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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"

34210 results found.

  1. WIRO observations in I of GRB 050908
  2. GRB 050906: Possible X-ray Counterpart
  3. GRB 050906: RTT150 optical observations
  4. GRB050908: VLT R-band decay index.
  5. GRB 050908: Swift-BAT refined analysis
  6. GRB 050908: Optical observations
  7. Gemini Spectroscopy of GRB 050908
  8. GRB 050908: spectroscopic redshift
  9. GRB 050908: Prompt PROMPT Observations
  10. GRB 050908 : Swift XRT position
  11. GRB 050908: KAIT observations
  12. GRB 050908: P60 Confirmation of Optical Afterglow
  13. GRB 050908: Optical Observations
  14. GRB 050908: Swift detection of a burst
  15. Swift trigger 154073 is not a GRB
  16. GRB 050906: Optical observations at the Very Large Telescope
  17. GRB050904: CrAO optical observations
  18. GRB 050904 BAT refined analysis of complete data set
  19. GRB 050904: Subaru Optical Spectroscopy
  20. GRB 050906: MARGE Optical Limits
  21. GRB 050906: Swift-BAT refined analysis
  22. GRB 050906: Swift XRT upper limit
  23. GRB 050906: Radio Observations
  24. GRB 050904: Keck I-band Imaging
  25. GRB 050904: more VLT NIR observations
  26. GRB 050904: BOOTES early R-band observation
  27. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  28. GRB 050906: Bright galaxy in BAT error box
  29. GRB 050906: Swift/BAT Detection of a possible burst
  30. GRB 050904: More SOAR
  31. GRB 050904: photometric redshift
  32. GRB 050904: Swift/UVOT observations
  33. GRB 050904: Afterglow Astrometry
  34. GRB 050904: NIR object inside the XRT error box
  35. GRB 050904: early Swift XRT analysis results
  36. GRB 050904: SOAR YJ and PROMPT Ic Observations
  37. GRB 050904: BAT refined analysis of partial data set
  38. GRB 050904: TAROT optical measurements
  39. GRB050904: Optical Observations
  40. GRB 050904: Environmental Constraints
  41. GRB 050904: Possible High-Redshift GRB
  42. GRB 050904: SOAR/PROMPT Observations
  43. GRB 050904: TAROT optical limits
  44. Swift-BAT triggers 153461-153465 are not GRBs
  45. GRB 050824: MDM Observations
  46. GRB 050827: Swift XRT preliminary analysis results
  47. IBAS Alerts 2641 and 2642: not a real GRB
  48. Swift Trigger #152652 is not a GRB
  49. GRB 050827 : OSN 1.5m optical observations
  50. GRB 050827: P200 NIR Observations
  51. GRB 050827: Optical Limit
  52. GRB 050827: XRT possible afterglow detection
  53. GRB 050826 : Lulin R band observation
  54. GRB050824: Maidanak optical limits
  55. GRB050820A: RTT150 optical observations
  56. GRB050827: RTT150 optical observations
  57. GRB 050827: Swift-BAT refined analysis
  58. GRB 050826: Optical Candidate
  59. GRB050824, HETE-2 Observation
  60. GRB 050826: Swift XRT preliminary analysis results
  61. GRB 050826: BAT refined analysis
  62. GRB050824: First 2 hours of power low optical decay?
  63. GRB 050826: Swift XRT position
  64. GRB050826: Swift-BAT detection of a long burst
  65. GRB050824: MASTER final analysis of the OT observations
  66. Possible GRB050825:MASTER optical observations
  67. Swift-BAT trigger 152038 is definitely not a GRB
  68. Swift-BAT trigger 152038 is probably not a GRB
  69. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  70. GRB050824, I-band imaging
  71. GRB050824: Radio Observations
  72. GRB 050824: Spectroscopic redshift from the VLT
  73. GRB 050822: refined XRT analysis
  74. GRB 050824: XRT refined analysis and possible afterglow detection
  75. GRB 050824: BAT refined analysis of a soft weak burst
  76. GRB050824: MASTER:OT decay
  77. GRB050824: MASTER observation OT
  78. GRB050805a: MASTER optical candidat
  79. GRB 050824: ROTSE-III Optical Limits
  80. GRB050824: Swift-BAT detection of a burst
  81. GRB 050824 optical candidate
  82. GRB050820A: RTT150 optical observations
  83. GRB050820a: PROMPT RcIc Observations
  84. GRB050815: Maidanak optical observation
  85. XRF050509c: Radio upper limits from GMRT
  86. VLT/UVES spectroscopy of GRB050820
  87. GRB 050820A BAT observations of second, larger episode of emission
  88. GRB050813: Maidanak I-band observations
  89. GRB 050822: Swift-BAT refined analysis
  90. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  91. GRB050820B at FRAM
  92. GRB050820A: RTT150 optical observations
  93. GRB 050820a - corrections to GCN 3846
  94. Swift/UVOT UV Photometry of GRB 050820B
  95. GRB 050822: ROTSE-III Prompt Optical Limits
  96. GRB 050822: Swift detection of a long burst
  97. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  98. GRB050820A: Radio Observation
  99. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  100. GRB050820a BVRcIc field photometry

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