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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"

22212 results found.

  1. Fermi GRB 220104A: Global MASTER-Net observations report
  2. Fermi GRB 220103A: Global MASTER-Net observations report
  3. GRB 211227A: Gemini South Optical Observations
  4. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  5. Alert from the HAWC Burst Monitor HAWC-220103A
  6. GRB 220101A: TNG NIR afterglow detection
  7. GRB 220101A: ALMA detection
  8. GRB 220101A: LCO Optical Observations
  9. GRB 220101A: Tautenburg observations
  10. GRB 220101A: GMG observation (2nd epoch)
  11. GRB 220101A: OASDG optical observations
  12. GRB 220101A: GMG observation
  13. Fermi trigger No 662768315: Global MASTER-Net observations report
  14. GRB 220101A: THO optical observations
  15. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  16. Swift GRB220101.22: Global MASTER-Net observations report
  17. GRB 220101: Swift/UVOT Detection
  18. GRB 211229A: Swift-XRT and UVOT observations
  19. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  20. GRB 211229C: Swift/BAT-GUANO detection likely outside the coded FOV
  21. Fermi GRB 211229B: Global MASTER-Net observations report
  22. GRB 211229A: Swift ToO observations
  23. GRB 211229A: Swift/BAT-GUANO arcminute localization
  24. Fermi GRB 211229A: Global MASTER-Net observations report
  25. GRB 211227A: Swift/UVOT Upper Limits
  26. Konus-Wind detection of the intermediate flare from SGR 1935+2154
  27. GRB 211227A: A possible short GRB with extended emission at z = 0.228?
  28. GRB 211227A: Liverpool Telescope upper limits
  29. GRB 211227A: LCO Optical Observations
  30. GRB 211227A: Nanshan/NEXT optical observations and host galaxy candidate
  31. GRB 211221A: Swift/UVOT Upper Limits
  32. Swift GRB211227.98: Global MASTER-Net observations report
  33. IceCube-20211216B: observations of SN2021gpw in the errorbox of the neutrino trigger
  34. GRB 211226A: Swift/BAT-GUANO detection outside the coded FOV
  35. Fermi trigger No 662216114: Global MASTER-Net observations report
  36. GRB 211225A: MITSuME Akeno optical upper limits
  37. Swift GRB 211225B: Global MASTER-Net observations report
  38. Fermi GRB 211225C: Global MASTER-Net observations report
  39. MAXI GRB211225.14: Global MASTER-Net observations report
  40. Fermi trigger No 662084433: Global MASTER-Net observations report
  41. GRB 211106A: Third HST Observation
  42. GRB 211211A: observations with the 3.6m Devasthal Optical Telescope
  43. Fermi trigger No 662010159: Global MASTER-Net observations report
  44. AGILE observations of a bright burst from SGR 1935+2154
  45. Swift GRB 211223C: Global MASTER-Net observations report
  46. Fermi GRB 211223B: Global MASTER-Net observations report
  47. GRB 211221A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  48. Fermi GRB 211222A: Global MASTER-Net observations report
  49. GRB 211218A: MITSuME Akeno optical upper limits
  50. GRB 211221A: MeerLICHT optical limits
  51. GRB 211221A: NOT optical limits
  52. Swift GRB 211221A: Global MASTER-Net observations report
  53. GRB 211219A: Swift/BAT-GUANO detection outside the coded FOV
  54. Fermi GRB 211219B: Global MASTER-Net observations report
  55. Fermi GRB 211219A: Global MASTER-Net observations report
  56. GRB 211211A: MMT/MMIRS Observations Indicate Fading of K-band Source
  57. MAXI GRB211218.04: Global MASTER-Net observations report
  58. GRB 211106A: XMM-Newton monitoring campaign detections
  59. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  60. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  61. IceCube-211216B: Upper limits from Fermi-GBM Observations
  62. IceCube-211216A: Upper limits from Fermi-GBM Observations
  63. Fermi trigger No 661417475: Global MASTER-Net observations report
  64. GRB 211216A: Swift/BAT-GUANO detection outside the coded FOV
  65. IceCube Alert 211216.99: Global MASTER-Net observations report
  66. Fermi GRB 211216B: Global MASTER-Net observations report
  67. IceCube Alert 211216.30: Global MASTER-Net observations report
  68. GRB 211211A: TNG NIR observations
  69. Fermi GRB 211216A: Global MASTER-Net observations report
  70. GRB 211211A - Gemini K-band detection
  71. GRB 211211A: SAO RAS optical observations
  72. GRB 211211A: AbAO optical observations
  73. Chandra observation of GW170817 at ~1575 days since merger (all epochs)
  74. GRB 211211A: Very fast decay observed from CAFOS/2.2mCAHA
  75. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  76. GRB 211211A: HCT and GIT optical follow up observations
  77. Fermi GRB 211212A: Global MASTER-Net observations report
  78. GRB 211211A: Swift/UVOT detection
  79. Fermi GRB 211212B: Global MASTER-Net observations report
  80. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  81. Swift GRB 211211A: Global MASTER-Net observations report
  82. GRB 211211A: LCO Optical Observations
  83. GRB 211211A: Nanshan/NEXT optical observations
  84. Fermi GRB 211211B: Global MASTER-Net observations report
  85. Fermi GRB 211211A: Global MASTER-Net observations report
  86. GRB 211207A: Swift/UVOT Detection
  87. GRB 211211A: KAIT Optical Afterglow Candidate
  88. Fermi trigger No 660868196: Global MASTER-Net observations report
  89. Fermi trigger No 660736561: Global MASTER-Net observations report
  90. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  91. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  92. IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  93. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211209A
  94. IceCube Alert 211208.84: Global MASTER-Net observations report
  95. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  96. Swift GRB 211207A: Global MASTER-Net observations report
  97. GRB 211206A: Swift/BAT-GUANO detection outside the coded FOV
  98. GRB 211204C: Swift/BAT-GUANO detection outside the coded FOV
  99. Fermi GRB 211204C: Global MASTER-Net observations report
  100. Fermi GRB 211204B: Global MASTER-Net observations report

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