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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"

12318 results found.

  1. GRB 070209: Swift XRT refined analysis
  2. GRB 070220: Swift detection of a burst
  3. GRB 070219: Swift/UVOT Upper limits
  4. GRB 070219: Swift detection of a burst
  5. GRB 070125 observations with the GMRT
  6. GRB 070125: Break in Optical Decay
  7. GRB 070209: Swift detection of a short hard burst
  8. GRB 070208: Swift detection of a burst
  9. GRB070124: Swift-XRT Follow-up Observation
  10. GRB070126: Swift-XRT Observation
  11. GRB 070129: Swift/UVOT Upper limits
  12. GRB070129: MITSuME optical observation
  13. GRB061217: MAGIC telescope GeV observation
  14. GRB 070129: Xinglong TNT optical Upper Limit
  15. GRB070126: Swift-XRT possible detection of an afterglow
  16. Possible GRB 070126: Swift/UVOT Upper Limit
  17. GRB 070125: Continued P60 Observations
  18. GRB 070110: Ep,i - Eiso correlation
  19. GRB 070110 declared a "Burst of Interest" by Swift team
  20. GRB 070107: Swift detection of a burst
  21. GRB 070103: Swift/UVOT Upper limits
  22. GRB 070103: Swift detection of a burst
  23. GRB 061222A: MITSuME Akeno optical upper limits
  24. GRB 061222B: MITSuME Akeno optical upper limits
  25. GRB061222A Swift/UVOT: Upper Limits
  26. GRB 061222B: Swift/UVOT Upper limits
  27. GRB 061222B: SARA upper limit
  28. GRB 061222B: Swift detection of a burst
  29. GRB 061222: Swift detection of a burst
  30. GRB 061218: TORTOREM optical upper limits
  31. Swift triggers (#251863) on a possible burst
  32. GRB061217: Swift/UVOT refined analysis.
  33. GRB061210: Swift/UVOT observations
  34. GRB 061210 : Faulkes North Telescope optical limit
  35. GRB 061214(?): Swift detection of a possible burst
  36. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  37. GRB 061202: TORTOREM optical upper limits
  38. GRB061202: Swift/UVOT Upper Limits
  39. GRB 061202: Swift detection of a burst
  40. GRB 061201, Swift-BAT refined analysis of the SHB
  41. GRB 061122: GETS observation
  42. GRB 061126: Swift/UVOT Observations
  43. GRB061122: Swift/UVOT Optical Observations
  44. Konus-Wind observation of GRB 061122
  45. GRB061121, optical observation
  46. GRB 050915B: optical afterglow
  47. GRB 060111B: Swift UVOT Refined Magnitudes
  48. Swift/UVOT Upper Limits for GRB061110b
  49. Swift/UVOT Upper Limits for GRB061110a
  50. GRB 061110B: Swift-UVOT Initial Observation
  51. GRB 061110: Swift detection of a burst
  52. GRB 061109: optical observation
  53. GRB061028: MAGIC telescope GeV observation
  54. GRB 061102: Swift/UVOT Magnitude Upper Limits
  55. GRB 061004: Further VLT/NTT observations
  56. GRB061102B: Super-LOTIS observations
  57. GRB 061102B: Swift detection of a possible burst
  58. GRB 061102: Swift detection of a burst
  59. GRB 061028: VLA Observation
  60. GRB 061028: SARA upper limit
  61. GRB 061028: Swift/UVOT Observations
  62. GRB 061028: TAROT Calern observatory late optical observations
  63. GRB 061028: Swift detection of a burst
  64. GRB 061027, Swift refined analysis of a possible burst
  65. GRB 061027: Swift detection of a possible burst
  66. GRB061025: Swift/UVOT observations
  67. GRB 061019: MITSuME upper limits
  68. Konus-Wind observation of GRB 061021
  69. GRB 061021 - VLT spectrum without lines
  70. GRB 061019: Super-LOTIS upper limit
  71. GRB 061019: SARA upper limit
  72. GRB 061019: Swift/UVOT upper limit
  73. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  74. GRB 061006: Swift/UVOT optical observations
  75. GRB 061006: Swift detection of a burst
  76. GRB061004: Swift/UVOT optical observations
  77. GRB 061004: Swift detection of a burst
  78. GRB061002: Swift UVOT followup observations
  79. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  80. GRB 061002: Swift detection of a burst
  81. GRB 060923A: Probable host galaxy in the R-band
  82. GRB 060929: Swift/UVOT Optical Observations
  83. GRB060923C: optical limit
  84. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  85. GRB 060927: Swift/UVOT Optical Observations
  86. GRB 060927 optical limit
  87. GRB 060927, optical observation
  88. GRB 060926: Swift-UVOT Detections
  89. GRB 060923C: VLA Observation
  90. GRB 060923C, optical observation
  91. GRB060923B: Swift/UVOT upper limits
  92. GRB 060923A: Keck and Gemini Observations
  93. GRB060919: Swift/UVOT optical observations
  94. GRB 060912A: VLA Observation
  95. GRB060825: MAGIC telescope GeV observation
  96. GRB060912: Swift/UVOT Observations
  97. GRB060906: Danish/DFOSC optical observations
  98. VLA observations of GRB 060908
  99. GRB 060906: Swift-UVOT observations
  100. GRB 060906: Swift detection of a probable burst

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