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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"

26504 results found.

  1. GRB050525A,optical observation
  2. GRB050525: Super-LOTIS observations
  3. GRB 050525, spectral lag pseudo-redshift
  4. GRB050306: optical afterglow not confirmed
  5. GRB 050525: BART optical observation
  6. GRB 050525A: BOOTES simultaneous optical observations
  7. GRB 050525A: Swift-BAT refined analysis
  8. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  9. GRB 050525: TAROT observations of the early afterglow
  10. INTEGRAL detection of GRB 050525
  11. GRB 050525, infrared observations
  12. GRB 050525: observatons of the optical afterglow
  13. GRB050525: ROTSE-III Refined Analysis
  14. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  15. XRF050522: Radio Observations
  16. Swift/UVOT observation of XRF 050522
  17. GRB 050509A: Further I-band imaging
  18. GRB050522,optical observation
  19. GRB050520,optical observation
  20. XRF 050522: Continued NIR P200 Monitoring
  21. RBO Observations of GRB050522
  22. Recent GRB BVRcIc field photometry
  23. GRB050520: Radio Observations
  24. XRF 050522: Swift XRT observation
  25. XRF050522, BVRcIc field photometry
  26. XRF050522: Optical Observations
  27. XRF050522: Near-infrared Observations
  28. GRB 050520: VLT/ULTRACAM observations
  29. GRB 050520: Swift XRT refined analysis
  30. XRF050509C: Chandra Afterglow Detection
  31. XRF 050509c: Swift XRT Upper Limit
  32. XRF050509c: Radio Observations
  33. GRB 050520: P200 Observations
  34. GRB050520: Liverpool Telescope follow-up
  35. GRB 050520: TAROT optical limit
  36. GRB 050520: VLT/ULTRACAM observations
  37. GRB 050509B and short GRB-SN association? (corrected)
  38. GRB 050509B and short GRB-SN association?
  39. GRB050502b: Early Observation
  40. GRB050509b, Bok telescope B-band imaging
  41. Refined Chandra analysis of GRB 050509b
  42. GRB050509b, SDSS pre-burst observations
  43. GRB 050509b: Keck/Chandra Cross-Correlation
  44. GRB 050509b: Keck/Chandra Cross-Correlation
  45. Chandra observation of GRB 050509b
  46. GRB 050509b Milagro GeV/TeV Observations
  47. GRB050509B: Optical observations at the Very Large Telescope
  48. GRB 050509b: No Optical Variability in XRT Error Circle
  49. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  50. GRB 050509c: ROTSE-III Optical Limits
  51. GRB 050505, early TAROT observation
  52. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  53. GRB050509c: REM NIR and Optical observations
  54. GRB 050505: SARA Observations
  55. GRB 050509B: Swift/XRT refined analysis
  56. GRB 050509A: Optical observations
  57. GRB050509b: Radio Observations
  58. Swift Detection of GRB050509b: A short duration burst
  59. Swift Detection of the Burst GRB050509
  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. Swift UVOT observation of GRB 050504
  72. GRB050504: P60 Observations
  73. GRB (?) 050504: IR Observations, Intriguing Source
  74. GRB 050502b, Optical observations
  75. GRB050502a: P60 Observations (Correction)
  76. GRB050502a: P60 Observations
  77. Renewal of SGR 1806-20 activity
  78. GRB 050502A: WSRT Radio Observations
  79. GRB050502B Swift-BAT refined analysis
  80. GRB050502B: I band source in XRT error circle
  81. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  82. GRB 050502: INTEGRAL results
  83. GRB 050502 - A long GRB detected with INTEGRAL
  84. GRB 050502: ROTSE-III Detection of Possible Counterpart
  85. Swift/BAT possible detection of a weak burst GRB050430
  86. GRB 050401: Rc observation
  87. GRB050416a: Radio Detection
  88. Swift Detection of GRB 050422
  89. GRB 050421: SLOTIS observations
  90. GRB 050421: Further Analysis of IR imaging
  91. GRB050421: Radio Observations
  92. GRB050421: Radio Observations
  93. GRB 050421: IR Observations
  94. GRB 050421: Swift-BAT refined analysis
  95. GRB050421
  96. GRB 050421: early Swift XRT analysis results
  97. GRB 050421: NIR observations
  98. GRB050421: P60 Observations
  99. GRB 050421: BOOTES-2 simultaneous optical observations
  100. GRB 050416b: Tentative Swift XRT Position

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