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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"

15684 results found.

  1. GRB050603: Radio Detection
  2. GRB 050525a, SMARTS optical/IR afterglow observations
  3. GRB050528: BOOTES optical candidate (retraction)
  4. GRB050528: BOOTES optical candidate
  5. GRB050525a: Radio Observations
  6. GRB 050525: RTT150, Optical observations
  7. GRB050525a: optical upper limits
  8. GRB 050525a: SARA Observations
  9. GRB 050525: MITSuME Optical Observation in VRI
  10. GRB 050525a: MDM Observations
  11. GRB050525A,optical observation
  12. GRB 050525 : Lulin optical afterglow observations
  13. GRB050525: Super-LOTIS observations
  14. GRB 050525a: Gemini/GMOS Spectra
  15. GRB050306: optical afterglow not confirmed
  16. GRB 050525: BART optical observation
  17. GRB 050525A: BOOTES simultaneous optical observations
  18. GRB 050525A: Swift-BAT refined analysis
  19. GRB050525: Optical observations
  20. Swift/UVOT UV and optical detections of GRB 050525
  21. GRB 050525, infrared observations
  22. GRB 050525: Optical observation
  23. GRB 050525: observatons of the optical afterglow
  24. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  25. GRB 050509A: Further I-band imaging
  26. GRB050522,optical observation
  27. GRB050520,optical observation
  28. XRF 050522: Continued NIR P200 Monitoring
  29. GRB050509b: optical observations
  30. Recent GRB BVRcIc field photometry
  31. XRF050522: Optical Observations
  32. XRF 050522 detected with INTEGRAL
  33. Swift UVOT Observations of GRB 050520
  34. XRF 050509c: Swift XRT Upper Limit
  35. GRB 050520: TAROT optical limit
  36. GRB 050520: OSN optical observations
  37. GRB 050520: BART optical limit
  38. GRB 050520 - A long GRB detected with INTEGRAL
  39. XRF 050509C: REM NIR and Optical refined analysis
  40. XRF 050509c optical afterglow
  41. GRB 050509B and short GRB-SN association? (corrected)
  42. GRB 050509B and short GRB-SN association?
  43. GRB 050509B: Subaru Optical Observations
  44. GRB050502b: Early Observation
  45. GRB050509B: Optical/Infared observations
  46. GRB 050509b: Swift/UVOT follow-up measurements
  47. GRB050509B: Optical observations at the Very Large Telescope
  48. GRB 050509b: No Optical Variability in XRT Error Circle
  49. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  50. GRB 050509c: ROTSE-III Optical Limits
  51. GRB 050509B: WSRT Radio Observations
  52. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  53. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  54. GRB 050509b: Further Analysis of Keck LRIS Images
  55. GRB050509c: REM NIR and Optical observations
  56. GRB 050505: SARA Observations
  57. Swift UVOT Follow-up Observations of GRB 050509B
  58. GRB 050509B, Optical Observations
  59. GRB050509a: Swift UVOT observations
  60. GRB 050509b: Optical observations
  61. GRB 050509b: Possible Optical Counterpart
  62. GRB 050509A: Optical observations
  63. GRB 050509b: Optical Counterpart Candidate
  64. GRB 050509b: optical observations
  65. GRB 050509b: Swift XRT Position
  66. GRB 050509B: ROTSE-III Optical Limits
  67. Swift Detection of GRB050509b: A short duration burst
  68. Swift Detection of the Burst GRB050509
  69. GRB 050505: early time observations
  70. GRB 050505 - Faulkes Telescope North observations
  71. GRB 050502a: Swift XRT Upper Limit
  72. GRB 050505, simultaneous optical observation
  73. GRB050505: Infrared observations
  74. GRB 050505: Further Swift UVOT observations.
  75. GRB050505: AAVSO observations
  76. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  77. GRB 050505 UVOT
  78. GRB050505: Optical Afterglow Candidate
  79. GRB 050502a: Optical Observations
  80. GRB050504: Faulkes North optical robotic limit
  81. GRB 050504: A long GRB detected with INTEGRAL
  82. GRB 050502b, Optical observations
  83. GRB 050502A: WSRT Radio Observations
  84. GRB050502A: Optical Observations
  85. GRB 050502a : R band observation at Lulin observatory
  86. GRB 050502b : optical observation at Lulin observatory
  87. GRB050502B: Optical Limits from ANU 1m
  88. Swift Detection of the Bright Burst GRB050502b
  89. GRB050502: ANU 1m optical Observations
  90. GRB 050502: Confirmed variability of the afterglow candidate +
  91. GRB050502 - Correction on the Optical Candidate from the Liverpool
  92. GRB050502 - Optical Candidate from the Liverpool Telescope
  93. Swift/BAT possible detection of a weak burst GRB050430
  94. GRB 050401: Rc observation
  95. GRB050416a: Radio Detection
  96. GRB 050422: Swift-UVOT observation
  97. Swift Detection of GRB 050422
  98. GRB 050421: NIR observations
  99. GRB 050416: Optical/NIR observations
  100. GRB 050421: Swift-UVOT observation

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