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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"

26332 results found.

  1. GRB050525: ROTSE-III Refined Analysis
  2. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  3. XRF050522: Radio Observations
  4. Swift/UVOT observation of XRF 050522
  5. GRB 050509A: Further I-band imaging
  6. GRB050522,optical observation
  7. GRB050520,optical observation
  8. XRF 050522: Continued NIR P200 Monitoring
  9. RBO Observations of GRB050522
  10. Recent GRB BVRcIc field photometry
  11. GRB050520: Radio Observations
  12. XRF 050522: Swift XRT observation
  13. XRF050522, BVRcIc field photometry
  14. XRF050522: Optical Observations
  15. XRF050522: Near-infrared Observations
  16. GRB 050520: VLT/ULTRACAM observations
  17. GRB 050520: Swift XRT refined analysis
  18. XRF050509C: Chandra Afterglow Detection
  19. XRF050509c: Radio Observations
  20. GRB 050520: P200 Observations
  21. GRB 050520: TAROT optical limit
  22. GRB 050520: VLT/ULTRACAM observations
  23. XRF 050509c optical afterglow
  24. GRB 050509B and short GRB-SN association? (corrected)
  25. GRB 050509B and short GRB-SN association?
  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 observations at the Very Large Telescope
  35. GRB 050509b: No Optical Variability in XRT Error Circle
  36. GRB 050509a: Swift-BAT refined analysis
  37. GRB 050509c: ROTSE-III Optical Limits
  38. GRB 050505, early TAROT observation
  39. GRB050509c: REM NIR and Optical observations
  40. GRB 050509b: Physical Properties of the Candidate Host galaxy
  41. GRB 050505: SARA Observations
  42. GRB 050509B, Optical Observations
  43. GRB 050509B: Swift/XRT refined analysis
  44. GRB 050509b: Optical observations
  45. GRB 050509A: Optical observations
  46. GRB050509b: Radio Observations
  47. GRB 050509b: PAIRITEL and WIYN Observations
  48. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  49. Swift Detection of GRB050509b: A short duration burst
  50. Swift Detection of the Burst GRB050509
  51. GRB 050505: early time observations
  52. GRB 050505, simultaneous optical observation
  53. GRB050505: AAVSO observations
  54. GRB050416A : 1 GHz limit from GMRT
  55. GRB050505: Optical Afterglow Candidate
  56. GRB050505 Swift-BAT refined analysis
  57. GRB 050416b:Swift XRT afterglow upper limits
  58. GRB 050416b:Swift XRT afterglow upper limits
  59. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  60. GRB050502b: Afterglow Confirmation
  61. GRB050502: P200 Observations (Correction)
  62. GRB050502: P200 Observations
  63. GRB 050504 : R band observation at Lulin observatory
  64. Swift UVOT observation of GRB 050504
  65. GRB 050504, R band Observations
  66. GRB 050502b, V band Observations
  67. GRB050504: P60 Observations
  68. GRB 050504: A long GRB detected with INTEGRAL
  69. GRB (?) 050504: IR Observations, Intriguing Source
  70. GRB 050502b, Optical observations
  71. GRB050502a: P60 Observations (Correction)
  72. GRB050502a: P60 Observations
  73. Renewal of SGR 1806-20 activity
  74. GRB050502B Swift-BAT refined analysis
  75. Swift UVOT refined analysis
  76. GRB 050502a : R band observation at Lulin observatory
  77. GRB 050502b : optical observation at Lulin observatory
  78. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  79. Swift Detection of the Bright Burst GRB050502b
  80. GRB 050502: INTEGRAL results
  81. GRB 050502: ROTSE-III Detection of Possible Counterpart
  82. Swift/BAT possible detection of a weak burst GRB050430
  83. GRB050416a: Radio Detection
  84. GRB 050422: Swift-UVOT observation
  85. GRB 050422: Swift-BAT refined analysis
  86. Swift Detection of GRB 050422
  87. GRB 050421: SLOTIS observations
  88. GRB 050421: Further Analysis of IR imaging
  89. GRB050421: Radio Observations
  90. GRB050421: Radio Observations
  91. GRB 050421: IR Observations
  92. GRB 050421: Swift-BAT refined analysis
  93. GRB050421
  94. GRB 050421: early Swift XRT analysis results
  95. GRB 050421: NIR observations
  96. GRB050421: P60 Observations
  97. GRB 050421: BOOTES-2 simultaneous optical observations
  98. GRB 050416b: Tentative Swift XRT Position
  99. GRB 050315: potential host galaxy
  100. GRB050326: analysis of the XMM-Newton observation

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