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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"

17823 results found.

  1. GRB090123: Enhanced Swift-XRT position
  2. GRB 090123: Swift detection of a burst
  3. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  4. Trigger 340734: Swift detection of a possible short burst
  5. GRB 090118: Subaru NIR Observation
  6. GRB 090118: KPNO 4m 2nd Epoch Observations
  7. GRB 090118 (BATSS): GRT Optical Observation
  8. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  9. GRB090118 Swift/UVOT upper limits
  10. GRB 090118: GROND Upper Limits
  11. GRB 090118: Possible burst detection from Swift-BAT slew data
  12. GRB 090117: GROND Upper Limits
  13. GRB090117 Swift/UVOT upper limits
  14. GRB090117: Swift-XRT detection of a possible candidate afterglow
  15. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  16. GRB 090113: Swift UVOT upper limits
  17. GRB 090113: GROND Upper Limits
  18. GRB 090113: Observations from NOT
  19. GRB 090113: Enhanced Swift-XRT position
  20. GRB 090113: ROTSE-III Optical Limits
  21. GRB 090112B: Fermi GBM Detection
  22. GRB 090113: Swift detection of a burst
  23. GRB 090111, Swift-BAT refined analysis
  24. GRB 090111: Swift UVOT Upper Limits
  25. GRB 090111: Enhanced Swift-XRT position
  26. GRB 090111: Swift detection of a burst
  27. GRB 090102: WSRT Radio Observations
  28. GRB 090107B: Swift XRT afterglow confirmation
  29. GRB 090107B: Swift/UVOT Observations
  30. GRB 090107B: Swift-XRT detection of possible afterglow
  31. VLA radio upper limit on GRB 090102
  32. GRB 090102: GRT Optical Observation
  33. Swift triggered on the HMXB 1A 1118-61
  34. GRB 090102: P60 Imaging and P200 Spectroscopy
  35. GRB 090102 Observations from IAC80
  36. GRB 090102: GROND observations of the optical afterglow
  37. GRB 090102: NOT redshift
  38. GRB 090102: Enhanced Swift-XRT position
  39. GRB 090102: REM observations of a bright afterglow
  40. GRB 090102: Swift detection of a burst with an optical counterpart
  41. GRB 090102: TAROT Calern observatory optical observations
  42. GRB 081230: GROND confirmation of the afterglow
  43. GRB081230: Swift-XRT refined analysis
  44. GRB 081230 Swift/UVOT Observations
  45. GRB 081230: Enhanced Swift-XRT position
  46. GRB 081230: Swift detection of a burst
  47. GRB 081228, Swift-BAT refined analysis
  48. VLA radio detection of GRB 081221
  49. GRB 081228: Swift/UVOT Upper Limits
  50. GRB 081228: Swift-XRT Team refined analysis
  51. GRB 081228: detection by GROND
  52. GRB 081228: Enhanced Swift-XRT position
  53. GRB 081228: TAROT Calern observatory optical observations
  54. GRB 081228: Swift detection of a burst
  55. VLA radio observation of GRB 081221
  56. GRB 081226B: Swift XRT and UVOT upper limits
  57. GRB 081226: Swift-XRT refined analysis
  58. GRB 081226A: Swift UVOT Upper Limits
  59. GRB 081226: GROND afterglow candidate
  60. GRB 081226: ROTSE-III Optical Limits
  61. GRB 081226: Swift detection of a possible short-hard burst
  62. GRB 080810: optical observations
  63. GRB 081211B: optical observations
  64. GRB 081224: Swift-XRT observation
  65. GRB 081222: MITSuME optical observation
  66. GRB 081221: GROND observations
  67. GRB 081222:Optical afterglow observation
  68. VLA radio upper limit on GRB 081222
  69. GRB 081222: Fermi GBM observation
  70. GRB 081221: Probable host galaxy in Keck imaging
  71. GRB 081222, Swift-BAT refined analysis
  72. GRB081222 optical limit by "Pi of the Sky"
  73. GRB 081222: Swift XRT refined analysis
  74. GRB081221: Fermi GBM observation
  75. IPN triangulation of bright GRB 081215A
  76. GRB 081221: Swift-XRT Refined Analysis
  77. GRB 081222: Faulkes Telescope South observations
  78. GRB 081221: Gemini-N nIR imaging
  79. GRB081222, optical observation
  80. GRB081203A: BTA observation
  81. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  82. GRB081222: REM candidate afterglow
  83. GRB 081222: Swift detection of a burst with a bright optical afterglow
  84. GRB 081221: Enhanced Swift-XRT position
  85. GRB 081221: further NOT observations
  86. GRB 081221: NOT observations
  87. GRB 081221: Swift detection of a burst
  88. GRB 081118: Zadko observations
  89. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  90. GRB 0811215A: MASTER prompt optical observations
  91. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  92. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  93. Possible GRB 081211B: Swift/UVOT Upper Limits
  94. Possible GRB 081211B - Swift-XRT analysis
  95. GRB 081209: Fermi GBM detection
  96. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  97. GRB 081210, SMARTS optical/IR observations
  98. GRB 081211: Enhanced Swift-XRT position
  99. GRB 081211: Swift detection of a burst
  100. GRB081203B: optical observations

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