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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. GRB051117b: No Swift/UVOT Detection
  2. GRB051111: Rc optical observations: correction
  3. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  4. GRB 051117A: Swift/UVOT Detection of an Afterglow
  5. GRB051111: Suzaku WAM observation of the prompt emission
  6. GRB051111: Rc optical observations
  7. GRB051008: Suzaku WAM observation of the prompt emission
  8. GRB 051109B: GAO 150cm telescope Optical limit
  9. GRB 051109A : GAO 150cm telescope Rc-band detection
  10. GRB 051021 Optical Observations
  11. GRB 051117B: MARGE Optical Limits
  12. GRB 051117A and B: Radio Observations
  13. GRB 051117B: R and I observations of possible host galaxy
  14. GRB 051117b: NIR observations
  15. GRB 051117A: Refined analysis of the Swift-BAT burst
  16. GRB 051117B: Refined analysis of the Swift-BAT burst
  17. GRB051117A : XRT refined analysis
  18. GRB 051117B,optical observation
  19. GRB 051117B: Lulin R and I band observation
  20. GRB 051117B: Optical observations
  21. GRB 051117B: ROTSE-III Optical Limits
  22. GRB051117B: Swift XRT position
  23. GRB 051117B: Swift detection of a burst
  24. GRB 051117: Swift detection of a bright burst
  25. GRB051114: results of the Swift-XRT observation
  26. GRB 051028 Optical Observations
  27. GRB 051109B : Nainital upper limits
  28. GRB 051114: Radio Observations
  29. GRB 051114: Swift-BAT refined analysis
  30. GRB050925: analysis of the XMM-Newton observation
  31. GRB051109A optical observations
  32. GRB 051114: Swift-BAT detection of a short burst
  33. GRB 051111: Further spectroscopic analysis
  34. GRB 051111: Radio afterglow
  35. GRB 051113: Swift-BAT refined analysis
  36. GRB 051113: Swift-BAT detection of a burst
  37. GRB 051111: AEOS optical observations
  38. GRB051103: Radio Observations
  39. GRB 051109A Milagro GeV/TeV Observations
  40. GRB/SGR 050925: XMM-Newton ToO observation
  41. GRB051111: Swift/UVOT Observations
  42. GRB 051111A : R-band temporal decay index based on Lulin
  43. GRB051111: XRT preliminary analysis
  44. GRB 051111: Swift-BAT refined analysis
  45. GRB 051109A Optical Observations
  46. GRB 051111A : Lulin BVRI multi band afterglow observation
  47. GRB051111a: SARA Observations
  48. GRB 051111a: IR photometry
  49. GRB 051111: Keck HIRES redshift
  50. GRB 051111A: KAIT optical observations
  51. GRB 051111a: Afterglow fading in Ic
  52. GRB051111: Super-LOTIS Early Detection
  53. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  54. Faulkes Telescope R-band detection of GRB051111
  55. GRB 051103 Milagro GeV/TeV Observations
  56. GRB051111: Swift-BAT detection of a bright burst
  57. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  58. GRB 051008 Tautenburg Supernova Search
  59. GRB 051109B. Radio Observations
  60. GRB 051109A
  61. GRB051109A - radio observations
  62. GRB 051105a: GETS optical limit
  63. GRB 051109b: GETS observation
  64. GRB 051109A: KAIT optical observations
  65. Early RAPTOR measurements of GRB 051109a - the movie.
  66. Konus-Wind observation of GRB 051109A
  67. GRB 051109B: Swift-BAT refined analysis
  68. GRB 051109B: ROTSE-III Optical Limits
  69. GRB 051109A: Swift-UVOT Observations
  70. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  71. GRB051109B: no UVOT source detected
  72. GRB051109B: XRT refined analysis
  73. GRB 051109B : Lulin Optical Observations
  74. GRB 051109A : Lulin BVRI Optical afterglow observation
  75. GRB051109A: further steepening in the X-ray light curve
  76. GRB051109A: XRT refined analysis
  77. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  78. GRB051109B: XRT position
  79. GRB 051109B: Super-LOTIS Observations
  80. GRB 051109B Kiso optical follow-up observation
  81. GRB051105B: REM Optical observation
  82. GRB 051109B: Swift detection of a burst
  83. GRB 051109: HET Optical Spectrum and Absorption Redshift
  84. GRB 051109: PROMPT Detections
  85. GRB 051109: Rc and Ic observations
  86. GRB051109: Early Super-LOTIS Detection
  87. GRB 051109: Swift-BAT refined analysis
  88. GRB 051109a: IR Photometry and Astrometry
  89. GRB 051109a: MDM Observations
  90. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  91. GRB051109: Swift detection of a burst
  92. GRB 051109a: IR Detections
  93. GRB 051109: ROTSE-III Detection of Possible Counterpart
  94. GRB051105B: Swift/XRT upper limit
  95. GRB051105B: Swift/UVOT upper limit
  96. GRB051103: optical observations
  97. GRB 051103, optical observations
  98. GRB051103: MASTER: OT limit and host galaxy candidates
  99. GRB051028: Swift-XRT refined analysis
  100. GRB 051105a, observation from Naini Tal and OSN

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