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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"

19572 results found.

  1. GRB 090618: Enhanced Swift-XRT position
  2. GRB 090618 Faulkes Telescope North observations
  3. GRB090618: P60 Optical Afterglow
  4. GRB 090618: Swift detection of a bright burst with optical afterglow
  5. GRB 090616: Fermi GBM detection
  6. GRB 090612: Fermi GBM detection
  7. GRB 090610C: Fermi GBM detection
  8. GRB 090610B: Fermi GBM detection
  9. GRB 090610: Fermi GBM detection
  10. RXTE Discovery of Pulsations from SGR 0418+5729
  11. GRB 090531B: Fermi GBM detection
  12. Konus-RF observation of SGR burst 090605A
  13. GRB 090608: Fermi GBM detection
  14. GRB 090606: Fermi GBM detection
  15. GRB 090607: XRT Team Refined Analysis
  16. GRB 090607: Swift/UVOT Upper Limits
  17. GRB 090607: GRAS001 optical observations
  18. GRB 090607: Faulkes Telescope North observations
  19. GRB 090607: Swift detection of a burst
  20. GRB 090530: Further NOT optical observations
  21. GRB 090530: RTT150 Optical Observation
  22. GRB 090602: Fermi GBM detection
  23. GRB 090529A: RTT150 Optical Observations
  24. GMRT observation of GRB 090424 afterglow
  25. GRB090529: Further NOT optical observations
  26. GRB 090531B: GROND observation
  27. GRB 090530: Early RAPTOR Optical Observations
  28. GRB090529B: ROVOR Upper Limits
  29. GRB 090531A: SARA upper limit
  30. GRB 090531B: Swift/BAT spectral lag results
  31. GRB 090529C: Fermi GBM detection
  32. GRB 090529B: Fermi GBM detection
  33. GRB 090530B: Fermi GBM detection
  34. Corrections to GRB 090531B Swift/UVOT Upper Limits
  35. GRB 090531B, RIMOTS optical upper limits
  36. GRB 090531B: Swift/UVOT Upper Limits
  37. GRB 090529: MITSuME optical observation
  38. GRB 090530: GRT Optical Observation
  39. GRB 090531B: Swift-XRT candidate afterglow position
  40. GRB 090531B: ROTSE-III Optical Limits
  41. GRB 090530: break in light curve
  42. GRB 090531: GROND upper limits
  43. GRB 090531: P60 Observations
  44. GRB 090529: NOT optical observations
  45. GRB 090530: NOT optical observations
  46. GRB090530: Swift/UVOT afterglow detection
  47. GRB 090528B: Fermi GBM detection
  48. GRB 090528: Fermi GBM detection
  49. GRB 090530: Enhanced Swift-XRT position
  50. GRB 090530: GRAS002 refined OA analysis
  51. GRB 090530: GRAS002 optical observations
  52. GRB 090530: PAIRITEL NIR Detections
  53. GRB 090530: Swift detection of a burst with an optical counterpart
  54. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  55. GRB 090529: Swift-BAT refined analysis
  56. GRB 090529: Enhanced Swift-XRT position
  57. GRB 090529: Preliminary Swift/UVOT Upper Limit
  58. GRB 090529: Swift detection of a burst
  59. GRB 090520D: Fermi GBM detection
  60. GRB 090520C: Fermi GBM detection
  61. GRB 090520B: Fermi GBM detection
  62. GRB 090522 : Fermi GBM detection
  63. GRB 090524: Fermi GBM detection
  64. GRB 090518 - NOT upper limit
  65. GRB 090520: GROND upper limits
  66. GRB 090518: Fermi GBM detection
  67. GRB 090516C: Fermi GBM detection
  68. GRB 090520 Swift-BAT detection of a burst in ground analysis
  69. GRB 090516: Fermi GBM observation
  70. GRB 090516B: Fermi GBM detection
  71. GRB 090519B: Fermi GBM detection
  72. GRB 090519: NOT refined analysis
  73. GRB 090519: GROND observation
  74. GRB 090519: Swift/UVOT Upper Limits
  75. GRB 090519: Enhanced Swift-XRT position
  76. GRB 090519: NOT afterglow candidate
  77. GRB 090519: FARO Chante Perdrix Observatory optical observations
  78. GRB 090519: TAROT Calern observatory optical observations
  79. GRB 090519: Swift detection of a burst
  80. GRB 090511: Fermi GBM Detection
  81. GRB 090514: Fermi GBM detection
  82. GRB 090518: Swift/UVOT Upper Limits
  83. GRB 090516: Observations from Stardome Observatory
  84. GRB090518: GROND upper limits
  85. GRB 090518: P60 Observations
  86. GRB 090518B: Fermi GBM detection
  87. GRB 090516, RIMOTS optical upper limits
  88. GRB090513: Fermi GBM detection
  89. GRB 090518: Enhanced Swift-XRT position
  90. GRB 090518: Swift detection of a burst
  91. GRB 090516: GROND OBSERVATIONS
  92. GRB 090516 - Zadko Telescope observations
  93. GRB 090516: NOT optical observations
  94. GRB 090516: Swift/UVOT Observations
  95. GRB 090516: Enhanced Swift-XRT position
  96. GRB 090516: Swift detection of a burst
  97. GRB 090515: VLA observations
  98. GRB 090515: Lick Upper Limits
  99. GRB 090515: ROVOR Upper Limit
  100. GRB 090515: MMT/MMIRS NIR Upper Limit

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