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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"

3139 results found.

  1. GRB 210926A: AstroSat CZTI detection
  2. GRB 210919A: LOAO and LSGT optical upper limits
  3. Konus-Wind observation of the recent SGR 1935+2154 activity
  4. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  5. Fermi trigger No 653022153: Global MASTER-Net observations report
  6. Fermi trigger No 653010039: Global MASTER-Net observations report
  7. GECAM observations of a series of bursts from SGR J1935+2154
  8. Fermi trigger No 652911693: Global MASTER-Net observations report
  9. Fermi trigger No 652906639: Global MASTER-Net observations report
  10. Fermi GRB 210909A: Global MASTER-Net observations report
  11. GRB 210905A: AstroSat CZTI detection
  12. Fermi trigger No 652585475: Global MASTER-Net observations report
  13. GRB 210610A: Maidanak and AbAO optical observations
  14. Fermi GRB 210904A: Global MASTER-Net observations report
  15. Fermi GRB 210903B: Global MASTER-Net observations report
  16. GRB 210827A: Fermi GBM Observation
  17. Fermi GRB 210827A: Global MASTER-Net observations report
  18. Fermi GRB 210827B: Global MASTER-Net observations report
  19. GRB 210826A: Swift-XRT observations
  20. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  21. Fermi GRB 210822B: Global MASTER-Net observations report
  22. GRB 210822A: Nanshan/NEXT optical observations
  23. Fermi trigger No 650046564: Global MASTER-Net observations report
  24. GRB 210807B: Fermi GBM Final Real-time Localization
  25. Fermi trigger No 649814537: Global MASTER-Net observations report
  26. Fermi trigger No 649519043: Global MASTER-Net observations report
  27. Swift GRB210731.62: Global MASTER-Net observations report
  28. GRB 210730A: Swift-BAT refined analysis
  29. GRB 210730A: Swift detection of a burst near M82
  30. GRB 210714A: Fermi GBM observation
  31. Fermi trigger No 648959581: Global MASTER-Net observations report
  32. GRB 210722A: continued Assy optical observations
  33. Fermi trigger No 648868114: Global MASTER-Net observations report
  34. Swift GRB210724.84: Global MASTER-Net observations report
  35. GRB 210722A: Assy optical detection
  36. GRB 210722A: Swift detection of a burst with a bright optical counterpart
  37. Fermi trigger No 648602917: Global MASTER-Net observations report
  38. Recent activity of SGR 1935+2154 as observed by CGBM
  39. Fermi trigger No 647805873: Global MASTER-Net observations report
  40. GRB 210709A: AstroSat CZTI detection
  41. Fermi trigger No 647653174: Global MASTER-Net observations report
  42. Fermi trigger No 647624281: Global MASTER-Net observations report
  43. Swift GRB 210708B: Global MASTER-Net observations report
  44. GRB 210704A: Assy optical afterglow candidate
  45. Fermi trigger No 647108723: Global MASTER-Net observations report
  46. GRB210702A: MeerLICHT multi-colour photometry
  47. IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  48. Fermi trigger No 646443989: Global MASTER-Net observations report
  49. Fermi GRB 210627B: Global MASTER-Net observations report
  50. Fermi GRB 210627A: Global MASTER-Net observations report
  51. Fermi GRB 210625A: Global MASTER-Net observations report
  52. Fermi trigger No 646189108: Global MASTER-Net observations report
  53. GRB 210619B: Abbey Ridge Observatory optical afterglow observation
  54. GRB 210619B: Liverpool telescope imaging of a red afterglow
  55. Swift GRB210619.99: Global MASTER-Net OT detection
  56. Swift GRB210619.99: Global MASTER-Net observations report
  57. GRB 210618A: Swift-XRT observations
  58. Fermi GRB 210615A: Global MASTER-Net observations report
  59. Follow-up on HAWC Transient Monitoring Alert J0020+3108
  60. GRB210610B: SARA-KP 0.9m Optical Afterglow Detection
  61. Fermi trigger No 645047470: Global MASTER-Net observations report
  62. Konus-Wind detection of GRB 210606B
  63. GRB 210606B: Fermi GBM detection
  64. Fermi trigger No 644449593: Global MASTER-Net observations report
  65. MAXI GRB210602.50: Global MASTER-Net observations report
  66. Fermi trigger No 644359567: Global MASTER-Net observations report
  67. GRB210529B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 644025222)
  68. MAXI GRB210528.95: Global MASTER-Net observations report
  69. GRB 210521A: MAXI/GSC detection
  70. Fermi GRB 210519A: Global MASTER-Net observations report
  71. IceCube Alert 210519.86: Global MASTER-Net observations report
  72. Fermi trigger No 643065622: Global MASTER-Net observations report
  73. Fermi trigger No 642991619: Global MASTER-Net observations report
  74. IceCube-210516A: No significant detection in HAWC
  75. Fermi GRB 210516A: Global MASTER-Net observations report
  76. AMON IC_HAWC NuEm-210515A / NuEm-210515B : No neutrino counterpart detected with ANTARES
  77. Fermi GRB 210515B: Global MASTER-Net observations report
  78. Fermi GRB 210515A: Global MASTER-Net observations report
  79. GRB 210515B: Fermi GBM Final Real-time Localization
  80. Fermi GRB 210511A: Global MASTER-Net observations report
  81. GRB 210511B: Fermi GBM Final Real-time Localization
  82. Fermi GRB 210510A: Global MASTER-Net observations report
  83. GRB 200716A: Swift/BAT-GUANO archival detection and arcminute localization
  84. Fermi GRB 210507A: Global MASTER-Net observations report
  85. GRB 210504A: MITSuME Akeno optical upper limits
  86. Fermi GRB 210501A: Global MASTER-Net observations report
  87. Fermi trigger No 641601187: Global MASTER-Net observations report
  88. GRB 210430B: Fermi GBM Final Real-time Localization
  89. Swift GRB210430.45: Global MASTER-Net observations report
  90. GRB 210430A: Swift detection of a burst
  91. IPN triangulation of GRB 210424B (short/hard)
  92. GRB 210422B: Fermi GBM Final Localization
  93. GRB 210420B: Assy optical observations
  94. GRB 210421B: AstroSat CZTI detection
  95. GRB 210421B: AstroSat CZTI detection
  96. GRB 210420B: Correction to AST3-3 YaoAn magnitude
  97. GRB 210420B: Swift-XRT refined Analysis
  98. GRB 210420B: DDOTI Detection of the Afterglow
  99. GRB 210420B: Multiband photometry from NOT
  100. GRB 210420B: Montarrenti Observatory optical afterglow detection

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