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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"

19594 results found.

  1. GRB 090123: Swift XRT refined analysis
  2. GRB 090123: Swift/UVOT Observations
  3. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  4. GRB 090123: Swift-BAT refined analysis
  5. GRB090123: Enhanced Swift-XRT position
  6. GRB 090123: Swift detection of a burst
  7. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  8. Swift-BAT trigger 340734 is not a GRB
  9. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  10. AXP 1E1547.0-5408: Fermi GBM observations
  11. Trigger 340734: Swift detection of a possible short burst
  12. AXP 1E1547.0-5408 activity with SGR bursts
  13. GRB 090118 (BATSS): GRT Optical Observation
  14. GRB 090118: Swift-XRT observations
  15. GRB090118 Swift/UVOT upper limits
  16. GRB 090118: GROND Upper Limits
  17. GRB 090118: Possible burst detection from Swift-BAT slew data
  18. GRB 090117: confirmation of the X-ray afterglow
  19. GRB 090117: GROND Upper Limits
  20. GRB090117 Swift/UVOT upper limits
  21. GRB090117: Swift-XRT detection of a possible candidate afterglow
  22. GRB 090113: Swift UVOT upper limits
  23. GRB 090113: GROND Upper Limits
  24. GRB 090113: Swift-XRT refined analysis
  25. GRB 090113: Enhanced Swift-XRT position
  26. GRB 090113: Swift-BAT refined analysis
  27. GRB 090113: ROTSE-III Optical Limits
  28. GRB090113: XRT position
  29. GRB 090113: Swift detection of a burst
  30. GRB 090111, Swift-BAT refined analysis
  31. GRB 090111: Swift UVOT Upper Limits
  32. GRB 090111: Swift-XRT refined analysis
  33. GRB 090111: Enhanced Swift-XRT position
  34. GRB 090111: Swift detection of a burst
  35. GRB 090107B: Swift XRT afterglow confirmation
  36. GRB 090107B: Swift/UVOT Observations
  37. GRB 090107B: Swift-XRT detection of possible afterglow
  38. Fermi/GBM detection of GRB 081226A
  39. GRB 090107: Swift-BAT refined analysis
  40. GRB 090107: Swift detection of a burst
  41. VLA radio upper limit on GRB 090102
  42. GRB 090102: GRT Optical Observation
  43. Swift triggered on the HMXB 1A 1118-61
  44. Konus-Wind observation of GRB 090102
  45. Swift UVOT observations of GRB 090102
  46. GRB 090102: Swift-BAT refined analysis
  47. GRB 090102: Swift burst of interest
  48. GRB 090102: Swift XRT refined analysis
  49. GRB 090102: Enhanced Swift-XRT position
  50. GRB 090102: TAROT Calern observatory optical light curve
  51. GRB 090102: Swift detection of a burst with an optical counterpart
  52. GRB 090102: TAROT Calern observatory optical observations
  53. GRB 081230: GROND confirmation of the afterglow
  54. GRB 081230, Swift-BAT refined analysis
  55. GRB081230: Swift-XRT refined analysis
  56. GRB 081230 Swift/UVOT Observations
  57. GRB 081230: Enhanced Swift-XRT position
  58. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  59. GRB 081230: ROTSE-III Detection of Optical Counterpart
  60. GRB 081230: Swift detection of a burst
  61. GRB 081228: GROND confirmation of the optical/NIR afterglow
  62. GRB 081228, Swift-BAT refined analysis
  63. GRB 081228: Swift/UVOT Upper Limits
  64. GRB 081228: Swift-XRT Team refined analysis
  65. GRB 081228: detection by GROND
  66. GRB 081228: Enhanced Swift-XRT position
  67. GRB 081228: TAROT Calern observatory optical observations
  68. GRB 081228: Swift detection of a burst
  69. GRB 081226B: Swift XRT and UVOT upper limits
  70. GRB 081226: Swift-XRT refined analysis
  71. GRB 081226A: Swift UVOT Upper Limits
  72. GRB 081226A: Swift-BAT refined analysis
  73. GRB 081226: ROTSE-III Optical Limits
  74. GRB 081226: Swift detection of a possible short-hard burst
  75. GRB 081224: Swift-XRT observation
  76. Konus-Wind observation of GRB 081222
  77. GRB 081221: GROND observations
  78. GRB 081222:Optical afterglow observation
  79. GRB 081222: Fermi GBM observation
  80. GRB081222: Swift/UVOT further observations
  81. GRB 081221: Probable host galaxy in Keck imaging
  82. GRB 081222, Swift-BAT refined analysis
  83. GRB 081221, Swift-BAT refined analysis
  84. GRB081222 optical limit by "Pi of the Sky"
  85. GRB 081222: Swift XRT refined analysis
  86. GRB081221: Fermi GBM observation
  87. Swift/UVOT observations of GRB 081221
  88. IPN triangulation of bright GRB 081215A
  89. GRB 081221: Swift-XRT Refined Analysis
  90. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  91. GRB081222, optical observation
  92. GRB081222: Swift/UVOT detection of an optical afterglow
  93. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  94. GRB 081222: Swift detection of a burst with a bright optical afterglow
  95. GRB 081221: Enhanced Swift-XRT position
  96. GRB 081221: Swift detection of a burst
  97. Modification of Swift/UVOT response to bright GRBs
  98. GRB 081211B: Further Swift-XRT analysis
  99. GRB 081211B - possibly a short burst with extended emission
  100. Possible GRB 081211B: Swift/UVOT Upper Limits

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