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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"

26340 results found.

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

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