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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"

26329 results found.

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

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