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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').
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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"

4252 results found.

  1. Fermi trigger No 623470566: Global MASTER-Net observations report
  2. Fermi trigger No 623493962: Global MASTER-Net observations report
  3. IceCube-200926B: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  4. IceCube-200929A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  5. GRB 201001A: Xinglong-2.16m optical upper limit
  6. IceCube-200929A: No significant detection in HAWC
  7. Swift-XRT observations of IceCube 200929A
  8. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  9. IceCube-200926B: No significant detection in HAWC
  10. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  11. IceCube Alert 200929.74: Global MASTER-Net observations report
  12. IceCube-200926A: No significant detection in HAWC
  13. Fermi GRB 200929A: Global MASTER-Net observations report
  14. GRB 200928B: AstroSat CZTI detection
  15. GRB 200929A: Fermi GBM Final Real-time Localization
  16. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  17. IceCube Alert 200926.33: Global MASTER-Net observations report
  18. Fermi GRB 200925A: Global MASTER-Net observations report
  19. Fermi GRB 200924A: Global MASTER-Net observations report
  20. GRB 200924B: Fermi GBM Final Localization
  21. Fermi GRB 200923A: Global MASTER-Net observations report
  22. Fermi GRB 200916A: Global MASTER-Net observations report
  23. IceCube Alert 200914.00: Global MASTER-Net observations report
  24. IceCube-200911A: No significant detection in HAWC
  25. IPN triangulation of GRB 200907A (short)
  26. Swift GRB200909.97: Global MASTER-Net observations report
  27. Fermi GRB 200909A: Global MASTER-Net observations report
  28. GRB 200906A: OSN 1.5m Upper Limit
  29. Fermi GRB 200903C: Global MASTER-Net observations report
  30. GRB 200903A: Swift-BAT refined analysis
  31. Fermi GRB 200903B: Global MASTER-Net observations report
  32. INTEGRAL Weak#8699: AROMA-N Optical Observation
  33. GRB 200901A: Swift detection of a burst
  34. GRB 200829A: Liverpool Telescope observations
  35. Fermi GRB 200830A: Global MASTER-Net observations report
  36. GRB 200829A: Fermi GBM detection
  37. GRB 200829A: Nanshan/NEXT optical observations
  38. GRB 200829A: THO optical observatios
  39. GRB200829A: optical afterglow detection
  40. GRB 200829A: Global MASTER-Net OT detection
  41. GRB 200829A: AGILE/MCAL detection
  42. GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
  43. Fermi trigger No 620402299: Global MASTER-Net observations report
  44. Swift GRB 200829A: Global MASTER-Net observations report
  45. GRB 200829A: TSHAO optical observations
  46. Fermi GRB 200826B: Global MASTER-Net observations report
  47. Konus-Wind detection of GRB 200826A
  48. IPN triangulation of GRB 200826A (short/bright)
  49. GRB 200826A: AGILE detection
  50. GRB 200826A: AstroSat CZTI detection
  51. GRB 200826A: Fermi GBM observation
  52. GRB 200826A: BALROG localization (Fermi Trigger 620108997 / GRB 200826187)
  53. GRB 200826A: Fermi GBM Final Real-time Localization
  54. Swift GRB200821.55: Global MASTER-Net observations report
  55. Fermi GRB 200817A: Global MASTER-Net observations report
  56. Fermi GRB 200809B: Global MASTER-Net observations report
  57. GRB 200806A: AstroSat CZTI detection
  58. Fermi GRB 200803B: Global MASTER-Net observations report
  59. Fermi GRB 200801B: Global MASTER-Net observations report
  60. Fermi GRB 200802A: Global MASTER-Net observations report
  61. AX J1846.4-0258: Swift-BAT refined analysis
  62. Fermi GRB 200801A: Global MASTER-Net observations report
  63. Swift Detection of an SGR-like flare from AX J1846.4-0258
  64. Fermi-GBM Sub-Threshold candidate for GRB 200729A
  65. GRB 200729A: IceCube neutrino search
  66. GRB 200729A: TNG NIR upper limits
  67. Swift GRB 200729A: Global MASTER-Net observations report
  68. IceCube Alert 200728.35: Global MASTER-Net observations report
  69. Baksan Neutrino Observatory Alert 200726.66: Global MASTER-Net observations report
  70. GRB 200716C: CrAO, Terskol, Assy-Turgen optical observations
  71. Fermi GBM trigger 616776657/200718619 is not a GRB
  72. GRB 200716C: Swift detection of a burst with an optical counterpart
  73. Fermi GRB 200714D: Global MASTER-Net observations report
  74. Fermi GRB 200714A: Global MASTER-Net observations report
  75. GRB 200711A: Swift-XRT refined Analysis
  76. GRB 200711A: Fermi GBM detection
  77. Fermi trigger No 615741133: Global MASTER-Net observations report
  78. Fermi-LAT-ANTARES 200407a Coincidence
  79. Fermi GRB 200702A: Global MASTER-Net observations report
  80. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  81. GRB 200701A: Swift detection of a burst
  82. GRB 200629A: AstroSat CZTI detection
  83. Fermi GRB 200629A: Global MASTER-Net observations report
  84. GRB 200629A: Fermi GBM Final Real-time Localization
  85. GRB 200629A: BALROG localization (Fermi Trigger 615127794 / GRB 200629535)
  86. Updated catalog of X-ray bursts of SGR J1935+2154 from Insight-HXMT observations
  87. GRB 200623A: TNG optical observations
  88. IceCube-200620A: No significant detection in HAWC
  89. GRB 200613A: CrAO optical observations
  90. GRB 200619A: Fermi GBM observation
  91. Fermi trigger No 614103490: Global MASTER-Net observations report
  92. GRB 200613A: MITSuME Akeno optical upper limits
  93. Fermi GRB 200615A: Global MASTER-Net observations report
  94. IceCube Alert 200614.53: Global MASTER-Net observations report
  95. GRB 200613A: Fermi-LAT detection
  96. Baksan Neutrino Observatory Alert 200611.74: Global MASTER-Net observations report
  97. Fermi GRB 200607A: Global MASTER-Net observations report
  98. IPN triangulation of GRB 200605A (short)
  99. 1RXS J1708−4009: Swift-BAT refined analysis
  100. Fermi GRB 200605A: Global MASTER-Net observations report

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