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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"

25905 results found.

  1. GRB 051221B: Optical Observations with Kuiper 1.54m
  2. GRB 051227: Likely host galaxy underlying afterglow position
  3. GRB 051227: optical observation
  4. GRB051221B: Radio observations
  5. GRB 051221A: VLA Radio Observations
  6. GRB051227: Radio Observations
  7. GRB 051227: optical afterglow
  8. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  9. GRB 051227: Gemini observations
  10. GRB 051227: Keck Spectroscopy
  11. GRB 051227: Magellan r'-band Imaging/Astrometry
  12. GRB 051227: refined analysis of VLT images
  13. GRB 051227: P60 Observations
  14. GRB 051227: MDM Observation
  15. GRB 051227: R-band object in the XRT error circle
  16. GRB 051227: Joint Swift-HETE Spectral Analysis
  17. GRB 051227: XRT refined analysis
  18. GRB 051227: Further analysis of the Swift-BAT burst
  19. GRB 051227: Refined analysis of the Swift-BAT burst
  20. GRB051227: SDSS pre-burst observations
  21. GRB 051227: Swift detection of a burst
  22. GRB051117B: optical observation
  23. Konus-Wind observation of GRB 051221A
  24. GRB051221A: Suzaku WAM observation of the prompt emission
  25. GRB 051221A: MDM Optical Observations
  26. GRB051016: analysis of the XMM-Newton observation
  27. GRB 051221A: Detection at 251nm with Swift UVOT
  28. GRB 051221A: Chandra Afterglow Position
  29. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  30. GRB 051221B: ROTSE-III Optical Limits
  31. GRB 051221B: TAROT optical limits
  32. GRB 051221A: WSRT Radio Observations
  33. GRB 051221: Redshift from Gemini
  34. GRB 051221: Continued fading of optical afterglow
  35. GRB 051221B: Refined analysis of the Swift-BAT burst
  36. Possible GRB 051221B: MDM Optical Detection
  37. GRB 051221A: RAPTOR Fading Counterpart Constraint
  38. GRB 051221B: BOOTES optical observations.
  39. Possible GRB 051221B: Swift XRT position
  40. GRB 051211A: Evidence This Is a Short Burst from Analysis of Spectral
  41. Swift-BAT detection of a possible burst
  42. GRB 051221: Discovery of fading optical afterglow
  43. GRB 051221: Swift XRT refined analysis
  44. GRB 051221: Swift/UVOT upper limits
  45. GRB 051221: Possible nearby cluster
  46. GRB 051221: No variability in Gemini data
  47. GRB 051221: Gemini observations
  48. GRB 051221: Improved astrometry of the IR counterpart
  49. GRB051221: K-band source
  50. GRB 051221: XRT position
  51. GRB 051221: Refined analysis of the Swift-BAT short hard burst
  52. GRB 051221: Swift detection of a bright short burst
  53. Refined analysis of the SWIFT J1626.6-5156
  54. Swift-BAT discovery of hard x-ray transient SWIFT J1626.6-5156
  55. Refined analysis of the Swift-BAT detection of the RS CVn star II Peg
  56. GRB 051211B: optical afterglow
  57. Swift detection of an RS CVn flare star
  58. GRB051211A: possible optical candidate
  59. Swift Trigger 172767 is not a GRB
  60. GRB 051215: Swift detection of a possible burst
  61. GRB 051215: A short GRB in a cluster?
  62. GRB051211B: Probable radio afterglow
  63. GRB051105: optical observations
  64. GRB 051213: Swift-BAT refined analysis
  65. GRB051211B: XRT refined analysis
  66. GRB 051213: Swift-BAT detection of a burst
  67. GRB 051211A: Swift/UVOT upper limits
  68. GRB 051211B: Swift/UVOT upper limits - correction
  69. GRB 051211B: Swift/UVOT upper limits
  70. GRB 051211B: Swift XRT confirmation of the afterglow
  71. GRB051211B: Liverpool Telescope observation
  72. GRB 051211b: RTT150 optical observations
  73. GRB051211b: P60 Observations
  74. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  75. GRB 051211B: Swift XRT Observations
  76. GRB 051210: Swift/UVOT upper limits
  77. GRB 051211B: a possible optical detection by TAROT
  78. GRB 051211: Swift XRT upper limit
  79. GRB 051210: Optical imaging from Las Campanas
  80. GRB 051210: SALT detection limit
  81. GRB 051210: BAT further refined analysis of the short burst
  82. GRB 051210: Swift XRT refined analysis
  83. GRB 051210: FRAM early limit
  84. GRB 051210: Swift-BAT refined analysis of a short burst
  85. GRB051210: Swift UVOT Observation
  86. GRB 051210: A short GRB in a cluster?
  87. GRB 051210: Swift detection of a burst
  88. IPN observations of SGR1806-20
  89. Swift XRT positions
  90. An extraordinary long burst on December 3 from SGR1806-20
  91. Swift UVOT Calibration Documentation
  92. GRB051117B: optical observation
  93. Swift-BAT trigger 165579 is not a GRB
  94. GRB 051127: Swift-BAT detection of a possible burst
  95. GRB051117B: Swift XRT refined analysis
  96. GRB051117b: No Swift/UVOT Detection
  97. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  98. GRB 051117A: Swift/UVOT Detection of an Afterglow
  99. GRB051111: Rc optical observations
  100. GRB051008: Suzaku WAM observation of the prompt emission

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