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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"

22085 results found.

  1. GRB050607,optical observation
  2. GRB 050607 - XRT refined data analysis
  3. Optical Afterglow of GRB 050607
  4. GRB050607: Swift Detection of a long GRB
  5. GRB050607: prompt REM observations
  6. GRB 050603: prediction of t_break
  7. Limits on a SN in the field of GRB 050509b
  8. Konus-Wind observation of GRB 050603
  9. GRB050603: Fading Afterglow observed by Swift UVOT
  10. GRB050603, submillimetre observations
  11. GRB050603: Radio Detection
  12. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  13. GRB 050603: INTEGRAL shows it is not a short GRB
  14. Swift/BAT Detection of GRB050603
  15. GRB 050525a, infrared observations
  16. GRB050528, XRT observations
  17. GRB050528: updated Liverpool Telescope limits
  18. Swift-BAT GRB 050528: a soft burst
  19. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  20. Possible GRB050528: no candidate from Liverpool Telescope
  21. Swift-BAT detection of possible GRB 050528
  22. GRB050525a: Radio Observations
  23. GRB 050509b: refined XRT/Chandra afterglow position analysis
  24. GRB 050525: RTT150, Optical observations
  25. GRB 050525a: SARA Observations
  26. GRB 050525B: Swift-BAT observations
  27. GRB 050525: MITSuME Optical Observation in VRI
  28. GRB050525A,optical observation
  29. GRB050525: Super-LOTIS observations
  30. GRB050306: optical afterglow not confirmed
  31. GRB 050525: BART optical observation
  32. GRB 050525A: BOOTES simultaneous optical observations
  33. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  34. Konus-Wind observation of GRB 050525
  35. GRB 050525: TAROT observations of the early afterglow
  36. INTEGRAL detection of GRB 050525
  37. GRB 050525, infrared observations
  38. GRB 050525: observatons of the optical afterglow
  39. GRB050525: ROTSE-III Refined Analysis
  40. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  41. XRF050522: Radio Observations
  42. Swift/UVOT observation of XRF 050522
  43. GRB 050509A: Further I-band imaging
  44. GRB050522,optical observation
  45. GRB050520,optical observation
  46. XRF 050522: Continued NIR P200 Monitoring
  47. Recent GRB BVRcIc field photometry
  48. GRB050520: Radio Observations
  49. XRF 050522: Swift XRT observation
  50. XRF050522, BVRcIc field photometry
  51. XRF050522: Optical Observations
  52. XRF050522: Near-infrared Observations
  53. GRB 050520: VLT/ULTRACAM observations
  54. Swift UVOT Observations of GRB 050520
  55. GRB 050520: Swift XRT refined analysis
  56. XRF 050509c: Swift XRT Upper Limit
  57. XRF050509c: Radio Observations
  58. RBO Observations of GRB050520
  59. GRB 050520: P200 Observations
  60. GRB050520: Liverpool Telescope follow-up
  61. GRB 050520: TAROT optical limit
  62. GRB 050520: VLT/ULTRACAM observations
  63. GRB 050520: OSN optical observations
  64. No Swift-BAT Lightcurves in real-time for next 3 weeks
  65. XRF 050509C: REM NIR and Optical refined analysis
  66. GRB 050504: Swift XRT afterglow candidate has faded
  67. GRB 050509B and short GRB-SN association? (corrected)
  68. GRB 050509B and short GRB-SN association?
  69. GRB050502b: Early Observation
  70. GRB050509b, Bok telescope B-band imaging
  71. GRB050509b, SDSS pre-burst observations
  72. GRB 050509b: Keck/Chandra Cross-Correlation
  73. GRB 050509b: Keck/Chandra Cross-Correlation
  74. Chandra observation of GRB 050509b
  75. GRB 050509b: Swift/UVOT follow-up measurements
  76. GRB050509B: Optical observations at the Very Large Telescope
  77. GRB 050509b: No Optical Variability in XRT Error Circle
  78. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  79. GRB 050509c: ROTSE-III Optical Limits
  80. GRB 050509B: WSRT Radio Observations
  81. GRB 050505, early TAROT observation
  82. GRB050509c: REM NIR and Optical observations
  83. GRB 050505: SARA Observations
  84. GRB 050509B: Swift/XRT refined analysis
  85. GRB 050509b: Optical observations
  86. GRB 050509b: Possible Optical Counterpart
  87. GRB 050509A: Optical observations
  88. GRB050509b: Radio Observations
  89. GRB 050509B: ROTSE-III Optical Limits
  90. Swift Detection of GRB050509b: A short duration burst
  91. Swift Detection of the Burst GRB050509
  92. Swift-BAT detection of GRB 050507
  93. GRB 050502a: Swift XRT Upper Limit
  94. GRB 050505, simultaneous optical observation
  95. GRB 050505: Further Swift UVOT observations.
  96. GRB050505: AAVSO observations
  97. GRB050416A : 1 GHz limit from GMRT
  98. GRB050505: Optical Afterglow Candidate
  99. GRB050505 Swift-BAT refined analysis
  100. GRB 050416b:Swift XRT afterglow upper limits

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