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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"

20351 results found.

  1. GRB 051016B,optical observation
  2. GRB 051016B: Swift detection of a soft burst
  3. GRB051016 XMM-Newton observation
  4. GRB 051016: PROMPT Observations
  5. GRB051016: Swift detection of a burst
  6. GRB 051012: Swift-BAT detection of burst yesterday
  7. GRB 051006: Swift/UVOT Upper Limits
  8. Konus-Wind observation of GRB 051008
  9. GRB051008: Radio Observation
  10. GRB 051008, optical observations
  11. GRB 051008: early Swift XRT analysis
  12. GRB 051008: Swift UVOT Candidate
  13. GRB051008: Swift-BAT detection of a bright burst
  14. GRB 051006: P60 Observations
  15. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  16. GRB051006: Swift detection of a burst
  17. GRB 050906, summary of radio observations
  18. GRB051001: Swift UVOT Upper Limits
  19. GRB 051001: AAT infra-red observations
  20. GRB 051001: Swift Detection of a Burst
  21. GRB 050820A: NIR photometry at the TNG
  22. GRB/SGR 050925: IR Observations
  23. GRB050925: Swift UVOT upper limits
  24. GRB050925: Faulkes Telescope North R-band limit
  25. GRB050925: Swift-BAT detection of a short burst
  26. GRB050922B: refined XRT analysis
  27. GRB050922B: Swift UVOT early upper limits.
  28. GRB 050922C: optical obserations
  29. GRB 050922C: NOT optical observations
  30. GRB 050922C: Swift detection of a bright burst
  31. GRB 050922B: ROTSE-III Optical Limits
  32. GRB 050922B,optical observation
  33. GRB050922B: Swift-BAT detection of a weak long burst
  34. GRB050820B: analysis of the XMM-Newton observation
  35. GRB050916: Swift/UVOT Upper Limits
  36. Swift-BAT trigger 155764 is not a GRB
  37. Swift-BAT trigger 155764 is probably not a GRB
  38. Swift trigger 155764: bad XRT centroid
  39. Swift-BAT trigger 155535 is definitely not a GRB
  40. GRB 050915B: Swift-BAT refined analysis
  41. GRB 050915B: Swift/UVOT Upper Limits
  42. GRB 050915a: IR Transient
  43. GRB 050915b, SMARTS optical/IR observations
  44. GRB050915B: Swift-BAT detection of a long bright burst
  45. GRB050915: Swift/UVOT upper limits
  46. GRB 050915: IR Observations
  47. GRB050915: P60 Optical Observations
  48. GRB 050915: Swift detection of a GRB
  49. GRB050911: Upper limit on X-ray afterglow
  50. Swift-BAT trigger 155072 ground analysis
  51. Swift-BAT trigger 155072 is probably not a GRB
  52. GRB 050911: z~0.16 cluster in the field
  53. GRB050911: Swift-BAT detection of a long burst
  54. GRB 050910a: TAROT early optical limits
  55. WIRO observations in I of GRB 050908
  56. GRB 050906: Possible X-ray Counterpart
  57. GRB050908: Swift/UVOT Early upper limits
  58. GRB050908 : Swift-XRT refined analysis
  59. GRB 050908: Optical observations
  60. Gemini Spectroscopy of GRB 050908
  61. GRB 050908: Swift detection of a burst
  62. GRB 050906: Optical observations at the Very Large Telescope
  63. GRB050904: CrAO optical observations
  64. GRB 050904: Subaru Optical Spectroscopy
  65. GRB 050906: Swift XRT upper limit
  66. GRB 050904: Keck I-band Imaging
  67. GRB050906: P60 Observations
  68. GRB 050904: photometric redshift
  69. GRB 050904: Swift/UVOT observations
  70. GRB 050904: NIR object inside the XRT error box
  71. GRB050904: Optical Observations
  72. GRB050904: P60 Observations
  73. GRB 050904: TAROT optical limits
  74. GRB050904: Swift-BAT detection of a probable burst
  75. GRB 050827: P200 NIR Observations
  76. GRB050827: Swift/UVOT upper limits
  77. GRB050824: Maidanak optical limits
  78. GRB 050827: Swift-BAT refined analysis
  79. Subaru Observations of GRB050724
  80. GRB 050826: BAT refined analysis
  81. GRB050826: Swift/UVOT early upper limits
  82. GRB050826: Swift-BAT detection of a long burst
  83. GRB050824, I-band imaging
  84. XRF050509c: Radio upper limits from GMRT
  85. GRB050822: Swift/UVOT upper limits
  86. GRB050813: Maidanak I-band observations
  87. GRB 050822: Swift-BAT refined analysis
  88. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  89. GRB050820B at FRAM
  90. Swift/UVOT UV Photometry of GRB 050820B
  91. GRB 050822: Swift detection of a long burst
  92. GRB050820a BVRcIc field photometry
  93. GRB050820B XMM-Newton observation
  94. GRB 050820B: Swift XRT position
  95. GRB050820: refined XRT analysis
  96. GRB050819: refined XRT analysis
  97. GRB 050820: Swift detection of a GRB
  98. GRB 050819 Swift-BAT refined analysis
  99. GRB050819: Swift-BAT detection of a weak burst
  100. Swift Trigger 150823 is HETE J1900.1-2455

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