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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"
  1. Swift Trigger #152652 is not a GRB
  2. GRB 050827 : OSN 1.5m optical observations
  3. GRB 050827: P200 NIR Observations
  4. GRB050827: Swift/UVOT upper limits
  5. GRB 050827: Optical Limit
  6. GRB 050827: XRT possible afterglow detection
  7. GRB 050826 : Lulin R band observation
  8. GRB050824: Maidanak optical limits
  9. GRB050820A: RTT150 optical observations
  10. GRB050827: RTT150 optical observations
  11. GRB 050827: Swift-BAT refined analysis
  12. GRB050827: Swift-BAT detection of a burst
  13. Subaru Observations of GRB050724
  14. GRB 050826: Optical Candidate
  15. GRB050824, HETE-2 Observation
  16. GRB 050826: Swift XRT preliminary analysis results
  17. GRB 050826: BAT refined analysis
  18. GRB050826: Swift/UVOT early upper limits
  19. GRB050824: First 2 hours of power low optical decay?
  20. GRB 050826: Swift XRT position
  21. GRB050826: Swift-BAT detection of a long burst
  22. GRB050824: MASTER final analysis of the OT observations
  23. Possible GRB050825:MASTER optical observations
  24. Swift-BAT trigger 152038 is definitely not a GRB
  25. GRB050824: CORRECTION to UVOT observing times
  26. Swift-BAT trigger 152038 is probably not a GRB
  27. GRB050824: Swift/UVOT detection of fading afterglow
  28. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  29. GRB050824, I-band imaging
  30. GRB050824: Radio Observations
  31. GRB 050824: Spectroscopic redshift from the VLT
  32. GRB 050822: refined XRT analysis
  33. GRB 050824: XRT refined analysis and possible afterglow detection
  34. GRB 050824: BAT refined analysis of a soft weak burst
  35. GRB050824: MASTER:OT decay
  36. GRB050824: MASTER observation OT
  37. GRB050805a: MASTER optical candidat
  38. GRB 050824: ROTSE-III Optical Limits
  39. GRB050824: Swift-BAT detection of a burst
  40. GRB 050824 optical candidate
  41. GRB050820A: RTT150 optical observations
  42. GRB050820a: PROMPT RcIc Observations
  43. GRB050815: Maidanak optical observation
  44. XRF050509c: Radio upper limits from GMRT
  45. VLT/UVES spectroscopy of GRB050820
  46. GRB050822: Swift/UVOT upper limits
  47. GRB 050820A BAT observations of second, larger episode of emission
  48. GRB050813: Maidanak I-band observations
  49. GRB 050822: Swift-BAT refined analysis
  50. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  51. GRB050820B at FRAM
  52. GRB050820A: RTT150 optical observations
  53. GRB 050820a - corrections to GCN 3846
  54. Swift/UVOT UV Photometry of GRB 050820B
  55. GRB 050822: ROTSE-III Prompt Optical Limits
  56. GRB 050822: Swift detection of a long burst
  57. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  58. GRB050820A: Radio Observation
  59. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  60. GRB050820a BVRcIc field photometry
  61. GRB050820B XMM-Newton observation
  62. GRB 050820a: NIR Observations by WIRO
  63. GRB 050820B: Swift XRT position
  64. GRB050820B: Planned XMM-Newton observation
  65. GRB050820B: Refined analysis of the Swift-BAT burst
  66. GRB050820B: BAT-Swift detection of a bright GRB
  67. Swift/UVOT photometry of GRB050820
  68. GRB050820: refined XRT analysis
  69. GRB 050820: Early RAPTOR detections
  70. GRB 050820 Swift-BAT refined analysis
  71. GRB 050820: P60 Temporal Decay Index
  72. GRB 050820: High Resolution Spectroscopy from Keck
  73. GRB050819: refined XRT analysis
  74. GRB050819: RTT150 optical observations
  75. GRB 050820: Swift detection of a GRB
  76. GRB050820: Optical afterglow from P60
  77. GRB 050819 Swift-BAT refined analysis
  78. GRB050819: Swift XRT position
  79. GRB050819: Swift-BAT detection of a weak burst
  80. Swift-BAT trigger 150993 is not a GRB
  81. Swift Trigger 150823 is HETE J1900.1-2455
  82. GRB 050817: Optical observations
  83. GRB 050815: Radio Observation
  84. GRB050814: Radio Observation
  85. GRB050817: Negative Optical Observations
  86. GRB050817: Swift-BAT Detection of a burst
  87. GRB 050814: continued fading
  88. GRB050815: Optical afterglow detection by Swift UVOT
  89. GRB050815: XRT refined analysis
  90. GRB 050813: Radio Observations
  91. GRB050815: Refined analysis of the Swift-BAT burst
  92. GRB 050815: ROTSE-III Optical Limits
  93. GRB050815: Swift XRT afterglow localization
  94. GRB050815: Swift-BAT detection of a burst
  95. GRB 050730: Third Epoch WSRT Radio Observations
  96. GRB050814: Fading red source
  97. GRB 050813: Gemini Spectra Revisited
  98. GRB050814: P60 Optical Afterglow Candidate
  99. GRB 050813: Non-fading of afterglow candidate
  100. GRB 050814: XRT refined analysis

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