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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 140428A: Keck detection of a red optical afterglow candidate
  2. GRB 140428A: NOT observations
  3. GRB 140428A: Swift-XRT detection of a source
  4. GRB 140428A: Swift Detection of a Possible Burst
  5. GRB 140423A: MITSuME Akeno upper limits
  6. GRB 140423A Third epoch pODI photometry
  7. GRB 140423A: Continued RATIR Optical and NIR Observations
  8. GRB 140423A: MITSuME Akeno Optical observation
  9. GRB 140413A: GROND Afterglow Confirmation
  10. DG CVn: optical observations
  11. GRB 140423A: RATIR Optical and NIR Observations
  12. GRB 140423A: NOT Afterglow Observations
  13. GRB 140419A: Continued Mondy optical observations
  14. GRB 140423A: Nishi-Harima NIR Observations
  15. GRB 140423A: TNG NIR observations
  16. GRB 140423A pODI/WIYN afterglow photometry
  17. GRB 140423A, Optical Observations
  18. GRB 140423A: Kanata/HONIR Optical and NIR Observations
  19. GRB 140423A: Swift-XRT refined Analysis
  20. GRB 140423A: Swift-BAT refined analysis
  21. GRB 140423A: MITSuME Okayama Optical Observation
  22. Swift Trigger 596958 is positionally consistent with V* DG CVn/2XMM J133146.4+291635
  23. Swift Trigger 596958 is probably the flare star: DG CVn
  24. GRB 140423A: Further Observations with Swift/UVOT
  25. GRB 140423A: KAIT Optical Detection
  26. GRB 140423A: Enhanced Swift-XRT position
  27. GRB 140423A: Nanshan optical upper limit
  28. GRB 140423A: P60 Observations
  29. GRB 140423A: Fermi GBM observation
  30. GRB 140423A: KWFC z-band photometry
  31. GRB 140423A: Gemini-N redshift
  32. GRB 140419A, LOAO R-band observations
  33. GRB 140423A: ISON-MN early photometry and correction to the GCN circ. 16143
  34. GRB 140423A: Swift/UVOT detection of a possible counterpart
  35. GRB 140423A: Swift-XRT observations
  36. GRB 140423A: ROTSE-III Detection of Optical Counterpart
  37. GRB 140423A optical observations with pODI/WIYN at KPNO
  38. GRB 140423A: optical afterglow candidate
  39. GRB 140423A: Swift detection of a burst
  40. GRB 140419A: Mondy optical observations
  41. GRB 140419A: Refined NOT photometry
  42. GRB 140419A: Continued RATIR Optical and NIR Observations
  43. GRB140419A: NOT optical observations
  44. GRB 140419A: KAIT Refined Analysis
  45. GRB 140419A: Continued RATIR Optical and NIR Observations
  46. Swift Trigger 596641 is not a GRB
  47. Konus-Wind observation of GRB 140419A
  48. GRB 140419A, Optical Observations
  49. GRB 140419A: MITSuME Ishigakijima Optical Observation
  50. GRB 140419A: MITSuME Okayama Optical Observation
  51. GRB 140419A: Swift UVOT refined analysis
  52. GRB 140419A: P60 Observations
  53. GRB 140419A: Swift-XRT refined Analysis
  54. GRB 140419A: Swift-BAT refined analysis
  55. GRB 140419A: T24 optical observations
  56. GRB 140419A: Gemini-N redshift
  57. GRB 140419A: Enhanced Swift-XRT position
  58. GRB140419A: UVOT detects fading afterglow in white but not in u filter
  59. GRB 140419A: CARMA early 3mm detection
  60. GRB 140419A: RATIR Optical and NIR Observations
  61. GRB 140419A: ROTSE-III Detection of Optical Counterpart
  62. GRB 140419A (Swift trigger 596426) : KAIT optical candidate
  63. GRB 140419A: Swift detection of a burst with optical afterglow
  64. Konus-Wind observation of GRB 140416A
  65. IPN Triangulation of GRB 140416A (long/very intense)
  66. GRB 140416A: Fermi GBM detection
  67. GRB 140414A: Swift/UVOT Upper Limit
  68. GRB 140414A: Swift-XRT observations
  69. GRB 140414A: TNG optical observations
  70. GRB 140414A: Swift-BAT refined analysis
  71. GRB 140414A: Short burst found in ground analysis of BAT slew data
  72. GRB 140413A: Swift/UVOT Observations of the Optical Afterglow
  73. GRB 140412A: Swift/UVOT Upper Limits
  74. Konus-Wind observation of GRB 140413A
  75. GRB 140413A: Swift-XRT refined Analysis
  76. GRB 140413A: Swift-BAT refined analysis
  77. GRB 140412A: Swift-XRT refined Analysis
  78. GRB 140412A: Swift-BAT refined analysis
  79. GRB 140413A: TAROT La Silla observatory optical observations
  80. GRB 140413A: Swift-XRT observations
  81. GRB 140412A: Enhanced Swift-XRT position
  82. GRB 140413A: GROND afterglow candidate
  83. Swift Trigger 595616: a possible GRB
  84. GRB 140412A: Swift detection of a burst
  85. GRB 140408A: 1.5m OSN optical upper limit
  86. Swift Trigger 595345 is not an astrophysical source
  87. Swift-BAT trigger 595162 is noise
  88. GRB 140408A: MITSuME Akeno Optical observation
  89. Fermi418277210: iPTF optical observations
  90. GRB 140408A: RATIR Optical Upper Limits
  91. GRB 140408A: Swift-BAT refined analysis
  92. GRB 140408A: GROND Detection of an Afterglow Candidate
  93. GRB 140408A: Swift/UVOT Upper Limits
  94. GRB 140408A: Swift-XRT refined Analysis
  95. GRB 140408A: MITSuME Okayama upper limits
  96. GRB 140408A: Enhanced Swift-XRT position
  97. GRB 140408A: Fermi GBM detection
  98. Swift Trigger 595162: a possible GRB
  99. GRB 140408A: Swift detection of a burst
  100. GRB 140406A: Fermi GBM observation

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