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

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