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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"

26330 results found.

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

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