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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"

28072 results found.

  1. GRB 050509A: Further I-band imaging
  2. RBO Observations of GRB050522
  3. GRB050509b: optical observations
  4. GRB050520: Radio Observations
  5. XRF 050522: Swift XRT observation
  6. XRF050522, BVRcIc field photometry
  7. XRF050522: Optical Observations
  8. XRF050522: Near-infrared Observations
  9. GRB 050520: VLT/ULTRACAM observations
  10. Swift UVOT Observations of GRB 050520
  11. GRB 050520: Swift XRT refined analysis
  12. XRF050509C: Chandra Afterglow Detection
  13. XRF 050509c: Swift XRT Upper Limit
  14. RBO Observations of GRB050520
  15. GRB 050520: P200 Observations
  16. GRB050520: Liverpool Telescope follow-up
  17. GRB 050520: TAROT optical limit
  18. GRB 050520: Swift XRT position
  19. GRB 050520: OSN optical observations
  20. XRF 050509C: REM NIR and Optical refined analysis
  21. GRB 050504: Swift XRT afterglow candidate has faded
  22. XRF 050509c optical afterglow
  23. GRB 050509B and short GRB-SN association? (corrected)
  24. GRB 050509B and short GRB-SN association?
  25. GRB 050509B: Subaru Optical Observations
  26. GRB050502b: Early Observation
  27. GRB050509b, Bok telescope B-band imaging
  28. Refined Chandra analysis of GRB 050509b
  29. GRB050509b, SDSS pre-burst observations
  30. GRB 050509b: Keck/Chandra Cross-Correlation
  31. GRB 050509b: Keck/Chandra Cross-Correlation
  32. Chandra observation of GRB 050509b
  33. GRB 050509b: RAPTOR deep, early limits.
  34. GRB050509B: Optical/Infared observations
  35. GRB 050509b: Swift/UVOT follow-up measurements
  36. GRB 050509b Milagro GeV/TeV Observations
  37. GRB050509B: Optical observations at the Very Large Telescope
  38. GRB 050509b: No Optical Variability in XRT Error Circle
  39. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  40. GRB 050509a: Swift-BAT refined analysis
  41. GRB 050509B: WSRT Radio Observations
  42. GRB 050505: SARA Observations
  43. Swift UVOT Follow-up Observations of GRB 050509B
  44. GRB 050509B, Optical Observations
  45. GRB 050509B: Swift/XRT refined analysis
  46. GRB050509a: Swift UVOT observations
  47. GRB 050509b: Optical observations
  48. GRB 050509b: Precision Astrometry
  49. GRB 050509b: Possible Optical Counterpart
  50. GRB 050509A: Optical observations
  51. GRB 050509b: Optical Counterpart Candidate
  52. GRB050509b: Radio Observations
  53. GRB 050509b: PAIRITEL and WIYN Observations
  54. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  55. GRB 050509b: optical observations
  56. GRB 050509b: Swift XRT Position
  57. Swift Detection of GRB050509b: A short duration burst
  58. GRB 050509a: Swift XRT Position
  59. Swift Detection of the Burst GRB050509
  60. Swift-BAT detection of GRB 050507
  61. GRB 050505: Keck I-band Magnitude
  62. GRB 050505: early time observations
  63. GRB 050502a: Swift XRT Upper Limit
  64. GRB 050505: Further Swift UVOT observations.
  65. GRB050505: AAVSO observations
  66. GRB050416A : 1 GHz limit from GMRT
  67. GRB 050505 UVOT
  68. GRB050505: Optical Afterglow Candidate
  69. GRB 050505: Swift XRT Position
  70. GRB 050502a: Optical Observations
  71. GRB 050416b:Swift XRT afterglow upper limits
  72. GRB 050416b:Swift XRT afterglow upper limits
  73. Swift-BAT detection of GRB050505
  74. GRB 050504: Swift XRT position
  75. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  76. GRB050502b: Afterglow Confirmation
  77. GRB050502: P200 Observations (Correction)
  78. GRB050502: P200 Observations
  79. GRB050502a: P60 Observations (Correction)
  80. GRB050502a: P60 Observations
  81. GRB 050502a: RBO Observations
  82. GRB 050502A: WSRT Radio Observations
  83. GRB050502A: Optical Observations
  84. GRB050502B Swift-BAT refined analysis
  85. GRB050502B: I band source in XRT error circle
  86. Swift UVOT refined analysis
  87. GRB 050502a : R band observation at Lulin observatory
  88. GRB 050502b : optical observation at Lulin observatory
  89. GRB 050502b: Swift XRT Position
  90. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  91. Swift Detection of the Bright Burst GRB050502b
  92. GRB 050502: Confirmed variability of the afterglow candidate +
  93. GRB 050502: PAIRITEL IR Observations
  94. GRB 050502: ROTSE-III Detection of Possible Counterpart
  95. Swift-BAT Trigger 115881 is not a real GRB
  96. Swift/BAT possible detection of a weak burst GRB050430
  97. GRB 050401: Rc observation
  98. GRB050416a: Radio Detection
  99. GRB 050422: Swift-UVOT observation
  100. GRB 050422: Swift XRT Position

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