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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"

26500 results found.

  1. GRB 050525: BART optical observation
  2. GRB 050525A: BOOTES simultaneous optical observations
  3. GRB 050525A: Swift-BAT refined analysis
  4. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  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. XRF 050509c: Swift XRT Upper Limit
  28. XRF050509c: Radio Observations
  29. GRB 050520: P200 Observations
  30. GRB050520: Liverpool Telescope follow-up
  31. GRB 050520: TAROT optical limit
  32. GRB 050520: VLT/ULTRACAM observations
  33. GRB 050509B and short GRB-SN association? (corrected)
  34. GRB 050509B and short GRB-SN association?
  35. GRB050502b: Early Observation
  36. GRB050509b, Bok telescope B-band imaging
  37. Refined Chandra analysis of GRB 050509b
  38. GRB050509b, SDSS pre-burst observations
  39. GRB 050509b: Keck/Chandra Cross-Correlation
  40. GRB 050509b: Keck/Chandra Cross-Correlation
  41. Chandra observation of GRB 050509b
  42. GRB 050509b Milagro GeV/TeV Observations
  43. GRB050509B: Optical observations at the Very Large Telescope
  44. GRB 050509b: No Optical Variability in XRT Error Circle
  45. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  46. GRB 050509c: ROTSE-III Optical Limits
  47. GRB 050505, early TAROT observation
  48. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  49. GRB050509c: REM NIR and Optical observations
  50. GRB 050505: SARA Observations
  51. GRB 050509B: Swift/XRT refined analysis
  52. GRB 050509A: Optical observations
  53. GRB050509b: Radio Observations
  54. Swift Detection of GRB050509b: A short duration burst
  55. Swift Detection of the Burst GRB050509
  56. GRB 050505, simultaneous optical observation
  57. GRB050505: AAVSO observations
  58. GRB050416A : 1 GHz limit from GMRT
  59. GRB050505: Optical Afterglow Candidate
  60. GRB050505 Swift-BAT refined analysis
  61. GRB 050416b:Swift XRT afterglow upper limits
  62. GRB 050416b:Swift XRT afterglow upper limits
  63. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  64. GRB050502b: Afterglow Confirmation
  65. GRB050502: P200 Observations (Correction)
  66. GRB050502: P200 Observations
  67. Swift UVOT observation of GRB 050504
  68. GRB050504: P60 Observations
  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. GRB 050502A: WSRT Radio Observations
  75. GRB050502B Swift-BAT refined analysis
  76. GRB050502B: I band source in XRT error circle
  77. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  78. GRB 050502: INTEGRAL results
  79. GRB 050502 - A long GRB detected with INTEGRAL
  80. GRB 050502: ROTSE-III Detection of Possible Counterpart
  81. Swift/BAT possible detection of a weak burst GRB050430
  82. GRB 050401: Rc observation
  83. GRB050416a: Radio Detection
  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. GRB 050412: Chandra observations

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