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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"

42197 results found.

  1. GRB 051221: Redshift from Gemini
  2. GRB 051221: Continued fading of optical afterglow
  3. GRB 051221B: Refined analysis of the Swift-BAT burst
  4. Possible GRB 051221B: MDM Optical Detection
  5. GRB 051221A: RAPTOR Fading Counterpart Constraint
  6. GRB 051221B: BOOTES optical observations.
  7. Possible GRB 051221B: Swift XRT position
  8. GRB 051211A: Evidence This Is a Short Burst from Analysis of Spectral
  9. Swift-BAT detection of a possible burst
  10. GRB 051221: Discovery of fading optical afterglow
  11. GRB 051221: Swift XRT refined analysis
  12. GRB 051221: Possible nearby cluster
  13. GRB 051221: No variability in Gemini data
  14. GRB 051221: Gemini observations
  15. GRB 051221: Improved astrometry of the IR counterpart
  16. GRB051221: K-band source
  17. GRB 051221: Refined analysis of the Swift-BAT short hard burst
  18. GRB 051221: IR Observations at GRB+1hr
  19. GRB 051221: Swift detection of a bright short burst
  20. Refined analysis of the SWIFT J1626.6-5156
  21. Swift-BAT discovery of hard x-ray transient SWIFT J1626.6-5156
  22. GRB051211A (=H3979): Refined Analysis
  23. GRB 051211B: optical afterglow
  24. Swift detection of an RS CVn flare star
  25. GRB051211A: possible optical candidate
  26. GRB 051215: near-infrared observations
  27. GRB051215 - SDSS pre-burst observations
  28. GRB 051215: Swift detection of a possible burst
  29. GRB 051215: A short GRB in a cluster?
  30. GRB051211B: Probable radio afterglow
  31. GRB051105: optical observations
  32. GRB 051213: Swift-BAT refined analysis
  33. GRB051211B: XRT refined analysis
  34. GRB 051211B, optical observation
  35. GRB 051213: Swift-BAT detection of a burst
  36. GRB 051211a: RTT150 optical observations
  37. GRB051211B, RBO optical observations
  38. GRB 051211A: Swift/UVOT upper limits
  39. GRB 051211A,optical observation
  40. GRB 051211B: Swift XRT confirmation of the afterglow
  41. GRB051211B: Liverpool Telescope observation
  42. GRB 051211b: RTT150 optical observations
  43. GRB051211b: P60 Observations
  44. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  45. GRB 051211B: Swift XRT Observations
  46. GRB 051210: Magellan Imaging
  47. GRB 051211: TAROT optical limits
  48. GRB 051211B: a possible optical detection by TAROT
  49. GRB 051211B: a long GRB detected by INTEGRAL
  50. GRB 051211: Swift XRT upper limit
  51. GRB 051211:IAC80 optical observations
  52. HETE SXC localization of GRB 051211 (=H3979)
  53. GRB 051210: Optical imaging from Las Campanas
  54. GRB 051210: SALT detection limit
  55. GRB 051210: BAT further refined analysis of the short burst
  56. GRB 051210: Swift XRT refined analysis
  57. GRB 051210: FRAM early limit
  58. GRB051210: Swift UVOT Observation
  59. GRB 051210: A short GRB in a cluster?
  60. GRB 051210: Swift detection of a burst
  61. IPN observations of SGR1806-20
  62. An extraordinary long burst on December 3 from SGR1806-20
  63. Possible resuming of the SGR 1806-20 activity
  64. GRB051117B: optical observation
  65. GRB051111: optical observaion
  66. GRB 051127: Swift-BAT detection of a possible burst
  67. GRB051117B: Swift XRT refined analysis
  68. GRB051117b: No Swift/UVOT Detection
  69. GRB051111: Rc optical observations: correction
  70. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  71. GRB 051117A: Swift/UVOT Detection of an Afterglow
  72. GRB051111: Suzaku WAM observation of the prompt emission
  73. GRB051111: Rc optical observations
  74. GRB051008: Suzaku WAM observation of the prompt emission
  75. GRB 051109B: GAO 150cm telescope Optical limit
  76. GRB 051109A : GAO 150cm telescope Rc-band detection
  77. GRB 051021 Optical Observations
  78. GRB 051117B: MARGE Optical Limits
  79. GRB 051117A and B: Radio Observations
  80. GRB 051117B: R and I observations of possible host galaxy
  81. GRB 051117b: NIR observations
  82. GRB 051117A: Refined analysis of the Swift-BAT burst
  83. GRB 051117B: Refined analysis of the Swift-BAT burst
  84. GRB051117A : XRT refined analysis
  85. GRB 051117B,optical observation
  86. GRB 051117B: Lulin R and I band observation
  87. GRB 051117B: Optical observations
  88. GRB 051117B: ROTSE-III Optical Limits
  89. GRB051117B: Swift XRT position
  90. GRB 051117B: Swift detection of a burst
  91. GRB 051117: Swift detection of a bright burst
  92. GRB 051028 Optical Observations
  93. GRB 051109B : Nainital upper limits
  94. GRB 051114: Radio Observations
  95. GRB050925: analysis of the XMM-Newton observation
  96. GRB051109A optical observations
  97. GRB 051114: Swift-BAT detection of a short burst
  98. GRB 051111: Further spectroscopic analysis
  99. GRB 051111: Radio afterglow
  100. GRB 051113: Swift-BAT detection of a burst

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