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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 050412 : XingLong optical observation
  2. GRB 050412: Early Optical/Ultraviolet Observations with
  3. GRB 050412: Optical limit
  4. GRB 050412: LCO Optical Observations
  5. GRB 050412: Optical observations
  6. GRB050412: optical limit before and during GRB
  7. GRB 050412: LCO optical observations
  8. GRB050412: ROTSE-III Optical Limits
  9. GRB 050412: IR and Optical observations
  10. GRB050408: Radio Observations
  11. GRB 050401: Optical limit
  12. GRB 050408: Optical limit
  13. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  14. GRB 050410, optical observations
  15. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  16. GRB 050410 R band Optical Observations
  17. GRB 050410, optical observations
  18. GRB050410: MASTER optical observations
  19. GRB 050410: Early observations with Swift-UVOT
  20. Swift-BAT detection of GRB 050410
  21. GRB 050408: WIDGET simultaneous optical observations
  22. GRB 050408: SOAR UBVRc Observations
  23. GRB 050408: Properties of the Host Galaxy
  24. GRB 050408: Mercator Optical Observations
  25. GRB050408: Radio Observations
  26. GRB 050408: Swift XRT analysis
  27. GRB 050408, SMARTS optical/IR afterglow observations
  28. GRB 050408: Optical limit at 20 min after the burst
  29. GRB 050408, optical observations
  30. GRB050408: REM NIR and Optical observation
  31. GRB 050408: Moderate-resolution Gemini Spectroscopy
  32. GRB 050408,optical observation
  33. GRB 050408 Optical Observations
  34. GRB 050408: Emission and absorption redshift
  35. GRB 050408: Mercator Optical Observations
  36. GRB 050408: First Optical observations with TFOSC at the RTT150
  37. GRB 050408: steepening of the optical decay
  38. GRB 050408: Optical afterglow confirmed
  39. GRB 050408, optical observations
  40. GRB 050408 optical candidate
  41. GRB 050408: ROTSE-III Optical Limits
  42. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  43. GRB050408: MASTER optical observations
  44. GRB050401: Radio Detection
  45. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  46. GRB 050406: Magellan optical observations
  47. GRB 050406: Early observations with Swift-UVOT
  48. Swift-BAT detection of GRB 050406
  49. GRB050401: Radio observation at 610 MHz with GMRT
  50. GRB 050401: VLT spectroscopic redshift
  51. GRB 050401 Optical Observations
  52. GRB050401: Maidanak optical observation
  53. GRB 050401 BAT refined analysis
  54. GRB050401: TNG R-band observation
  55. GRB 050402: Early observations with Swift-UVOT
  56. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  57. GRB 050401: Optical afterglow confirmed
  58. GRB 050401: Optical afterglow candidate
  59. GRB050331: No Afterglow Detected
  60. GRB 050331: Swift UVOT Source
  61. GRB050326: optical limit
  62. GRB 050326: Early observations with Swift-UVOT
  63. GRB050326: optical limit 33min before GRB
  64. GRB050319, optical observations
  65. GRB050319, color indices
  66. GRB050319: optical observation, March 20-22
  67. GRB050319: RTT150 Optical Observations
  68. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  69. GRB 050318: Swift-BAT refined analysis
  70. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  71. GRB050319: VLA Observations
  72. GRB050319: radio observation
  73. GRB 050319 R band observations
  74. GRB 050319: Swift-UVOT detection of the afterglow
  75. GRB050319: Radio Observations
  76. GRB 050319: NIR afterglow candidate
  77. GRB 050319:Near IR afterglow
  78. GRB050319: BR optical photometry
  79. GRB 050319: Optical observation
  80. GRB 050319 : Confirmation of optical afterglow decay
  81. GRB050319,optical observation
  82. GRB 050319: Detection of Possible Optical Counterpart
  83. GRB 050318: Swift/UVOT detection of afterglow emission
  84. GRB 050318: Magellan optical afterglow identification
  85. GRB 050315, SMARTS optical afterglow decay
  86. GRB050223: analysis of the XMM-Newton observation
  87. GRB050316: MASTER before, simultanious and follow up optical
  88. GRB 050306: ROTSE-III early limits
  89. GRB050316: MASTER optical observations
  90. GRB 050315: Swift-BAT further refined analysis
  91. GRB 050315, SMARTS optical/IR afterglow observations
  92. GRB 050315 I-band observations
  93. GRB050315: Radio afterglow
  94. GRB 050315: Optical afterglow identification
  95. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  96. GRB 050315: Early Observations with Swift/UVOT
  97. GRB050223: No XMM-Newton OM detection of afterglow emission
  98. GRB 050306: Radio Observations
  99. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  100. GRB050309: CONCAM pre-trigger and trigger coincident optical

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