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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"

26326 results found.

  1. GRB050520,optical observation
  2. XRF 050522: Continued NIR P200 Monitoring
  3. RBO Observations of GRB050522
  4. Recent GRB BVRcIc field photometry
  5. GRB050520: Radio Observations
  6. XRF 050522: Swift XRT observation
  7. XRF050522, BVRcIc field photometry
  8. XRF050522: Optical Observations
  9. XRF050522: Near-infrared Observations
  10. GRB 050520: VLT/ULTRACAM observations
  11. GRB 050520: Swift XRT refined analysis
  12. XRF050509C: Chandra Afterglow Detection
  13. XRF050509c: Radio Observations
  14. GRB 050520: P200 Observations
  15. GRB 050520: TAROT optical limit
  16. GRB 050520: VLT/ULTRACAM observations
  17. XRF 050509c optical afterglow
  18. GRB 050509B and short GRB-SN association? (corrected)
  19. GRB 050509B and short GRB-SN association?
  20. GRB050502b: Early Observation
  21. GRB050509b, Bok telescope B-band imaging
  22. Refined Chandra analysis of GRB 050509b
  23. GRB050509b, SDSS pre-burst observations
  24. GRB 050509b: Keck/Chandra Cross-Correlation
  25. GRB 050509b: Keck/Chandra Cross-Correlation
  26. Chandra observation of GRB 050509b
  27. GRB 050509b: RAPTOR deep, early limits.
  28. GRB050509B: Optical observations at the Very Large Telescope
  29. GRB 050509b: No Optical Variability in XRT Error Circle
  30. GRB 050509a: Swift-BAT refined analysis
  31. GRB 050509c: ROTSE-III Optical Limits
  32. GRB 050505, early TAROT observation
  33. GRB050509c: REM NIR and Optical observations
  34. GRB 050509b: Physical Properties of the Candidate Host galaxy
  35. GRB 050505: SARA Observations
  36. GRB 050509B, Optical Observations
  37. GRB 050509B: Swift/XRT refined analysis
  38. GRB 050509b: Optical observations
  39. GRB 050509A: Optical observations
  40. GRB050509b: Radio Observations
  41. GRB 050509b: PAIRITEL and WIYN Observations
  42. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  43. Swift Detection of GRB050509b: A short duration burst
  44. Swift Detection of the Burst GRB050509
  45. GRB 050505: early time observations
  46. GRB 050505, simultaneous optical observation
  47. GRB050505: AAVSO observations
  48. GRB050416A : 1 GHz limit from GMRT
  49. GRB050505: Optical Afterglow Candidate
  50. GRB050505 Swift-BAT refined analysis
  51. GRB 050416b:Swift XRT afterglow upper limits
  52. GRB 050416b:Swift XRT afterglow upper limits
  53. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  54. GRB050502b: Afterglow Confirmation
  55. GRB050502: P200 Observations (Correction)
  56. GRB050502: P200 Observations
  57. GRB 050504 : R band observation at Lulin observatory
  58. Swift UVOT observation of GRB 050504
  59. GRB 050504, R band Observations
  60. GRB 050502b, V band Observations
  61. GRB050504: P60 Observations
  62. GRB 050504: A long GRB detected with INTEGRAL
  63. GRB (?) 050504: IR Observations, Intriguing Source
  64. GRB 050502b, Optical observations
  65. GRB050502a: P60 Observations (Correction)
  66. GRB050502a: P60 Observations
  67. Renewal of SGR 1806-20 activity
  68. GRB050502B Swift-BAT refined analysis
  69. Swift UVOT refined analysis
  70. GRB 050502a : R band observation at Lulin observatory
  71. GRB 050502b : optical observation at Lulin observatory
  72. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  73. Swift Detection of the Bright Burst GRB050502b
  74. GRB 050502: INTEGRAL results
  75. GRB 050502: ROTSE-III Detection of Possible Counterpart
  76. Swift/BAT possible detection of a weak burst GRB050430
  77. GRB050416a: Radio Detection
  78. GRB 050422: Swift-UVOT observation
  79. GRB 050422: Swift-BAT refined analysis
  80. Swift Detection of GRB 050422
  81. GRB 050421: SLOTIS observations
  82. GRB 050421: Further Analysis of IR imaging
  83. GRB050421: Radio Observations
  84. GRB050421: Radio Observations
  85. GRB 050421: IR Observations
  86. GRB 050421: Swift-BAT refined analysis
  87. GRB050421
  88. GRB 050421: early Swift XRT analysis results
  89. GRB 050421: NIR observations
  90. GRB050421: P60 Observations
  91. GRB 050421: BOOTES-2 simultaneous optical observations
  92. GRB 050416b: Tentative Swift XRT Position
  93. GRB 050315: potential host galaxy
  94. GRB050326: analysis of the XMM-Newton observation
  95. GRB050418: Null Optical Observations
  96. GRB050416A, optical observations
  97. GRB 050418: Swift-BAT refined analysis
  98. GRB 050416: Mitsume optical observation
  99. GRB050416B: IR observations
  100. GRB050412: Radio Observations

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