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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"

18334 results found.

  1. GRB 050922C: optical obserations
  2. GRB 050922C: NOT optical observations
  3. GRB 050922C: Swift detection of a bright burst
  4. GRB 050922B: ROTSE-III Optical Limits
  5. GRB 050922B,optical observation
  6. GRB050922B: Swift-BAT detection of a weak long burst
  7. GRB050820B: analysis of the XMM-Newton observation
  8. GRB050916: Swift/UVOT Upper Limits
  9. Swift-BAT trigger 155764 is not a GRB
  10. Swift-BAT trigger 155764 is probably not a GRB
  11. Swift trigger 155764: bad XRT centroid
  12. Swift-BAT trigger 155535 is definitely not a GRB
  13. GRB 050915B: Swift/UVOT Upper Limits
  14. GRB 050915a: IR Transient
  15. GRB 050915b, SMARTS optical/IR observations
  16. GRB050915B: Swift-BAT detection of a long bright burst
  17. GRB050915: Swift/UVOT upper limits
  18. GRB 050915: IR Observations
  19. GRB 050915: Swift detection of a GRB
  20. Swift-BAT trigger 155072 is probably not a GRB
  21. GRB 050911: z~0.16 cluster in the field
  22. GRB050911: Swift-BAT detection of a long burst
  23. GRB 050910a: TAROT early optical limits
  24. GRB 050906: Possible X-ray Counterpart
  25. GRB050908: Swift/UVOT Early upper limits
  26. GRB050908 : Swift-XRT refined analysis
  27. GRB 050908: Optical observations
  28. GRB 050908: Swift detection of a burst
  29. GRB 050906: Optical observations at the Very Large Telescope
  30. GRB 050904: Subaru Optical Spectroscopy
  31. GRB 050906: Swift XRT upper limit
  32. GRB 050904: Keck I-band Imaging
  33. GRB050906: P60 Observations
  34. GRB 050904: photometric redshift
  35. GRB 050904: Swift/UVOT observations
  36. GRB 050904: NIR object inside the XRT error box
  37. GRB 050904: early Swift XRT analysis results
  38. GRB050904: Optical Observations
  39. GRB050904: P60 Observations
  40. GRB 050904: TAROT optical limits
  41. GRB 050827: P200 NIR Observations
  42. GRB050827: Swift/UVOT upper limits
  43. GRB050824: Maidanak optical limits
  44. GRB 050827: Swift-BAT refined analysis
  45. Subaru Observations of GRB050724
  46. GRB050826: Swift/UVOT early upper limits
  47. GRB050826: Swift-BAT detection of a long burst
  48. GRB050824: MASTER:OT decay
  49. GRB050824: MASTER observation OT
  50. GRB050805a: MASTER optical candidat
  51. XRF050509c: Radio upper limits from GMRT
  52. GRB050822: Swift/UVOT upper limits
  53. GRB050813: Maidanak I-band observations
  54. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  55. GRB050820B at FRAM
  56. Swift/UVOT UV Photometry of GRB 050820B
  57. GRB 050822: Swift detection of a long burst
  58. GRB050820a BVRcIc field photometry
  59. GRB050820B XMM-Newton observation
  60. GRB 050820B: Swift XRT position
  61. GRB050820: refined XRT analysis
  62. GRB 050820 Swift-BAT refined analysis
  63. GRB050819: refined XRT analysis
  64. GRB 050820: Swift detection of a GRB
  65. GRB050819: Swift-BAT detection of a weak burst
  66. GRB 050817: Optical observations
  67. GRB050817: Negative Optical Observations
  68. GRB 050814: continued fading
  69. GRB050815: XRT refined analysis
  70. GRB 050815: ROTSE-III Optical Limits
  71. GRB050815: Swift-BAT detection of a burst
  72. GRB050814: Fading red source
  73. GRB050814: P60 Optical Afterglow Candidate
  74. GRB 050813: Non-fading of afterglow candidate
  75. GRB050814: SWIFT/UVOT observation
  76. GRB 050814: Swift XRT Afterglow Localization
  77. GRB 050814: Swift detection of a burst
  78. GRB 050813: Magellan detection of a high redshift galaxy cluster
  79. GRB050813, SDSS pre-burst observations
  80. GRB050813: SWIFT/UVOT observation
  81. GRB 050813: Swift XRT afterglow localization
  82. GRB050805b: CrAO optical limit
  83. GRB050803, optical observations
  84. Retraction of Swift Trigger 149131 (GRB 050805B)
  85. GRB 050805b: OHP optical limits
  86. GRB 050805b: TAROT optical limits
  87. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  88. GRB050802: TNG optical observations
  89. GRB050803: Radio Observation
  90. GRB 050803: RTT150 optical observations
  91. GRB050801: Radio Observation
  92. GRB050730: Radio Detection
  93. GRB 050803: Keck Observations
  94. GRB 050802.422: Fading of the afterglow and detection of the host
  95. GRB 050803: TAROT optical limits
  96. GRB050802 radio non-detection
  97. GRB 050730: OHP optical observations
  98. GRB050801: Optical photometry and decay index
  99. GRB 050802: Swift Gamma-ray Burst
  100. GCN 050801: early Swift XRT analysis results

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