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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"

18335 results found.

  1. GRB050922B: Swift UVOT early upper limits.
  2. GRB 050922C: optical obserations
  3. GRB 050922C: NOT optical observations
  4. GRB 050922C: Swift detection of a bright burst
  5. GRB 050922B: ROTSE-III Optical Limits
  6. GRB 050922B,optical observation
  7. GRB050922B: Swift-BAT detection of a weak long burst
  8. GRB050820B: analysis of the XMM-Newton observation
  9. GRB050916: Swift/UVOT Upper Limits
  10. Swift-BAT trigger 155764 is not a GRB
  11. Swift-BAT trigger 155764 is probably not a GRB
  12. Swift trigger 155764: bad XRT centroid
  13. Swift-BAT trigger 155535 is definitely not a GRB
  14. GRB 050915B: Swift/UVOT Upper Limits
  15. GRB 050915a: IR Transient
  16. GRB 050915b, SMARTS optical/IR observations
  17. GRB050915B: Swift-BAT detection of a long bright burst
  18. GRB050915: Swift/UVOT upper limits
  19. GRB 050915: IR Observations
  20. GRB 050915: Swift detection of a GRB
  21. Swift-BAT trigger 155072 is probably not a GRB
  22. GRB 050911: z~0.16 cluster in the field
  23. GRB050911: Swift-BAT detection of a long burst
  24. GRB 050910a: TAROT early optical limits
  25. GRB 050906: Possible X-ray Counterpart
  26. GRB050908: Swift/UVOT Early upper limits
  27. GRB050908 : Swift-XRT refined analysis
  28. GRB 050908: Optical observations
  29. GRB 050908: Swift detection of a burst
  30. GRB 050906: Optical observations at the Very Large Telescope
  31. GRB 050904: Subaru Optical Spectroscopy
  32. GRB 050906: Swift XRT upper limit
  33. GRB 050904: Keck I-band Imaging
  34. GRB050906: P60 Observations
  35. GRB 050904: photometric redshift
  36. GRB 050904: Swift/UVOT observations
  37. GRB 050904: NIR object inside the XRT error box
  38. GRB 050904: early Swift XRT analysis results
  39. GRB050904: Optical Observations
  40. GRB050904: P60 Observations
  41. GRB 050904: TAROT optical limits
  42. GRB 050827: P200 NIR Observations
  43. GRB050827: Swift/UVOT upper limits
  44. GRB050824: Maidanak optical limits
  45. GRB 050827: Swift-BAT refined analysis
  46. Subaru Observations of GRB050724
  47. GRB050826: Swift/UVOT early upper limits
  48. GRB050826: Swift-BAT detection of a long burst
  49. GRB050824: MASTER:OT decay
  50. GRB050824: MASTER observation OT
  51. GRB050805a: MASTER optical candidat
  52. XRF050509c: Radio upper limits from GMRT
  53. GRB050822: Swift/UVOT upper limits
  54. GRB050813: Maidanak I-band observations
  55. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  56. GRB050820B at FRAM
  57. Swift/UVOT UV Photometry of GRB 050820B
  58. GRB 050822: Swift detection of a long burst
  59. GRB050820a BVRcIc field photometry
  60. GRB050820B XMM-Newton observation
  61. GRB 050820B: Swift XRT position
  62. GRB050820: refined XRT analysis
  63. GRB 050820 Swift-BAT refined analysis
  64. GRB050819: refined XRT analysis
  65. GRB 050820: Swift detection of a GRB
  66. GRB050819: Swift-BAT detection of a weak burst
  67. GRB 050817: Optical observations
  68. GRB050817: Negative Optical Observations
  69. GRB 050814: continued fading
  70. GRB050815: XRT refined analysis
  71. GRB 050815: ROTSE-III Optical Limits
  72. GRB050815: Swift-BAT detection of a burst
  73. GRB050814: Fading red source
  74. GRB050814: P60 Optical Afterglow Candidate
  75. GRB 050813: Non-fading of afterglow candidate
  76. GRB050814: SWIFT/UVOT observation
  77. GRB 050814: Swift XRT Afterglow Localization
  78. GRB 050814: Swift detection of a burst
  79. GRB 050813: Magellan detection of a high redshift galaxy cluster
  80. GRB050813, SDSS pre-burst observations
  81. GRB050813: SWIFT/UVOT observation
  82. GRB 050813: Swift XRT afterglow localization
  83. GRB050805b: CrAO optical limit
  84. GRB050803, optical observations
  85. Retraction of Swift Trigger 149131 (GRB 050805B)
  86. GRB 050805b: OHP optical limits
  87. GRB 050805b: TAROT optical limits
  88. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  89. GRB050802: TNG optical observations
  90. GRB050803: Radio Observation
  91. GRB 050803: RTT150 optical observations
  92. GRB050801: Radio Observation
  93. GRB050730: Radio Detection
  94. GRB 050803: Keck Observations
  95. GRB 050802.422: Fading of the afterglow and detection of the host
  96. GRB 050803: TAROT optical limits
  97. GRB050802 radio non-detection
  98. GRB 050730: OHP optical observations
  99. GRB050801: Optical photometry and decay index
  100. GRB 050802: Swift Gamma-ray Burst

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