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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"

23410 results found.

  1. GRB 050410: Early observations with Swift-UVOT
  2. GRB 050408: Inconsistency of host galaxy identification
  3. GRB 050408: Subaru Observations
  4. GRB 050408: WIDGET simultaneous optical observations
  5. GRB 050408: Properties of the Host Galaxy
  6. GRB050408: Radio Observations
  7. GRB 050408, optical observations
  8. GRB050408: REM NIR and Optical observation
  9. GRB 050408,optical observation
  10. GRB 050408: Emission and absorption redshift
  11. GRB 050408: Mercator Optical Observations
  12. GRB 050408: Optical afterglow confirmed
  13. GRB 050408: opitcal observation
  14. GRB 050408, optical observations
  15. GRB 050408: Swift XRT Position
  16. GRB 050408: ROTSE-III Optical Limits
  17. GRB050408: MASTER optical observations
  18. GRB050401: Radio Detection
  19. GRB 050406: Magellan optical observations
  20. GRB 050406 BAT refined analysis
  21. GRB 050406: Early observations with Swift-UVOT
  22. Swift-BAT detection of GRB 050406
  23. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  24. GRB 050401 BAT refined analysis
  25. GRB050401: TNG R-band observation
  26. GRB 050402: Early observations with Swift-UVOT
  27. Swift Trigger 113225: P60 Observations
  28. GRB 050401: Optical afterglow confirmed
  29. GRB050331: No Afterglow Detected
  30. GRB 050331: Swift UVOT Source
  31. Konus-Wind observation of GRB 050326
  32. GRB 050326: Early observations with Swift-UVOT
  33. GRB 050326 XMM-Newton observation
  34. GRB 050326: Swift XRT Position
  35. GRB050326: optical limit 33min before GRB
  36. GRB 050326 BAT refined analysis
  37. GRB050326: delayed XRT observation
  38. GRB050319, optical observations
  39. GRB050319: optical observation, March 20-22
  40. GRB050319: RTT150 Optical Observations
  41. GRB050319: VLA Observations
  42. GRB050319: radio observation
  43. GRB 050319: Swift-UVOT detection of the afterglow
  44. GRB050319: Radio Observations
  45. GRB 050319: NIR afterglow candidate
  46. GRB 050319:Near IR afterglow
  47. GRB 050318: SWIFT-UVOT refined analysis
  48. GRB050319,optical observation
  49. GRB 050318: Swift/UVOT detection of afterglow emission
  50. RXTE Observations of GRB050318
  51. Swift-BAT detection of GRB 050318
  52. GRB050223: analysis of the XMM-Newton observation
  53. GRB050316: MASTER before, simultanious and follow up optical
  54. GRB 050306: ROTSE-III early limits
  55. GRB050316: MASTER optical observations
  56. GRB 050315 I-band observations
  57. GRB050315: Radio afterglow
  58. Non-detection of GRB050315 in ATCA Radio Observations
  59. GRB 050315: Early Observations with Swift/UVOT
  60. Swift-BAT detection of GRB 050315
  61. GRB 050306: Radio Observations
  62. GRB 050306: optical afterglow
  63. Swift-BAT trigger 107873: No Swift XRT counterpart
  64. GRB 050306: Confirmation of X-ray afterglow
  65. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  66. GRB 050309 : Lulin R-band observation
  67. Swift 107873: P60 Optical Observations
  68. GRB 050306: R-band observations
  69. GRB 050306: REM optical-infrared observations
  70. GRB 050306: Possible X-ray Afterglow Position from the Swift
  71. GRB 050306: TAROT optical observations
  72. GRB 050306,optical observation
  73. GRB 050306: Swift-BAT detection of a long burst
  74. Ongoing activity of SGR 1806-20 after the giant flare
  75. GRB050215B: Late-Time Swift UVOT Observations
  76. PROMPT VRcIc Observations of GRB 050223
  77. XRF/GRB 050215B: Radio Observations
  78. XMM-Newton Images of GRB 050223
  79. GRB 050219b: candidate NIR afterglow
  80. GRB050223 XMM-Newton observation
  81. INTEGRAL detection of GRB 050223
  82. GRB050223: ROTSE-III Optical Observations
  83. GRB 050223: Swift XRT Position
  84. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  85. GRB050219b: CORRECTION to time of UVOT observations
  86. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  87. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  88. GRB 050219a: Optical observations from LCO
  89. GRB 050219b: Optical and near-IR observations from LCO
  90. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  91. GRB 050219b: Refined XRT position
  92. GRB 050219b: CORRECTION: Swift XRT Position
  93. GRB 050219b: Swift XRT Position
  94. GRB 050219a, optical observations
  95. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  96. GRB 050215B: Radio Observations
  97. GRB 050215b: XRT confirmation of IR afterglow candidate
  98. GRB050215b: P60 Optical Observations
  99. GRB 050215b: Swift XRT Source Variability
  100. GRB 050215b : Lulin follow-up observation

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