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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"

33671 results found.

  1. GRB050520: Liverpool Telescope follow-up
  2. GRB 050520: TAROT optical limit
  3. GRB 050520: Swift XRT position
  4. GRB 050520: VLT/ULTRACAM observations
  5. GRB 050520: OSN optical observations
  6. GRB 050520: BART optical limit
  7. GRB 050520 - A long GRB detected with INTEGRAL
  8. Swift-BAT trigger 122203 is not a real GRB
  9. GRB 050504: Swift XRT afterglow candidate has faded
  10. XRF 050509c optical afterglow
  11. GRB 050509B and short GRB-SN association? (corrected)
  12. GRB 050509B and short GRB-SN association?
  13. GRB 050509B: Subaru Optical Observations
  14. GRB050502b: Early Observation
  15. GRB050509b, Bok telescope B-band imaging
  16. Refined Chandra analysis of GRB 050509b
  17. GRB050509b, SDSS pre-burst observations
  18. GRB 050509b: Keck/Chandra Cross-Correlation
  19. GRB 050509b: Keck/Chandra Cross-Correlation
  20. Chandra observation of GRB 050509b
  21. GRB 050509b: RAPTOR deep, early limits.
  22. GRB050509B: Optical/Infared observations
  23. GRB 050509b: Swift/UVOT follow-up measurements
  24. GRB 050509b Milagro GeV/TeV Observations
  25. GRB050509B: Optical observations at the Very Large Telescope
  26. GRB 050509b: No Optical Variability in XRT Error Circle
  27. GRB 050509a: Swift-BAT refined analysis
  28. GRB 050509c: ROTSE-III Optical Limits
  29. GRB 050509B: WSRT Radio Observations
  30. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  31. GRB 050505, early TAROT observation
  32. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  33. GRB 050509b: Further Analysis of Keck LRIS Images
  34. GRB050509c: REM NIR and Optical observations
  35. GRB 050509b: Physical Properties of the Candidate Host galaxy
  36. GRB 050505: SARA Observations
  37. Swift UVOT Follow-up Observations of GRB 050509B
  38. GRB 050509B, Optical Observations
  39. GRB 050509B: Swift/XRT refined analysis
  40. GRB 050509b: Optical observations
  41. GRB 050509b: Precision Astrometry
  42. GRB 050509b: Possible Optical Counterpart
  43. Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
  44. GRB 050509A: Optical observations
  45. GRB 050509b: Optical Counterpart Candidate
  46. GRB 050509b: PAIRITEL and WIYN Observations
  47. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  48. GRB 050509b: optical observations
  49. GRB 050509b: Swift XRT Position
  50. GRB 050509B: ROTSE-III Optical Limits
  51. GRB 050509a: Swift XRT Position
  52. Swift-BAT detection of GRB 050507
  53. GRB 050505: Keck I-band Magnitude
  54. GRB 050505: early time observations
  55. GRB 050505 - Faulkes Telescope North observations
  56. GRB 050502a: Swift XRT Upper Limit
  57. GRB 050505, simultaneous optical observation
  58. GRB 050505: Further Swift UVOT observations.
  59. GRB050505: AAVSO observations
  60. GRB050416A : 1 GHz limit from GMRT
  61. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  62. GRB 050505 UVOT
  63. GRB050505: Optical Afterglow Candidate
  64. GRB 050505: Swift XRT Position
  65. GRB 050502a: Optical Observations
  66. GRB 050416b:Swift XRT afterglow upper limits
  67. GRB 050416b:Swift XRT afterglow upper limits
  68. GRB 050504: Swift XRT position
  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. GRB 050502a: RBO Observations
  83. GRB 050502A: WSRT Radio Observations
  84. GRB050502A: Optical Observations
  85. Swift UVOT refined analysis
  86. Retraction of Swift-BAT trigger 116145
  87. GRB 050502a : R band observation at Lulin observatory
  88. GRB 050502b : optical observation at Lulin observatory
  89. GRB 050502b: Swift XRT Position
  90. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  91. GRB 050502: INTEGRAL results
  92. GRB050502: ANU 1m optical Observations
  93. GRB 050502: Confirmed variability of the afterglow candidate +
  94. GRB 050502: PAIRITEL IR Observations
  95. GRB050502 - Correction on the Optical Candidate from the Liverpool
  96. GRB 050502 - A long GRB detected with INTEGRAL
  97. GRB 050502: ROTSE-III Detection of Possible Counterpart
  98. Swift-BAT Trigger 115881 is not a real GRB
  99. Swift/BAT possible detection of a weak burst GRB050430
  100. GRB 050401: Rc observation

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