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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"

20554 results found.

  1. GRB 050408: SDSS Field Calibration
  2. GRB 050412: LCO Optical Observations
  3. GRB 050412: Optical observations
  4. GRB050412: P60 Observations
  5. GRB 050412: LCO optical observations
  6. GRB 050412: IR and Optical observations
  7. GRB 050412: IR Observations
  8. GRB050408: Radio Observations
  9. GRB050410: P60 Observations
  10. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  11. GRB 050410, optical observations
  12. GRB 050408: PROMPT VRcIc Observations
  13. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  14. GRB 050410 R band Optical Observations
  15. GRB 050410, optical observations
  16. GRB050410: Radio Observations
  17. GRB 050408: Swift XRT measurement of possible jet break
  18. GRB050410: MASTER optical observations
  19. GRB 050410: Early observations with Swift-UVOT
  20. GRB 050408: Retraction of Proposed Host Galaxy
  21. GRB 050408: Inconsistency of host galaxy identification
  22. GRB 050408: Subaru Observations
  23. GRB 050408: WIDGET simultaneous optical observations
  24. GRB 050408: SOAR UBVRc Observations
  25. GRB 050408: Properties of the Host Galaxy
  26. GRB 050408: Mercator Optical Observations
  27. GRB050408: Radio Observations
  28. GRB 050408, SMARTS optical/IR afterglow observations
  29. GRB 050408, optical observations
  30. GRB 050408: Moderate-resolution Gemini Spectroscopy
  31. GRB 050408 Optical Observations
  32. GRB 050408: Mercator Optical Observations
  33. GRB 050408: First Optical observations with TFOSC at the RTT150
  34. GRB 050408, optical observations
  35. GRB 050408 optical candidate
  36. GRB050408: MASTER optical observations
  37. GRB050401: Radio Detection
  38. GRB 050406: Magellan optical observations
  39. GRB 050406: Early observations with Swift-UVOT
  40. GRB050401: Radio observation at 610 MHz with GMRT
  41. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  42. GRB 050401 Optical Observations
  43. GRB050401: TNG R-band observation
  44. GRB 050402A: IR Observations
  45. GRB 050402: Early observations with Swift-UVOT
  46. Swift Trigger 113225: P60 Observations
  47. GRB 050401: Optical afterglow confirmed
  48. GRB 050401: Optical afterglow candidate
  49. GRB050331: No Afterglow Detected
  50. GRB 050331: Swift UVOT Source
  51. GRB050319: radio observation
  52. GRB 050326: Early observations with Swift-UVOT
  53. GRB 050326: Swift XRT Position
  54. GRB050326: delayed XRT observation
  55. GRB050319, optical observations
  56. GRB050319, color indices
  57. GRB050319: optical observation, March 20-22
  58. GRB050319: RTT150 Optical Observations
  59. GRB 050319: ROTSE-III Refined Analysis
  60. GRB050319: VLA Observations
  61. GRB 050319 R band observations
  62. GRB 050319: Swift-UVOT detection of the afterglow
  63. GRB050319: Radio Observations
  64. GRB 050319: NIR afterglow candidate
  65. GRB 050319:Near IR afterglow
  66. GRB 050319 : Confirmation of optical afterglow decay
  67. GRB 050319: Detection of Possible Optical Counterpart
  68. GRB 050318: Swift/UVOT detection of afterglow emission
  69. RXTE Observations of GRB050318
  70. GRB 050315, SMARTS optical afterglow decay
  71. GRB050316: MASTER before, simultanious and follow up optical
  72. GRB050316: MASTER optical observations
  73. GRB 050315, SMARTS optical/IR afterglow observations
  74. GRB 050315 I-band observations
  75. GRB050315: Radio afterglow
  76. Non-detection of GRB050315 in ATCA Radio Observations
  77. GRB 050315: Swift XRT Position
  78. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  79. GRB 050315: Early Observations with Swift/UVOT
  80. Swift-BAT detection of GRB 050315
  81. GRB050223: No XMM-Newton OM detection of afterglow emission
  82. GRB 050306: Radio Observations
  83. GRB 050306: optical afterglow
  84. GRB 050126: Redshift determination
  85. Swift-BAT trigger 107873: No Swift XRT counterpart
  86. GRB050309: Early optical limit from P60
  87. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  88. Swift 107873: P60 Optical Observations
  89. GRB 050306: CORRECTION to date of observation
  90. GRB 050306: R-band observations
  91. GRB 050306: No Swift UVOT Optical Counterpart Detected
  92. GRB 050306: REM optical-infrared observations
  93. GRB 050306: Possible X-ray Afterglow Position from the Swift
  94. GRB 050306: TAROT optical observations
  95. GRB050215B: Late-Time Swift UVOT Observations
  96. GRB 050126: Confirmation of the NIR afterglow candidate
  97. PROMPT VRcIc Observations of GRB 050223
  98. XRF/GRB 050215B: Radio Observations
  99. GRB 050219b: candidate NIR afterglow
  100. GRB 050223: optical observations

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