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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"

19588 results found.

  1. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  2. Swift-BAT trigger 340734 is not a GRB
  3. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  4. AXP 1E1547.0-5408: Fermi GBM observations
  5. Trigger 340734: Swift detection of a possible short burst
  6. AXP 1E1547.0-5408 activity with SGR bursts
  7. GRB 090118 (BATSS): GRT Optical Observation
  8. GRB 090118: Swift-XRT observations
  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: confirmation of the X-ray afterglow
  13. GRB 090117: GROND Upper Limits
  14. GRB090117 Swift/UVOT upper limits
  15. GRB090117: Swift-XRT detection of a possible candidate afterglow
  16. GRB 090113: Swift UVOT upper limits
  17. GRB 090113: GROND Upper Limits
  18. GRB 090113: Swift-XRT refined analysis
  19. GRB 090113: Enhanced Swift-XRT position
  20. GRB 090113: Swift-BAT refined analysis
  21. GRB 090113: ROTSE-III Optical Limits
  22. GRB090113: XRT position
  23. GRB 090113: Swift detection of a burst
  24. GRB 090111, Swift-BAT refined analysis
  25. GRB 090111: Swift UVOT Upper Limits
  26. GRB 090111: Swift-XRT refined analysis
  27. GRB 090111: Enhanced Swift-XRT position
  28. GRB 090111: Swift detection of a burst
  29. GRB 090107B: Swift XRT afterglow confirmation
  30. GRB 090107B: Swift/UVOT Observations
  31. GRB 090107B: Swift-XRT detection of possible afterglow
  32. Fermi/GBM detection of GRB 081226A
  33. GRB 090107: Swift-BAT refined analysis
  34. GRB 090107: Swift detection of a burst
  35. VLA radio upper limit on GRB 090102
  36. GRB 090102: GRT Optical Observation
  37. Swift triggered on the HMXB 1A 1118-61
  38. Konus-Wind observation of GRB 090102
  39. Swift UVOT observations of GRB 090102
  40. GRB 090102: Swift-BAT refined analysis
  41. GRB 090102: Swift burst of interest
  42. GRB 090102: Swift XRT refined analysis
  43. GRB 090102: Enhanced Swift-XRT position
  44. GRB 090102: TAROT Calern observatory optical light curve
  45. GRB 090102: Swift detection of a burst with an optical counterpart
  46. GRB 090102: TAROT Calern observatory optical observations
  47. GRB 081230: GROND confirmation of the afterglow
  48. GRB 081230, Swift-BAT refined analysis
  49. GRB081230: Swift-XRT refined analysis
  50. GRB 081230 Swift/UVOT Observations
  51. GRB 081230: Enhanced Swift-XRT position
  52. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  53. GRB 081230: ROTSE-III Detection of Optical Counterpart
  54. GRB 081230: Swift detection of a burst
  55. GRB 081228: GROND confirmation of the optical/NIR afterglow
  56. GRB 081228, Swift-BAT refined analysis
  57. GRB 081228: Swift/UVOT Upper Limits
  58. GRB 081228: Swift-XRT Team refined analysis
  59. GRB 081228: detection by GROND
  60. GRB 081228: Enhanced Swift-XRT position
  61. GRB 081228: TAROT Calern observatory optical observations
  62. GRB 081228: Swift detection of a burst
  63. GRB 081226B: Swift XRT and UVOT upper limits
  64. GRB 081226: Swift-XRT refined analysis
  65. GRB 081226A: Swift UVOT Upper Limits
  66. GRB 081226A: Swift-BAT refined analysis
  67. GRB 081226: ROTSE-III Optical Limits
  68. GRB 081226: Swift detection of a possible short-hard burst
  69. GRB 081224: Swift-XRT observation
  70. Konus-Wind observation of GRB 081222
  71. GRB 081221: GROND observations
  72. GRB 081222:Optical afterglow observation
  73. GRB 081222: Fermi GBM observation
  74. GRB081222: Swift/UVOT further observations
  75. GRB 081221: Probable host galaxy in Keck imaging
  76. GRB 081222, Swift-BAT refined analysis
  77. GRB 081221, Swift-BAT refined analysis
  78. GRB081222 optical limit by "Pi of the Sky"
  79. GRB 081222: Swift XRT refined analysis
  80. GRB081221: Fermi GBM observation
  81. Swift/UVOT observations of GRB 081221
  82. IPN triangulation of bright GRB 081215A
  83. GRB 081221: Swift-XRT Refined Analysis
  84. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  85. GRB081222, optical observation
  86. GRB081222: Swift/UVOT detection of an optical afterglow
  87. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  88. GRB 081222: Swift detection of a burst with a bright optical afterglow
  89. GRB 081221: Enhanced Swift-XRT position
  90. GRB 081221: Swift detection of a burst
  91. Modification of Swift/UVOT response to bright GRBs
  92. GRB 081211B: Further Swift-XRT analysis
  93. GRB 081211B - possibly a short burst with extended emission
  94. Possible GRB 081211B: Swift/UVOT Upper Limits
  95. GRB 081210: optical observations
  96. Possible GRB 081211B - Swift-XRT analysis
  97. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  98. GRB 081211: Swift-BAT refined analysis
  99. GRB 081211: Swift XRT refined analysis
  100. GRB 081211: Swift/UVOT detection of an optical afterglow

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