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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"

37504 results found.

  1. Swift is in normal operation
  2. GRB 050911, optical content of Swift/XRT error box
  3. GRB 050911: LCO observations
  4. GRB 050911, optical observations
  5. GRB 050911: Swift-BAT refined analysis
  6. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  7. GRB 050911: z~0.16 cluster in the field
  8. GRB 050910a: TAROT early optical limits
  9. RBO GRB 050908 observations
  10. WIRO observations in I of GRB 050908
  11. GRB 050906: Possible X-ray Counterpart
  12. GRB 050906: RTT150 optical observations
  13. GRB050908: VLT R-band decay index.
  14. GRB 050908: Swift-BAT refined analysis
  15. GRB 050908: Optical observations
  16. Gemini Spectroscopy of GRB 050908
  17. GRB 050908: spectroscopic redshift
  18. GRB 050908: Prompt PROMPT Observations
  19. GRB 050908 : Swift XRT position
  20. GRB 050908: KAIT observations
  21. GRB 050908: P60 Confirmation of Optical Afterglow
  22. GRB 050908: Optical Observations
  23. GRB 050908: Swift detection of a burst
  24. Swift trigger 154073 is not a GRB
  25. GRB 050906: Optical observations at the Very Large Telescope
  26. GRB050904: CrAO optical observations
  27. GRB 050904 BAT refined analysis of complete data set
  28. GRB 050904: Subaru Optical Spectroscopy
  29. GRB 050906: MARGE Optical Limits
  30. GRB 050906: Swift-BAT refined analysis
  31. GRB 050906: Swift XRT upper limit
  32. GRB 050906: Radio Observations
  33. GRB 050904: Keck I-band Imaging
  34. GRB 050904: more VLT NIR observations
  35. GRB 050904: BOOTES early R-band observation
  36. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  37. GRB 050906: Bright galaxy in BAT error box
  38. GRB 050906: Swift/BAT Detection of a possible burst
  39. GRB 050904: More SOAR
  40. GRB 050904: photometric redshift
  41. GRB 050904: Swift/UVOT observations
  42. GRB 050904: Afterglow Astrometry
  43. GRB 050904: NIR object inside the XRT error box
  44. GRB 050904: early Swift XRT analysis results
  45. GRB 050904: SOAR YJ and PROMPT Ic Observations
  46. GRB 050904: BAT refined analysis of partial data set
  47. GRB 050904: TAROT optical measurements
  48. GRB050904: Optical Observations
  49. GRB 050904: Environmental Constraints
  50. GRB 050904: Possible High-Redshift GRB
  51. GRB 050904: SOAR/PROMPT Observations
  52. GRB 050904: TAROT optical limits
  53. Swift-BAT triggers 153461-153465 are not GRBs
  54. GRB 050824: MDM Observations
  55. GRB 050827: Swift XRT preliminary analysis results
  56. IBAS Alerts 2641 and 2642: not a real GRB
  57. Swift Trigger #152652 is not a GRB
  58. GRB 050827 : OSN 1.5m optical observations
  59. GRB 050827: P200 NIR Observations
  60. GRB 050827: Optical Limit
  61. GRB 050827: XRT possible afterglow detection
  62. GRB 050826 : Lulin R band observation
  63. GRB050824: Maidanak optical limits
  64. GRB050820A: RTT150 optical observations
  65. GRB050827: RTT150 optical observations
  66. GRB 050827: Swift-BAT refined analysis
  67. GRB 050826: Optical Candidate
  68. GRB050824, HETE-2 Observation
  69. GRB 050826: Swift XRT preliminary analysis results
  70. GRB 050826: BAT refined analysis
  71. GRB050824: First 2 hours of power low optical decay?
  72. GRB 050826: Swift XRT position
  73. GRB050826: Swift-BAT detection of a long burst
  74. GRB050824: MASTER final analysis of the OT observations
  75. Possible GRB050825:MASTER optical observations
  76. Swift-BAT trigger 152038 is definitely not a GRB
  77. Swift-BAT trigger 152038 is probably not a GRB
  78. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  79. GRB050824, I-band imaging
  80. GRB050824: Radio Observations
  81. GRB 050824: Spectroscopic redshift from the VLT
  82. GRB 050822: refined XRT analysis
  83. GRB 050824: XRT refined analysis and possible afterglow detection
  84. GRB 050824: BAT refined analysis of a soft weak burst
  85. GRB050824: MASTER:OT decay
  86. GRB050824: MASTER observation OT
  87. GRB050805a: MASTER optical candidat
  88. GRB 050824: ROTSE-III Optical Limits
  89. GRB050824: Swift-BAT detection of a burst
  90. GRB 050824 optical candidate
  91. GRB050820A: RTT150 optical observations
  92. GRB050820a: PROMPT RcIc Observations
  93. GRB050815: Maidanak optical observation
  94. XRF050509c: Radio upper limits from GMRT
  95. VLT/UVES spectroscopy of GRB050820
  96. GRB 050820A BAT observations of second, larger episode of emission
  97. GRB050813: Maidanak I-band observations
  98. GRB 050822: Swift-BAT refined analysis
  99. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  100. GRB050820B at FRAM

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