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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"

30652 results found.

  1. Refined Chandra analysis of GRB 050509b
  2. GRB050509b, SDSS pre-burst observations
  3. GRB 050509b: Keck/Chandra Cross-Correlation
  4. Chandra observation of GRB 050509b
  5. GRB 050509b: RAPTOR deep, early limits.
  6. GRB050509B: Optical/Infared observations
  7. GRB 050509b: Swift/UVOT follow-up measurements
  8. GRB 050509b Milagro GeV/TeV Observations
  9. GRB050509B: Optical observations at the Very Large Telescope
  10. GRB 050509b: No Optical Variability in XRT Error Circle
  11. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  12. GRB 050509a: Swift-BAT refined analysis
  13. GRB 050509c: ROTSE-III Optical Limits
  14. GRB 050509B: WSRT Radio Observations
  15. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  16. GRB 050505, early TAROT observation
  17. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  18. GRB 050509b: Further Analysis of Keck LRIS Images
  19. GRB 050509b: Physical Properties of the Candidate Host galaxy
  20. GRB 050505: SARA Observations
  21. Swift UVOT Follow-up Observations of GRB 050509B
  22. GRB 050509B, Optical Observations
  23. GRB 050509B: Swift/XRT refined analysis
  24. GRB050509a: Swift UVOT observations
  25. GRB 050509b: Optical observations
  26. GRB 050509b: Precision Astrometry
  27. GRB 050509b: Possible Optical Counterpart
  28. GRB 050509A: Optical observations
  29. GRB 050509b: Optical Counterpart Candidate
  30. GRB050509b: Radio Observations
  31. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  32. GRB 050509b: optical observations
  33. GRB 050509b: Swift XRT Position
  34. GRB 050509B: ROTSE-III Optical Limits
  35. GRB 050509a: Swift XRT Position
  36. GRB 050505: Keck I-band Magnitude
  37. GRB 050505: early time observations
  38. GRB 050502a: Swift XRT Upper Limit
  39. GRB 050505, simultaneous optical observation
  40. GRB050505: Infrared observations
  41. GRB 050505: Further Swift UVOT observations.
  42. GRB050505: AAVSO observations
  43. GRB050416A : 1 GHz limit from GMRT
  44. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  45. GRB 050505 UVOT
  46. GRB050505: Optical Afterglow Candidate
  47. GRB 050505: Swift XRT Position
  48. GRB050505 Swift-BAT refined analysis
  49. GRB 050502a: Optical Observations
  50. GRB 050416b:Swift XRT afterglow upper limits
  51. GRB 050416b:Swift XRT afterglow upper limits
  52. Swift-BAT detection of GRB050505
  53. GRB 050504: Swift XRT position
  54. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  55. GRB050502b: Afterglow Confirmation
  56. GRB050502: P200 Observations (Correction)
  57. GRB050502: P200 Observations
  58. GRB 050504 : R band observation at Lulin observatory
  59. Swift UVOT observation of GRB 050504
  60. GRB 050504, R band Observations
  61. GRB050504: P60 Observations
  62. GRB 050502b, Optical observations
  63. GRB050502a: P60 Observations (Correction)
  64. GRB050502a: P60 Observations
  65. GRB 050502a: RBO Observations
  66. GRB 050502A: WSRT Radio Observations
  67. GRB050502A: Optical Observations
  68. GRB050502B Swift-BAT refined analysis
  69. GRB050502B: I band source in XRT error circle
  70. Swift UVOT refined analysis
  71. Retraction of Swift-BAT trigger 116145
  72. GRB 050502a : R band observation at Lulin observatory
  73. GRB 050502b : optical observation at Lulin observatory
  74. GRB 050502b: Swift XRT Position
  75. GRB050502B: Optical Limits from ANU 1m
  76. GRB 050502: INTEGRAL results
  77. GRB050502: ANU 1m optical Observations
  78. GRB 050502: Confirmed variability of the afterglow candidate +
  79. GRB 050502: PAIRITEL IR Observations
  80. GRB 050502: ROTSE-III Detection of Possible Counterpart
  81. Swift-BAT Trigger 115881 is not a real GRB
  82. Swift/BAT possible detection of a weak burst GRB050430
  83. GRB 050401: Rc observation
  84. GRB050416a: Radio Detection
  85. GRB 050422: Swift-UVOT observation
  86. GRB 050422: Swift-BAT refined analysis
  87. GRB 050422: Swift XRT Position
  88. GRB 050421: NIR observations
  89. GRB 050416: Optical/NIR observations
  90. GRB 050421: SLOTIS observations
  91. GRB 050421: Further Analysis of IR imaging
  92. GRB050421: Radio Observations
  93. GRB050421: Radio Observations
  94. GRB 050421: Swift-UVOT observation
  95. GRB 050421: IR Observations
  96. GRB 050421: Swift-BAT refined analysis
  97. GRB 050421: ROTSE-III Optical Limits
  98. GRB 050421: NIR observations re-examination
  99. GRB050421
  100. GRB 050421: early Swift XRT analysis results

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