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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"

7405 results found.

  1. GRB 051105: Optical limit
  2. GRB051016B: optical observation
  3. GRB051028: optical observations
  4. GRB051028: confirmation of the afterglow
  5. GRB051028: WHT optical candidate
  6. GRB051028:MASTER observations
  7. GRB051028:MASTER optical observations
  8. GRB 051022: XRT Refined Spectral and Temporal Analysis
  9. GRB051021A: Swift XRT refined analysis
  10. GRB051021b: Magellan IR Imaging
  11. GRB 051021, SMARTS optical/IR observations
  12. GRB 051021: Optical observations
  13. GRB 051021: Optical observations and candidate afterglow
  14. GRB051021.63
  15. GRB051021.6: MASTER optical observation
  16. GRB 051016b: Optical limit
  17. Afterglow candidate of GRB 051016B observed at Lulin
  18. GRB 051016b: Gemini Near IR Observations
  19. GRB050805A: Rc optical observations
  20. GRB051008: optical candidate
  21. GRB051011: MASTER optical observation
  22. GRB051008 - Swift UVOT upper limits
  23. GRB 051008, optical observations
  24. GRB 051008: Swift UVOT Candidate
  25. grb test
  26. GRB050925: Faulkes Telescope North R-band limit
  27. GRB 050911, optical content of Swift/XRT error box
  28. GRB050911: Swift-XRT position
  29. GRB050908 : Swift-XRT refined analysis
  30. GRB 050908: Optical observations
  31. Gemini Spectroscopy of GRB 050908
  32. GRB 050908: P60 Confirmation of Optical Afterglow
  33. GRB 050908: Optical Observations
  34. GRB 050904: Subaru Optical Spectroscopy
  35. GRB 050906: Swift-BAT refined analysis
  36. GRB 050904: Keck I-band Imaging
  37. GRB 050904: TAROT optical measurements
  38. GRB 050827: Optical Limit
  39. GRB 050826 : Lulin R band observation
  40. GRB 050826: Optical Candidate
  41. GRB050824: MASTER final analysis of the OT observations
  42. GRB050824, I-band imaging
  43. GRB 050824: XRT refined analysis and possible afterglow detection
  44. GRB 050824: BAT refined analysis of a soft weak burst
  45. GRB050824: MASTER:OT decay
  46. GRB 050824 optical candidate
  47. GRB050814: P60 Optical Afterglow Candidate
  48. GRB 050813: Non-fading of afterglow candidate
  49. GRB050803: CrAO optical observations, no OT candidate
  50. GRB050802: TNG optical observations
  51. GRB 050803: RTT150 optical observations
  52. GRB050803: CrAO optical observations, possible OT candidate
  53. GRB 050803, optical observations
  54. GRB 050802: Swift/UVOT optical and UV detections
  55. GRB050801: Optical photometry and decay index
  56. GRB 050730, SMARTS optical/IR afterglow observations
  57. GRB050730: Liverpool Telescope optical observations
  58. GRB 050730, optical candidate
  59. GRB 050721a: Optical Observations
  60. GRB 050714a: Refined XRT analysis and afterglow confirmation
  61. GRB 050716; J-band observations
  62. GRB 050716 - UKIRT identification of candidate afterglow
  63. GRB 050716: Refined XRT analysis.
  64. GRB050716: Faulkes North Telescope observation
  65. GRB 050714B: refined XRT analysis
  66. GRB 050714B: candidate afterglow does not fade
  67. GRB 050709: optical afterglow candidate
  68. GRB 050714, R-band candidate
  69. GRB 050709: Spectroscopy
  70. GRB050713B: Faulkes North Telescope observation
  71. RBO RI observations of GRB 050713A
  72. GRB050709: Candidate X-ray Afterglow from Chandra
  73. GRB 050713: ARC NIR Detections and Identification of Fading
  74. GRB050712: UVOT candidate optical counterpart
  75. GRB 050626: Swift XRT observations
  76. GRB 050607: MDM Observations
  77. GRB 050603: Swift XRT Position
  78. GRB050528: BOOTES optical candidate (retraction)
  79. GRB050528: BOOTES optical candidate
  80. Possible GRB050528: no candidate from Liverpool Telescope
  81. GRB050525: Super-LOTIS observations
  82. GRB 050525a: Gemini/GMOS Spectra
  83. GRB050306: optical afterglow not confirmed
  84. GRB050525: Optical observations
  85. GRB 050525: Optical observation
  86. XRF050522: NIR observations of XRT candidate
  87. XRF 050522: Swift XRT refined analysis
  88. XRF050522: Optical Observations
  89. GRB050520: Liverpool Telescope follow-up
  90. XRF 050509C: REM NIR and Optical refined analysis
  91. GRB 050504: Swift XRT afterglow candidate has faded
  92. Chandra observation of GRB 050509b
  93. GRB 050509b: RAPTOR deep, early limits.
  94. GRB 050509b: Further Analysis of Keck LRIS Images
  95. GRB 050509b: Physical Properties of the Candidate Host galaxy
  96. GRB 050509B, Optical Observations
  97. GRB 050509b: Optical observations
  98. GRB 050509b: Optical Counterpart Candidate
  99. GRB 050505 - Faulkes Telescope North observations
  100. GRB050505: Infrared observations

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