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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"

41698 results found.

  1. GRB 150818A: 10.4m GTC spectroscopy and host galaxy
  2. IPN Triangulation of GRB 150819B (short / very intense)
  3. GRB 150818A: Mondy optical observations
  4. GRB 150818A: MITSuME Ishigakijima upper limits
  5. GRB 150819A: RATIR Optical Observations
  6. GRB 150819A: Swift-XRT refined Analysis
  7. GRB 150818A: MITSuME Akeno optical upper limits
  8. GRB 150819A: Swift-BAT refined analysis
  9. GRB 150819A: MASTER-IAC early upper limit
  10. GRB 150819A: Swift/UVOT Upper Limits
  11. GRB 150818A: Swift-XRT update, correction to GCN 18162
  12. GRB150818A: NOT imaging
  13. GRB 150819A: Swift detection of a burst
  14. GRB 150818A: Swift-XRT refined Analysis
  15. GRB 150818A: Swift/UVOT Detection
  16. GRB 150817A: AAO optical observations
  17. GRB 150817A: LCOGT observations
  18. GRB 150818A: Swift-BAT refined analysis
  19. GRB 150817A: Continued RATIR Optical Observations - Afterglow Confirmation
  20. GRB 150818A: Swift/UVOT candidate afterglow
  21. GRB 150818A: Planned XMM-Newton observation
  22. GRB 150817A: P60 Observations
  23. GRB 150818A: Swift detection of a burst
  24. MASTER OT inside bright ESO240-010 galaxy detection during FERMI trigger GRB150816.83 inspection
  25. GRB 150817A: Swift/UVOT Upper Limits
  26. GRB 150817A: Fermi GBM observation
  27. GRB 150817A: Swift-BAT refined analysis
  28. GRB 150817A: Swift-XRT refined Analysis
  29. GRB 150817A: Continued RATIR Observations, Revised Candidate
  30. GRB 150817A: RATIR Optical Afterglow Candidate
  31. GRB 150817A: Swift detection of a burst
  32. Fermi GBM Trigger 150815694 is not a GRB
  33. GRB 150811A: Continued RATIR Observations
  34. GRB 150811A: Continued RATIR Observations
  35. GBM Trigger 150813665 is not a GRB
  36. Swift Trigger 652046 is a particle shower event
  37. Konus-Wind observation of GRB 150811B
  38. Swift Trigger 652046 is probably not a GRB
  39. GRB 150811A: KAIT Refined Analysis
  40. GRB 150811A: VLA Detection
  41. IPN Triangulation of GRB 150811B
  42. GRB 150811A: Continued RATIR Observations
  43. GRB 150811A: Swift/UVOT further observations
  44. GRB 150811B: Fermi GBM detection
  45. GRB 150811A: Swift-BAT refined analysis
  46. GRB 150811A: SAO RAS optical observations
  47. GRB 150811A: Swift-XRT refined Analysis
  48. GRB 150810A: Fermi GBM detection
  49. GRB 150811A: P60 Observations
  50. GRB 150811A: LCOGT-McDonald afterglow detection
  51. GRB 150811A: Swift/UVOT Detection
  52. GRB 150811A: KAIT optical candidate
  53. GRB 150811A: RATIR Optical Afterglow Detection
  54. GRB 150811A: Swift detection of a burst
  55. Fermi GBM GRB Trigger 460608875: iPTF P48 Observations
  56. Fermi GBM trigger 150807969 is not a GRB
  57. Fermi GBM trigger 150806450 is not a GRB
  58. GRB 150728A: TNG optical observations
  59. Fermi GBM trigger 150805556 is not a GRB
  60. GRB 150727A: IRSF NIR observation
  61. GRB 150801A: Swift-XRT observations
  62. GRB 150801B: Swift/UVOT Upper Limits
  63. GRB 150801B: Swift-BAT refined analysis
  64. GRB 150801B: Swift-XRT refined Analysis
  65. Fermi GBM triggers 150730606 150731173 and 150801590 are not due to GRBs
  66. Fermi GBM GRB Trigger 458852670: iPTF P48 Observations
  67. GRB 150721A (Fermi GBM Trigger 459150552): iPTF P48 Observations
  68. GRB 150801B: Swift detection of a burst
  69. GRB 150801A: Tiled Swift observations
  70. GRB 150801A: MAXI/GSC detection
  71. GRB 150724B: Swift-XRT afterglow detection
  72. GRB 150424A: HST imaging
  73. GRB150724B: Retraction of the uvot detection
  74. GRB 150728A: Continued RATIR Optical Observations
  75. GRB 150728A: TSHAO optical observations
  76. GRB 150728A: RATIR Optical Observations
  77. GRB 150727A: Continued RATIR Optical Observations - Fading
  78. GRB 150728A: AAO optical observations
  79. GRB 150728A: Swift-XRT refined Analysis
  80. GRB 150728A: Swift/UVOT Upper Limits
  81. GRB 150728A: Swift-BAT refined analysis
  82. GRB 150728A: FTN observations
  83. GRB 150727A: RATIR Optical Observations
  84. GRB 150728A: Swift detection of a GRB
  85. GRB 150727A: Swift-BAT refined analysis
  86. GRB 150727A: Watcher optical upper limit
  87. GRB 150727A: Swift/UVOT Detection
  88. GRB 150727A: LCOGT-Cerro Tololo observations
  89. GRB 150727A: Swift-XRT refined Analysis
  90. GRB 150727A: Fermi GBM detection
  91. GRB 150727A: VLT/X-shooter redshift
  92. GRB 150724B: Continued RATIR Optical Observations
  93. GRB 150724B: MASTER upper limit
  94. GRB 150727A: Swift detection of a burst with an optical counterpart
  95. GRB 150724B: Swift/UVOT Detection
  96. Konus-Wind observation of GRB 150724B
  97. Konus-Wind observation of GRB 150725A
  98. GRB 150724B: RATIR Optical Observations
  99. Swift 650221/IGR J00291+5934: Liverpool Telescope observations
  100. GRB 150724B: Swift-XRT observations

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