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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 050525: observatons of the optical afterglow
  2. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  3. GRB 050509A: Further I-band imaging
  4. GRB050522,optical observation
  5. GRB050520,optical observation
  6. XRF 050522: Continued NIR P200 Monitoring
  7. GRB050509b: optical observations
  8. Recent GRB BVRcIc field photometry
  9. XRF050522: Optical Observations
  10. XRF 050522 detected with INTEGRAL
  11. Swift UVOT Observations of GRB 050520
  12. XRF 050509c: Swift XRT Upper Limit
  13. GRB 050520: TAROT optical limit
  14. GRB 050520: OSN optical observations
  15. GRB 050520: BART optical limit
  16. GRB 050520 - A long GRB detected with INTEGRAL
  17. XRF 050509C: REM NIR and Optical refined analysis
  18. XRF 050509c optical afterglow
  19. GRB 050509B and short GRB-SN association? (corrected)
  20. GRB 050509B and short GRB-SN association?
  21. GRB 050509B: Subaru Optical Observations
  22. GRB050502b: Early Observation
  23. GRB050509B: Optical/Infared observations
  24. GRB 050509b: Swift/UVOT follow-up measurements
  25. GRB050509B: Optical observations at the Very Large Telescope
  26. GRB 050509b: No Optical Variability in XRT Error Circle
  27. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  28. GRB 050509c: ROTSE-III Optical Limits
  29. GRB 050509B: WSRT Radio Observations
  30. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  31. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  32. GRB 050509b: Further Analysis of Keck LRIS Images
  33. GRB050509c: REM NIR and Optical observations
  34. GRB 050505: SARA Observations
  35. Swift UVOT Follow-up Observations of GRB 050509B
  36. GRB 050509B, Optical Observations
  37. GRB050509a: Swift UVOT observations
  38. GRB 050509b: Optical observations
  39. GRB 050509b: Possible Optical Counterpart
  40. GRB 050509A: Optical observations
  41. GRB 050509b: Optical Counterpart Candidate
  42. GRB 050509b: optical observations
  43. GRB 050509b: Swift XRT Position
  44. GRB 050509B: ROTSE-III Optical Limits
  45. Swift Detection of GRB050509b: A short duration burst
  46. Swift Detection of the Burst GRB050509
  47. GRB 050505: early time observations
  48. GRB 050505 - Faulkes Telescope North observations
  49. GRB 050502a: Swift XRT Upper Limit
  50. GRB 050505, simultaneous optical observation
  51. GRB050505: Infrared observations
  52. GRB 050505: Further Swift UVOT observations.
  53. GRB050505: AAVSO observations
  54. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  55. GRB 050505 UVOT
  56. GRB050505: Optical Afterglow Candidate
  57. GRB 050502a: Optical Observations
  58. GRB050504: Faulkes North optical robotic limit
  59. GRB 050504: A long GRB detected with INTEGRAL
  60. GRB 050502b, Optical observations
  61. GRB 050502A: WSRT Radio Observations
  62. GRB050502A: Optical Observations
  63. GRB 050502a : R band observation at Lulin observatory
  64. GRB 050502b : optical observation at Lulin observatory
  65. GRB050502B: Optical Limits from ANU 1m
  66. Swift Detection of the Bright Burst GRB050502b
  67. GRB050502: ANU 1m optical Observations
  68. GRB 050502: Confirmed variability of the afterglow candidate +
  69. GRB050502 - Correction on the Optical Candidate from the Liverpool
  70. GRB050502 - Optical Candidate from the Liverpool Telescope
  71. Swift/BAT possible detection of a weak burst GRB050430
  72. GRB 050401: Rc observation
  73. GRB050416a: Radio Detection
  74. GRB 050422: Swift-UVOT observation
  75. Swift Detection of GRB 050422
  76. GRB 050421: NIR observations
  77. GRB 050416: Optical/NIR observations
  78. GRB 050421: Swift-UVOT observation
  79. GRB 050421: ROTSE-III Optical Limits
  80. GRB 050421: early Swift XRT analysis results
  81. GRB 050421: BOOTES-2 simultaneous optical observations
  82. GRB 050421: Optical observations at the INT
  83. Swift Detection of GRB050421
  84. GRB 050315: potential host galaxy
  85. GRB050326: analysis of the XMM-Newton observation
  86. GRB050418: Null Optical Observations
  87. GRB050416A, optical observations
  88. GRB 050416: Mitsume optical observation
  89. GRB 050416 : optical observation at Xinglong observatory
  90. GRB 050416B: optical observations
  91. GRB 050416: Swift/UVOT refined analysis
  92. GRB 050416: Swift/UVOT detection of afterglow emission
  93. GRB050416: Maidanak optical observations
  94. GRB 050416: ART observations
  95. GRB 050416,optical observation
  96. GRB 050416: Swift XRT Position
  97. GRB 050408: RTT150 optical observations
  98. GRB050408: optical observation
  99. GRB 050412: optical limit
  100. GRB 050412: optical observations

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