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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 150817A: Continued RATIR Observations, Revised Candidate
  2. GRB 150817A: RATIR Optical Afterglow Candidate
  3. GRB 150817A: Swift detection of a burst
  4. Fermi GBM Trigger 150815694 is not a GRB
  5. GRB 150811A: Continued RATIR Observations
  6. GRB 150811A: Continued RATIR Observations
  7. GBM Trigger 150813665 is not a GRB
  8. Swift Trigger 652046 is a particle shower event
  9. Konus-Wind observation of GRB 150811B
  10. Swift Trigger 652046 is probably not a GRB
  11. GRB 150811A: KAIT Refined Analysis
  12. GRB 150811A: VLA Detection
  13. IPN Triangulation of GRB 150811B
  14. GRB 150811A: Continued RATIR Observations
  15. GRB 150811A: Swift/UVOT further observations
  16. GRB 150811B: Fermi GBM detection
  17. GRB 150811A: Swift-BAT refined analysis
  18. GRB 150811A: SAO RAS optical observations
  19. GRB 150811A: Swift-XRT refined Analysis
  20. GRB 150810A: Fermi GBM detection
  21. GRB 150811A: P60 Observations
  22. GRB 150811A: Enhanced Swift-XRT position
  23. GRB 150811A: LCOGT-McDonald afterglow detection
  24. GRB 150811A: Swift/UVOT Detection
  25. GRB 150811A: KAIT optical candidate
  26. GRB 150811A: RATIR Optical Afterglow Detection
  27. GRB 150811A: Swift detection of a burst
  28. Fermi GBM GRB Trigger 460608875: iPTF P48 Observations
  29. Fermi GBM trigger 150807969 is not a GRB
  30. Fermi GBM trigger 150806450 is not a GRB
  31. GRB 150728A: TNG optical observations
  32. Fermi GBM trigger 150805556 is not a GRB
  33. GRB 150727A: IRSF NIR observation
  34. GRB 150801A: Swift-XRT observations
  35. GRB 150801B: Swift/UVOT Upper Limits
  36. GRB 150801B: Swift-BAT refined analysis
  37. GRB 150801B: Swift-XRT refined Analysis
  38. GRB 150801B: Enhanced Swift-XRT position
  39. Fermi GBM triggers 150730606 150731173 and 150801590 are not due to GRBs
  40. Fermi GBM GRB Trigger 458852670: iPTF P48 Observations
  41. GRB 150721A (Fermi GBM Trigger 459150552): iPTF P48 Observations
  42. GRB 150801B: Swift detection of a burst
  43. GRB 150801A: Tiled Swift observations
  44. GRB 150801A: MAXI/GSC detection
  45. GRB 150724B: Swift-XRT afterglow detection
  46. GRB 150424A: HST imaging
  47. GRB150724B: Retraction of the uvot detection
  48. GRB 150728A: Continued RATIR Optical Observations
  49. GRB 150728A: TSHAO optical observations
  50. GRB 150728A: RATIR Optical Observations
  51. GRB 150727A: Continued RATIR Optical Observations - Fading
  52. GRB 150728A: AAO optical observations
  53. GRB 150728A: Swift-XRT refined Analysis
  54. GRB 150728A: Swift/UVOT Upper Limits
  55. GRB 150728A: Swift-BAT refined analysis
  56. GRB 150728A: FTN observations
  57. GRB 150727A: RATIR Optical Observations
  58. GRB 150728A: Enhanced Swift-XRT position
  59. GRB 150728A: Swift detection of a GRB
  60. GRB 150727A: Swift-BAT refined analysis
  61. GRB 150727A: Watcher optical upper limit
  62. GRB 150727A: Swift/UVOT Detection
  63. GRB 150727A: LCOGT-Cerro Tololo observations
  64. GRB 150727A: Swift-XRT refined Analysis
  65. GRB 150727A: Fermi GBM detection
  66. GRB 150727A: VLT/X-shooter redshift
  67. GRB 150727A: Enhanced Swift-XRT position
  68. GRB 150724B: Continued RATIR Optical Observations
  69. GRB 150724B: MASTER upper limit
  70. GRB 150727A: Swift detection of a burst with an optical counterpart
  71. GRB 150724B: Swift/UVOT Detection
  72. Konus-Wind observation of GRB 150724B
  73. Konus-Wind observation of GRB 150725A
  74. GRB 150724B: RATIR Optical Observations
  75. Swift Trigger 650408 is not a burst
  76. Swift 650221/IGR J00291+5934: Liverpool Telescope observations
  77. GRB 150724B: Swift-XRT observations
  78. GRB 150724B: Swift ToO observations
  79. IGR J00291+5934, Swift-BAT refined analysis
  80. GRB 150724B: Fermi GBM detection
  81. GRB 150724B: Fermi-LAT detection
  82. Swift Trigger 650221 / IGR J00291+5934: MASTER-IAC OT observations
  83. Fermi GBM trigger 150725291 is not a GRB
  84. GRB 150725A: MAXI/GSC detection
  85. Trigger 650221: Swift detection of a IGR J00291+5934
  86. Correction to GCN 18059: Parameterisation of Swift-XRT light curve
  87. GRB 150724A: Swift-XRT refined Analysis
  88. Swift IGR J00291+5934: MASTER Optical flare detection
  89. GRB 150724A: Swift/UVOT Upper Limits
  90. IGR J00291+5934: Swift-BAT refined analysis
  91. GRB 150724A: Swift-BAT refined analysis
  92. GRB 150724A: Enhanced Swift-XRT position
  93. SGR 1E 1841-045 (Swift trigger 649113): Terskol upper limit
  94. GRB 150724A: Prompt enhanced Swift-XRT position
  95. Trigger 650140: Swift detection of IGR J00291+5934
  96. GRB 150724A: Swift detection of a burst
  97. GRB 150722A: LCOGT-Sutherland observations
  98. GRB 150722A: Swift-BAT refined analysis
  99. GRB 150722A: Swift-XRT refined Analysis
  100. GRB 150722A: Swift/UVOT Upper Limits

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