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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 140430A: Further VATT Optical Observations
  2. GRB 140430A: Swift-BAT refined analysis
  3. GRB 140501A: Fermi GBM detection
  4. GRB 140430A: Swift/UVOT Observations
  5. GRB 140430A: Swift-XRT refined Analysis
  6. GRB 140430A: VATT Optical Observations
  7. GRB 140430A: Enhanced Swift-XRT position
  8. GRB 140430A: VLT/X-shooter redshift
  9. GRB 140430A: NOT optical observations
  10. GRB 140430A : Liverpool Telescope optical afterglow observations
  11. GRB 140428A: GROND observations
  12. GRB140430A: Swift detection of a burst with an optical counterpart
  13. GRB 140428B: Fermi GBM observation
  14. Konus-Wind observation of GRB 140428B
  15. GRB 140428A: Swift/UVOT Upper Limits
  16. GRB 140428A: Swift-BAT refined analysis
  17. GRB 140423A: RTT150 optical observations
  18. IPN Triangulation of GRB 140428B (short/hard)
  19. Trigger 597570: Swift detection of SGR 1806-20
  20. GRB 140428A: 1.5m OSN I-band detection
  21. GRB 140428A: Keck redshift estimate
  22. GRB 140428A: Keck detection of a red optical afterglow candidate
  23. GRB 140428A: NOT observations
  24. GRB 140428A: Swift-XRT detection of a source
  25. GRB 140428A: Swift Detection of a Possible Burst
  26. GRB 140423A: MITSuME Akeno upper limits
  27. GRB 140423A Third epoch pODI photometry
  28. GRB 140423A: Continued RATIR Optical and NIR Observations
  29. GRB 140423A: MITSuME Akeno Optical observation
  30. GRB 140413A: GROND Afterglow Confirmation
  31. DG CVn: optical observations
  32. GRB 140423A: RATIR Optical and NIR Observations
  33. GRB 140423A: NOT Afterglow Observations
  34. GRB 140419A: Continued Mondy optical observations
  35. GRB 140423A: Nishi-Harima NIR Observations
  36. GRB 140423A: TNG NIR observations
  37. GRB 140423A pODI/WIYN afterglow photometry
  38. GRB 140423A, Optical Observations
  39. GRB 140423A: Kanata/HONIR Optical and NIR Observations
  40. GRB 140423A: Swift-XRT refined Analysis
  41. GRB 140423A: Swift-BAT refined analysis
  42. GRB 140423A: MITSuME Okayama Optical Observation
  43. Swift Trigger 596958 is positionally consistent with V* DG CVn/2XMM J133146.4+291635
  44. Swift Trigger 596958 is probably the flare star: DG CVn
  45. GRB 140423A: Further Observations with Swift/UVOT
  46. GRB 140423A: KAIT Optical Detection
  47. GRB 140423A: Enhanced Swift-XRT position
  48. GRB 140423A: Nanshan optical upper limit
  49. GRB 140423A: P60 Observations
  50. GRB 140423A: Fermi GBM observation
  51. GRB 140423A: KWFC z-band photometry
  52. GRB 140423A: Gemini-N redshift
  53. GRB 140419A, LOAO R-band observations
  54. GRB 140423A: ISON-MN early photometry and correction to the GCN circ. 16143
  55. GRB 140423A: Swift/UVOT detection of a possible counterpart
  56. GRB 140423A: Swift-XRT observations
  57. GRB 140423A: ROTSE-III Detection of Optical Counterpart
  58. GRB 140423A optical observations with pODI/WIYN at KPNO
  59. GRB 140423A: optical afterglow candidate
  60. GRB 140423A: Swift detection of a burst
  61. GRB 140419A: Mondy optical observations
  62. GRB 140419A: Refined NOT photometry
  63. GRB 140419A: Continued RATIR Optical and NIR Observations
  64. GRB140419A: NOT optical observations
  65. GRB 140419A: KAIT Refined Analysis
  66. GRB 140419A: Continued RATIR Optical and NIR Observations
  67. Swift Trigger 596641 is not a GRB
  68. Konus-Wind observation of GRB 140419A
  69. GRB 140419A, Optical Observations
  70. GRB 140419A: MITSuME Ishigakijima Optical Observation
  71. GRB 140419A: MITSuME Okayama Optical Observation
  72. GRB 140419A: Swift UVOT refined analysis
  73. GRB 140419A: P60 Observations
  74. GRB 140419A: Swift-XRT refined Analysis
  75. GRB 140419A: Swift-BAT refined analysis
  76. GRB 140419A: T24 optical observations
  77. GRB 140419A: Gemini-N redshift
  78. GRB 140419A: Enhanced Swift-XRT position
  79. GRB140419A: UVOT detects fading afterglow in white but not in u filter
  80. GRB 140419A: CARMA early 3mm detection
  81. GRB 140419A: RATIR Optical and NIR Observations
  82. GRB 140419A: ROTSE-III Detection of Optical Counterpart
  83. GRB 140419A (Swift trigger 596426) : KAIT optical candidate
  84. GRB 140419A: Swift detection of a burst with optical afterglow
  85. Konus-Wind observation of GRB 140416A
  86. IPN Triangulation of GRB 140416A (long/very intense)
  87. GRB 140416A: Fermi GBM detection
  88. GRB 140414A: Swift/UVOT Upper Limit
  89. GRB 140414A: Swift-XRT observations
  90. GRB 140414A: TNG optical observations
  91. GRB 140414A: Swift-BAT refined analysis
  92. GRB 140414A: Short burst found in ground analysis of BAT slew data
  93. GRB 140413A: Swift/UVOT Observations of the Optical Afterglow
  94. GRB 140412A: Swift/UVOT Upper Limits
  95. Konus-Wind observation of GRB 140413A
  96. GRB 140413A: Swift-XRT refined Analysis
  97. GRB 140413A: Swift-BAT refined analysis
  98. GRB 140412A: Swift-XRT refined Analysis
  99. GRB 140412A: Swift-BAT refined analysis
  100. GRB 140413A: TAROT La Silla observatory optical observations

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