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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"

20542 results found.

  1. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  2. GRB 050410 R band Optical Observations
  3. GRB 050410, optical observations
  4. GRB050410: Radio Observations
  5. GRB 050408: Swift XRT measurement of possible jet break
  6. GRB050410: MASTER optical observations
  7. GRB 050410: Early observations with Swift-UVOT
  8. GRB 050408: Retraction of Proposed Host Galaxy
  9. GRB 050408: Inconsistency of host galaxy identification
  10. GRB 050408: Subaru Observations
  11. GRB 050408: WIDGET simultaneous optical observations
  12. GRB 050408: SOAR UBVRc Observations
  13. GRB 050408: Properties of the Host Galaxy
  14. GRB 050408: Mercator Optical Observations
  15. GRB050408: Radio Observations
  16. GRB 050408, SMARTS optical/IR afterglow observations
  17. GRB 050408, optical observations
  18. GRB 050408: Moderate-resolution Gemini Spectroscopy
  19. GRB 050408 Optical Observations
  20. GRB 050408: Mercator Optical Observations
  21. GRB 050408: First Optical observations with TFOSC at the RTT150
  22. GRB 050408, optical observations
  23. GRB 050408 optical candidate
  24. GRB050408: MASTER optical observations
  25. GRB050401: Radio Detection
  26. GRB 050406: Magellan optical observations
  27. GRB 050406: Early observations with Swift-UVOT
  28. GRB050401: Radio observation at 610 MHz with GMRT
  29. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  30. GRB 050401 Optical Observations
  31. GRB050401: TNG R-band observation
  32. GRB 050402A: IR Observations
  33. GRB 050402: Early observations with Swift-UVOT
  34. Swift Trigger 113225: P60 Observations
  35. GRB 050401: Optical afterglow confirmed
  36. GRB 050401: Optical afterglow candidate
  37. GRB050331: No Afterglow Detected
  38. GRB 050331: Swift UVOT Source
  39. GRB050319: radio observation
  40. GRB 050326: Early observations with Swift-UVOT
  41. GRB 050326: Swift XRT Position
  42. GRB050326: delayed XRT observation
  43. GRB050319, optical observations
  44. GRB050319, color indices
  45. GRB050319: optical observation, March 20-22
  46. GRB050319: RTT150 Optical Observations
  47. GRB 050319: ROTSE-III Refined Analysis
  48. GRB050319: VLA Observations
  49. GRB 050319 R band observations
  50. GRB 050319: Swift-UVOT detection of the afterglow
  51. GRB050319: Radio Observations
  52. GRB 050319: NIR afterglow candidate
  53. GRB 050319:Near IR afterglow
  54. GRB 050319 : Confirmation of optical afterglow decay
  55. GRB 050319: Detection of Possible Optical Counterpart
  56. GRB 050318: Swift/UVOT detection of afterglow emission
  57. RXTE Observations of GRB050318
  58. GRB 050315, SMARTS optical afterglow decay
  59. GRB050316: MASTER before, simultanious and follow up optical
  60. GRB050316: MASTER optical observations
  61. GRB 050315, SMARTS optical/IR afterglow observations
  62. GRB 050315 I-band observations
  63. GRB050315: Radio afterglow
  64. Non-detection of GRB050315 in ATCA Radio Observations
  65. GRB 050315: Swift XRT Position
  66. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  67. GRB 050315: Early Observations with Swift/UVOT
  68. Swift-BAT detection of GRB 050315
  69. GRB050223: No XMM-Newton OM detection of afterglow emission
  70. GRB 050306: Radio Observations
  71. GRB 050306: optical afterglow
  72. GRB 050126: Redshift determination
  73. Swift-BAT trigger 107873: No Swift XRT counterpart
  74. GRB050309: Early optical limit from P60
  75. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  76. Swift 107873: P60 Optical Observations
  77. GRB 050306: CORRECTION to date of observation
  78. GRB 050306: R-band observations
  79. GRB 050306: No Swift UVOT Optical Counterpart Detected
  80. GRB 050306: REM optical-infrared observations
  81. GRB 050306: Possible X-ray Afterglow Position from the Swift
  82. GRB 050306: TAROT optical observations
  83. GRB050215B: Late-Time Swift UVOT Observations
  84. GRB 050126: Confirmation of the NIR afterglow candidate
  85. PROMPT VRcIc Observations of GRB 050223
  86. XRF/GRB 050215B: Radio Observations
  87. GRB 050219b: candidate NIR afterglow
  88. GRB 050223: optical observations
  89. GRB050223: No Swift UVOT Detection of Afterglow Emission
  90. GRB050223: ROTSE-III Optical Observations
  91. GRB 050223: Swift XRT Position
  92. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  93. GRB050219b: CORRECTION to time of UVOT observations
  94. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  95. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  96. GRB 050219a: Optical observations from LCO
  97. GRB 050219b: Optical and near-IR observations from LCO
  98. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  99. GRB 050219b: CORRECTION: Swift XRT Position
  100. GRB 050219b: Swift XRT Position

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