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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"

22215 results found.

  1. Fermi GRB 211024A: Global MASTER-Net observations report
  2. IceCube Alert 211023.36: Global MASTER-Net observations report
  3. GRB 211018A: Swift ToO observations
  4. Fermi trigger No 656506979: Global MASTER-Net observations report
  5. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211020A
  6. Fermi trigger No 656268212: Global MASTER-Net observations report
  7. GRB 211019A: Detection by GRBAlpha
  8. GRB 211018A: Detection by GRBAlpha
  9. Fermi GRB 211019A: Global MASTER-Net observations report
  10. Fermi trigger No 656288898: Global MASTER-Net observations report
  11. Swift GRB211017.99: Global MASTER-Net observations report
  12. Integral GRB211016.42: Global MASTER-Net observations report
  13. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  14. Swift trigger 1078701: MITSuME Akeno optical upper limits
  15. Fermi trigger No 655673024: Global MASTER-Net observations report
  16. GRB 210919A: LDT optical observations and candidate host galaxies
  17. IceCube-20210922A: No optical counterparts found by MITSuME observations
  18. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  19. Fermi trigger No 655646385: Global MASTER-Net observations report
  20. Swift GRB211010.45: Global MASTER-Net observations report
  21. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  22. Fermi trigger No 655401471: Global MASTER-Net observations report
  23. GRB 210928A: MeerKAT detection
  24. IceCube-210922A: DESI Observations
  25. Konus-Wind detection of GRB 210928A
  26. Fermi trigger No 654854799: Global MASTER-Net observations report
  27. GRB 210928A: Kinder SLT-40cm optical limits
  28. SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
  29. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  30. Fermi trigger No 654739449: Global MASTER-Net observations report
  31. Swift GRB211001.03: Global MASTER-Net observations report
  32. GRB 210930A: Swift/UVOT Upper Limits
  33. Swift GRB 210930A: Global MASTER-Net observations report
  34. Fermi trigger No 654658271: Global MASTER-Net observations report
  35. Fermi GRB 210929B: Global MASTER-Net observations report
  36. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  37. GRB 210919A OSN 1.5m Source Confirmation
  38. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  39. IceCube-210922A: JCMT/SCUBA2 observations
  40. IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
  41. IceCube-210922A: Upper limits from Fermi-GBM Observations
  42. IceCube-210922A: No Candidate Counterparts from the Zwicky Transient Facility
  43. GECAM observations of a series of bursts from SGR J1935+2154 (2021-09-15T14 to 2021-09-23T14)
  44. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  45. IceCube Alert 210922.76: Global MASTER-Net observations report
  46. GRB 210912A: LBT optical observations
  47. GRB 210919A: Lowell Discovery Telescope upper limits (correction to GCN 30859)
  48. GRB210919A: Keck NIRC2 Kp band upper limits
  49. GRB 210919A: Swift/UVOT Upper Limits
  50. GRB 210919A: LOAO and LSGT optical upper limits
  51. GRB 210919A: NOT upper limits
  52. GRB 210919A: AbAO optical upper limit
  53. Swift GRB 210919A: Global MASTER-Net observations report
  54. Swift trigger 1073821: detection of IGR J16418-4532
  55. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  56. GECAM observations of bursts from SGR J1935+2154 (2021-09-13T01 to 2021-09-15T14)
  57. GRB 210909A: Detection by GRBAlpha
  58. GRB 210912A: Tautenburg observations
  59. GECAM observations of bursts from SGR J1935+2154 (2021-09-12T05 to 2021-09-13T01)
  60. AGILE observations of two bright bursts from SGR 1935+2154
  61. GRB 210912A: CAHA 2.2m Detection
  62. GRB 210912A: Swift/UVOT Detection
  63. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  64. Fermi trigger No 653151835: Global MASTER-Net observations report
  65. Fermi trigger No 653124492: Global MASTER-Net observations report
  66. Fermi trigger No 653122278: Global MASTER-Net observations report
  67. Swift GRB 210912A: Global MASTER-Net observations report
  68. GRB 210912A: BOOTES-5/JGT optical afterglow candidate
  69. GECAM observations of bursts from SGR J1935+2154 (2021-09-11T07 to 2021-09-12T08)
  70. Fermi trigger No 653093506: Global MASTER-Net observations report
  71. Fermi trigger No 653066776: Global MASTER-Net observations report
  72. Fermi trigger No 653084584: Global MASTER-Net observations report
  73. Fermi trigger No 653083551: Global MASTER-Net observations report
  74. Fermi trigger No 653079281: Global MASTER-Net observations report
  75. Fermi trigger No 653066130: Global MASTER-Net observations report
  76. Fermi trigger No 653072474: Global MASTER-Net observations report
  77. Fermi trigger No 653071808: Global MASTER-Net observations report
  78. Fermi trigger No 653054042: Global MASTER-Net observations report
  79. Fermi trigger No 653049776: Global MASTER-Net observations report
  80. Fermi trigger No 653022153: Global MASTER-Net observations report
  81. Fermi trigger No 653031163: Global MASTER-Net observations report
  82. Swift GRB210910.42: Global MASTER-Net observations report
  83. Fermi GBM observation of a bright flare in the direction of SGR 1935+2154
  84. Fermi trigger No 653010039: Global MASTER-Net observations report
  85. Fermi trigger No 652957973: Global MASTER-Net observations report
  86. Fermi trigger No 652944960: Global MASTER-Net observations report
  87. Fermi trigger No 652981861: Global MASTER-Net observations report
  88. GRB 210826A: further Swift-XRT observations
  89. GECAM observations of a series of bursts from SGR J1935+2154
  90. Fermi trigger No 652934203: Global MASTER-Net observations report
  91. Fermi trigger No 652927551: Global MASTER-Net observations report
  92. GRB 210619B: Maidanak and Assy optical observations, broken power law parametrization
  93. Fermi trigger No 652911693: Global MASTER-Net observations report
  94. Fermi trigger No 652906639: Global MASTER-Net observations report
  95. Fermi GRB 210909A: Global MASTER-Net observations report
  96. GRB 210905A: Swift/UVOT Upper Limits
  97. GRB 210905A: ATCA detection
  98. GRB 210905A: ALMA detection
  99. GRB 210905A, GROND observations
  100. Fermi trigger No 652585475: Global MASTER-Net observations report

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