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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"
  1. GRB 051227: R-band object in the XRT error circle
  2. GRB 051227: Joint Swift-HETE Spectral Analysis
  3. GRB 051227: XRT refined analysis
  4. GRB 051227: Further analysis of the Swift-BAT burst
  5. GRB 051227: Refined analysis of the Swift-BAT burst
  6. GRB051227: SDSS pre-burst observations
  7. GRB 051227, optical observation
  8. GRB 051227: Swift detection of a burst
  9. GRB051117B: optical observation
  10. IBAS_alert n. 2719 : not a real GRB
  11. Konus-Wind observation of GRB 051221A
  12. GRB051221A: Suzaku WAM observation of the prompt emission
  13. GRB 051221A: MDM Optical Observations
  14. GRB051016: analysis of the XMM-Newton observation
  15. GRB 051221A: Detection at 251nm with Swift UVOT
  16. GRB 051221A: Chandra Afterglow Position
  17. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  18. GRB 051221B: ROTSE-III Optical Limits
  19. GRB 051221B: TAROT optical limits
  20. GRB 051221A: WSRT Radio Observations
  21. GRB 051221: Redshift from Gemini
  22. GRB 051221: Continued fading of optical afterglow
  23. GRB 051221B: Refined analysis of the Swift-BAT burst
  24. Possible GRB 051221B: MDM Optical Detection
  25. GRB 051221A: RAPTOR Fading Counterpart Constraint
  26. GRB 051221B: BOOTES optical observations.
  27. Possible GRB 051221B: Swift XRT position
  28. GRB 051211A: Evidence This Is a Short Burst from Analysis of Spectral
  29. Swift-BAT detection of a possible burst
  30. GRB 051221: Discovery of fading optical afterglow
  31. GRB 051221: Swift XRT refined analysis
  32. GRB 051221: Swift/UVOT upper limits
  33. GRB 051221: Possible nearby cluster
  34. GRB 051221: No variability in Gemini data
  35. GRB 051221: Correction to GCN #4368
  36. GRB 051221: Gemini observations
  37. GRB 051221: Improved astrometry of the IR counterpart
  38. GRB051221: K-band source
  39. GRB 051221: XRT position
  40. GRB 051221: Refined analysis of the Swift-BAT short hard burst
  41. GRB 051221: IR Observations at GRB+1hr
  42. GRB 051221: Swift detection of a bright short burst
  43. Refined analysis of the SWIFT J1626.6-5156
  44. Swift-BAT discovery of hard x-ray transient SWIFT J1626.6-5156
  45. Refined analysis of the Swift-BAT detection of the RS CVn star II Peg
  46. GRB051211A (=H3979): Refined Analysis
  47. GRB 051211B: optical afterglow
  48. Swift detection of an RS CVn flare star
  49. GRB051211A: possible optical candidate
  50. Swift Trigger 172767 is not a GRB
  51. GRB 051215: near-infrared observations
  52. GRB051215 - SDSS pre-burst observations
  53. GRB 051215: Swift detection of a possible burst
  54. GRB 051215: A short GRB in a cluster?
  55. GRB051211B: Probable radio afterglow
  56. GRB051105: optical observations
  57. GRB 051213: Swift-BAT refined analysis
  58. GRB051211B: XRT refined analysis
  59. GRB 051211B, optical observation
  60. GRB 051213: Swift-BAT detection of a burst
  61. GRB 051211a: RTT150 optical observations
  62. GRB051211B, RBO optical observations
  63. GRB 051211A: Swift/UVOT upper limits
  64. GRB 051211B: Swift/UVOT upper limits - correction
  65. GRB 051211B: Swift/UVOT upper limits
  66. GRB 051211A,optical observation
  67. GRB 051211B: Swift XRT confirmation of the afterglow
  68. GRB051211B: Liverpool Telescope observation
  69. GRB 051211b: RTT150 optical observations
  70. GRB051211b: P60 Observations
  71. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  72. GRB 051211B: Swift XRT Observations
  73. GRB 051210: Swift/UVOT upper limits
  74. GRB 051210: Magellan Imaging
  75. GRB 051211: TAROT optical limits
  76. GRB 051211B: a possible optical detection by TAROT
  77. GRB 051211B: a long GRB detected by INTEGRAL
  78. GRB 051211: Swift XRT upper limit
  79. GRB 051211:IAC80 optical observations
  80. HETE SXC localization of GRB 051211 (=H3979)
  81. GRB 051210: Optical imaging from Las Campanas
  82. GRB 051210: SALT detection limit
  83. GRB 051210: BAT further refined analysis of the short burst
  84. GRB 051210: Swift XRT refined analysis
  85. GRB 051210: FRAM early limit
  86. GRB 051210: Swift-BAT refined analysis of a short burst
  87. GRB051210: Swift UVOT Observation
  88. GRB 051210: A short GRB in a cluster?
  89. GRB 051210: Swift detection of a burst
  90. IPN observations of SGR1806-20
  91. Swift XRT positions
  92. An extraordinary long burst on December 3 from SGR1806-20
  93. IBAS Alert 2706 : not a real GRB
  94. Possible resuming of the SGR 1806-20 activity
  95. Swift UVOT Calibration Documentation
  96. GRB051117B: optical observation
  97. GRB051111: optical observaion
  98. Swift-BAT trigger 165579 is not a GRB
  99. GRB 051127: Swift-BAT detection of a possible burst
  100. GRB051117B: Swift XRT refined analysis

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