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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"
  1. XRF 050522 detected with INTEGRAL
  2. GRB 050520: VLT/ULTRACAM observations
  3. Swift UVOT Observations of GRB 050520
  4. GRB 050520: Swift XRT refined analysis
  5. XRF050509C: Chandra Afterglow Detection
  6. XRF 050509c: Swift XRT Upper Limit
  7. XRF050509c: Radio Observations
  8. RBO Observations of GRB050520
  9. GRB 050520: P200 Observations
  10. GRB050520: Liverpool Telescope follow-up
  11. RBO Observations of GRB050520
  12. GRB 050520: TAROT optical limit
  13. GRB 050520: Swift XRT position
  14. GRB 050520: VLT/ULTRACAM observations
  15. GRB 050520: OSN optical observations
  16. GRB 050520: BART optical limit
  17. GRB 050520 - A long GRB detected with INTEGRAL
  18. No Swift-BAT Lightcurves in real-time for next 3 weeks
  19. Swift-BAT trigger 122203 is not a real GRB
  20. XRF 050509C: REM NIR and Optical refined analysis
  21. GRB 050504: Swift XRT afterglow candidate has faded
  22. XRF 050509c optical afterglow
  23. GRB 050509B and short GRB-SN association? (corrected)
  24. GRB 050509B and short GRB-SN association?
  25. GRB 050509B: Subaru Optical Observations
  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/Infared observations
  35. GRB 050509b: Swift/UVOT follow-up measurements
  36. GRB 050509b Milagro GeV/TeV Observations
  37. GRB050509B: Optical observations at the Very Large Telescope
  38. GRB 050509b: No Optical Variability in XRT Error Circle
  39. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  40. GRB 050509a: Swift-BAT refined analysis
  41. GRB 050509c: ROTSE-III Optical Limits
  42. GRB 050509B: WSRT Radio Observations
  43. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  44. GRB 050505, early TAROT observation
  45. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  46. GRB 050509b: Further Analysis of Keck LRIS Images
  47. GRB050509c: REM NIR and Optical observations
  48. GRB 050509b: Physical Properties of the Candidate Host galaxy
  49. GRB 050505: SARA Observations
  50. Swift UVOT Follow-up Observations of GRB 050509B
  51. GRB 050509B, Optical Observations
  52. GRB 050509B: Swift/XRT refined analysis
  53. GRB050509a: Swift UVOT observations
  54. GRB 050509b: Optical observations
  55. GRB 050509b: Precision Astrometry
  56. GRB 050509b: Possible Optical Counterpart
  57. Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
  58. GRB 050509A: Optical observations
  59. GRB 050509b: Optical Counterpart Candidate
  60. GRB050509b: Radio Observations
  61. GRB 050509b: PAIRITEL and WIYN Observations
  62. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  63. GRB 050509b: optical observations
  64. GRB 050509b: Swift XRT Position
  65. GRB 050509B: ROTSE-III Optical Limits
  66. Swift Detection of GRB050509b: A short duration burst
  67. GRB 050509a: Swift XRT Position
  68. Swift Detection of the Burst GRB050509
  69. Swift-BAT detection of GRB 050507
  70. GRB 050505: Keck I-band Magnitude
  71. GRB 050505: early time observations
  72. GRB 050505 - Faulkes Telescope North observations
  73. GRB 050502a: Swift XRT Upper Limit
  74. GRB 050505, simultaneous optical observation
  75. GRB050505: Infrared observations
  76. GRB 050505: Further Swift UVOT observations.
  77. GRB050505: AAVSO observations
  78. GRB050416A : 1 GHz limit from GMRT
  79. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  80. GRB 050505 UVOT
  81. GRB050505: Optical Afterglow Candidate
  82. GRB 050505: Swift XRT Position
  83. GRB050505 Swift-BAT refined analysis
  84. GRB 050502a: Optical Observations
  85. GRB 050416b:Swift XRT afterglow upper limits
  86. GRB 050416b:Swift XRT afterglow upper limits
  87. Swift-BAT detection of GRB050505
  88. GRB 050504: Swift XRT position
  89. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  90. GRB050502b: Afterglow Confirmation
  91. GRB050502: P200 Observations (Correction)
  92. GRB050502: P200 Observations
  93. GRB 050504 : R band observation at Lulin observatory
  94. Swift UVOT observation of GRB 050504
  95. GRB 050504, R band Observations
  96. GRB050504: Faulkes North optical robotic limit
  97. GRB 050502b, V band Observations
  98. GRB050504: P60 Observations
  99. GRB 050504: A long GRB detected with INTEGRAL
  100. GRB (?) 050504: IR Observations, Intriguing Source

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