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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"

35991 results found.

  1. GRB 050412: Optical observations
  2. GRB050412: P60 Observations
  3. GRB 050412: Swift XRT Position
  4. GRB050412: optical limit before and during GRB
  5. GRB 050412: LCO optical observations
  6. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  7. GRB 050412: IR and Optical observations
  8. GRB 050412: IR Observations
  9. GRB050408: Radio Observations
  10. GRB 050401: Optical limit
  11. GRB 050408: Optical limit
  12. GRB050410: P60 Observations
  13. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  14. GRB 050410, optical observations
  15. GRB 050408: PROMPT VRcIc Observations
  16. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  17. GRB 050410 R band Optical Observations
  18. GRB050410 : Null detection report
  19. GRB 050410, optical observations
  20. GRB050410: Radio Observations
  21. GRB 050408: Swift XRT measurement of possible jet break
  22. GRB050410: MASTER optical observations
  23. GRB 050410: Early observations with Swift-UVOT
  24. Swift-BAT detection of GRB 050410
  25. GRB 050410: Swift XRT Position
  26. GRB 050408: Retraction of Proposed Host Galaxy
  27. GRB 050408: Inconsistency of host galaxy identification
  28. GRB 050408: Subaru Observations
  29. GRB 050408: WIDGET simultaneous optical observations
  30. GRB 050408: SOAR UBVRc Observations
  31. GRB 050408: Properties of the Host Galaxy
  32. GRB 050408: Mercator Optical Observations
  33. GRB050408: Radio Observations
  34. GRB 050408: Swift XRT analysis
  35. GRB 050408, SMARTS optical/IR afterglow observations
  36. GRB 050408: Optical limit at 20 min after the burst
  37. GRB 050408, optical observations
  38. GRB 050408: Moderate-resolution Gemini Spectroscopy
  39. GRB 050408,optical observation
  40. GRB 050408 Optical Observations
  41. GRB 050408: Emission and absorption redshift
  42. GRB 050408: Mercator Optical Observations
  43. GRB 050408: Magellan astrometry and photometry
  44. GRB 050408: First Optical observations with TFOSC at the RTT150
  45. GRB 050408: steepening of the optical decay
  46. GRB 050408: Optical afterglow confirmed
  47. GRB 050408: opitcal observation
  48. GRB 050408, optical observations
  49. GRB 050408 optical candidate
  50. GRB 050408: Swift XRT Position
  51. GRB 050408: ROTSE-III Optical Limits
  52. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  53. GRB050408: MASTER optical observations
  54. GRB050401: Radio Detection
  55. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  56. GRB 050406: Magellan optical observations
  57. GRB 050406: early Swift XRT analysis results
  58. GRB 050406 BAT refined analysis
  59. GRB 050406: Early observations with Swift-UVOT
  60. GRB 050406: Swift XRT Position
  61. Swift-BAT detection of GRB 050406
  62. Konus-Wind observation of GRB 050401
  63. GRB050401: Radio observation at 610 MHz with GMRT
  64. GRB 050401: VLT spectroscopic redshift
  65. GRB 050401 Optical Observations
  66. GRB 050401 BAT refined analysis
  67. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  68. GRB050401: TNG R-band observation
  69. GRB 050402A: IR Analysis
  70. GRB 050402A: IR Observations
  71. GRB 050402: Early observations with Swift-UVOT
  72. Swift Trigger 113225: P60 Observations
  73. GRB 050401: Optical afterglow confirmed
  74. GRB 050401: Optical afterglow candidate
  75. Swift-BAT detection of GRB 050401
  76. GRB 050401: Prompt XRT position
  77. Retraction of three Swift GRB triggers
  78. GRB050331: No Afterglow Detected
  79. Swift-BAT detection of GRB 050331b
  80. GRB 050331: Swift UVOT Source
  81. Swift-BAT detection of GRB 050331
  82. GRB 050331: Swift XRT Position
  83. GRB050319: radio observation
  84. Konus-Wind observation of GRB 050326
  85. GRB 050326: Early observations with Swift-UVOT
  86. GRB 050326 XMM-Newton observation
  87. GRB 050326 : Planned XMM-Newton observation
  88. GRB 050326: Swift XRT Position
  89. GRB050326: optical limit 33min before GRB
  90. GRB 050326 BAT refined analysis
  91. GRB050326: delayed XRT observation
  92. Swift-BAT detection of a bright GRB 050326
  93. GRB050319, color indices
  94. GRB050319: RTT150 Optical Observations
  95. Swift-BAT trigger 112060 is not a real GRB
  96. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  97. GRB 050319: ROTSE-III Refined Analysis
  98. GRB 050318: Swift-BAT refined analysis
  99. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  100. GRB050319: VLA Observations

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