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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. Fermi trigger No 663967527: Global MASTER-Net observations report
  2. Fermi trigger No 663923149: Global MASTER-Net observations report
  3. Fermi trigger No 663899819: Global MASTER-Net observations report
  4. Fermi trigger No 663886592: Global MASTER-Net observations report
  5. Fermi trigger No 663966693: Global MASTER-Net observations report
  6. GRB 220115B: Fermi GBM Final Real-time Localization
  7. IceCube Alert 220115.51: Global MASTER-Net observations report
  8. Fermi trigger No 663927396: Global MASTER-Net observations report
  9. Fermi trigger No 663921434: Global MASTER-Net observations report
  10. GRB 210919A: LBT spectroscopic redshift of the host galaxy candidates
  11. GRB 220115A: Fermi GBM Final Real-time Localization
  12. IceCube-220115A - IceCube observation of a high-energy neutrino candidate track-like event
  13. Fermi Gamma-ray Burst Monitor trigger 663917434/220115230 is not a GRB
  14. GRB 220114A: Fermi GBM Final Localization
  15. GECAM observations of a series of bursts from SGR J1935+2154
  16. Fermi trigger No 663763320: Global MASTER-Net observations report
  17. Fermi trigger No 663710289: Global MASTER-Net observations report
  18. Fermi-GBM Observations of Recent Bursting Activity from SGR J1935+2154
  19. AGILE observations of a burst from SGR 1935+2154
  20. GECAM observations of a series of bursts from SGR J1935+2154
  21. GRB 220101A: continued 1.3m DFOT optical observations of a high-redshift afterglow
  22. Fermi trigger No 663669570: Global MASTER-Net observations report
  23. GRB 220111A: AstroSat CZTI detection
  24. Fermi trigger No 663658976: Global MASTER-Net observations report
  25. Fermi trigger No 663618072: Global MASTER-Net observations report
  26. Fermi GRB 220111A: Global MASTER-Net observations report
  27. Konus-Wind detection of GRB 220101A (correction to GCN 31433)
  28. GRB 220111A: BALROG localization (Fermi Trigger 663621714 / GRB 220111807)
  29. GRB 220111A: Fermi GBM Final Real-time Localization
  30. Konus-Wind detection of GRB 220101A
  31. Fermi Gamma-ray Burst Monitor trigger 220111325/663580106 is not a GRB
  32. GRB 220107A: SAO RAS optical observations
  33. Konus-Wind detection of GRB 220107B
  34. Konus-Wind detection of GRB 220107A
  35. GECAM observations of a series of bursts from SGR J1935+2154
  36. Confirmation of the X-ray afterglow of GRB 220107B
  37. GRB 220107A: further SAO RAS optical observations
  38. GRB 220101A: Additional Liverpool telescope photometry
  39. Fermi trigger No 663406755: Global MASTER-Net observations report
  40. GRB 220107A: 6m BTA spectroscopic redshift
  41. GRB 220107A: SAO RAS optical observations
  42. GRB 220108A: Swift/BAT-GUANO detection outside the coded FOV
  43. GRB 220101A: SAO RAS optical observations
  44. GRB 220107A: AbAO and Terskol optical observations
  45. GRB 220107B: MITSuME Akeno optical upper limits
  46. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  47. GRB 220107A: Nanshan/NEXT optical observations
  48. GRB 220107A: Swift/UVOT Detection
  49. GRB 220107B: Fermi GBM observations
  50. GRB 220107A: MITSuME Akeno optical observation
  51. GRB 220107B: AstroSat CZTI detection
  52. GRB 220107B: Swift-XRT afterglow detection
  53. GRB 220107A: Swift-XRT afterglow detection
  54. GRB 220107B: Fermi-LAT detection
  55. GRB 220107A: AstroSat CZTI detection
  56. GRB 220107B: Tiled Swift observations
  57. GRB 220107A: Fermi GBM observations
  58. Fermi trigger No 663274898: Global MASTER-Net observations report
  59. GRB 220107A: Swift ToO observations
  60. Fermi GRB 220107A: Global MASTER-Net observations report
  61. GRB 220107A: Swift/BAT-GUANO arcminute localization
  62. GRB 220101A: Tautenburg observations
  63. GRB 220107A: BALROG localization (Fermi Trigger 663259536 / GRB 220107615)
  64. GRB 220107A: Fermi GBM Final Real-time Localization
  65. GRB 220101A: Continued Mondy optical observations
  66. GECAM observation of a burst from SGR J1555.2-5402
  67. GECAM detection of a short burst from SGR 1935+2154
  68. GRB 220101A: further TNG NIR observations
  69. GRB 220101A: continued 1.3m DFOT Optical Observations
  70. Fermi trigger No 663129379: Global MASTER-Net observations report
  71. GRB 220104A: Fermi GBM Observation
  72. GECAM observations of a series of bursts from SGR J1935+2154
  73. GRB 220101A: Mondy optical observations
  74. GRB 220101A: 3rd LCO Optical Observation
  75. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  76. GRB 220101A: iTelescope optical observations
  77. GRB 211227A: Lijiang 2.4m Telescope Optical Observations
  78. GRB 220101A: VLA detection
  79. GRB 220101A: 1.3m DFOT observations
  80. GRB 220101A: LCO Continued Optical Observations
  81. GRB 220104A：GECAM detection
  82. Fermi GRB 220104A: Global MASTER-Net observations report
  83. GRB 220104A: Fermi GBM Final Real-time Localization
  84. GRB 211229B: Fermi GBM observation
  85. Fermi GRB 220103A: Global MASTER-Net observations report
  86. GRB 220103A: Fermi GBM Final Real-time Localization
  87. GRB 211227A: Gemini South Optical Observations
  88. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  89. Alert from the HAWC Burst Monitor HAWC-220103A
  90. GRB 220101A: TNG NIR afterglow detection
  91. GRB 220101A: ALMA detection
  92. GRB 220101A: LCO Optical Observations
  93. GRB 220101A: Tautenburg observations
  94. GRB 220101A: Swift-BAT refined analysis
  95. GRB 220101A: GMG observation (2nd epoch)
  96. GRB 211231A: AstroSat CZTI detection
  97. GRB 220101A: OASDG optical observations
  98. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  99. GRB 220101A: GMG observation
  100. GRB 220101A: Asiago spectroscopic and photometric detection

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