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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"

22086 results found.

  1. GRB 050607: Optical decay and spectral slope
  2. GRB050607,optical observation
  3. GRB 050607 - XRT refined data analysis
  4. Optical Afterglow of GRB 050607
  5. GRB050607: Swift Detection of a long GRB
  6. GRB050607: prompt REM observations
  7. GRB 050603: prediction of t_break
  8. Limits on a SN in the field of GRB 050509b
  9. Konus-Wind observation of GRB 050603
  10. GRB050603: Fading Afterglow observed by Swift UVOT
  11. GRB050603, submillimetre observations
  12. GRB050603: Radio Detection
  13. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  14. GRB 050603: INTEGRAL shows it is not a short GRB
  15. Swift/BAT Detection of GRB050603
  16. GRB 050525a, infrared observations
  17. GRB050528, XRT observations
  18. GRB050528: updated Liverpool Telescope limits
  19. Swift-BAT GRB 050528: a soft burst
  20. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  21. Possible GRB050528: no candidate from Liverpool Telescope
  22. Swift-BAT detection of possible GRB 050528
  23. GRB050525a: Radio Observations
  24. GRB 050509b: refined XRT/Chandra afterglow position analysis
  25. GRB 050525: RTT150, Optical observations
  26. GRB 050525a: SARA Observations
  27. GRB 050525B: Swift-BAT observations
  28. GRB 050525: MITSuME Optical Observation in VRI
  29. GRB050525A,optical observation
  30. GRB050525: Super-LOTIS observations
  31. GRB050306: optical afterglow not confirmed
  32. GRB 050525: BART optical observation
  33. GRB 050525A: BOOTES simultaneous optical observations
  34. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  35. Konus-Wind observation of GRB 050525
  36. GRB 050525: TAROT observations of the early afterglow
  37. INTEGRAL detection of GRB 050525
  38. GRB 050525, infrared observations
  39. GRB 050525: observatons of the optical afterglow
  40. GRB050525: ROTSE-III Refined Analysis
  41. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  42. XRF050522: Radio Observations
  43. Swift/UVOT observation of XRF 050522
  44. GRB 050509A: Further I-band imaging
  45. GRB050522,optical observation
  46. GRB050520,optical observation
  47. XRF 050522: Continued NIR P200 Monitoring
  48. Recent GRB BVRcIc field photometry
  49. GRB050520: Radio Observations
  50. XRF 050522: Swift XRT observation
  51. XRF050522, BVRcIc field photometry
  52. XRF050522: Optical Observations
  53. XRF050522: Near-infrared Observations
  54. GRB 050520: VLT/ULTRACAM observations
  55. Swift UVOT Observations of GRB 050520
  56. GRB 050520: Swift XRT refined analysis
  57. XRF 050509c: Swift XRT Upper Limit
  58. XRF050509c: Radio Observations
  59. RBO Observations of GRB050520
  60. GRB 050520: P200 Observations
  61. GRB050520: Liverpool Telescope follow-up
  62. GRB 050520: TAROT optical limit
  63. GRB 050520: VLT/ULTRACAM observations
  64. GRB 050520: OSN optical observations
  65. No Swift-BAT Lightcurves in real-time for next 3 weeks
  66. XRF 050509C: REM NIR and Optical refined analysis
  67. GRB 050504: Swift XRT afterglow candidate has faded
  68. GRB 050509B and short GRB-SN association? (corrected)
  69. GRB 050509B and short GRB-SN association?
  70. GRB050502b: Early Observation
  71. GRB050509b, Bok telescope B-band imaging
  72. GRB050509b, SDSS pre-burst observations
  73. GRB 050509b: Keck/Chandra Cross-Correlation
  74. GRB 050509b: Keck/Chandra Cross-Correlation
  75. Chandra observation of GRB 050509b
  76. GRB 050509b: Swift/UVOT follow-up measurements
  77. GRB050509B: Optical observations at the Very Large Telescope
  78. GRB 050509b: No Optical Variability in XRT Error Circle
  79. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  80. GRB 050509c: ROTSE-III Optical Limits
  81. GRB 050509B: WSRT Radio Observations
  82. GRB 050505, early TAROT observation
  83. GRB050509c: REM NIR and Optical observations
  84. GRB 050505: SARA Observations
  85. GRB 050509B: Swift/XRT refined analysis
  86. GRB 050509b: Optical observations
  87. GRB 050509b: Possible Optical Counterpart
  88. GRB 050509A: Optical observations
  89. GRB050509b: Radio Observations
  90. GRB 050509B: ROTSE-III Optical Limits
  91. Swift Detection of GRB050509b: A short duration burst
  92. Swift Detection of the Burst GRB050509
  93. Swift-BAT detection of GRB 050507
  94. GRB 050502a: Swift XRT Upper Limit
  95. GRB 050505, simultaneous optical observation
  96. GRB 050505: Further Swift UVOT observations.
  97. GRB050505: AAVSO observations
  98. GRB050416A : 1 GHz limit from GMRT
  99. GRB050505: Optical Afterglow Candidate
  100. GRB050505 Swift-BAT refined analysis

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