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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"

25992 results found.

  1. GRB 060108: Evidence for an XRT Position Offset
  2. GRB 060110: KAIT observations
  3. GRB 060111B: Swift XRT refined analysis
  4. GRB 060111B: MITSuME detection of optical afterglow
  5. GRB 060111B: TAROT optical observation
  6. GRB060111A: RTT150 optical observations
  7. GRB060111B: RTT150, possible host galaxy
  8. GRB 060111B: Refined analysis of the Swift-BAT burst
  9. GRB 060111(a): P60 Observations
  10. GRB 060111B: Gualba observatory limit
  11. GRB 060111B: Swift detection of a burst
  12. GRB 060111: Swift-BAT Refined Analysis
  13. GRB060111.2:_MASTER optical limit
  14. GRB 060108: VLT K-band observations
  15. GRB 060111: TAROT optical observation
  16. GRB 060111: Swift detection of a burst
  17. GRB 060110: Mitsume optical observations
  18. GRB 060110: Swift-BAT refined analysis
  19. GRB 060109: Swift-BAT refined analysis
  20. GRB 060108: z-band imaging from Gemini-North
  21. GRB 060110a: RAPTOR detection of early optical emission.
  22. GRB 060110: UKIRT K-band observations
  23. GRB 060110: IR Candidate Afterglow
  24. GRB060110, optical observation
  25. GRB 060110: Correction
  26. Correction to GRB 060109 XRT analysis
  27. GRB 050110: IR Observations
  28. GRB 060109: Refined Swift-XRT analysis
  29. GRB 060109: Swift/UVOT upper limits
  30. GRB060109, optical observation
  31. GRB 060108: ISAS early observations and near IR upper limit
  32. GRB060108: P200 Ks Observations
  33. GRB 060108: early UKIRT K-band observations
  34. GRB 060108: a dark burst?
  35. GRB 060108: Refined XRT analysis
  36. GRB 060108: VLT J-band observations
  37. GRB 060108: Mitsume optical observations
  38. GRB 060108: Swift/UVOT upper limits
  39. GRB 060105: quick look analysis of the Suzaku/XIS afterglow observation
  40. GRB060108: SDSS pre-burst observations
  41. GRB060108: Faulkes Telescope observation
  42. GRB060108, optical observation
  43. GRB 060108: Refined analysis of the Swift-BAT burst
  44. GRB060108: Swift detection of its 100th GRB
  45. GRB 060105: ISAS observations and near IR upper limit
  46. GRB 060105: Swift/UVOT upper limits
  47. GRB 060105: Mitsume optical observations
  48. GRB 060105: BAT refined analysis
  49. GRB 060105: XRT refined analysis
  50. GRB060105: Suzaku-XIS and -HXD observation plan
  51. GRB060105, optical observation
  52. GRB060105: Swift detection of a bright long burst
  53. Swift-BAT trigger 175653 is probably not a GRB
  54. GRB 060102: Swift-BAT refined analysis
  55. GRB 060102: Swift-BAT detection of a burst
  56. GRB 051221B: Optical Observations with Kuiper 1.54m
  57. GRB 051227: Likely host galaxy underlying afterglow position
  58. GRB 051227: optical observation
  59. GRB 051227: optical afterglow
  60. GRB 051227: Magellan r'-band Imaging/Astrometry
  61. GRB 051227: refined analysis of VLT images
  62. GRB 051227: P60 Observations
  63. GRB 051227: MDM Observation
  64. GRB 051227: R-band object in the XRT error circle
  65. GRB 051227: XRT refined analysis
  66. GRB 051227: Further analysis of the Swift-BAT burst
  67. GRB 051227: Refined analysis of the Swift-BAT burst
  68. GRB051227: SDSS pre-burst observations
  69. GRB 051227, optical observation
  70. GRB051117B: optical observation
  71. Konus-Wind observation of GRB 051221A
  72. GRB051221A: Suzaku WAM observation of the prompt emission
  73. GRB 051221A: MDM Optical Observations
  74. GRB051016: analysis of the XMM-Newton observation
  75. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  76. GRB 051221B: TAROT optical limits
  77. GRB 051221B: Refined analysis of the Swift-BAT burst
  78. GRB 051221B: BOOTES optical observations.
  79. Swift-BAT detection of a possible burst
  80. GRB 051221: Swift XRT refined analysis
  81. GRB 051221: Swift/UVOT upper limits
  82. GRB 051221: No variability in Gemini data
  83. GRB 051221: Improved astrometry of the IR counterpart
  84. GRB 051221: Refined analysis of the Swift-BAT short hard burst
  85. GRB 051221: Swift detection of a bright short burst
  86. Swift detection of an RS CVn flare star
  87. GRB051211A: possible optical candidate
  88. GRB 051215: near-infrared observations
  89. GRB051215 - SDSS pre-burst observations
  90. GRB 051215: Swift detection of a possible burst
  91. GRB051105: optical observations
  92. GRB 051213: Swift-BAT refined analysis
  93. GRB051211B: XRT refined analysis
  94. GRB 051211B, optical observation
  95. GRB 051211A: Swift/UVOT upper limits
  96. GRB 051211B: Swift/UVOT upper limits
  97. GRB 051211A,optical observation
  98. GRB051211B: Liverpool Telescope observation
  99. GRB051211b: P60 Observations
  100. GRB 051211A and GRB051211B: BOOTES simultaneous observations

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