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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. GRB 091202 - UVOT-enhanced XRT position
  2. GRB 091127: Zadko Telescope Observations
  3. GRB 091126A: Suzaku WAM observation of the prompt emission
  4. GRB 091202: TAROT Calern observatory optical observations
  5. GRB 091202: Liverpool Telescope Observations
  6. GRB 091202: a long GRB detected by INTEGRAL
  7. GRB 091127: redshift confirmation with X-shooter
  8. GRB 091117: Chandra Observations
  9. GRB 091020: MASTER-Net optical polarization observations
  10. GRB 091127: Skynet/PROMPT Continued Observations of Fading
  11. Short X-ray Transient Detection by MAXI/GSC
  12. Konus-Wind observation of very long GRB 091123
  13. GRB 091130A: Xinglong TNT upper limit
  14. GRB 091123: Fermi GBM detection of a very long burst
  15. GRB 091126B: Fermi GBM detection
  16. GRB 091127: Suzaku WAM observation of the prompt emission
  17. GRB 091126: Fermi GBM detection
  18. GRB 091130B: Swift-XRT team refined analysis
  19. GRB 091130B: Swift-BAT refined analysis
  20. GRB 091130B: Swift/UVOT Upper Limits
  21. GRB 091127: Skynet/PROMPT Observations of Fading
  22. GRB 091130B: Enhanced Swift-XRT position
  23. Swift trigger 377436 (possible GRB 091130A) is not a burst
  24. GRB 091130B: MASTER observations
  25. GRB 091130B: SDSS galaxy at XRT location
  26. GRB 091130B: Swift detection of a burst
  27. GRB 091130: MASTER observations
  28. GRB 091130: Swift detection of a possible burst
  29. GRB 091127: Radio observations
  30. GRB 091128: Fermi GBM detection
  31. Konus-Wind observation of GRB 091127
  32. GRB 091127: TAROT La Silla observatory optical observations
  33. GRB 091127: optical observations
  34. GRB 091127: LABOCA/APEX submm observations
  35. GRB 091127: Further NOT optical observations
  36. GRB 091127: Fermi GBM detection
  37. GRB 091127: MASTER early optical transient polarimetry
  38. GRB 091127: Gemini-N redshift
  39. GRB 091127: Swift-XRT afterglow detection and analysis
  40. GRB 091127: TAROT La Silla observatory optical decay
  41. GRB 091127: Swift/UVOT observations
  42. GRB 091127: CAHA 1.23m I-band observations
  43. GRB 091127: Swift-BAT refined analysis
  44. GRB 091127: NOT observations
  45. GRB 091127 : GROND observations
  46. GRB 091127: REM NIR afterglow detection
  47. GRB 091127: Swift/UVOT Detection of an Optical Afterglow
  48. GRB 091127: Liverpool Telescope afterglow candidate
  49. GRB 091127: Swift detection of a burst
  50. IPN Triangulation of GRB091120
  51. Konus-Wind observation of GRB 091120
  52. GRB 091120: MAXI GSC detection
  53. GRB 091120: Fermi GBM observation
  54. GRB 091117A: Suzaku WAM observation of the prompt emission
  55. GRB 091117: TNG optical observations
  56. GRB 091117A: Swift/UVOT followup observations
  57. GRB 091117: 2nd epoch of Magellan optical observations
  58. GRB 091117: VLA radio observations
  59. GRB 091117: Swift-XRT observations
  60. GRB 091117 BAT refined analysis
  61. GRB 091117: Evidence for Variability of XRT Source #1
  62. GRB091117: Gemini South Observations
  63. GRB 091117: Swift XRT refined analysis
  64. GRB 091117: Gemini-North spectroscopy of DSS galaxy
  65. Konus-Wind observations of GRB 091117A
  66. GRB 091117: Magellan optical observations
  67. GRB 091117: XRT source coincident with a DSS galaxy
  68. GRB 091117: OSN I-band observations
  69. GRB 091117A Detected in ground analysis of BAT data and IPN triangulation
  70. GRB 091112: Suzaku WAM observation of the prompt emission
  71. GRB 091102A: Suzaku WAM observation of the prompt emission
  72. GRB 091109B: Suzaku WAM observation of the prompt emission
  73. GRB091111: Swift XRT refined analysis
  74. Konus-Wind and Konus-RF observations of GRB 091031
  75. GRB 091112: Swift-BAT refined analysis
  76. GRB 091112: Fermi GBM observation
  77. GRB 091031: Fermi LAT detection of a faint burst
  78. GRB 091112: Swift detection of a possible burst
  79. GRB 091111: BOOTES-3 contemporaneous imaging
  80. GRB 091111: BOOTES-3 observations
  81. GRB 091111: a faint long GRB detected with INTEGRAL
  82. GRB 091109A: GROND and VLT observations
  83. GRB 091109B: Swift/UVOT Upper Limits
  84. GRB 091109B: VLT afterglow confirmation
  85. GRB 091109B: Swift-XRT Team refined analysis
  86. GRB 091109B: VLT observations
  87. GRB 091109b: Magellan Observations
  88. GRB 091109B: Swift-BAT refined analysis
  89. GRB 091109B: Enhanced Swift-XRT position
  90. GRB 091109B: Optical limits from Watcher
  91. GRB 091109B: ROTSE-III Optical Limits
  92. GRB 091109B: Swift detection of a short burst
  93. GRB091109: Correction to GCN 10139
  94. GRB 091030: Fermi GBM detection
  95. GRB 091109: Swift-XRT refined analysis
  96. GRB 091109: BOOTES-3 observations
  97. GRB 091109: Swift/UVOT observations
  98. GRB 091109: Faulkes Telescope South observations
  99. GRB 091109: Swift-BAT refined analysis
  100. GRB 091109: Enhanced Swift-XRT position

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