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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"

19042 results found.

  1. GRB 150527A: Continued RATIR Observations
  2. GRB 150530B: Swift ToO observations
  3. GRB 150530A: RATIR Optical Observations
  4. GRB 150530A: Swift/UVOT Upper Limits
  5. GRB 150530A: Enhanced Swift-XRT position
  6. GRB 150530A: Swift detection of a burst
  7. GRB 150527A: Swift-XRT refined Analysis
  8. GRB 150527A: MITSuME Okayama upper limits
  9. GRB 150527A: Swift/UVOT Upper Limits
  10. GRB150527A: REM - NIR afterglow
  11. GRB 150527A: Enhanced Swift-XRT position
  12. GRB 150527A: LCOGT McDonald observations
  13. GRB 150527A: RATIR Afterglow Detection
  14. GRB 150527A: Swift detection of a burst
  15. GRB 150523A: Swift ToO observations
  16. GRB 150523A: Swift/UVOT Detection
  17. GRB 150523B: Swift ToO observations
  18. Swift trigger 641332 is probably not an astrophysical source
  19. GRB 150518A: Continued RATIR optical observations
  20. GRB 150518A: MAXI-GSC further analysis
  21. GRB 150518A: Mondy optical observations
  22. GRB 150518A: Swift-XRT follow-up observations
  23. GRB 150518A: SAO RAS optical observations
  24. GRB 150518A: RATIR optical observations
  25. GRB 150518A: GMG observation
  26. GRB 150518A: Xinglong2.16m optical afterglow detection
  27. Swift/UVOT observations of GRB150518A
  28. GRB 150518A: Tiled Swift observations
  29. GRB 150514A: GROND Bright Afterglow Confirmation
  30. GRB 150514A: Swift/UVOT Detection
  31. GRB 150514A: Swift ToO observations
  32. GRB 150423A: GMG observation limit
  33. Swift Trigger 639636: a possible GRB
  34. GRB 150430A: GROND Upper Limits
  35. GRB 150430A: Swift-XRT refined Analysis
  36. GRB 150430A: Swift/UVOT Upper Limits
  37. GRB 150430A: Swift detection of a burst
  38. GRB 150428B: IRSF NIR upper limits
  39. GRB 150428B: Swift/UVOT Upper Limits
  40. GRB 150428C: Swift-XRT observations
  41. GRB 150428A: Swift/UVOT Upper Limits
  42. GRB 150413A: CrAO optical observations
  43. GRB 150428A: Swift-XRT refined Analysis
  44. GRB 150428C: Tiled Swift observations
  45. GRB 150428B: Enhanced Swift-XRT position
  46. GRB 150428A: Danish1.56m optical observations
  47. GRB 150428A: RATIR optical observations
  48. GRB 150428A: P60 observations
  49. GRB 150428A: Enhanced Swift-XRT position
  50. GRB 150428A: GROND Dark Burst Host Candidate
  51. GRB 150428B: Swift detection of a burst
  52. GRB 150428A: Swift detection of a burst
  53. Trigger 639199: Swift detection of IGRJ16418-4532
  54. GRB 150424A: RATIR Observations
  55. GRB 150424A: GROND detects strong fading
  56. GRB 150423A: Continued RATIR optical afterglow monitoring
  57. GRB 150424B: Fermi GBM detection
  58. GRB 150424A: Swift/UVOT Observations
  59. GRB 150423A: TSHAO optical observations
  60. GRB 150424A: Enhanced Swift-XRT position
  61. GRB 150424B: Tiled Swift observations
  62. GRB 150423A: WHT observations
  63. GRB 150424A: Keck detection of optical afterglow
  64. GRB 150424A: Swift detection of a short burst
  65. GRB 150423A: MITSuME Okayama upper limits
  66. GRB 150423A: UKIRT NIR observations
  67. GRB 150423A: Swift/UVOT Upper Limits
  68. GRB 150423A: RATIR optical afterglow monitoring
  69. GRB 150423A: Enhanced Swift-XRT position
  70. GRB 150423A: GROND afterglow candidate
  71. GRB 150423A: GROND observation
  72. GRB 150423A: Swift detection of a short burst
  73. Further Swift XRT observations of GRB 150418A
  74. Swift trigger 638589 is probably not an astrophysical source
  75. GRB 150413A: RTT150 optical observations
  76. GRB 150418A: Tiled Swift observations
  77. GRB 150413A: ISON-Ussuriysk optical observations
  78. GRB 150413A: MITSuME Akeno Optical observation
  79. GRB 150413A: SAO RAS observations
  80. LOAO B, R Observations of GRB150413A
  81. Swift Trigger 638217 is probably not an astrophysical source
  82. GRB 150416A: Fermi-LAT detection
  83. GRB 150413A: GMG observation
  84. GRB 150413A
  85. GRB 150413A: Bassano Bresciano Observatory optical observations
  86. GRB150413A, optical observations
  87. GRB 150413A: optical observations
  88. GRB 150413A: P60 photometry
  89. GRB 150413A: Khureltogot optical observations
  90. GRB 150413A: Nanshan optical and radio follow-ups
  91. GRB 150413A: Khureltogot optical observations
  92. Swift detection of SAX J1808.4-3658
  93. GRB 150407A: Swift-XRT observations
  94. GRB 150407A: optical observations
  95. GRB 150407A: Swift ToO observations
  96. Swift triggered on a source in Terzan 5 (trigger=637212)
  97. Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
  98. GRB 150403A: Swift/UVOT Detection
  99. GRB 150323C: CrAO optical observations
  100. GRB 150323C: additional optical observations in Mondy

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