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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"

26033 results found.

  1. Konus-Wind observation of GRB 050525
  2. GRB 050525: TAROT observations of the early afterglow
  3. INTEGRAL detection of GRB 050525
  4. GRB 050525, infrared observations
  5. GRB 050525: Optical observation
  6. GRB 050525: observatons of the optical afterglow
  7. GRB050525: ROTSE-III Refined Analysis
  8. GRB 050525 - Very Bright, Not Short
  9. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  10. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  11. XRF050522: NIR observations of XRT candidate
  12. XRF 050522: Swift XRT refined analysis
  13. Swift/UVOT observation of XRF 050522
  14. GRB 050509A: Further I-band imaging
  15. RBO Observations of GRB050522
  16. GRB050509b: optical observations
  17. GRB050520: Radio Observations
  18. XRF 050522: Swift XRT observation
  19. XRF050522, BVRcIc field photometry
  20. XRF050522: Optical Observations
  21. XRF050522: Near-infrared Observations
  22. GRB 050520: VLT/ULTRACAM observations
  23. Swift UVOT Observations of GRB 050520
  24. GRB 050520: Swift XRT refined analysis
  25. XRF050509C: Chandra Afterglow Detection
  26. XRF 050509c: Swift XRT Upper Limit
  27. RBO Observations of GRB050520
  28. GRB 050520: P200 Observations
  29. GRB050520: Liverpool Telescope follow-up
  30. GRB 050520: TAROT optical limit
  31. GRB 050520: Swift XRT position
  32. No Swift-BAT Lightcurves in real-time for next 3 weeks
  33. Swift-BAT trigger 122203 is not a real GRB
  34. GRB 050504: Swift XRT afterglow candidate has faded
  35. XRF 050509c optical afterglow
  36. GRB 050509B and short GRB-SN association? (corrected)
  37. GRB 050509B and short GRB-SN association?
  38. GRB 050509B: Subaru Optical Observations
  39. GRB050502b: Early Observation
  40. GRB050509b, Bok telescope B-band imaging
  41. Refined Chandra analysis of GRB 050509b
  42. GRB050509b, SDSS pre-burst observations
  43. GRB 050509b: Keck/Chandra Cross-Correlation
  44. GRB 050509b: Keck/Chandra Cross-Correlation
  45. Chandra observation of GRB 050509b
  46. GRB 050509b: RAPTOR deep, early limits.
  47. GRB050509B: Optical/Infared observations
  48. GRB 050509b: Swift/UVOT follow-up measurements
  49. GRB 050509b Milagro GeV/TeV Observations
  50. GRB050509B: Optical observations at the Very Large Telescope
  51. GRB 050509b: No Optical Variability in XRT Error Circle
  52. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  53. GRB 050509a: Swift-BAT refined analysis
  54. GRB 050509B: WSRT Radio Observations
  55. GRB 050505: SARA Observations
  56. Swift UVOT Follow-up Observations of GRB 050509B
  57. GRB 050509B, Optical Observations
  58. GRB 050509B: Swift/XRT refined analysis
  59. GRB050509a: Swift UVOT observations
  60. GRB 050509b: Optical observations
  61. GRB 050509b: Precision Astrometry
  62. GRB 050509b: Possible Optical Counterpart
  63. GRB 050509A: Optical observations
  64. GRB 050509b: Optical Counterpart Candidate
  65. GRB050509b: Radio Observations
  66. GRB 050509b: PAIRITEL and WIYN Observations
  67. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  68. GRB 050509b: optical observations
  69. GRB 050509b: Swift XRT Position
  70. GRB 050509B: ROTSE-III Optical Limits
  71. Swift Detection of GRB050509b: A short duration burst
  72. GRB 050509a: Swift XRT Position
  73. Swift Detection of the Burst GRB050509
  74. Swift-BAT detection of GRB 050507
  75. GRB 050505: Keck I-band Magnitude
  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. GRB050505: AAVSO observations
  82. GRB050416A : 1 GHz limit from GMRT
  83. GRB 050505 UVOT
  84. GRB050505: Optical Afterglow Candidate
  85. GRB 050505: Swift XRT Position
  86. GRB050505 Swift-BAT refined analysis
  87. GRB 050502a: Optical Observations
  88. GRB 050416b:Swift XRT afterglow upper limits
  89. GRB 050416b:Swift XRT afterglow upper limits
  90. Swift-BAT detection of GRB050505
  91. GRB 050504: Swift XRT position
  92. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  93. GRB050502b: Afterglow Confirmation
  94. GRB050502: P200 Observations (Correction)
  95. GRB050502: P200 Observations
  96. Swift UVOT observation of GRB 050504
  97. GRB 050502b, V band Observations
  98. GRB050502a: P60 Observations (Correction)
  99. GRB050502a: P60 Observations
  100. GRB 050502a: RBO Observations

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