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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. GRB 111117A: NOT observations
  2. GRB 111117A: Chandra ToO observation scheduled
  3. GRB 111117A: Swift-BAT refined analysis of a short hard burst
  4. GRB 111117A: GMG upper limit
  5. GRB 111117A: Swift detection of a short hard burst
  6. GRB111107A: ATCA observations - upper limit and a possible detection
  7. Konus-Wind observation of GRB 111113A
  8. IPN Triangulation of GRB 111113A (short/hard/intense)
  9. XRF 111111A/MAXI J0158-744: MAXI GSC refined analysis
  10. XRF 111111A/MAXI J0158-744: MAXI GSC and SSC detection of a soft X-ray transient near SMC
  11. GRB 111109A: Swift-XRT refined Analysis
  12. GRB 111109A: Swift/UVOT Photometry
  13. GRB 111109A: Swift-BAT refined analysis
  14. GRB 111109A: Enhanced Swift-XRT position
  15. GRB 111109A: Swift-XRT observations
  16. GRB 111109A: Swift detection of a burst
  17. GRB 111103B: optical upper limit of CrAO
  18. GRB 111103B: optical upper limit of Mt. Terskol observatory
  19. GRB 111107A: Fermi GBM observation
  20. Continued Skynet observations of GRB111107A
  21. GRB 111107A: Swift-XRT refined Analysis
  22. GRB 111107A: VLT/X-shooter spectroscopy
  23. GRB 111107A: APEX submm observation
  24. GRB 111107A: Swift/UVOT Afterglow Analysis
  25. GRB 111107A: Swift-BAT refined analysis
  26. GRB 111107A: Enhanced Swift-XRT position
  27. GRB 111107A: Gemini-South Redshift
  28. GRB 111107A: GROND observations
  29. Skynet observations of GRB 111107A
  30. GRB 111107A: Swift detection of a burst with an optical counterpart
  31. GRB 111103B: MITSuME Akeno Optical upper limits
  32. Konus-Wind observation of GRB 111103B
  33. GRB 111103B : WIYN 3.5m NIR observations
  34. GRB 111103B: Swift-XRT refined Analysis
  35. GRB 111103A: Fermi GBM observation
  36. GRB111103B Swift/UVOT Upper Limits
  37. GRB 111103B: optical observations from TAU, Ka-Dar
  38. Trigger 506913: MASTER detection of Swift J1922.7-1716 optical counterpart
  39. GRB 111103B: Enhanced Swift-XRT position
  40. GRB 111103B: Swift-BAT refined analysis
  41. GRB 111103A: Swift-BAT refined analysis
  42. Trigger 506913: Swift detection of Swift J1922.7-1716 and its optical counterpart
  43. GRB 111022B: MASTER OT observations
  44. GRB 111103B: optical observations
  45. GRB 111103B: Swift detection of a strong burst from a GRB or Galactic source
  46. GRB 111103A: Swift detection of a burst
  47. Swift-BAT trigger 506884 is not a GRB
  48. GRB 111029A: RAPTOR Limits During the Gamma-ray Emitting Interval
  49. GRB 111029A: SAO RAS optical limits
  50. GRB 111029A: Super-LOTIS early limits
  51. All GCN Circulars available in a tarfile for data mining
  52. GRB 111026A: spectral lag value inconclusive for a short burst
  53. GRB111029A: MITSuME Ishigakijima Optical Upper Limits
  54. GRB 111029A: TNT optical upper limit, Correction to GCN 12503
  55. GRB 111029A: Swift-XRT refined Analysis
  56. GRB 111029A: PAIRITEL NIR Upper Limits
  57. GRB 111026A: Swift-BAT refined analysis
  58. GRB 111029A: Swift/UVOT Upper Limits
  59. GRB 111029A: KAIT optical limits
  60. GRB 111029A: Swift-BAT refined analysis
  61. GRB 111029A: TNT optical upper limit
  62. GRB 111029A: Enhanced Swift-XRT position
  63. GRB 111029A: Faulkes Telescope North observations
  64. GRB 111029A: optical upper limit
  65. GRB 111029A: ROTSE-III Optical Limits
  66. GRB 111029A: Swift detection of a burst
  67. GRB 111026A: Swift detection of a burst
  68. GRB 111022B: EVLA observations - correction to GCN 12495
  69. GRB 111022B: EVLA observations
  70. GRB 111022B: 10.4m GTC z'-band observations
  71. GRB111022B: D50 optical limit
  72. GRB 111020A: Chandra Observation
  73. GRB 111022B: BTA Optical Observations
  74. GRB 111022A: MITSuME Akeno Optical upper limits
  75. GRB 111024A: MAXI/GSC detection of a burst
  76. GRB 111022B: Swift/UVOT upper limits
  77. GRB 111022A: Swift/UVOT Upper Limits
  78. GRB 111016A: optical upper limit
  79. GRB 111022B, Swift-BAT refined analysis
  80. GRB 111022B: Swift-XRT refined Analysis
  81. GRB 111022A: RIzY Observation
  82. GRB 111022A: Swift-XRT refined Analysis
  83. GRB 111022B: Gemini infrared observations
  84. GRB 111022B: MITSuME Akeno Optical upper limits
  85. GRB 111022B: NOT observations
  86. GRB 111022B: Enhanced Swift-XRT position
  87. GRB 111020A Spectral lag analysis
  88. GRB 111022A: Swift-BAT refined analysis
  89. GRB 111022B: MASTER-Net early limit
  90. GRB 111022A: Preliminary UVOT TDRSS Non-Detection
  91. GRB 111022A: MASTER-Net early limit
  92. GRB 111022B: Swift detection of a burst
  93. GRB 111022A: Swift detection of a burst
  94. GRB 111020A: Gemini-South additional observations and limit on an optical afterglow
  95. GRB 111020A: EVLA observations
  96. GRB 111020A: Swift-XRT refined Analysis
  97. GRB 111020A: Gemini-South i-band observations
  98. GRB 111020A: Swift/UVOT Upper Limits
  99. GRB 111020A: Faulkes Telescope South observations
  100. GRB 111020A: Swift-BAT refined analysis

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