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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. GRB090530: R-band Observation
  2. GRB 090530: break in light curve
  3. GRB 090529: VLT spectroscopic redshift
  4. GRB 090531: GROND upper limits
  5. GRB 090531: P60 Observations
  6. GRB 090531: Swift detection of a burst
  7. GRB 090529: NOT optical observations
  8. GRB 090530: NOT optical observations
  9. GRB090530: Swift XRT refined analysis
  10. GRB090530: Swift/UVOT afterglow detection
  11. GRB 090529: Swift-XRT refined analysis
  12. GRB 090529: OSN optical observations
  13. GRB 090528B: Fermi GBM detection
  14. GRB 090528: Fermi GBM detection
  15. GRB 090530: Enhanced Swift-XRT position
  16. Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet?
  17. GRB 090530: Swift-BAT refined analysis
  18. GRB 090530: GRAS002 refined OA analysis
  19. GRB 090530: GRAS002 optical observations
  20. GRB 090530: PAIRITEL NIR Detections
  21. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  22. GRB 090530: Swift detection of a burst with an optical counterpart
  23. GRB 090529: optical observations
  24. GRB 090529: TLS Afterglow Observations
  25. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  26. GRB 090529: Swift-BAT refined analysis
  27. GRB 090529: Enhanced Swift-XRT position
  28. GRB 090529: Preliminary Swift/UVOT Upper Limit
  29. GRB 090529: Xinglong TNT optical observation
  30. GRB 090529: Swift detection of a burst
  31. GRB 090520D: Fermi GBM detection
  32. GRB 090520C: Fermi GBM detection
  33. GRB 090520B: Fermi GBM detection
  34. GRB090518B optical limit by "Pi of the Sky"
  35. GRB 090522 : Fermi GBM detection
  36. GRB 090524: Fermi GBM detection
  37. GRB 090518 - NOT upper limit
  38. GRB 090516A: Konus-Wind and Swift/BAT joint spectral analysis
  39. GRB 090513B: Fermi GBM detection
  40. GRB 090520: GROND upper limits
  41. GRB 090518: Fermi GBM detection
  42. GRB 090516C: Fermi GBM detection
  43. GRB 090520 Swift-BAT detection of a burst in ground analysis
  44. GRB 090423: Fermi GBM T90 follow-up analysis results
  45. GRB 090516: Fermi GBM observation
  46. GRB 090516B: Fermi GBM detection
  47. GRB 090519B: Fermi GBM detection
  48. GRB 090519: Swift-XRT refined analysis
  49. GRB 090519: NOT refined analysis
  50. GRB 090519: VLT spectroscopic redshift
  51. GRB 090519: GROND observation
  52. GRB 090519: Swift/UVOT Upper Limits
  53. GRB 090519, Swift-BAT refined analysis
  54. GRB 090519: Enhanced Swift-XRT position
  55. GRB 090519: Limits from BOOTES-1B
  56. GRB 090519: NOT afterglow candidate
  57. GRB 090519: FARO Chante Perdrix Observatory optical observations
  58. GRB 090519: TAROT Calern observatory optical observations
  59. GRB 090519: Swift detection of a burst
  60. GRB 090511: Fermi GBM Detection
  61. GRB 090514: Fermi GBM detection
  62. GRB 090518: Swift/UVOT Upper Limits
  63. GRB 090516: Observations from Stardome Observatory
  64. GRB090518: GROND upper limits
  65. GRB 090518: P60 Observations
  66. GRB 090518, Swift-BAT refined analysis
  67. GRB 090518B: Fermi GBM detection
  68. GRB 090516, RIMOTS optical upper limits
  69. GRB090513: Fermi GBM detection
  70. GRB090518 : Optical upper limit by MOA-II telescope
  71. GRB 090518: Swift-XRT refined analysis
  72. GRB 090518: Enhanced Swift-XRT position
  73. GRB 090518: Swift detection of a burst
  74. GRB 090515: Swift/BAT spectral lag results
  75. GRB 090516: Swift-BAT refined analysis
  76. GRB 090516: VLT spectrum (correction & update)
  77. GRB 090516: GROND OBSERVATIONS
  78. GRB 090516: VLT redshift
  79. GRB 090516 - Zadko Telescope observations
  80. GRB 090516: NOT optical observations
  81. GRB 090516: Swift XRT refined analysis
  82. GRB 090516: Swift/UVOT Observations
  83. GRB 090516: Enhanced Swift-XRT position
  84. GRB 090516: Faulkes Telescope South optical afterglow
  85. GRB 090516: Swift detection of a burst
  86. GRB 090515: VLA observations
  87. GRB 090515: Lick Upper Limits
  88. GRB 090515: ROVOR Upper Limit
  89. GRB 090515: MMT/MMIRS NIR Upper Limit
  90. GRB 090515: Swift/UVOT Observations
  91. GRB 090515: Swift-XRT refined analysis
  92. GRB 090515: Enhanced Swift-XRT position
  93. GRB 090509: Fermi GBM observation
  94. GRB 090515: Swift-BAT refined spectral analysis
  95. GRB 090515: Swift-BAT refined analysis
  96. GRB 090509 - Zadko Telescope observations
  97. GRB 090515: Gemini-N upper limit
  98. GRB 090515: WIYN NIR Upper Limit
  99. GRB 090515: Super-LOTIS Upper Limits
  100. GRB 090515: PAIRITEL Upper Limits

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