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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"

25905 results found.

  1. GRB 050904: early Swift XRT analysis results
  2. GRB 050904: SOAR YJ and PROMPT Ic Observations
  3. GRB 050904: BAT refined analysis of partial data set
  4. GRB050904: Optical Observations
  5. GRB 050904: Environmental Constraints
  6. GRB 050904: Possible High-Redshift GRB
  7. GRB 050904: SOAR/PROMPT Observations
  8. GRB050904: P60 Observations
  9. GRB 050904: TAROT optical limits
  10. GRB050904: Swift-BAT detection of a probable burst
  11. Swift-BAT triggers 153461-153465 are not GRBs
  12. Retraction of Swift-BAT trigger #153355
  13. GRB 050824: MDM Observations
  14. GRB 050827: Swift XRT preliminary analysis results
  15. Swift Trigger #152652 is not a GRB
  16. GRB 050827 : OSN 1.5m optical observations
  17. GRB 050827: P200 NIR Observations
  18. GRB050827: Swift/UVOT upper limits
  19. GRB 050827: Optical Limit
  20. GRB 050827: XRT possible afterglow detection
  21. GRB 050826 : Lulin R band observation
  22. GRB050827: RTT150 optical observations
  23. GRB 050827: Swift-BAT refined analysis
  24. GRB050827: Swift-BAT detection of a burst
  25. GRB 050826: Optical Candidate
  26. GRB050824, HETE-2 Observation
  27. GRB 050826: Swift XRT preliminary analysis results
  28. GRB 050826: BAT refined analysis
  29. GRB050826: Swift/UVOT early upper limits
  30. GRB050824: First 2 hours of power low optical decay?
  31. GRB 050826: Swift XRT position
  32. GRB050826: Swift-BAT detection of a long burst
  33. GRB050824: MASTER final analysis of the OT observations
  34. Possible GRB050825:MASTER optical observations
  35. Swift-BAT trigger 152038 is definitely not a GRB
  36. GRB050824: CORRECTION to UVOT observing times
  37. Swift-BAT trigger 152038 is probably not a GRB
  38. GRB050824: Swift/UVOT detection of fading afterglow
  39. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  40. GRB050824, I-band imaging
  41. GRB050824: Radio Observations
  42. GRB 050824: Spectroscopic redshift from the VLT
  43. GRB 050822: refined XRT analysis
  44. GRB 050824: XRT refined analysis and possible afterglow detection
  45. GRB 050824: BAT refined analysis of a soft weak burst
  46. GRB050824: MASTER:OT decay
  47. GRB050824: MASTER observation OT
  48. GRB050805a: MASTER optical candidat
  49. GRB 050824: ROTSE-III Optical Limits
  50. GRB050824: Swift-BAT detection of a burst
  51. GRB050820A: RTT150 optical observations
  52. GRB050820a: PROMPT RcIc Observations
  53. GRB050815: Maidanak optical observation
  54. XRF050509c: Radio upper limits from GMRT
  55. VLT/UVES spectroscopy of GRB050820
  56. GRB050822: Swift/UVOT upper limits
  57. GRB 050820A BAT observations of second, larger episode of emission
  58. GRB 050822: Swift-BAT refined analysis
  59. GRB050820A: RTT150 optical observations
  60. GRB 050820a - corrections to GCN 3846
  61. Swift/UVOT UV Photometry of GRB 050820B
  62. GRB 050822: ROTSE-III Prompt Optical Limits
  63. GRB 050822: Swift detection of a long burst
  64. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  65. GRB050820A: Radio Observation
  66. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  67. GRB050820a BVRcIc field photometry
  68. GRB050820B XMM-Newton observation
  69. GRB 050820a: NIR Observations by WIRO
  70. GRB 050820B: Swift XRT position
  71. GRB050820B: Refined analysis of the Swift-BAT burst
  72. GRB050820B: BAT-Swift detection of a bright GRB
  73. Swift/UVOT photometry of GRB050820
  74. GRB050820: refined XRT analysis
  75. GRB 050820: Early RAPTOR detections
  76. GRB 050820 Swift-BAT refined analysis
  77. GRB 050820: P60 Temporal Decay Index
  78. GRB 050820: High Resolution Spectroscopy from Keck
  79. GRB050819: refined XRT analysis
  80. GRB 050820: Swift detection of a GRB
  81. GRB050820: Optical afterglow from P60
  82. GRB 050819 Swift-BAT refined analysis
  83. GRB050819: Swift XRT position
  84. GRB050819: Swift-BAT detection of a weak burst
  85. Swift-BAT trigger 150993 is not a GRB
  86. Swift Trigger 150823 is HETE J1900.1-2455
  87. GRB 050815: Radio Observation
  88. GRB050814: Radio Observation
  89. GRB050817: Swift-BAT Detection of a burst
  90. GRB 050814: continued fading
  91. GRB050815: Optical afterglow detection by Swift UVOT
  92. GRB050815: XRT refined analysis
  93. GRB 050813: Radio Observations
  94. GRB050815: Refined analysis of the Swift-BAT burst
  95. GRB 050815: ROTSE-III Optical Limits
  96. GRB050815: Swift XRT afterglow localization
  97. GRB050815: Swift-BAT detection of a burst
  98. GRB 050730: Third Epoch WSRT Radio Observations
  99. GRB050814: Fading red source
  100. GRB 050813: Gemini Spectra Revisited

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