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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"

18435 results found.

  1. GRB 130502A: Swift-BAT refined analysis
  2. GRB130502A: MASTER-Net optical observations
  3. GRB 130502A: Swift-XRT refined Analysis
  4. IPN Triangulation of GRB 130502B
  5. GRB 130502A: Fermi GBM detection
  6. GRB 130502B: Swift/UVOT Upper Limits
  7. GRB 130502A: Swift/UVOT Upper Limits
  8. GRB 130502B Swift-XRT observations
  9. GRB 130502A: RATIR Optical and NIR Observations
  10. GRB 130502A: Enhanced Swift-XRT position
  11. GRB 130502B: Fermi LAT Detection
  12. GRB 130502A: T100 Observations
  13. GRB 130502A: Swift detection of a burst
  14. GRB 130427A: Predictions about the occurrence of a supernova
  15. GRB 130427A: High-energy neutrino search
  16. Swift-BAT trigger 554135 is noise
  17. GRB 130427A: Challis Observatory optical observations
  18. GRB 130427A: Continued Skynet/PROMPT Observations
  19. GRB 130427A: Fermi-LAT refined analysis
  20. GRB 130418A: Bassano Bresciano Observatory lightcurve analisis
  21. GRB 130427A: Improved Swift-XRT analysis
  22. GRB 100728A: GROND host detection and X-shooter redshift
  23. GRB 130427A: Skynet/PROMPT Observations
  24. GRB 130427B: RATIR Optical and NIR Observations
  25. GRB 130427A, Optical Observations
  26. Konus-Wind observation of GRB 130427A
  27. GRB 130427A: Kanata/HOWPol optical imaging polarimetry
  28. GRB 130427A: Swift-XRT refined Analysis
  29. GRB 130427A: SPI-ACS/INTEGRAL observations
  30. GRB 130427B: Swift-XRT refined Analysis
  31. GRB 130427A: RAPTOR Bright Counterpart Before Swift Trigger
  32. GRB 130427A: T100 observations
  33. GRB 130427A: optical observations in CrAO
  34. GRB 130427A: Fermi GBM observation
  35. GRB130427A: Swift/UVOT followup observations of an Optical Afterglow
  36. GRB 130427A: Fermi-LAT detection of a burst
  37. GRB 130427A: Swift-BAT refined analysis
  38. GRB 130427B: Swift-BAT refined analysis
  39. GRB 130427A: Zadko observatory - Gingin optical observations
  40. GRB 130427B: Enhanced Swift-XRT position
  41. GRB 130427A: MAXI/GSC detection
  42. GRB 130427B: Faulkes Telescope North afterglow detection
  43. GRB 130427B: Swift detection of a burst with optical counterpart
  44. GRB 130427A: Continued P60 follow-up of an extremely bright optical afterglow
  45. GRB 130427A: PAIRITEL NIR Detections
  46. GRB 130427A: Faulkes Telescope North detection
  47. GRB 130427A: early optical observations
  48. GRB 130427A: Swift detection of a very bright burst with a likely bright optical counterpart
  49. GRB 130420A: Continued Skynet/GORT Observations/Detections
  50. GRB 130420B: CARMA and VLA radio observations
  51. Trigger 554491: Swift detection of a spike possibly from Sgr A*
  52. GRB 130420A: Continued RATIR Optical and NIR Observations
  53. GRB 130420A: ROTSE-III data analysis
  54. GRB 130420A: Continued RATIR Optical and NIR Observations
  55. GRB 130420A: Early RAPTOR Simultaneous Multi-Color Observations
  56. GRB 130420B: Fermi GBM observation
  57. Swift Trigger 554135 is probably not a GRB or transient
  58. GRB 130420B: RATIR Optical and NIR Observations
  59. GRB 130420B: Swift-XRT refined Analysis
  60. GRB 130420A: Fermi GBM observation
  61. GRB 130420A: ISON-NM optical observations
  62. Skynet/GORT observations of GRB130420A
  63. GRB 130420B: Swift/UVOT Upper Limits
  64. GRB 130420A: Swift/UVOT Detection
  65. GRB 130420A: Swift-XRT refined Analysis
  66. GRB 130420B: Enhanced Swift-XRT position
  67. GRB 130420B, Swift-BAT refined analysis
  68. GRB 130420A, Swift-BAT refined analysis
  69. Konus-Wind observation of GRB 130418A
  70. GRB 130420A: Enhanced Swift-XRT position
  71. GRB 130420B: MASTER-Net optical observations
  72. GRB 130420B: Swift detection of a burst
  73. GRB 130420A: RATIR Optical and NIR Observations
  74. GRB 130420A: PAIRITEL NIR detections
  75. GRB 130420A: ROTSE-III Detection of Optical Counterpart
  76. GRB 130420A: Swift detection of a burst with an optical counterpart
  77. GRB 130420A: Faulkes Telescope North candidate
  78. GRB 130418A: Swift-XRT refined Analysis
  79. Swift Trigger 553930 is not an astrophysical source
  80. GRB 130419A, Swift-BAT refined analysis
  81. GRB 130327B: Swift/XRT source is not the afterglow
  82. GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
  83. Trigger 553930: Swift detection of a possible flare from HR 5110
  84. GRB 130418A, Swift-BAT refined analysis
  85. GRB 130419A: Swift detection of a burst
  86. GRB 130418A: RATIR Optical and NIR Observations
  87. GRB 130418A: GROND detection of the optical-NIR afterglow
  88. GRB 130418A: Swift/UVOT Detection and request for continuing coverage
  89. GRB 130418A: Enhanced Swift-XRT position
  90. GRB 130418A: TAROT Calern and TAROT la Silla observatory optical observations
  91. GRB 130418A: Bassano Bresciano Observatory optical observations
  92. GRB 130418A: Swift detection of a burst with an optical counterpart
  93. GRB 130408a: Skynet Optical Observations
  94. GRB 130408A, Swift-BAT refined analysis
  95. GRB 130408A: Zadko observatory - Gingin optical observations
  96. GRB 130407A: Swift-XRT observations
  97. GRB130408A: Swift/UVOT followup observations
  98. GRB 130408A: Swift-XRT refined Analysis
  99. Konus-Wind observation of GRB 130408A
  100. GRB 130408A: Enhanced Swift-XRT position

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