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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. Swift Trigger 575905/ GRB 131026A: MITSuME Okayama and Ishigakijima Optical upper limits
  2. Swift Trigger 575905/possible GRB 131026A: Swift-XRT observations
  3. Swift Trigger 575905: ROTSE-III Optical Limits
  4. Swift Trigger 575905: KAIT Optical Upper Limit
  5. GRB 131026A: TAROT La Silla observatory optical observations
  6. Swift Trigger 575905: a possible GRB
  7. GRB 131024B, Swift-BAT refined analysis
  8. GRB 131024B: Fermi GBM observation
  9. GRB 131024B: RATIR Optical and NIR Observations
  10. GRB 131024B: Swift/UVOT Upper Limits
  11. GRB 131024B : Xinglong TNT upper limit
  12. GRB 131024B: Swift-XRT refined Analysis
  13. Fermi GBM trigger 13121024.436 is not a GRB
  14. GRB 131024B: Nanshan optical upper limit
  15. GRB 131024A: Swift/UVOT Upper Limits
  16. GRB 131024B: Enhanced Swift-XRT position
  17. GRB 131024A: GROND upper limits
  18. GRB 131024A: Swift-XRT refined Analysis
  19. GRB 131024B: Swift detection of a burst
  20. GRB 131024A, Swift-BAT refined analysis
  21. GRB 131024A: Skynet R-COP optical observations
  22. Konus-Wind observation of GRB 131011B
  23. GRB 131024A: Enhanced Swift-XRT position
  24. IPN triangulation of GRB 131011B (Swift Trigger 574266)
  25. GRB 131024A: Swift detection of a burst
  26. GRB 131014A: RATIR Optical/NIR Afterglow Retraction
  27. IPN Triangulation of GRB 131014A
  28. GRB 131018B: Swift/UVOT Upper Limits
  29. GRB 131018B: Swift-XRT observations
  30. GRB 131018B: Fermi GBM observation
  31. GRB 131018A: RATIR Optical and NIR Observations
  32. GRB 131018A: Swift/UVOT Upper Limits
  33. GRB 131018B: Fermi-LAT detection of a burst
  34. GRB 131018A: Swift-XRT refined Analysis
  35. GRB 131018A: KAIT Optical Upper Limit
  36. GRB 131018A, Swift-BAT refined analysis
  37. GRB 131018A: P60 Observations
  38. GRB 131018A: Enhanced Swift-XRT position
  39. GRB 131014A: XRT position information
  40. GRB131018A, optical observations
  41. GRB 131018A: Swift detection of a burst
  42. GRB 131014A: Suzaku WAM observation of the prompt emission
  43. GRB 131014A: GROND observations
  44. GRB 131014A: RATIR Optical/NIR Afterglow Confirmation
  45. Fermi GBM data availability during U.S. government shutdown
  46. GRB 131014A: Swift-XRT refined Analysis
  47. GRB 131011A: Swift/UVOT Upper Limits
  48. GRB 131014A: Swift/UVOT Upper Limits
  49. Fermi 403206457 / GRB 131011A: AAO optical observations
  50. GRB 131014A: RATIR Optical and NIR Observations
  51. GRB 131014A: Enhanced XRT position
  52. Konus-Wind observation of GRB 131014A
  53. GRB 131014A: NOT afterglow candidate
  54. GRB 131014A: Nanshan optical observations
  55. GRB 131014A: Swift detection of a possible X-ray afterglow
  56. GRB 131014A Tiled Swift observations
  57. GRB 131014A: Fermi-LAT detection
  58. GRB 131014A: Fermi GBM detection
  59. GRB 131011A: Fermi GBM detection
  60. iPTF 13dsw/Fermi403206457: X-Shooter redshift
  61. Swift-XRT detection of iPTF 13dsw/Fermi403206457
  62. GRB 131011A: GROND afterglow observations
  63. Fermi403206457: continued P60 observations and fading behavior
  64. Fermi403206457: Weihai optical upper limit
  65. Fermi403206457: NOT optical observations
  66. Fermi403206457: iPTF detection of a possible optical afterglow
  67. Trigger 574266 is not a Swift detection of a known source
  68. GRB 130925A: Possible signatures of binary nature in the afterglow - Request for observations
  69. GRB 130831A: Continued RATIR Optical and NIR Observations
  70. GRB 130831A: VLT/FORS2 spectroscopic detection of a supernova
  71. GRB 131004A: MOSFIRE NIR imaging
  72. GRB 131004A: Correction to XRT refined analysis
  73. GRB 131004A: Skynet PROMPT/DSO-14 upper limits
  74. GRB 131004A, Swift-BAT refined analysis
  75. GRB 131004A: Fermi GBM observation
  76. GRB 131004A: CARMA 93 GHz upper limit
  77. GRB 131004A: Swift/UVOT Detection
  78. GRB 131004A: RATIR Optical and NIR Upper Limits
  79. GRB 131004A: Swift-XRT refined Analysis
  80. GRB131004A: TNG Redshift confirmation
  81. GRB 131004A: GROND observations of the afterglow
  82. GRB 131004A: Enhanced Swift-XRT position
  83. GRB131004A: Magellan Redshift
  84. GRB 131004A: Liverpool Telescope optical afterglow observations
  85. GRB 131004A: TNG optical afterglow confirmation
  86. GRB 131004A: optical afterglow from the NOT
  87. GRB 131004A: Swift detection of a burst (may be short)
  88. GRB 131002A, Swift-BAT refined analysis
  89. GRB 130925A: 3mm observations with CARMA
  90. GRB 131002A: Fermi GBM observation
  91. GRB 130925A/Sw J0244-2609: mm observations at PdBI
  92. GRB 131002B, Swift-BAT refined analysis
  93. GRB 131002B: GROND upper limits
  94. GRB 131002B: Swift-XRT Refined Analysis
  95. GRB 131002B: Swift/UVOT Upper Limits
  96. GRB 131002A: Swift/UVOT Detection
  97. GRB 131001A, Swift-BAT refined analysis
  98. GRB 131002A: Swift-XRT refined Analysis
  99. GRB 131002B: Enhanced Swift-XRT position
  100. GRB 131002A: ISON-NM optical observations

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