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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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. IPN triangulation of GRB 200405B (short)
  2. Baksan Neutrino Observatory Alert 200406.3: Global MASTER-Net observations report
  3. GRB 200407B: Fermi GBM Final Real-time Localization
  4. GRB 200407A: Fermi GBM Final Real-time Localization
  5. GRB 200405B: LCO Optical Upper Limits
  6. GRB 200405B: Swift-XRT observations
  7. GRB 200405B: Swift ToO observations
  8. Fermi GRB 200405A: Global MASTER-Net observations report
  9. GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
  10. GRB 200405A: Fermi GBM Final Real-time Localization
  11. GRB 200404A: Fermi GBM Final Localization
  12. Fermi GRB 200403C: Global MASTER-Net observations report
  13. GRB 200404A: BALROG localization (Fermi Trigger 607712227 / GRB 200404706)
  14. GRB 200403A: AstroSat CZTI detection
  15. Fermi GRB 200403B: Global MASTER-Net observations report
  16. Fermi GRB 200403A: Global MASTER-Net observations report
  17. GRB 200403C: Fermi GBM Final Real-time Localization
  18. LIGO/Virgo S200316bj: Upper limits from Konus-Wind observations
  19. LIGO/Virgo S200311bg: Upper limits from Konus-Wind observations
  20. LIGO/Virgo S200302c: Upper limits from Konus-Wind observations
  21. LIGO/Virgo S200225q: Upper limits from Konus-Wind observations
  22. GRB 200403B: Fermi GBM Final Real-time Localization
  23. LIGO/Virgo S200224ca: Upper limits from Konus-Wind observations
  24. GRB 200403A: Fermi GBM Final Real-time Localization
  25. GRB 200325B: Mondy continued observations
  26. Fermi GRB 200402C: Global MASTER-Net observations report
  27. GRB 200402C: Fermi GBM Final Localization
  28. GRB 200402B: Fermi GBM Final Localization
  29. Fermi trigger No 607537834: Global MASTER-Net observations report
  30. GRB 200402B: BALROG localization (Fermi Trigger 607537834 / GRB 200402688)
  31. Fermi GRB 200402A: Global MASTER-Net observations report
  32. GRB 200402A: BALROG localization (Fermi Trigger 607513182 / GRB 200402403)
  33. GRB 200325B: Optical upper limit
  34. GRB 200402A: Fermi GBM Final Real-time Localization
  35. GRB 200325B: further Swift-XRT observations
  36. Fermi GRB 200401A: Global MASTER-Net observations report
  37. GRB 200401A: Fermi GBM Final Real-time Localization
  38. GRB 200325B: Mondy continued observations
  39. GRB 200325B: Mondy continued observations
  40. GRB 200327A: Fermi GBM detection
  41. GRB 200325B: Mondy continued observations
  42. GRB 200325B: Tautenburg observations
  43. IPN triangulation of GRB 200327A (short)
  44. GRB 200326B: AstroSat CZTI detection
  45. GRB 200327A: AGILE/MCAL observations
  46. GRB 200325B: Fermi GBM observation
  47. Fermi trigger No 607035413: Global MASTER-Net observations report
  48. GRB 200327A: Fermi GBM Final Real-time Localization
  49. GRB 200325B: Swift-XRT and UVOT observations
  50. GRB 200325B: LCO Optical Detection
  51. GRB 200325B: Mondy, CrAO, AbAO afterglow confirmation and refined photometry of MASTER OT J111012.51+274912.8
  52. GRB 200326B: AstroSat LAXPC detection
  53. GRB 200325A: Fermi GBM observation
  54. GRB 200325B: Mondy and CrAO observations, Master MASTER OT J111012.51+274912.8 confirmation
  55. Fermi trigger No 606918292: Global MASTER-Net observations report
  56. GRB 200325B: Swift ToO observations
  57. IPN triangulation of GRB 200325A (short)
  58. Fermi trigger No 606799116: Global MASTER-Net observations report
  59. GRB 200326A: Fermi GBM Final Real-time Localization
  60. GRB 200325B: MASTERt OT detection
  61. GRB 200324A: AROMA-N Optical Observation
  62. GRB 200325A: Swift/BAT detection and probable arcminute localization of a short GRB from GUANO
  63. GRB 200324A, Swift-BAT refined analysis
  64. Fermi trigger No 606840801: Global MASTER-Net observations report
  65. GRB 200325B: Fermi GBM Final Real-time Localization
  66. GRB 200324A:: TSHAO optical upper limit
  67. GRB 200324A: Swift/UVOT Upper Limits
  68. GRB 200325A: AstroSat CZTI detection
  69. GRB 200325A: AGILE/MCAL observations
  70. GRB 200324A: LCO Optical Upper Limit
  71. GRB 200324A: Swift-XRT refined Analysis
  72. GRB 200325A: Fermi GBM Final Real-time Localization
  73. GRB 200324A: Konkoly Obs. optical upper limit
  74. GRB 200324A: NOT optical upper limit
  75. GRB 200324A: Tautenburg observations
  76. GRB 200324A: Enhanced Swift-XRT position
  77. GRB 200324A:MITSuME Akeno optical upper limits
  78. GRB 200324A: Swift detection of a burst
  79. Swift GRB200324.69: Global MASTER-Net observations report
  80. GRB 200318A : AstroSat CZTI detection
  81. GRB 200317A: AstroSat CZTI detection
  82. Fermi trigger No 606681997: Global MASTER-Net observations report
  83. GRB 200323A: Fermi GBM detection
  84. GRB 200323A: Fermi GBM Final Real-time Localization
  85. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  86. Fermi trigger No 606614927: Global MASTER-Net observations report
  87. LIGO/Virgo S200316bj: Updated Sky Localization and EM Bright Classification
  88. GRB 200320B: MAXI/GSC detection
  89. GRB 200320A: Fermi GBM Final Localization
  90. GRB 200319A: BALROG localization (Fermi Trigger 606296685 / GRB 200319323)
  91. GRB 200319A: Fermi GBM Final Real-time Localization
  92. Chandra observations of GW170817 at 2.5 years since merger (All epochs 4 of 4)
  93. Fermi trigger No 606263732: Global MASTER-Net observations report
  94. GRB 200318A: Fermi GBM Final Real-time Localization
  95. GW170817: Continued X-ray emission detected with Chandra at 940 days post-merger
  96. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  97. LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
  98. Konus-Wind observation of GRB 200313B
  99. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  100. LIGO/Virgo S200316bj: Upper limits from CALET observations

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