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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"

4255 results found.

  1. IceCube-201007A: No significant detection in HAWC
  2. IceCube-200926A: Upper limits from Insight-HXMT Observations
  3. Fermi GRB 201007A: Global MASTER-Net observations report
  4. Fermi trigger No 623470566: Global MASTER-Net observations report
  5. Fermi trigger No 623493962: Global MASTER-Net observations report
  6. IceCube-200926B: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  7. IceCube-200929A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  8. GRB 201001A: Xinglong-2.16m optical upper limit
  9. IceCube-200929A: No significant detection in HAWC
  10. Swift-XRT observations of IceCube 200929A
  11. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  12. IceCube-200926B: No significant detection in HAWC
  13. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  14. IceCube Alert 200929.74: Global MASTER-Net observations report
  15. IceCube-200926A: No significant detection in HAWC
  16. Fermi GRB 200929A: Global MASTER-Net observations report
  17. GRB 200928B: AstroSat CZTI detection
  18. GRB 200929A: Fermi GBM Final Real-time Localization
  19. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  20. IceCube Alert 200926.33: Global MASTER-Net observations report
  21. Fermi GRB 200925A: Global MASTER-Net observations report
  22. Fermi GRB 200924A: Global MASTER-Net observations report
  23. GRB 200924B: Fermi GBM Final Localization
  24. Fermi GRB 200923A: Global MASTER-Net observations report
  25. Fermi GRB 200916A: Global MASTER-Net observations report
  26. IceCube Alert 200914.00: Global MASTER-Net observations report
  27. IceCube-200911A: No significant detection in HAWC
  28. IPN triangulation of GRB 200907A (short)
  29. Swift GRB200909.97: Global MASTER-Net observations report
  30. Fermi GRB 200909A: Global MASTER-Net observations report
  31. GRB 200906A: OSN 1.5m Upper Limit
  32. Fermi GRB 200903C: Global MASTER-Net observations report
  33. GRB 200903A: Swift-BAT refined analysis
  34. Fermi GRB 200903B: Global MASTER-Net observations report
  35. INTEGRAL Weak#8699: AROMA-N Optical Observation
  36. GRB 200901A: Swift detection of a burst
  37. GRB 200829A: Liverpool Telescope observations
  38. Fermi GRB 200830A: Global MASTER-Net observations report
  39. GRB 200829A: Fermi GBM detection
  40. GRB 200829A: Nanshan/NEXT optical observations
  41. GRB 200829A: THO optical observatios
  42. GRB200829A: optical afterglow detection
  43. GRB 200829A: Global MASTER-Net OT detection
  44. GRB 200829A: AGILE/MCAL detection
  45. GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
  46. Fermi trigger No 620402299: Global MASTER-Net observations report
  47. Swift GRB 200829A: Global MASTER-Net observations report
  48. GRB 200829A: TSHAO optical observations
  49. Fermi GRB 200826B: Global MASTER-Net observations report
  50. Konus-Wind detection of GRB 200826A
  51. IPN triangulation of GRB 200826A (short/bright)
  52. GRB 200826A: AGILE detection
  53. GRB 200826A: AstroSat CZTI detection
  54. GRB 200826A: Fermi GBM observation
  55. GRB 200826A: BALROG localization (Fermi Trigger 620108997 / GRB 200826187)
  56. GRB 200826A: Fermi GBM Final Real-time Localization
  57. Swift GRB200821.55: Global MASTER-Net observations report
  58. Fermi GRB 200817A: Global MASTER-Net observations report
  59. Fermi GRB 200809B: Global MASTER-Net observations report
  60. GRB 200806A: AstroSat CZTI detection
  61. Fermi GRB 200803B: Global MASTER-Net observations report
  62. Fermi GRB 200801B: Global MASTER-Net observations report
  63. Fermi GRB 200802A: Global MASTER-Net observations report
  64. AX J1846.4-0258: Swift-BAT refined analysis
  65. Fermi GRB 200801A: Global MASTER-Net observations report
  66. Swift Detection of an SGR-like flare from AX J1846.4-0258
  67. Fermi-GBM Sub-Threshold candidate for GRB 200729A
  68. GRB 200729A: IceCube neutrino search
  69. GRB 200729A: TNG NIR upper limits
  70. Swift GRB 200729A: Global MASTER-Net observations report
  71. IceCube Alert 200728.35: Global MASTER-Net observations report
  72. Baksan Neutrino Observatory Alert 200726.66: Global MASTER-Net observations report
  73. GRB 200716C: CrAO, Terskol, Assy-Turgen optical observations
  74. Fermi GBM trigger 616776657/200718619 is not a GRB
  75. GRB 200716C: Swift detection of a burst with an optical counterpart
  76. Fermi GRB 200714D: Global MASTER-Net observations report
  77. Fermi GRB 200714A: Global MASTER-Net observations report
  78. GRB 200711A: Swift-XRT refined Analysis
  79. GRB 200711A: Fermi GBM detection
  80. Fermi trigger No 615741133: Global MASTER-Net observations report
  81. Fermi-LAT-ANTARES 200407a Coincidence
  82. Fermi GRB 200702A: Global MASTER-Net observations report
  83. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  84. GRB 200701A: Swift detection of a burst
  85. GRB 200629A: AstroSat CZTI detection
  86. Fermi GRB 200629A: Global MASTER-Net observations report
  87. GRB 200629A: Fermi GBM Final Real-time Localization
  88. GRB 200629A: BALROG localization (Fermi Trigger 615127794 / GRB 200629535)
  89. Updated catalog of X-ray bursts of SGR J1935+2154 from Insight-HXMT observations
  90. GRB 200623A: TNG optical observations
  91. IceCube-200620A: No significant detection in HAWC
  92. GRB 200613A: CrAO optical observations
  93. GRB 200619A: Fermi GBM observation
  94. Fermi trigger No 614103490: Global MASTER-Net observations report
  95. GRB 200613A: MITSuME Akeno optical upper limits
  96. Fermi GRB 200615A: Global MASTER-Net observations report
  97. IceCube Alert 200614.53: Global MASTER-Net observations report
  98. GRB 200613A: Fermi-LAT detection
  99. Baksan Neutrino Observatory Alert 200611.74: Global MASTER-Net observations report
  100. Fermi GRB 200607A: Global MASTER-Net observations report

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