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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"

16162 results found.

  1. GRB 050306: optical afterglow
  2. GRB 050309, Early optical limits from RAPTOR
  3. GRB 050306: further TAROT optical data
  4. GRB050309: Early optical limit from P60
  5. Swift 107873: P60 Optical Observations
  6. GRB 050306: CORRECTION to date of observation
  7. GRB 050306: No Swift UVOT Optical Counterpart Detected
  8. GRB 050306: REM optical-infrared observations
  9. Swift trigger 107518: optical observation
  10. GRB 050306: TAROT optical observations
  11. GRB 050306,optical observation
  12. GRB050215B: Late-Time Swift UVOT Observations
  13. PROMPT VRcIc Observations of GRB 050223
  14. GRB 050219b: candidate NIR afterglow
  15. GRB 050223: optical observations
  16. GRB050223: No Swift UVOT Detection of Afterglow Emission
  17. GRB050223: ROTSE-III Optical Observations
  18. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  19. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  20. GRB 050219a: Optical observations from LCO
  21. GRB 050219b: Optical and near-IR observations from LCO
  22. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  23. GRB 050219a, optical observations
  24. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  25. GRB050215b: Swift UVOT Detection of Afterglow Emission
  26. GRB 050215B: Radio Observations
  27. GRB 050215b: XRT confirmation of IR afterglow candidate
  28. GRB050215b: P60 Optical Observations
  29. GRB 050215b: Swift XRT Source Variability
  30. GRB 050215b, BOOTES-2 simultaneous optical observations
  31. GRB 050215b: Swift XRT Observations
  32. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  33. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  34. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  35. GRB 050215b, BOOTES-1B optical limit
  36. GRB050215B: ROTSE-III optical observations
  37. GRB050215A: ROTSE-III Optical Observations
  38. GRB050209: TAROT optical observations
  39. GRB 050209(=U11568): Duration and spectrum
  40. short/hard GRB 050202, optical observations
  41. GRB050209: REM optical observations
  42. GRB 050209 Optical observations
  43. GRB050209: P60 Optical Observations
  44. GRB050209 (=U11568): A Long GRB Detected by HETE
  45. GRB 050209: Optical observation
  46. Further analysis of the short Swift-BAT GRB 050202
  47. GRB 050129: Optical observations
  48. GRB 050202: Optical observations with LCO40
  49. GRB 050128 Optical observation with REM
  50. GRB 050128: near-infrared observations with REM
  51. GRB050128,optical observations
  52. GRB 050128: Swift XRT prompt afterglow position
  53. GRB050126: MASTER optical limit for KECK OT
  54. GRB050126: MASTER optical observations
  55. GRB050124: No Swift UVOT Detection of Afterglow Emission
  56. GRB 050124, SMARTS optical/IR observations
  57. GRB050124,optical observation
  58. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  59. GRB050123: optical limit 1.8h before GRB
  60. GRB050123,optical observation
  61. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  62. CFHTLS optical transient unlikely to be a GRB
  63. Unusual optical transient (GRB ???)
  64. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  65. GRB050117: optical observation
  66. GRB 050117: Optical observation
  67. GRB050117: MASTER optical observations
  68. MASTER:GRB050117 SWIFT
  69. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  70. SGR 1806-20 and extragalactic short-duration GRBs
  71. GRB 041217: Optical observations
  72. GRB041219, early time observations
  73. GRB041228: ROTSE-III Optical Observations
  74. GRB041226: ROTSE-III Optical Observations
  75. GRB041223: decay of the afterglow
  76. GRB041224: ROTSE-III Optical Observations
  77. GRB 041224: near-infrared observations with REM
  78. GRB 041223: XRT afterglow spectrum and light curve
  79. GRB041223: optical and NIR observations with REM
  80. Swift-BAT Time History of GRB041219
  81. GRB 041219: TAROT optical observations
  82. GRB 041218: TAROT optical observations
  83. GRB 041223: Detection of Optical Transient with LCO40
  84. GRB041223: ROTSE-III Optical Observations
  85. GRB 041218: optical observations
  86. GRB 041218: Optical observations
  87. GRB 041219 : optical follow-up observations
  88. Deep RAPTOR observations during GRB 041219
  89. GRB 041218 Optical Observations
  90. GRB 041219 Optical Observations
  91. GRB041219: Optical Afterglow Detection
  92. GRB041219: Continued NIR Observations
  93. GRB 041219 ,optical observation
  94. GRB 041219: Radio Afterglow Detection
  95. GRB 041218 : Radio Observations
  96. GRB 041218: R-band optical observations
  97. GRB041218: Liverpool Telescope optical observations
  98. GRB041218: optical observations
  99. GRB041218: Continued P60 Optical Observations
  100. GRB 041218: Optical Observation

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