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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"
  1. GRB 200412B: MASTER Optical Couterpart in Gagarin day!
  2. Konus-Wind observation of a bright burst from SGR 1935+2154
  3. Correction to GCN 27551 - Swift is observing GRB 200412*B*
  4. IceCube-200410A: Upper limits from a search for additional neutrino events in IceCube
  5. GRB 200412B: Tiled Swift observations
  6. GRB 200412A: Fermi GBM detection
  7. Fermi GRB 200412B: Global MASTER-Net observations report
  8. GRB 200412B: BALROG localization (Fermi Trigger 608375325 / GRB 200412381)
  9. GRB 200412B: Fermi GBM Final Real-time Localization
  10. GRB 200412A: BALROG localization (Fermi Trigger 608367436 / GRB 200412290)
  11. GRB 200411A: Swift-BAT refined analysis
  12. Fermi-LAT Gamma-ray Observations of IceCube-200410A
  13. GRB 200411A: Fermi GBM observation
  14. Swift GRB 200411A: Global MASTER-Net observations report
  15. IceCube-200410A: Upper limits from Fermi-GBM Observations
  16. GRB 200411A: Swift-XRT refined Analysis
  17. GRB 200411A: Swift/UVOT Upper Limits
  18. GRB 200411A: Enhanced Swift-XRT position
  19. IceCube-200410A: Possible associated excess in INTEGRAL SPI-ACS prompt observation
  20. GRB 200411A: Swift detection of a short burst
  21. GRB 200411A: Fermi GBM Final Real-time Localization
  22. IceCube-200410A - IceCube observation of a high-energy neutrino candidate event
  23. IceCube Alert 200410.97: Global MASTER-Net observations report
  24. GRB 200410A: Swift/UVOT Detection
  25. SGR 1935+2154: Fermi GBM observation
  26. Baksan Neutrino Observatory Alert 200410.82: Global MASTER-Net observations report
  27. Fermi trigger No 608204639: Global MASTER-Net observations report
  28. Baksan Neutrino Observatory Alert 200409.81: Global MASTER-Net observations report
  29. IPN Triangulation of a bright burst from SGR 1935+2154
  30. LIGO/Virgo S200225q: Swift XRT observations, 1 X-ray sources
  31. Konus-Wind observation of GRB 200327A
  32. LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
  33. GRB 200410A: Swift-XRT refined Analysis
  34. GRB 200410A: Enhanced Swift-XRT position
  35. GRB 200409A: No detection of radio emission 5 hours post-burst
  36. GRB 200410A: Ondrejov D50 afterglow confirmation
  37. GRB 200409A: Swift-BAT refined analysis
  38. GRB 200410A: Swift detection of a burst with a possible optical counterpart
  39. Swift GRB200410.10: Global MASTER-Net observations report
  40. GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
  41. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  42. Fermi GBM Sub-Threshold Detection of GRB 200409A
  43. Baksan Neutrino Observatory Alert 200409.23: Global MASTER-Net observations report
  44. Swift GRB 200409A: Global MASTER-Net observations report
  45. GRB 200409A: Swift-XRT refined Analysis
  46. GRB 200409A: Enhanced Swift-XRT position
  47. GRB 200409A: Swift detection of a burst with an optical counterpart
  48. Fermi GRB 200407A: Global MASTER-Net observations report
  49. Fermi GRB 200407B: Global MASTER-Net observations report
  50. IPN triangulation of GRB 200407A (short)
  51. IPN triangulation of GRB 200405B (short)
  52. Baksan Neutrino Observatory Alert 200406.3: Global MASTER-Net observations report
  53. GRB 200407B: Fermi GBM Final Real-time Localization
  54. GRB 200407A: Fermi GBM Final Real-time Localization
  55. GRB 200405B: LCO Optical Upper Limits
  56. GRB 200405B: Swift-XRT observations
  57. GRB 200405B: Swift ToO observations
  58. Fermi GRB 200405A: Global MASTER-Net observations report
  59. GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
  60. GRB 200405A: Fermi GBM Final Real-time Localization
  61. GRB 200404A: Fermi GBM Final Localization
  62. Fermi GRB 200403C: Global MASTER-Net observations report
  63. GRB 200404A: BALROG localization (Fermi Trigger 607712227 / GRB 200404706)
  64. GRB 200403A: AstroSat CZTI detection
  65. Fermi GRB 200403B: Global MASTER-Net observations report
  66. Fermi GRB 200403A: Global MASTER-Net observations report
  67. GRB 200403C: Fermi GBM Final Real-time Localization
  68. LIGO/Virgo S200316bj: Upper limits from Konus-Wind observations
  69. LIGO/Virgo S200311bg: Upper limits from Konus-Wind observations
  70. LIGO/Virgo S200302c: Upper limits from Konus-Wind observations
  71. LIGO/Virgo S200225q: Upper limits from Konus-Wind observations
  72. GRB 200403B: Fermi GBM Final Real-time Localization
  73. LIGO/Virgo S200224ca: Upper limits from Konus-Wind observations
  74. GRB 200403A: Fermi GBM Final Real-time Localization
  75. GRB 200325B: Mondy continued observations
  76. Fermi GRB 200402C: Global MASTER-Net observations report
  77. GRB 200402C: Fermi GBM Final Localization
  78. GRB 200402B: Fermi GBM Final Localization
  79. Fermi trigger No 607537834: Global MASTER-Net observations report
  80. GRB 200402B: BALROG localization (Fermi Trigger 607537834 / GRB 200402688)
  81. Fermi GRB 200402A: Global MASTER-Net observations report
  82. GRB 200402A: BALROG localization (Fermi Trigger 607513182 / GRB 200402403)
  83. GRB 200325B: Optical upper limit
  84. GRB 200402A: Fermi GBM Final Real-time Localization
  85. GRB 200325B: further Swift-XRT observations
  86. Fermi GRB 200401A: Global MASTER-Net observations report
  87. GRB 200401A: Fermi GBM Final Real-time Localization
  88. GRB 200325B: Mondy continued observations
  89. GRB 200325B: Mondy continued observations
  90. GRB 200327A: Fermi GBM detection
  91. GRB 200325B: Mondy continued observations
  92. GRB 200325B: Tautenburg observations
  93. IPN triangulation of GRB 200327A (short)
  94. GRB 200326B: AstroSat CZTI detection
  95. GRB 200327A: AGILE/MCAL observations
  96. GRB 200325B: Fermi GBM observation
  97. Fermi trigger No 607035413: Global MASTER-Net observations report
  98. GRB 200327A: Fermi GBM Final Real-time Localization
  99. GRB 200325B: Swift-XRT and UVOT observations
  100. GRB 200325B: LCO Optical Detection

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