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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"

20953 results found.

  1. GRB150819A: NOT imaging
  2. GRB 150818A: Continued NOT monitoring - afterglow confirmation
  3. GRB 150818A: Mondy optical observations
  4. GRB 150819A: RATIR Optical Observations
  5. GRB 150819A: Swift/UVOT Upper Limits
  6. GRB150818A: NOT imaging
  7. GRB 150818A: Swift/UVOT Detection
  8. GRB 150817A: AAO optical observations
  9. GRB 150817A: LCOGT observations
  10. GRB 150817A: Continued RATIR Optical Observations - Afterglow Confirmation
  11. GRB 150817A: P60 Observations
  12. MASTER OT inside bright ESO240-010 galaxy detection during FERMI trigger GRB150816.83 inspection
  13. GRB 150817A: Swift/UVOT Upper Limits
  14. GRB 150817A: Continued RATIR Observations, Revised Candidate
  15. GRB 150817A: RATIR Optical Afterglow Candidate
  16. GRB 150811A: Continued RATIR Observations
  17. GRB 150811A: Continued RATIR Observations
  18. GRB 150811A: KAIT Refined Analysis
  19. GRB 150811A: VLA Detection
  20. GRB 150811A: Continued RATIR Observations
  21. GRB 150811A: Swift/UVOT further observations
  22. GRB 150811A: SAO RAS optical observations
  23. GRB 150811A: P60 Observations
  24. GRB 150811A: LCOGT-McDonald afterglow detection
  25. GRB 150811A: Swift/UVOT Detection
  26. GRB 150811A: KAIT optical candidate
  27. GRB 150811A: RATIR Optical Afterglow Detection
  28. Fermi GBM GRB Trigger 460608875: iPTF P48 Observations
  29. GRB 150728A: TNG optical observations
  30. GRB 150727A: IRSF NIR observation
  31. GRB 150801A: Swift-XRT observations
  32. GRB 150801B: Swift/UVOT Upper Limits
  33. Fermi GBM GRB Trigger 458852670: iPTF P48 Observations
  34. GRB 150721A (Fermi GBM Trigger 459150552): iPTF P48 Observations
  35. GRB 150801A: Tiled Swift observations
  36. GRB 150724B: Swift-XRT afterglow detection
  37. GRB 150424A: HST imaging
  38. GRB 150728A: Continued RATIR Optical Observations
  39. GRB 150728A: TSHAO optical observations
  40. GRB 150728A: RATIR Optical Observations
  41. GRB 150727A: Continued RATIR Optical Observations - Fading
  42. GRB 150728A: AAO optical observations
  43. GRB 150728A: Swift/UVOT Upper Limits
  44. GRB 150728A: FTN observations
  45. GRB 150727A: RATIR Optical Observations
  46. GRB 150727A: Swift-BAT refined analysis
  47. GRB 150727A: Watcher optical upper limit
  48. GRB 150727A: Swift/UVOT Detection
  49. GRB 150727A: LCOGT-Cerro Tololo observations
  50. GRB 150724B: Continued RATIR Optical Observations
  51. GRB 150724B: Swift/UVOT Detection
  52. GRB 150724B: RATIR Optical Observations
  53. Swift 650221/IGR J00291+5934: Liverpool Telescope observations
  54. GRB 150724B: Swift-XRT observations
  55. GRB 150724B: Swift ToO observations
  56. Swift Trigger 650221 / IGR J00291+5934: MASTER-IAC OT observations
  57. Trigger 650221: Swift detection of a IGR J00291+5934
  58. GRB 150724A: Swift/UVOT Upper Limits
  59. SGR 1E 1841-045 (Swift trigger 649113): Terskol upper limit
  60. GRB 150722A: LCOGT-Sutherland observations
  61. GRB 150722A: Swift/UVOT Upper Limits
  62. GRB 150720A: Swift/UVOT Upper Limits
  63. GRB 150722A: Swift-XRT observations
  64. GRB 150716A: KAIT Optical Upper Limit
  65. GRB 150711A: Burakan-ISON optical observations
  66. GRB 150716A: Swift/UVOT Upper Limits
  67. GRB 150716A: Continued RATIR Optical Observations
  68. Swift trigger 649143 is not AX J1619.4-4945 or other astrophysical source
  69. GRB 150716A: P60 Candidate Optical Afterglow
  70. GRB 150716A: RATIR Optical Observations
  71. Trigger 649143: Swift detection of AX J1619.4-4945
  72. GRB 150710B: Swift-XRT afterglow detection
  73. GRB 150710B: Swift-XRT and Swift-UVOT observations
  74. GRB 150711A: Swift/UVOT Upper Limits
  75. GRB 150711A: Observations from the 2.5m NOT
  76. GRB 150710B: Swift ToO observations
  77. GRB 150710A: Swift/UVOT Upper Limits
  78. Swift-XRT observations of GRB 150710A
  79. GRB 150710A: RATIR Observations
  80. Swift trigger 648437: A GRB or a burst from 1RXS J125754.7+141850
  81. Swift Trigger 648422: Swift-XRT observations
  82. GRB 150626B: AMI 16 GHz detection of the radio counterpart
  83. GRB 150702A: MASTER-SAAO inspection
  84. GRB 150702A: Swift-XRT observations
  85. GRB 150702A: Swift ToO observations
  86. Fermi GBM Observations is no longer triggerin on V404 Cyg
  87. GRB 150622A: Swift-XRT afterglow detection
  88. V404 Cyg activity (Swift, Fermi, INTGRAL, KONUS, MAXI detection): optical observations in TSHAO, Khureltogot, and AAO
  89. GRB 150627A: Swift/UVOT Detection
  90. GRB 150627A: Swift-XRT afterglow detection
  91. GRB 150627A: Swift ToO observations
  92. GRB 150626B: Swift/UVOT Upper Limits
  93. GRB 150626B: MASTER observations
  94. GRB 150626A: Swift/UVOT Upper Limits
  95. V404 Cyg: MASTER Swift, Integral alert observations
  96. GRB 150622A: Swift-XRT observations
  97. GRB 150622A: Tiled Swift observations
  98. V404 Cyg: Fermi GBM observations
  99. GRB 150616A: Watcher optical upper limit
  100. Swift triggers again on V404 Cyg

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