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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 131004A: Liverpool Telescope optical afterglow observations
  2. GRB 131004A: TNG optical afterglow confirmation
  3. GRB 131004A: optical afterglow from the NOT
  4. GRB 131004A: Swift detection of a burst (may be short)
  5. GRB 131002A, Swift-BAT refined analysis
  6. GRB 130925A: 3mm observations with CARMA
  7. GRB 131002A: Fermi GBM observation
  8. GRB 130925A/Sw J0244-2609: mm observations at PdBI
  9. GRB 131002B, Swift-BAT refined analysis
  10. GRB 131002B: GROND upper limits
  11. GRB 131002B: Swift-XRT Refined Analysis
  12. GRB 131002B: Swift/UVOT Upper Limits
  13. GRB 131002A: Swift/UVOT Detection
  14. GRB 131001A, Swift-BAT refined analysis
  15. GRB 131002A: Swift-XRT refined Analysis
  16. GRB 131002B: Enhanced Swift-XRT position
  17. GRB 131002A: ISON-NM optical observations
  18. Swift J1242.9-3530, Swift-BAT refined analysis
  19. GRB 131001A: Swift UVOT and XRT Upper Limits
  20. GRB 131002A: Enhanced Swift-XRT position
  21. NuSTAR observations of GRB 130925A
  22. Fermi Gamma-ray Burst Monitor trigger 402405063 / 131002466 is not a GRB
  23. GRB 131002B: Swift detection of a burst
  24. GRB 131002A: Swift detection of a burst
  25. GRB 131002A: Faulkes Telescope North optical afterglow
  26. GRB 131001A detected in ground analysis of Swift-BAT data
  27. GRB 130925A: continuing Swift/XRT monitoring
  28. Swift Operations in the event of a US Government shutdown
  29. IPN Observations of GRB 130925A
  30. US Government shutdown may impact GRB operation of GCN
  31. GRB 130930A: Swift detection of a burst
  32. GRB 130929A: Swift/UVOT Upper Limits
  33. GRB 130831A: Continued RATIR Optical and NIR Observations
  34. GRB 130929A: Swift-XRT refined Analysis
  35. GRB 130929A, Swift-BAT refined analysis
  36. GRB 130929A: Enhanced Swift-XRT position
  37. GRB 130929A: TAROT La Silla observatory optical observations
  38. GRB 130929A: Swift detection of a burst
  39. Fermi LAT Upper Limits on GRB 130925A
  40. GRB 130925A: Swift/UVOT Detection of the Host Galaxy
  41. GRB 130925A: Swift/UVOT Upper Limits
  42. GRB 130925A: sub-mm non-detection with SMA
  43. GRB 130925A: optical upper limit
  44. GRB 130925A: Continued RATIR Optical and NIR Observations
  45. GRB 130925A: Fermi GBM Detection
  46. Konus-Wind observation of GRB 130925A
  47. Observation of possible GRB/TDE 130925A by INTEGRAL/SPI-ACS: three activity episodes
  48. GRB 130925A: RATIR Optical and NIR Observations
  49. GRB 130925A Swift-BAT refined analysis
  50. GRB 130925A: Historical non-detection from Rosat-HRI
  51. Fermi GBM detection of GRB 130925A and a possible precursor
  52. GRB 130925A: Swift-XRT refined Analysis
  53. GRB 130925A: Initial Similarities to Swift J1644+57
  54. GRB 130925A: TAROT La Silla observatory optical observations
  55. GRB 130925A: Enhanced Swift-XRT position
  56. GRB 130925A: VLT/X-shooter redshift
  57. GRB 130925A: VLT/UVES observations
  58. GRB 130925A: MAXI/GSC detection
  59. GRB 130925A: GROND afterglow candidate
  60. GRB 130925A: Swift detection of a burst
  61. IPN Triangulation of SGR-like burst 130913 - probable association with SGR/AXP 1E1841-045
  62. GRB 130831A: RTT150 optical observations
  63. GRB 130702A: RTT150 optical observations
  64. GRB 130831A: RATIR Confirmation of NIR/Optical Afterglow Flattening
  65. GRB 130903A: optical observations
  66. GRB 130907A: Maidanak optical observations
  67. GRB 130912A: AAO optical upper limit
  68. Fermi Trigger 401326696: MASTER prompt optical observations
  69. GRB 130831A: Maidanak optical observations, possible emerging Supernova
  70. INTEGRAL detection of a SGR-like burst likely from SGR J1745-29
  71. GRB 130919A: Skynet PROMPT-CTIO optical upper limits
  72. GRB 130919A, Swift-BAT refined analysis
  73. GRB 130913A detected in ground analysis of Swift-BAT data
  74. GRB 130919A: Swift detection of a burst
  75. GRB 130903A: Further Swift XRT observations.
  76. GRB 130606A: Chandra observation
  77. GRB 130912A: Swift/UVOT Upper Limits
  78. Fermi/GBM Detection of two SGR-like bursts possibly associated with SGR J1833-0832
  79. GRB 130912A: 5.8 GHz VLA upper limit
  80. GRB 130912A: RATIR Optical and NIR Upper Limits
  81. Konus-Wind observation of GRB 130912A
  82. GRB 130912A: WHT confirmation of optical counterpart
  83. GRB 130907A: Continued RATIR Optical and NIR Observations
  84. GRB 130912A: P60 Observations
  85. GRB 130912A: Swift-XRT refined Analysis
  86. GRB 130907A: MASTER refined analysis
  87. GRB 130912A: Fermi GBM detection
  88. GRB 130912A: Skynet DSO-14/Yerkes-41/PROMPT-CTIO observations
  89. GRB 130912A: Enhanced Swift-XRT position
  90. GRB 130912A, Swift-BAT refined analysis
  91. GRB 130912A: REM optical/NIR upper limits
  92. GRB 130912A: GROND observations
  93. GRB 130912A: KAIT optical upper limit
  94. GRB 130912A: Swift detection of a short burst
  95. GRB 130907A: AMI radio detection
  96. GRB 120419A: Swift XRT confirmation of the afterglow
  97. GRB 130907A: Continued RATIR Optical and NIR Observations
  98. GRB 130907A: RATIR Optical and NIR Observations
  99. GRB 130907A: WSRT radio detection
  100. GRB 130828A: Further Swift XRT observations

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