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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"

19595 results found.

  1. GRB 130427A: MAXI/GSC detection
  2. GRB 130427B: Faulkes Telescope North afterglow detection
  3. GRB 130427B: Swift detection of a burst with optical counterpart
  4. GRB 130427A: Continued P60 follow-up of an extremely bright optical afterglow
  5. GRB 130427A: PAIRITEL NIR Detections
  6. GRB 130427A: Faulkes Telescope North detection
  7. GRB 130427A: early optical observations
  8. GRB 130427A: Swift detection of a very bright burst with a likely bright optical counterpart
  9. GRB 130420A: Continued Skynet/GORT Observations/Detections
  10. GRB 130420B: CARMA and VLA radio observations
  11. Trigger 554491: Swift detection of a spike possibly from Sgr A*
  12. GRB 130420A: Continued RATIR Optical and NIR Observations
  13. GRB 130420A: ROTSE-III data analysis
  14. GRB 130420A: Continued RATIR Optical and NIR Observations
  15. GRB 130420A: Early RAPTOR Simultaneous Multi-Color Observations
  16. GRB 130420B: Fermi GBM observation
  17. Swift Trigger 554135 is probably not a GRB or transient
  18. GRB 130420B: RATIR Optical and NIR Observations
  19. GRB 130420B: Swift-XRT refined Analysis
  20. GRB 130420A: Fermi GBM observation
  21. GRB 130420A: ISON-NM optical observations
  22. Skynet/GORT observations of GRB130420A
  23. GRB 130420B: Swift/UVOT Upper Limits
  24. GRB 130420A: Swift/UVOT Detection
  25. GRB 130420A: Swift-XRT refined Analysis
  26. GRB 130420B: Enhanced Swift-XRT position
  27. GRB 130420B, Swift-BAT refined analysis
  28. GRB 130420A, Swift-BAT refined analysis
  29. Konus-Wind observation of GRB 130418A
  30. GRB 130420A: Enhanced Swift-XRT position
  31. GRB 130420B: MASTER-Net optical observations
  32. GRB 130420B: Swift detection of a burst
  33. GRB 130420A: RATIR Optical and NIR Observations
  34. GRB 130420A: PAIRITEL NIR detections
  35. GRB 130420A: ROTSE-III Detection of Optical Counterpart
  36. GRB 130420A: Swift detection of a burst with an optical counterpart
  37. GRB 130420A: Faulkes Telescope North candidate
  38. GRB 130418A: Swift-XRT refined Analysis
  39. Swift Trigger 553930 is not an astrophysical source
  40. GRB 130419A, Swift-BAT refined analysis
  41. GRB 130327B: Swift/XRT source is not the afterglow
  42. GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
  43. Trigger 553930: Swift detection of a possible flare from HR 5110
  44. GRB 130418A, Swift-BAT refined analysis
  45. GRB 130419A: Swift detection of a burst
  46. GRB 130418A: RATIR Optical and NIR Observations
  47. GRB 130418A: GROND detection of the optical-NIR afterglow
  48. GRB 130418A: Swift/UVOT Detection and request for continuing coverage
  49. GRB 130418A: Enhanced Swift-XRT position
  50. GRB 130418A: TAROT Calern and TAROT la Silla observatory optical observations
  51. GRB 130418A: Bassano Bresciano Observatory optical observations
  52. GRB 130418A: Swift detection of a burst with an optical counterpart
  53. GRB 130408a: Skynet Optical Observations
  54. GRB 130408A, Swift-BAT refined analysis
  55. GRB 130408A: Zadko observatory - Gingin optical observations
  56. GRB 130407A: Swift-XRT observations
  57. GRB130408A: Swift/UVOT followup observations
  58. GRB 130408A: Swift-XRT refined Analysis
  59. Konus-Wind observation of GRB 130408A
  60. GRB 130408A: Enhanced Swift-XRT position
  61. GRB 130408A: GROND detection of the afterglow
  62. GRB 130408A: Swift/UVOT Detection of the Optical Afterglow
  63. GRB 130408A: Liverpool Telescope Optical candidate detection
  64. GRB 130408A: Swift detection of a burst
  65. GRB 130407A Tiled Swift observations
  66. GRB 130211A: Retraction of afterglow candidate
  67. GRB 130327B: Suzaku WAM observation of the prompt emission
  68. Swift detection of IGR J18245-2452
  69. IPN Triangulation of GRB 130320B (very long/bright)
  70. Swift/XRT observation of GRB 130327B
  71. GRB 130306A: Confirmation of the X-ray Afterglow
  72. Swift Trigger 552142 is a noise event
  73. GRB 130327B: Fermi-LAT detection of a burst
  74. Swift Trigger 552142: a possible GRB
  75. GRB 130327A: Swift-BAT refined analysis
  76. GRB 130327A: Swift-XRT refined Analysis
  77. GRB 130327A: Swift/UVOT Upper Limits
  78. GRB 130327A: ISON-NM optical upper limit
  79. GRB 130325A Tiled Swift observations
  80. GRB 130327A: Enhanced Swift-XRT position
  81. GRB 130327A: PAIRITEL NIR Afterglow Candidate
  82. GRB 130325A: Fermi LAT detection
  83. GRB 130327A: Swift detection of a burst
  84. report: GRB 130315A: Zadko observatory - Gingin optical observations
  85. GRB 130315A: GROND afterglow candidate
  86. GRB 130305A: optical upper limit in Mondy observatory
  87. GRB 130315A: Swift/UVOT Upper Limits
  88. GRB 130313A: optical upper limit in CrAO
  89. GRB 130313A: optical upper limit in Mondy observatory
  90. GRB 130315A: SALT optical observations
  91. GRB 130315A: Swift-XRT refined Analysis
  92. Swift XRT observations of GRB 130310A
  93. GRB 130315A, Swift-BAT refined analysis
  94. GRB 130313A: Swift/UVOT Upper Limits
  95. GRB 130305A: PTF P48 optical upper limits
  96. GRB130315A BOOTES-3 optical limit
  97. GRB 130315A: Swift detection of a burst
  98. GRB 130305A: TLS Tautenburg observations
  99. GRB 130313A: RATIR Optical and NIR Observations
  100. GRB 130313A: Swift-BAT Spectral lag analysis

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