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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"

26342 results found.

  1. GRB 050525: BART optical observation
  2. GRB 050525A: BOOTES simultaneous optical observations
  3. GRB 050525A: Swift-BAT refined analysis
  4. GRB050525: Optical observations
  5. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  6. Konus-Wind observation of GRB 050525
  7. GRB 050525: TAROT observations of the early afterglow
  8. INTEGRAL detection of GRB 050525
  9. GRB 050525, infrared observations
  10. GRB 050525: observatons of the optical afterglow
  11. GRB050525: ROTSE-III Refined Analysis
  12. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  13. XRF050522: Radio Observations
  14. Swift/UVOT observation of XRF 050522
  15. GRB 050509A: Further I-band imaging
  16. GRB050522,optical observation
  17. GRB050520,optical observation
  18. XRF 050522: Continued NIR P200 Monitoring
  19. RBO Observations of GRB050522
  20. Recent GRB BVRcIc field photometry
  21. GRB050520: Radio Observations
  22. XRF 050522: Swift XRT observation
  23. XRF050522, BVRcIc field photometry
  24. XRF050522: Optical Observations
  25. XRF050522: Near-infrared Observations
  26. GRB 050520: VLT/ULTRACAM observations
  27. GRB 050520: Swift XRT refined analysis
  28. XRF050509C: Chandra Afterglow Detection
  29. XRF050509c: Radio Observations
  30. GRB 050520: P200 Observations
  31. GRB 050520: TAROT optical limit
  32. GRB 050520: VLT/ULTRACAM observations
  33. XRF 050509c optical afterglow
  34. GRB 050509B and short GRB-SN association? (corrected)
  35. GRB 050509B and short GRB-SN association?
  36. GRB050502b: Early Observation
  37. GRB050509b, Bok telescope B-band imaging
  38. Refined Chandra analysis of GRB 050509b
  39. GRB050509b, SDSS pre-burst observations
  40. GRB 050509b: Keck/Chandra Cross-Correlation
  41. GRB 050509b: Keck/Chandra Cross-Correlation
  42. Chandra observation of GRB 050509b
  43. GRB 050509b: RAPTOR deep, early limits.
  44. GRB050509B: Optical observations at the Very Large Telescope
  45. GRB 050509b: No Optical Variability in XRT Error Circle
  46. GRB 050509a: Swift-BAT refined analysis
  47. GRB 050509c: ROTSE-III Optical Limits
  48. GRB 050505, early TAROT observation
  49. GRB050509c: REM NIR and Optical observations
  50. GRB 050509b: Physical Properties of the Candidate Host galaxy
  51. GRB 050505: SARA Observations
  52. GRB 050509B, Optical Observations
  53. GRB 050509B: Swift/XRT refined analysis
  54. GRB 050509b: Optical observations
  55. GRB 050509A: Optical observations
  56. GRB050509b: Radio Observations
  57. GRB 050509b: PAIRITEL and WIYN Observations
  58. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  59. Swift Detection of GRB050509b: A short duration burst
  60. Swift Detection of the Burst GRB050509
  61. GRB 050505: early time observations
  62. GRB 050505, simultaneous optical observation
  63. GRB050505: AAVSO observations
  64. GRB050416A : 1 GHz limit from GMRT
  65. GRB050505: Optical Afterglow Candidate
  66. GRB050505 Swift-BAT refined analysis
  67. GRB 050416b:Swift XRT afterglow upper limits
  68. GRB 050416b:Swift XRT afterglow upper limits
  69. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  70. GRB050502b: Afterglow Confirmation
  71. GRB050502: P200 Observations (Correction)
  72. GRB050502: P200 Observations
  73. GRB 050504 : R band observation at Lulin observatory
  74. Swift UVOT observation of GRB 050504
  75. GRB 050504, R band Observations
  76. GRB 050502b, V band Observations
  77. GRB050504: P60 Observations
  78. GRB 050504: A long GRB detected with INTEGRAL
  79. GRB (?) 050504: IR Observations, Intriguing Source
  80. GRB 050502b, Optical observations
  81. GRB050502a: P60 Observations (Correction)
  82. GRB050502a: P60 Observations
  83. Renewal of SGR 1806-20 activity
  84. GRB050502B Swift-BAT refined analysis
  85. Swift UVOT refined analysis
  86. GRB 050502a : R band observation at Lulin observatory
  87. GRB 050502b : optical observation at Lulin observatory
  88. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  89. Swift Detection of the Bright Burst GRB050502b
  90. GRB 050502: INTEGRAL results
  91. GRB 050502: ROTSE-III Detection of Possible Counterpart
  92. Swift/BAT possible detection of a weak burst GRB050430
  93. GRB050416a: Radio Detection
  94. GRB 050422: Swift-UVOT observation
  95. GRB 050422: Swift-BAT refined analysis
  96. Swift Detection of GRB 050422
  97. GRB 050421: SLOTIS observations
  98. GRB 050421: Further Analysis of IR imaging
  99. GRB050421: Radio Observations
  100. GRB050421: Radio Observations

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