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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"

28095 results found.

  1. GRB 050408: Properties of the Host Galaxy
  2. GRB 050408: Mercator Optical Observations
  3. GRB050408: Radio Observations
  4. GRB 050408: Swift XRT analysis
  5. GRB 050408, SMARTS optical/IR afterglow observations
  6. GRB 050408: Optical limit at 20 min after the burst
  7. GRB 050408, optical observations
  8. GRB050408: REM NIR and Optical observation
  9. GRB 050408: Moderate-resolution Gemini Spectroscopy
  10. GRB 050408 Optical Observations
  11. GRB 050408: Emission and absorption redshift
  12. GRB 050408: Mercator Optical Observations
  13. GRB 050408: Magellan astrometry and photometry
  14. GRB 050408: Optical afterglow confirmed
  15. GRB 050408, optical observations
  16. GRB 050408 optical candidate
  17. GRB 050408: Swift XRT Position
  18. GRB050401: Radio Detection
  19. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  20. GRB 050406: Magellan optical observations
  21. GRB 050406: early Swift XRT analysis results
  22. GRB 050406: Swift XRT Position
  23. Swift-BAT detection of GRB 050406
  24. GRB050401: Radio observation at 610 MHz with GMRT
  25. GRB 050401: VLT spectroscopic redshift
  26. GRB 050401 Optical Observations
  27. GRB050401: Maidanak optical observation
  28. GRB 050401 BAT refined analysis
  29. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  30. GRB050401: TNG R-band observation
  31. GRB 050402A: IR Analysis
  32. GRB050402: XDSS counterpart
  33. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  34. GRB 050401: Optical afterglow confirmed
  35. GRB 050401: Optical afterglow candidate
  36. Swift-BAT detection of GRB 050401
  37. GRB 050401: Prompt XRT position
  38. GRB050331: No Afterglow Detected
  39. Swift-BAT detection of GRB 050331b
  40. GRB 050331: Swift UVOT Source
  41. Swift-BAT detection of GRB 050331
  42. GRB 050331: Swift XRT Position
  43. GRB050319: radio observation
  44. GRB 050326 XMM-Newton observation
  45. GRB 050326: Swift XRT Position
  46. GRB050326: delayed XRT observation
  47. Swift-BAT detection of a bright GRB 050326
  48. GRB050319, color indices
  49. GRB050319: optical observation, March 20-22
  50. Swift-BAT detection of a bright outburst from SGR1806-20
  51. Swift-BAT trigger 112060 is not a real GRB
  52. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  53. GRB 050319: ROTSE-III Refined Analysis
  54. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  55. GRB050319: VLA Observations
  56. GRB050319: radio observation
  57. GRB 050319 R band observations
  58. GRB 050319: Swift-UVOT detection of the afterglow
  59. GRB050319: Radio Observations
  60. GRB 050319: NIR afterglow candidate
  61. GRB 050319:Near IR afterglow
  62. GRB050319: BR optical photometry
  63. GRB 050318: Absorption redshift from Magellan
  64. GRB 050319: Optical observation
  65. GRB 050319 : Confirmation of optical afterglow decay
  66. Swift Detection of GRB 050319
  67. GRB 050319: Detection of Possible Optical Counterpart
  68. GRB 050318: Swift/UVOT detection of afterglow emission
  69. GRB 050318: Magellan optical afterglow identification
  70. GRB050318: Swift XRT position
  71. Swift-BAT detection of GRB 050318
  72. GRB 050315, SMARTS optical afterglow decay
  73. GRB050223: analysis of the XMM-Newton observation
  74. GRB 050306: ROTSE-III early limits
  75. GRB 050315, SMARTS optical/IR afterglow observations
  76. GRB 050315 I-band observations
  77. GRB050315: Radio afterglow
  78. GRB 050315: Absorption redshift
  79. GRB 050315: Optical afterglow identification
  80. Non-detection of GRB050315 in ATCA Radio Observations
  81. GRB 050315: Swift XRT Position
  82. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  83. Swift-BAT detection of GRB 050315
  84. GRB050223: No XMM-Newton OM detection of afterglow emission
  85. GRB 050306: Radio Observations
  86. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  87. GRB 050306: optical afterglow
  88. Swift-BAT trigger 107873: No Swift XRT counterpart
  89. GRB 050306: Confirmation of X-ray afterglow
  90. GRB050309: Early optical limit from P60
  91. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  92. GRB 050306: R-band observations
  93. GRB 050306: REM optical-infrared observations
  94. GRB 050306: Possible X-ray Afterglow Position from the Swift
  95. GRB 050306: Swift-BAT detection of a long burst
  96. GRB050215B: Late-Time Swift UVOT Observations
  97. GRB 050126: Confirmation of the NIR afterglow candidate
  98. PROMPT VRcIc Observations of GRB 050223
  99. XRF/GRB 050215B: Radio Observations
  100. GRB 050219b: candidate NIR afterglow

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