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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"

19061 results found.

  1. GRB 050603: Analysis of UVOT data
  2. GRB050603: Fading Afterglow observed by Swift UVOT
  3. GRB 050603: Swift XRT Position
  4. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  5. Swift/BAT Detection of GRB050603
  6. GRB 050408: jet break in the XRT light curve
  7. GRB050528, XRT observations
  8. Correction to GCN Circ 3502 on GRB 050528
  9. Swift-BAT GRB 050528: a soft burst
  10. Update on Swift-BAT GRB 050528 (Trigger 130679)
  11. Possible GRB050528: no candidate from Liverpool Telescope
  12. Swift-BAT detection of possible GRB 050528
  13. GRB 050509b: refined XRT/Chandra afterglow position analysis
  14. GRB050525a: optical upper limits
  15. GRB 050525B: Swift-BAT observations
  16. GRB050525A,optical observation
  17. GRB050525: Super-LOTIS observations
  18. GRB 050525, spectral lag pseudo-redshift
  19. GRB050306: optical afterglow not confirmed
  20. GRB 050525A: BOOTES simultaneous optical observations
  21. GRB 050525A: Swift-BAT refined analysis
  22. Swift/UVOT UV and optical detections of GRB 050525
  23. Konus-Wind observation of GRB 050525
  24. GRB 050525: TAROT observations of the early afterglow
  25. INTEGRAL detection of GRB 050525
  26. GRB 050525: Optical observation
  27. GRB050525: ROTSE-III Refined Analysis
  28. GRB 050525 - Very Bright, Not Short
  29. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  30. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  31. XRF 050522: Swift XRT refined analysis
  32. Swift/UVOT observation of XRF 050522
  33. GRB 050509A: Further I-band imaging
  34. RBO Observations of GRB050522
  35. XRF 050522: Swift XRT observation
  36. GRB 050520: VLT/ULTRACAM observations
  37. Swift UVOT Observations of GRB 050520
  38. GRB 050520: Swift XRT refined analysis
  39. XRF050509C: Chandra Afterglow Detection
  40. XRF 050509c: Swift XRT Upper Limit
  41. RBO Observations of GRB050520
  42. GRB 050520: TAROT optical limit
  43. GRB 050520: Swift XRT position
  44. No Swift-BAT Lightcurves in real-time for next 3 weeks
  45. Swift-BAT trigger 122203 is not a real GRB
  46. GRB 050504: Swift XRT afterglow candidate has faded
  47. GRB 050509B: Subaru Optical Observations
  48. GRB050502b: Early Observation
  49. Refined Chandra analysis of GRB 050509b
  50. GRB050509b, SDSS pre-burst observations
  51. Chandra observation of GRB 050509b
  52. GRB 050509b: RAPTOR deep, early limits.
  53. GRB050509B: Optical/Infared observations
  54. GRB 050509b: Swift/UVOT follow-up measurements
  55. GRB 050509b Milagro GeV/TeV Observations
  56. GRB050509B: Optical observations at the Very Large Telescope
  57. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  58. GRB 050509a: Swift-BAT refined analysis
  59. GRB 050509B: WSRT Radio Observations
  60. GRB 050505: SARA Observations
  61. Swift UVOT Follow-up Observations of GRB 050509B
  62. GRB 050509B, Optical Observations
  63. GRB 050509B: Swift/XRT refined analysis
  64. GRB050509a: Swift UVOT observations
  65. GRB 050509b: Optical observations
  66. GRB 050509b: Possible Optical Counterpart
  67. GRB 050509A: Optical observations
  68. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  69. GRB 050509b: optical observations
  70. GRB 050509b: Swift XRT Position
  71. GRB 050509B: ROTSE-III Optical Limits
  72. Swift Detection of GRB050509b: A short duration burst
  73. GRB 050509a: Swift XRT Position
  74. Swift Detection of the Burst GRB050509
  75. Swift-BAT detection of GRB 050507
  76. GRB 050505: early time observations
  77. GRB 050505 - Faulkes Telescope North observations
  78. GRB 050502a: Swift XRT Upper Limit
  79. GRB 050505, simultaneous optical observation
  80. GRB 050505: Further Swift UVOT observations.
  81. GRB050416A : 1 GHz limit from GMRT
  82. GRB 050505 UVOT
  83. GRB 050505: Swift XRT Position
  84. GRB050505 Swift-BAT refined analysis
  85. GRB 050416b:Swift XRT afterglow upper limits
  86. GRB 050416b:Swift XRT afterglow upper limits
  87. Swift-BAT detection of GRB050505
  88. GRB 050504: Swift XRT position
  89. Swift UVOT observation of GRB 050504
  90. GRB 050502b, V band Observations
  91. GRB050502B Swift-BAT refined analysis
  92. GRB050502B: I band source in XRT error circle
  93. Swift UVOT refined analysis
  94. Retraction of Swift-BAT trigger 116145
  95. GRB 050502b : optical observation at Lulin observatory
  96. GRB 050502b: Swift XRT Position
  97. GRB050502B: Optical Limits from ANU 1m
  98. Swift Detection of the Bright Burst GRB050502b
  99. GRB050502: ANU 1m optical Observations
  100. Swift-BAT Trigger 115881 is not a real GRB

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