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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"

3797 results found.

  1. Konus-Wind detection of GRB 220310A
  2. GRB 220310A: GIT confirmation of optical afterglow.
  3. GRB 220310A: MASTER optical counterpart detection
  4. GRB 220310A: Swift ToO observations
  5. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  6. GRB 220310A: MAXI/GSC detection
  7. MAXI GRB220310.02: Global MASTER-Net observations report
  8. Konus-Wind detection of GRB 220308A
  9. Fermi GRB 220309A: Global MASTER-Net observations report
  10. IPN triangulation of GRB 220308A (long / very bright)
  11. IPN triangulation of GRB 220305B
  12. Fermi GRB 220223A: Global MASTER-Net observations report
  13. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  14. ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
  15. Fermi GRB 220222A: Global MASTER-Net observations report
  16. ZTF22aabjpxh/AT2022cva: Assy optical observations
  17. ZTF22aaajecb/AT2022cmc: Submillimeter Array detection
  18. IceCube Alert 220221.03: Global MASTER-Net observations report
  19. Konus-Wind observation of GRB 220219A
  20. IPN triangulation of GRB 220219A
  21. IceCube Alert 220220.60: Global MASTER-Net observations report
  22. Fermi trigger No 666962499: Global MASTER-Net observations report
  23. ZTF22aaajecp/AT2022cmc: VLA radio detection
  24. Fermi trigger No 666489765: Global MASTER-Net observations report
  25. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  26. IceCube Alert 220202.49: Global MASTER-Net observations report
  27. IPN triangulation of GRB 220128A (long)
  28. GRB 220129A: Fermi GBM Final Real-time Localization
  29. Fermi trigger No 664738369: Global MASTER-Net observations report
  30. GRB 220118A: TARGET optical upper limit
  31. GRB 220117A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  32. GRB 220117A: Nanshan/NEXT optical observations and a nearby PanSTARRS source
  33. Fermi trigger No 663966693: Global MASTER-Net observations report
  34. IceCube Alert 220115.51: Global MASTER-Net observations report
  35. Fermi trigger No 663927396: Global MASTER-Net observations report
  36. GECAM observations of a series of bursts from SGR J1935+2154
  37. Fermi-GBM Observations of Recent Bursting Activity from SGR J1935+2154
  38. Fermi GRB 220111A: Global MASTER-Net observations report
  39. Fermi trigger No 663274898: Global MASTER-Net observations report
  40. Fermi GRB 220107A: Global MASTER-Net observations report
  41. GRB 220101A: Continued Mondy optical observations
  42. GRB 220101A: TNG NIR afterglow detection
  43. GRB 220101A: Swift-BAT refined analysis
  44. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  45. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  46. GRB 211227A: MAXI/GSC detection
  47. IceCube-20211216B: observations of SN2021gpw in the errorbox of the neutrino trigger
  48. GRB 211225B: Swift-BAT refined analysis
  49. GRB 211225A: MITSuME Akeno optical upper limits
  50. MAXI GRB211225.14: Global MASTER-Net observations report
  51. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  52. Fermi trigger No 662084433: Global MASTER-Net observations report
  53. GRB 211218A: MITSuME Akeno optical upper limits
  54. Fermi GRB 211219B: Global MASTER-Net observations report
  55. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  56. MAXI GRB211218.04: Global MASTER-Net observations report
  57. Fermi GRB 211216A: Global MASTER-Net observations report
  58. GRB 211211A: LCO Optical Observations
  59. Fermi GRB 211211B: Global MASTER-Net observations report
  60. IceCube-211208A: No significant detection in HAWC
  61. Fermi trigger No 660736561: Global MASTER-Net observations report
  62. GRB 211204C: AstroSat CZTI detection
  63. GRB 211129A: Nanshan/NEXT optical upper limit
  64. Fermi trigger No 659106591: Global MASTER-Net observations report
  65. Fermi trigger No 658971499: Global MASTER-Net observations report
  66. Fermi trigger No 658755664: Global MASTER-Net observations report
  67. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  68. GRB 211115A: MAXI/GSC detection
  69. Fermi GRB 211112A: Global MASTER-Net observations report
  70. IPN triangulation of GRB 211106A (short)
  71. Fermi trigger No 658214822: Global MASTER-Net observations report
  72. Fermi GRB 211109B: Global MASTER-Net observations report
  73. GRB 211023B: MITSuME Akeno optical upper limits
  74. Fermi GRB 211031A: Global MASTER-Net observations report
  75. GRB 211023A: continued Mondy optical observations
  76. Fermi GRB 211027A: Global MASTER-Net observations report
  77. GRB 211024A: Swift-XRT observations
  78. Swift GRB 211025A: Global MASTER-Net observations report
  79. GRB 211023A: 1.5m OSN optical observation
  80. Fermi GRB 211024A: Global MASTER-Net observations report
  81. Fermi trigger No 656288898: Global MASTER-Net observations report
  82. Fermi trigger No 655673024: Global MASTER-Net observations report
  83. Fermi trigger No 655646385: Global MASTER-Net observations report
  84. Swift GRB211010.45: Global MASTER-Net observations report
  85. Fermi Gamma-ray Burst Monitor trigger 211008665/655401471 is not a GRB
  86. GRB 211008A: BALROG localization (Fermi Trigger 655401471 / GRB 211008665)
  87. Fermi trigger No 655401471: Global MASTER-Net observations report
  88. Fermi GRB 210929B: Global MASTER-Net observations report
  89. GRB 210927A: Fermi GBM Final Real-time Localization
  90. Fermi trigger No 653151835: Global MASTER-Net observations report
  91. GRB 210912A: Mondy optical afterglow confirmation
  92. Swift GRB 210912A: Global MASTER-Net observations report
  93. Fermi trigger No 653093506: Global MASTER-Net observations report
  94. Fermi trigger No 653083551: Global MASTER-Net observations report
  95. Fermi trigger No 653079281: Global MASTER-Net observations report
  96. Fermi trigger No 653022153: Global MASTER-Net observations report
  97. Fermi GBM observation of a bright flare in the direction of SGR 1935+2154
  98. Fermi trigger No 652927551: Global MASTER-Net observations report
  99. Fermi trigger No 652911693: Global MASTER-Net observations report
  100. Fermi trigger No 652906639: Global MASTER-Net observations report

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