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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"

21795 results found.

  1. GRB 111109A: Swift-BAT refined analysis
  2. GRB 111109A: Enhanced Swift-XRT position
  3. GRB 111109A: Swift-XRT observations
  4. GRB 111103B: optical upper limit of CrAO
  5. GRB 111103B: optical upper limit of Mt. Terskol observatory
  6. Continued Skynet observations of GRB111107A
  7. GRB 111107A: APEX submm observation
  8. GRB 111107A: Swift/UVOT Afterglow Analysis
  9. GRB 111107A: Enhanced Swift-XRT position
  10. GRB 111107A: GROND observations
  11. Skynet observations of GRB 111107A
  12. GRB 111107A: Swift detection of a burst with an optical counterpart
  13. Konus-Wind observation of GRB 111103B
  14. GRB 111103B : WIYN 3.5m NIR observations
  15. GRB111103B Swift/UVOT Upper Limits
  16. GRB 111103B: optical observations from TAU, Ka-Dar
  17. GRB 111103B: Enhanced Swift-XRT position
  18. Trigger 506913: Swift detection of Swift J1922.7-1716 and its optical counterpart
  19. GRB 111103B: optical observations
  20. GRB 111103B: Swift detection of a strong burst from a GRB or Galactic source
  21. GRB 111029A: RAPTOR Limits During the Gamma-ray Emitting Interval
  22. GRB 111029A: SAO RAS optical limits
  23. GRB 111029A: Super-LOTIS early limits
  24. GRB111029A: MITSuME Ishigakijima Optical Upper Limits
  25. GRB 111029A: PAIRITEL NIR Upper Limits
  26. GRB 111029A: Swift/UVOT Upper Limits
  27. GRB 111029A: Enhanced Swift-XRT position
  28. GRB 111029A: optical upper limit
  29. GRB 111029A: ROTSE-III Optical Limits
  30. GRB 111029A: Swift detection of a burst
  31. GRB 111022B: 10.4m GTC z'-band observations
  32. GRB111022B: D50 optical limit
  33. GRB 111020A: Chandra Observation
  34. GRB 111022B: BTA Optical Observations
  35. GRB 111022B: Swift/UVOT upper limits
  36. GRB 111022A: Swift/UVOT Upper Limits
  37. GRB 111016A: optical upper limit
  38. GRB 111022B: NOT observations
  39. GRB 111022B: Enhanced Swift-XRT position
  40. GRB 111022B: MASTER-Net early limit
  41. GRB 111022A: Preliminary UVOT TDRSS Non-Detection
  42. GRB 111022A: MASTER-Net early limit
  43. GRB 111022B: Swift detection of a burst
  44. GRB 111022A: Swift detection of a burst
  45. GRB 111020A: Gemini-South additional observations and limit on an optical afterglow
  46. GRB 111020A: Swift/UVOT Upper Limits
  47. GRB 111020A: Enhanced Swift-XRT position
  48. GRB 111020A: BOOTES-3 Optical Upper Limit.
  49. GRB 111020A: Swift detection of a short burst
  50. GRB 111018A: Swift/UVOT Upper Limits
  51. GRB 111018A: Swift-BAT refined analysis
  52. Konus-Wind observation of GRB 111016B
  53. GRB 111018A: GROND Upper Limits
  54. GRB 111018A: Enhanced Swift-XRT position
  55. IPN Triangulation of GRB 111016B (long duration, intense)
  56. GRB111016A : WIYN 3.5m NIR observations
  57. GRB 111018A: Swift detection of a burst
  58. GRB111016A: D50 optical limit
  59. GRB 111016A: Gemini Detection of the NIR Counterpart
  60. GRB 111016A: Swift/UVOT Detection of a Source
  61. GRB 111016A: Swift-BAT refined analysis
  62. GRB 111016A: P60 Afterglow Candidate
  63. GRB 111016A: Enhanced Swift-XRT position
  64. GRB 111016A: Swift-XRT observations
  65. GRB 111016A: Swift detection of a burst
  66. GRB 110921A: optical observations
  67. GRB 111008A: Swift/UVOT Upper Limits
  68. GRB 111008A: IAC80 I-band observations
  69. GRB 111008A: Gemini spectroscopic redshift
  70. GRB 111008A, GROND observations
  71. GRB 111008A: NOT optical observation
  72. GRB 111008A: Gemini optical counterpart
  73. GRB 111008A: Enhanced Swift-XRT position
  74. GRB 111008A: Swift detection of a burst
  75. GRB 111005A: ATCA 18 GHz detection
  76. GRB 111005A: ATCA radio upper limit
  77. GRB 111005A : miniTAO/ANIR NIR observations
  78. GRB 111005A: EVLA Observations
  79. GRB 111005A: VLT optical observations
  80. GRB 111005A: GROND NIR observations
  81. GRB 111005A: VLT IR observations
  82. GRB 110905A / MAXI J1836-194: optical monitoring
  83. GRB 110921A: MITSuME-Akeno Optical photometry
  84. Skynet/Dolomiti observations of GRB 110928A
  85. Skynet observations of GRB 110928A
  86. GRB 110928A: RAPTOR Limits During Gamma-ray Emitting Interval
  87. GRB 110928A: Swift/UVOT Upper Limits
  88. GRB 110825A: GROND Observations
  89. GRB 110928A: Enhanced Swift-XRT position
  90. GRB 110928A: P60 Observations
  91. GRB 110928A: Further PAIRITEL NIR Observations
  92. GRB 110928A: Swift-XRT observations
  93. GRB 110928A: Swift/UVOT finding chart observation
  94. GRB 110928A: PAIRITEL NIR Observations
  95. GRB 110928A: ROTSE-III Optical Limits
  96. GRB 110924A: Swift detection of a possible burst
  97. GRB 110921A: Swift/UVOT Observations
  98. GRB 110921A: NOT observations
  99. GRB 110921A: TNT astrometry
  100. GRB 110921A: optical observations in Mt. Terskol and Maidanak observatories

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