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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 131002B: GROND upper limits
  2. GRB 131002B: Swift-XRT Refined Analysis
  3. GRB 131002B: Swift/UVOT Upper Limits
  4. GRB 131002A: Swift/UVOT Detection
  5. GRB 131001A, Swift-BAT refined analysis
  6. GRB 131002A: Swift-XRT refined Analysis
  7. GRB 131002B: Enhanced Swift-XRT position
  8. GRB 131002A: ISON-NM optical observations
  9. Swift J1242.9-3530, Swift-BAT refined analysis
  10. GRB 131001A: Swift UVOT and XRT Upper Limits
  11. GRB 131002A: Enhanced Swift-XRT position
  12. NuSTAR observations of GRB 130925A
  13. Fermi Gamma-ray Burst Monitor trigger 402405063 / 131002466 is not a GRB
  14. GRB 131002B: Swift detection of a burst
  15. GRB 131002A: Swift detection of a burst
  16. GRB 131002A: Faulkes Telescope North optical afterglow
  17. GRB 131001A detected in ground analysis of Swift-BAT data
  18. GRB 130925A: continuing Swift/XRT monitoring
  19. Swift Operations in the event of a US Government shutdown
  20. IPN Observations of GRB 130925A
  21. US Government shutdown may impact GRB operation of GCN
  22. GRB 130930A: Swift detection of a burst
  23. GRB 130929A: Swift/UVOT Upper Limits
  24. GRB 130831A: Continued RATIR Optical and NIR Observations
  25. GRB 130929A: Swift-XRT refined Analysis
  26. GRB 130929A, Swift-BAT refined analysis
  27. GRB 130929A: Enhanced Swift-XRT position
  28. GRB 130929A: TAROT La Silla observatory optical observations
  29. GRB 130929A: Swift detection of a burst
  30. Fermi LAT Upper Limits on GRB 130925A
  31. GRB 130925A: Swift/UVOT Detection of the Host Galaxy
  32. GRB 130925A: Swift/UVOT Upper Limits
  33. GRB 130925A: sub-mm non-detection with SMA
  34. GRB 130925A: optical upper limit
  35. GRB 130925A: Continued RATIR Optical and NIR Observations
  36. GRB 130925A: Fermi GBM Detection
  37. Konus-Wind observation of GRB 130925A
  38. Observation of possible GRB/TDE 130925A by INTEGRAL/SPI-ACS: three activity episodes
  39. GRB 130925A: RATIR Optical and NIR Observations
  40. GRB 130925A Swift-BAT refined analysis
  41. GRB 130925A: Historical non-detection from Rosat-HRI
  42. Fermi GBM detection of GRB 130925A and a possible precursor
  43. GRB 130925A: Swift-XRT refined Analysis
  44. GRB 130925A: Initial Similarities to Swift J1644+57
  45. GRB 130925A: TAROT La Silla observatory optical observations
  46. GRB 130925A: Enhanced Swift-XRT position
  47. GRB 130925A: VLT/X-shooter redshift
  48. GRB 130925A: VLT/UVES observations
  49. GRB 130925A: MAXI/GSC detection
  50. GRB 130925A: GROND afterglow candidate
  51. GRB 130925A: Swift detection of a burst
  52. IPN Triangulation of SGR-like burst 130913 - probable association with SGR/AXP 1E1841-045
  53. GRB 130831A: RTT150 optical observations
  54. GRB 130702A: RTT150 optical observations
  55. GRB 130831A: RATIR Confirmation of NIR/Optical Afterglow Flattening
  56. GRB 130903A: optical observations
  57. GRB 130907A: Maidanak optical observations
  58. GRB 130912A: AAO optical upper limit
  59. Fermi Trigger 401326696: MASTER prompt optical observations
  60. GRB 130831A: Maidanak optical observations, possible emerging Supernova
  61. INTEGRAL detection of a SGR-like burst likely from SGR J1745-29
  62. GRB 130919A: Skynet PROMPT-CTIO optical upper limits
  63. GRB 130919A, Swift-BAT refined analysis
  64. GRB 130913A detected in ground analysis of Swift-BAT data
  65. GRB 130919A: Swift detection of a burst
  66. GRB 130903A: Further Swift XRT observations.
  67. GRB 130606A: Chandra observation
  68. GRB 130912A: Swift/UVOT Upper Limits
  69. Fermi/GBM Detection of two SGR-like bursts possibly associated with SGR J1833-0832
  70. GRB 130912A: 5.8 GHz VLA upper limit
  71. GRB 130912A: RATIR Optical and NIR Upper Limits
  72. Konus-Wind observation of GRB 130912A
  73. GRB 130912A: WHT confirmation of optical counterpart
  74. GRB 130907A: Continued RATIR Optical and NIR Observations
  75. GRB 130912A: P60 Observations
  76. GRB 130912A: Swift-XRT refined Analysis
  77. GRB 130907A: MASTER refined analysis
  78. GRB 130912A: Fermi GBM detection
  79. GRB 130912A: Skynet DSO-14/Yerkes-41/PROMPT-CTIO observations
  80. GRB 130912A: Enhanced Swift-XRT position
  81. GRB 130912A, Swift-BAT refined analysis
  82. GRB 130912A: REM optical/NIR upper limits
  83. GRB 130912A: GROND observations
  84. GRB 130912A: KAIT optical upper limit
  85. GRB 130912A: Swift detection of a short burst
  86. GRB 130907A: AMI radio detection
  87. GRB 120419A: Swift XRT confirmation of the afterglow
  88. GRB 130907A: Continued RATIR Optical and NIR Observations
  89. GRB 130907A: RATIR Optical and NIR Observations
  90. GRB 130907A: WSRT radio detection
  91. GRB 130828A: Further Swift XRT observations
  92. GRB 130907A: Further Swift-BAT refined analysis
  93. GRB 130907A: INTEGRAL/SPI-ACS light curve
  94. Konus-Wind observation of GRB 130907A
  95. GRB 130907A, Swift-BAT refined analysis
  96. GRB 130907A: T21 optical observations
  97. GRB 130907A: VLA detection
  98. GRB 130907A: Swift-XRT refined Analysis
  99. GRB 130907A: Enhanced Swift-XRT position
  100. Errata of GRB name in GCN 15196: should have been GRB 130907A instead of GRB 120916A

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