619.99: Global MASTER-Net observations report
  69. GRB 210618A: Swift-XRT observations
  70. Fermi GRB 210615A: Global MASTER-Net observations report
  71. Follow-up on HAWC Transient Monitoring Alert J0020+3108
  72. GRB210610B: SARA-KP 0.9m Optical Afterglow Detection
  73. Fermi trigger No 645047470: Global MASTER-Net observations report
  74. Konus-Wind detection of GRB 210606B
  75. GRB 210606B: Fermi GBM detection
  76. Fermi trigger No 644449593: Global MASTER-Net observations report
  77. MAXI GRB210602.50: Global MASTER-Net observations report
  78. Fermi trigger No 644359567: Global MASTER-Net observations report
  79. GRB210529B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 644025222)
  80. MAXI GRB210528.95: Global MASTER-Net observations report
  81. GRB 210521A: MAXI/GSC detection
  82. Fermi GRB 210519A: Global MASTER-Net observations report
  83. IceCube Alert 210519.86: Global MASTER-Net observations report
  84. Fermi trigger No 643065622: Global MASTER-Net observations report
  85. Fermi trigger No 642991619: Global MASTER-Net observations report
  86. IceCube-210516A: No significant detection in HAWC
  87. Fermi GRB 210516A: Global MASTER-Net observations report
  88. AMON IC_HAWC NuEm-210515A / NuEm-210515B : No neutrino counterpart detected with ANTARES
  89. Fermi GRB 210515B: Global MASTER-Net observations report
  90. Fermi GRB 210515A: Global MASTER-Net observations report
  91. GRB 210515B: Fermi GBM Final Real-time Localization
  92. Fermi GRB 210511A: Global MASTER-Net observations report
  93. GRB 210511B: Fermi GBM Final Real-time Localization
  94. Fermi GRB 210510A: Global MASTER-Net observations report
  95. GRB 200716A: Swift/BAT-GUANO archival detection and arcminute localization
  96. Fermi GRB 210507A: Global MASTER-Net observations report
  97. GRB 210504A: MITSuME Akeno optical upper limits
  98. Fermi GRB 210501A: Global MASTER-Net observations report
  99. Fermi trigger No 641601187: Global MASTER-Net observations report
  100. GRB 210430B: Fermi GBM Final Real-time Localization

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