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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"

7417 results found.

  1. GRB 090418A: R and I band observation
  2. GRB 090423: Swift detection of a burst
  3. GRB 090422: Liverpool Telescope possible candidate
  4. GRB 090422: Swift detection of a burst
  5. Swift-BAT trigger 349718 is not a burst
  6. GRB 090417B: Optical observation
  7. GRB 090419: GROND detection of afterglow candidate
  8. GRB 090419: Swift detection of a burst
  9. GRB 090418: Swift detection of a burst with optical afterglow
  10. GRB 090418 OA candidate
  11. GRB 090417A: Early-type nature of the putative host
  12. GRB 090417B: Swift detection of a burst
  13. Swift-BAT trigger 348781: almost certainly not a burst
  14. GRB 090407: Swift detection of a burst
  15. GRB 090404: Swift detection of a burst
  16. GRB 090401B: Swift detection of a burst
  17. GRB 090328: Gemini South Redshift
  18. GRB 090328: Swift UVOT observations
  19. GRB 090328: Updated position/optical afterglow candidate
  20. GRB 090328: Possible Swift/XRT detection
  21. GRB 090323: UVOT Detection of Afterglow
  22. GRB 090313: Swift-XRT refined analysis
  23. GRB 090313, GROND observations
  24. GRB 090313 OA candidate
  25. GRB 090205: Zadko Telescope late-time observations
  26. GRB 090309: Swift detection of a burst
  27. GRB 090308: Swift detection of a burst
  28. Swift Trigger 345551 is probably not a GRB
  29. GRB090305: GMOS-S Candidate Optical Afterglow
  30. GRB 090305: Swift detection of a short burst
  31. GRB 090205: Swift/UVOT Upper Limits
  32. GRB 090205: VLT candidate afterglow
  33. GRB 090205: Swift detection of a burst
  34. GRB090201: Swift UVOT upper limits
  35. GRB 090201: VLT NIR observations
  36. GRB 090201: VLT afterglow candidate
  37. GRB 090118: no afterglow candidate
  38. GRB 090123: Swift detection of a burst
  39. Trigger 340734: Swift detection of a possible short burst
  40. GRB 090118: Subaru NIR Observation
  41. GRB 090118: KPNO 4m 2nd Epoch Observations
  42. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  43. GRB090118 Swift/UVOT upper limits
  44. GRB 090118: Possible burst detection from Swift-BAT slew data
  45. GRB090117: Swift-XRT detection of a possible candidate afterglow
  46. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  47. GRB 090113: Swift detection of a burst
  48. GRB 090111: Swift detection of a burst
  49. GRB 090107B: Swift/UVOT Observations
  50. Swift UVOT observations of GRB 090102
  51. GRB 090102: Swift detection of a burst with an optical counterpart
  52. GRB 081230: GROND confirmation of the afterglow
  53. GRB 081230: Swift detection of a burst
  54. GRB 081228: GROND confirmation of the optical/NIR afterglow
  55. GRB 081228: Swift detection of a burst
  56. GRB 081226B: Swift XRT and UVOT upper limits
  57. GRB 081226: GROND afterglow candidate
  58. GRB 081222: MITSuME optical observation
  59. GRB 081222:Optical afterglow observation
  60. GRB081222: REM candidate afterglow
  61. GRB 081222: Swift detection of a burst with a bright optical afterglow
  62. GRB 081221: Swift detection of a burst
  63. GRB 081118: Zadko observations
  64. GRB 081215A: Gamma Repeater?
  65. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  66. GRB 081211: Swift detection of a burst
  67. GRB 081210: Swift detection of a burst with optical afterglow
  68. GRB 081128: afterglow observations
  69. GRB 081128: Optical afterglow observations
  70. GRB 081204: GROND Observations
  71. GRB 081204: Swift XRT afterglow confirmation
  72. GRB 081204: Swift XRT afterglow candidate
  73. GRB 081203B: Swift-XRT candidate afterglow.
  74. GRB 081203A: Burst detection from Swift-BAT slew data
  75. GRB 081203: Swift detection of a burst with a bright optical counterpart
  76. Trigger 335971: Swift possible detection of a burst
  77. GRB 081128: Liverpool Telescope afterglow confirmation
  78. GRB 081128: Swift detection of a burst
  79. GRB 081127: Swift detection of a burst
  80. GRB 081126: Swift detection of a burst
  81. GRB081121: Swift/UVOT observations
  82. GRB 081121: ROTSE-III Detection of Optical Counterpart
  83. GRB 081118: VLT redshift
  84. GRB 081118: optical afterglow candidate
  85. GRB 081118: Swift detection of a burst
  86. GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
  87. GRB 081109: Swift detection of a burst
  88. GRB 081104: GROND Detection of the Optical/NIR Afterglow Candidate?
  89. GRB 081102: Swift detection of a burst
  90. Swift-BAT triggered on a probable GRB 081101 (trigger=333320)
  91. GRB 081024B: new Swift-XRT observations
  92. GRB 081029: ROTSE-III Detection of Optical Counterpart
  93. GRB 081028: GROND Detection of the Optical/NIR Afterglow Candidate
  94. GRB 081028: Swift detection of a burst
  95. GRB 081025: TLS upper limits
  96. GRB 081025 BAT refined analysis
  97. GRB 081025: Burst detection from Swift-BAT slew data
  98. GRB 081024: Swift detection of a burst
  99. Swift detection of a possible burst (trigger 332287)
  100. GRB 081017: REM early observations

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