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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. Swift GRB220118.50: Global MASTER-Net observations report
  2. GRB 220118A: MITSuME Akeno optical observation
  3. GRB 220117B: z-band limit
  4. Swift GRB 220118A: Global MASTER-Net observations report
  5. GRB 220118A: Swift detection of a burst with an optical counterpart
  6. GRB 220118A: Fermi GBM Final Real-time Localization
  7. GRB 220117A: MITSuME Akeno optical upper limits
  8. Fermi GBM Sub-Threshold Detection of GRB 220117A
  9. GRB 220117B: Swift-BAT refined analysis
  10. GRB 220117A: Swift-BAT refined analysis
  11. IceCube-220115A: Upper limits from a search for additional neutrino events in IceCube
  12. GRB 220117B: Swift/UVOT Upper Limits
  13. GRB 220117A: Swift/UVOT Upper Limits
  14. GRB 220117A: LCO Optical Observations
  15. GRB 220117A: VLT/X-shooter optical afterglow and redshift
  16. Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620
  17. GRB 220117B: Swift-XRT refined Analysis
  18. GRB 220117A: Swift-XRT refined Analysis
  19. AMON IC_HAWC NuEm-220116A: No neutrino counterpart detected with ANTARES
  20. GRB 220117B: Nanshan/NEXT optical upper limit
  21. GRB 220117B: MITSuME Akeno optical upper limits
  22. GRB 220117B: Enhanced Swift-XRT position
  23. GRB 220117A: Enhanced Swift-XRT position
  24. GRB 220101A: TSHAO optical observation, Terskol, AbAO upper limits
  25. Swift GRB 220117A: Global MASTER-Net observations report
  26. Swift GRB 220117B: Global MASTER-Net observations report
  27. GRB 220117B: Swift detection of a burst
  28. GRB 220117A: Nanshan/NEXT optical observations and a nearby PanSTARRS source
  29. GRB 220117A: Swift detection of a burst
  30. GRB 220101A: The most powerful GRB and BDHN I in 26 years
  31. GECAM observations of a series of bursts from SGR J1935+2154
  32. Fermi trigger No 663960124: Global MASTER-Net observations report
  33. Fermi trigger No 663967527: Global MASTER-Net observations report
  34. Fermi trigger No 663923149: Global MASTER-Net observations report
  35. Fermi trigger No 663899819: Global MASTER-Net observations report
  36. Fermi trigger No 663886592: Global MASTER-Net observations report
  37. Fermi trigger No 663966693: Global MASTER-Net observations report
  38. GRB 220115B: Fermi GBM Final Real-time Localization
  39. IceCube Alert 220115.51: Global MASTER-Net observations report
  40. Fermi trigger No 663927396: Global MASTER-Net observations report
  41. Fermi trigger No 663921434: Global MASTER-Net observations report
  42. GRB 210919A: LBT spectroscopic redshift of the host galaxy candidates
  43. GRB 220115A: Fermi GBM Final Real-time Localization
  44. IceCube-220115A - IceCube observation of a high-energy neutrino candidate track-like event
  45. Fermi Gamma-ray Burst Monitor trigger 663917434/220115230 is not a GRB
  46. GRB 220114A: Fermi GBM Final Localization
  47. GECAM observations of a series of bursts from SGR J1935+2154
  48. Fermi trigger No 663763320: Global MASTER-Net observations report
  49. Fermi trigger No 663710289: Global MASTER-Net observations report
  50. Fermi-GBM Observations of Recent Bursting Activity from SGR J1935+2154
  51. AGILE observations of a burst from SGR 1935+2154
  52. GECAM observations of a series of bursts from SGR J1935+2154
  53. GRB 220101A: continued 1.3m DFOT optical observations of a high-redshift afterglow
  54. Fermi trigger No 663669570: Global MASTER-Net observations report
  55. GRB 220111A: AstroSat CZTI detection
  56. Fermi trigger No 663658976: Global MASTER-Net observations report
  57. Fermi trigger No 663618072: Global MASTER-Net observations report
  58. Fermi GRB 220111A: Global MASTER-Net observations report
  59. Konus-Wind detection of GRB 220101A (correction to GCN 31433)
  60. GRB 220111A: BALROG localization (Fermi Trigger 663621714 / GRB 220111807)
  61. GRB 220111A: Fermi GBM Final Real-time Localization
  62. Konus-Wind detection of GRB 220101A
  63. Fermi Gamma-ray Burst Monitor trigger 220111325/663580106 is not a GRB
  64. GRB 220107A: SAO RAS optical observations
  65. Konus-Wind detection of GRB 220107B
  66. Konus-Wind detection of GRB 220107A
  67. GECAM observations of a series of bursts from SGR J1935+2154
  68. Confirmation of the X-ray afterglow of GRB 220107B
  69. GRB 220107A: further SAO RAS optical observations
  70. GRB 220101A: Additional Liverpool telescope photometry
  71. Fermi trigger No 663406755: Global MASTER-Net observations report
  72. GRB 220107A: 6m BTA spectroscopic redshift
  73. GRB 220107A: SAO RAS optical observations
  74. GRB 220108A: Swift/BAT-GUANO detection outside the coded FOV
  75. GRB 220101A: SAO RAS optical observations
  76. GRB 220107A: AbAO and Terskol optical observations
  77. GRB 220107B: MITSuME Akeno optical upper limits
  78. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  79. GRB 220107A: Nanshan/NEXT optical observations
  80. GRB 220107A: Swift/UVOT Detection
  81. GRB 220107B: Fermi GBM observations
  82. GRB 220107A: MITSuME Akeno optical observation
  83. GRB 220107B: AstroSat CZTI detection
  84. GRB 220107B: Swift-XRT afterglow detection
  85. GRB 220107A: Swift-XRT afterglow detection
  86. GRB 220107B: Fermi-LAT detection
  87. GRB 220107A: AstroSat CZTI detection
  88. GRB 220107B: Tiled Swift observations
  89. GRB 220107A: Fermi GBM observations
  90. Fermi trigger No 663274898: Global MASTER-Net observations report
  91. GRB 220107A: Swift ToO observations
  92. Fermi GRB 220107A: Global MASTER-Net observations report
  93. GRB 220107A: Swift/BAT-GUANO arcminute localization
  94. GRB 220101A: Tautenburg observations
  95. GRB 220107A: BALROG localization (Fermi Trigger 663259536 / GRB 220107615)
  96. GRB 220107A: Fermi GBM Final Real-time Localization
  97. GRB 220101A: Continued Mondy optical observations
  98. GECAM observation of a burst from SGR J1555.2-5402
  99. GECAM detection of a short burst from SGR 1935+2154
  100. GRB 220101A: further TNG NIR observations

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