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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"

3147 results found.

  1. Fermi trigger No 656506979: Global MASTER-Net observations report
  2. Fermi GRB 211019A: Global MASTER-Net observations report
  3. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  4. Swift Trigger 1078701 is probably not a GRB
  5. Fermi trigger No 654658271: Global MASTER-Net observations report
  6. Fermi GRB 210929B: Global MASTER-Net observations report
  7. GRB 210929B: Fermi GBM Final Real-time Localization
  8. GRB 210925B: AstroSat CZTI detection
  9. GRB 210926A: AstroSat CZTI detection
  10. GRB 210919A: LOAO and LSGT optical upper limits
  11. Konus-Wind observation of the recent SGR 1935+2154 activity
  12. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  13. Fermi trigger No 653022153: Global MASTER-Net observations report
  14. Fermi trigger No 653010039: Global MASTER-Net observations report
  15. GECAM observations of a series of bursts from SGR J1935+2154
  16. Fermi trigger No 652911693: Global MASTER-Net observations report
  17. Fermi trigger No 652906639: Global MASTER-Net observations report
  18. Fermi GRB 210909A: Global MASTER-Net observations report
  19. GRB 210905A: AstroSat CZTI detection
  20. Fermi trigger No 652585475: Global MASTER-Net observations report
  21. GRB 210610A: Maidanak and AbAO optical observations
  22. Fermi GRB 210904A: Global MASTER-Net observations report
  23. Fermi GRB 210903B: Global MASTER-Net observations report
  24. GRB 210827A: Fermi GBM Observation
  25. Fermi GRB 210827A: Global MASTER-Net observations report
  26. Fermi GRB 210827B: Global MASTER-Net observations report
  27. GRB 210826A: Swift-XRT observations
  28. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  29. Fermi GRB 210822B: Global MASTER-Net observations report
  30. GRB 210822A: Nanshan/NEXT optical observations
  31. Fermi trigger No 650046564: Global MASTER-Net observations report
  32. GRB 210807B: Fermi GBM Final Real-time Localization
  33. Fermi trigger No 649814537: Global MASTER-Net observations report
  34. Fermi trigger No 649519043: Global MASTER-Net observations report
  35. Swift GRB210731.62: Global MASTER-Net observations report
  36. GRB 210730A: Swift-BAT refined analysis
  37. GRB 210730A: Swift detection of a burst near M82
  38. GRB 210714A: Fermi GBM observation
  39. Fermi trigger No 648959581: Global MASTER-Net observations report
  40. GRB 210722A: continued Assy optical observations
  41. Fermi trigger No 648868114: Global MASTER-Net observations report
  42. Swift GRB210724.84: Global MASTER-Net observations report
  43. GRB 210722A: Assy optical detection
  44. GRB 210722A: Swift detection of a burst with a bright optical counterpart
  45. Fermi trigger No 648602917: Global MASTER-Net observations report
  46. Recent activity of SGR 1935+2154 as observed by CGBM
  47. Fermi trigger No 647805873: Global MASTER-Net observations report
  48. GRB 210709A: AstroSat CZTI detection
  49. Fermi trigger No 647653174: Global MASTER-Net observations report
  50. Fermi trigger No 647624281: Global MASTER-Net observations report
  51. Swift GRB 210708B: Global MASTER-Net observations report
  52. GRB 210704A: Assy optical afterglow candidate
  53. Fermi trigger No 647108723: Global MASTER-Net observations report
  54. GRB210702A: MeerLICHT multi-colour photometry
  55. IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  56. Fermi trigger No 646443989: Global MASTER-Net observations report
  57. Fermi GRB 210627B: Global MASTER-Net observations report
  58. Fermi GRB 210627A: Global MASTER-Net observations report
  59. Fermi GRB 210625A: Global MASTER-Net observations report
  60. Fermi trigger No 646189108: Global MASTER-Net observations report
  61. GRB 210619B: Abbey Ridge Observatory optical afterglow observation
  62. GRB 210619B: Liverpool telescope imaging of a red afterglow
  63. Swift GRB210619.99: Global MASTER-Net OT detection
  64. Swift GRB210619.99: Global MASTER-Net observations report
  65. GRB 210618A: Swift-XRT observations
  66. Fermi GRB 210615A: Global MASTER-Net observations report
  67. Follow-up on HAWC Transient Monitoring Alert J0020+3108
  68. GRB210610B: SARA-KP 0.9m Optical Afterglow Detection
  69. Fermi trigger No 645047470: Global MASTER-Net observations report
  70. Konus-Wind detection of GRB 210606B
  71. GRB 210606B: Fermi GBM detection
  72. Fermi trigger No 644449593: Global MASTER-Net observations report
  73. MAXI GRB210602.50: Global MASTER-Net observations report
  74. Fermi trigger No 644359567: Global MASTER-Net observations report
  75. GRB210529B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 644025222)
  76. MAXI GRB210528.95: Global MASTER-Net observations report
  77. GRB 210521A: MAXI/GSC detection
  78. Fermi GRB 210519A: Global MASTER-Net observations report
  79. IceCube Alert 210519.86: Global MASTER-Net observations report
  80. Fermi trigger No 643065622: Global MASTER-Net observations report
  81. Fermi trigger No 642991619: Global MASTER-Net observations report
  82. IceCube-210516A: No significant detection in HAWC
  83. Fermi GRB 210516A: Global MASTER-Net observations report
  84. AMON IC_HAWC NuEm-210515A / NuEm-210515B : No neutrino counterpart detected with ANTARES
  85. Fermi GRB 210515B: Global MASTER-Net observations report
  86. Fermi GRB 210515A: Global MASTER-Net observations report
  87. GRB 210515B: Fermi GBM Final Real-time Localization
  88. Fermi GRB 210511A: Global MASTER-Net observations report
  89. GRB 210511B: Fermi GBM Final Real-time Localization
  90. Fermi GRB 210510A: Global MASTER-Net observations report
  91. GRB 200716A: Swift/BAT-GUANO archival detection and arcminute localization
  92. Fermi GRB 210507A: Global MASTER-Net observations report
  93. GRB 210504A: MITSuME Akeno optical upper limits
  94. Fermi GRB 210501A: Global MASTER-Net observations report
  95. Fermi trigger No 641601187: Global MASTER-Net observations report
  96. GRB 210430B: Fermi GBM Final Real-time Localization
  97. Swift GRB210430.45: Global MASTER-Net observations report
  98. GRB 210430A: Swift detection of a burst
  99. IPN triangulation of GRB 210424B (short/hard)
  100. GRB 210422B: Fermi GBM Final Localization

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