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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

21114 results found.

  1. Swift GRB 211223C: Global MASTER-Net observations report
  2. Fermi GRB 211223B: Global MASTER-Net observations report
  3. GRB 211221A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  4. Fermi GRB 211222A: Global MASTER-Net observations report
  5. GRB 211218A: MITSuME Akeno optical upper limits
  6. GRB 211221A: MeerLICHT optical limits
  7. GRB 211221A: NOT optical limits
  8. Swift GRB 211221A: Global MASTER-Net observations report
  9. Fermi GRB 211219B: Global MASTER-Net observations report
  10. Fermi GRB 211219A: Global MASTER-Net observations report
  11. GRB 211211A: MMT/MMIRS Observations Indicate Fading of K-band Source
  12. MAXI GRB211218.04: Global MASTER-Net observations report
  13. GRB 211106A: XMM-Newton monitoring campaign detections
  14. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  15. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  16. IceCube-211216B: Upper limits from Fermi-GBM Observations
  17. IceCube-211216A: Upper limits from Fermi-GBM Observations
  18. Fermi trigger No 661417475: Global MASTER-Net observations report
  19. IceCube Alert 211216.99: Global MASTER-Net observations report
  20. Fermi GRB 211216B: Global MASTER-Net observations report
  21. IceCube Alert 211216.30: Global MASTER-Net observations report
  22. GRB 211211A: TNG NIR observations
  23. Fermi GRB 211216A: Global MASTER-Net observations report
  24. GRB 211211A - Gemini K-band detection
  25. GRB 211211A: SAO RAS optical observations
  26. GRB 211211A: AbAO optical observations
  27. Chandra observation of GW170817 at ~1575 days since merger (all epochs)
  28. GRB 211211A: Very fast decay observed from CAFOS/2.2mCAHA
  29. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  30. GRB 211211A: HCT and GIT optical follow up observations
  31. Fermi GRB 211212A: Global MASTER-Net observations report
  32. GRB 211211A: Swift/UVOT detection
  33. Fermi GRB 211212B: Global MASTER-Net observations report
  34. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  35. Swift GRB 211211A: Global MASTER-Net observations report
  36. GRB 211211A: LCO Optical Observations
  37. GRB 211211A: Nanshan/NEXT optical observations
  38. Fermi GRB 211211B: Global MASTER-Net observations report
  39. Fermi GRB 211211A: Global MASTER-Net observations report
  40. GRB 211207A: Swift/UVOT Detection
  41. GRB 211211A: KAIT Optical Afterglow Candidate
  42. Fermi trigger No 660868196: Global MASTER-Net observations report
  43. Fermi trigger No 660736561: Global MASTER-Net observations report
  44. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  45. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  46. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211209A
  47. IceCube Alert 211208.84: Global MASTER-Net observations report
  48. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  49. Swift GRB 211207A: Global MASTER-Net observations report
  50. Fermi GRB 211204C: Global MASTER-Net observations report
  51. Fermi GRB 211204B: Global MASTER-Net observations report
  52. Fermi GRB 211204A: Global MASTER-Net observations report
  53. Swift GRB 211203A: Global MASTER-Net observations report
  54. Fermi GRB 211201A: Global MASTER-Net observations report
  55. Fermi GRB 211130A: Global MASTER-Net observations report
  56. GRB 211129A: Swift/UVOT Upper Limits
  57. GRB 211106A: HST Observations
  58. GRB 211106A: Chandra Observations
  59. Swift GRB 211129A: Global MASTER-Net observations report
  60. GRB 211023A: Xinglong 2.16m optical observations
  61. GRB 211023A: Xinglong 2.16m optical observations
  62. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  63. Chandra observations of GRB 210905A
  64. IceCube Alert 211125.27: Global MASTER-Net observations report
  65. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  66. IceCube-211123A: INTEGRAL was inactive at the time of the event
  67. IceCube-211123A: Upper limits from Fermi-GBM Observations
  68. IceCube-211023A: not observable by Fermi-GBM
  69. IceCube Alert 211123.60: Global MASTER-Net observations report
  70. Fermi trigger No 659413798: Global MASTER-Net observations report
  71. Trigger_21473: Tiled Swift observations
  72. GRB 211023B: LBT likely spectroscopic redshift of the host galaxy
  73. Alert from the HAWC Burst Monitor HAWC-211123A
  74. Fermi trigger No 659183098: Global MASTER-Net observations report
  75. Fermi trigger No 659106591: Global MASTER-Net observations report
  76. GRB 211023A: optical observations and photometric evidence of supernova
  77. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  78. Fermi trigger No 658971499: Global MASTER-Net observations report
  79. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  80. IceCube Alert 211116.44: Global MASTER-Net observations report
  81. Fermi trigger No 658755664: Global MASTER-Net observations report
  82. Fermi trigger No 658764238: Global MASTER-Net observations report
  83. Fermi trigger No 658686687: Global MASTER-Net observations report
  84. Fermi GRB 211112A: Global MASTER-Net observations report
  85. Fermi trigger No 658214822: Global MASTER-Net observations report
  86. GRB 211107B: Swift-XRT afterglow detection
  87. GRB 211106A: VLT/FORS2 optical observations
  88. GRB 211106A, GROND observations
  89. GRB 211106A: Swift-XRT afterglow detection
  90. Fermi GRB 211109B: Global MASTER-Net observations report
  91. GRB 211023A: SAO RAS optical observations
  92. GRB 211107B: Swift-XRT observations
  93. MeerLICHT follow-up of GRB 211106A
  94. GRB 211107B: Swift ToO observations
  95. Fermi GRB 211109A: Global MASTER-Net observations report
  96. GRB 211107B: Swift/BAT detection
  97. GRB 211023A: A BdHN of type I
  98. GRB 211106A: Swift-XRT observations
  99. GRB 211106A: Swift ToO observations
  100. GRB 211106A: Swift/BAT-GUANO candidate arcminute localization of a short burst

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