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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"

20601 results found.

  1. GRB 051221: Improved astrometry of the IR counterpart
  2. GRB 051221: Swift detection of a bright short burst
  3. Swift-BAT discovery of hard x-ray transient SWIFT J1626.6-5156
  4. Swift detection of an RS CVn flare star
  5. GRB051211A: possible optical candidate
  6. GRB 051215: near-infrared observations
  7. GRB051215 - SDSS pre-burst observations
  8. GRB 051215: Swift detection of a possible burst
  9. GRB051105: optical observations
  10. GRB 051213: Swift-BAT refined analysis
  11. GRB 051211B, optical observation
  12. GRB 051211A: Swift/UVOT upper limits
  13. GRB 051211B: Swift/UVOT upper limits
  14. GRB 051211A,optical observation
  15. GRB051211B: Liverpool Telescope observation
  16. GRB051211b: P60 Observations
  17. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  18. GRB 051210: Swift/UVOT upper limits
  19. GRB 051210: Magellan Imaging
  20. GRB 051211: TAROT optical limits
  21. GRB 051211B: a possible optical detection by TAROT
  22. GRB 051211:IAC80 optical observations
  23. GRB 051210: Optical imaging from Las Campanas
  24. GRB 051210: SALT detection limit
  25. GRB 051210: FRAM early limit
  26. GRB051210: Swift UVOT Observation
  27. GRB 051210: Swift detection of a burst
  28. An extraordinary long burst on December 3 from SGR1806-20
  29. Possible resuming of the SGR 1806-20 activity
  30. GRB051117b: No Swift/UVOT Detection
  31. GRB 051117A: Swift/UVOT Detection of an Afterglow
  32. GRB051111: Suzaku WAM observation of the prompt emission
  33. GRB051008: Suzaku WAM observation of the prompt emission
  34. GRB 051109B: GAO 150cm telescope Optical limit
  35. GRB 051117B: R and I observations of possible host galaxy
  36. GRB 051117B,optical observation
  37. GRB 051117B: ROTSE-III Optical Limits
  38. GRB051114: results of the Swift-XRT observation
  39. GRB 051109B : Nainital upper limits
  40. GRB 051114: Radio Observations
  41. GRB050925: analysis of the XMM-Newton observation
  42. GRB 051111: Radio afterglow
  43. GRB051103: Radio Observations
  44. GRB051111: Swift/UVOT Observations
  45. GRB051111: XRT preliminary analysis
  46. GRB 051109A Optical Observations
  47. GRB 051111a: IR photometry
  48. GRB 051109B. Radio Observations
  49. GRB 051109A
  50. GRB051109A - radio observations
  51. Early RAPTOR measurements of GRB 051109a - the movie.
  52. GRB 051109B: ROTSE-III Optical Limits
  53. GRB 051109A: Swift-UVOT Observations
  54. GRB051109B: no UVOT source detected
  55. GRB 051109B: Super-LOTIS Observations
  56. GRB051105B: REM Optical observation
  57. GRB 051109: PROMPT Detections
  58. GRB 051109: Rc and Ic observations
  59. GRB 051109: Swift-BAT refined analysis
  60. GRB 051109a: IR Photometry and Astrometry
  61. GRB051109: Swift detection of a burst
  62. GRB 051109a: IR Detections
  63. GRB051105B: Swift/XRT upper limit
  64. GRB051105B: Swift/UVOT upper limit
  65. GRB 051105a, observation from Naini Tal and OSN
  66. GRB 051105a: MDM Observations
  67. GRB 051105A: TNG optical observations
  68. GRB051105A: Swift/UVOT Observations
  69. GRB 051105A, radio observations
  70. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  71. XRT observations of GRB 051105A
  72. GRB 051105b: ART optical limits
  73. GRB051105B - A long GRB detected by INTEGRAL
  74. GRB 051105: Optical limit
  75. GRB 051105: Swift detection of a short burst
  76. Recent GRB UBVRcIc field photometry
  77. GRB051028 SARA Observation
  78. GRB051028: Swift/UVOT upper limits
  79. GRB051028: Swift XRT Position
  80. GRB051021B: Swift/UVOT Upper limits
  81. GRB 051021, Optical Observations
  82. GRB 051022, refined optical astrometry
  83. GRB051012: Swift-XRT analysis
  84. GRB 051022: Swift/UVOT Upper Limits
  85. GRB051022: Radio Counterpart
  86. GRB051022: IR observations
  87. GRB051021A: Swift XRT refined analysis
  88. Konus-Wind observation of GRB 051022
  89. GRB051022: Optical Observations
  90. GRB 051021: PROMPT RcIc Observations
  91. GRB051021b: Magellan IR Imaging
  92. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  93. GRB051022: Swift XRT Position
  94. GRB 051021: P200 Ks Observations
  95. GRB 051021: MDM Upper Limit
  96. GRB 051022 (=H3950): SXC Flight Localization is Valid
  97. GRB051021: Swift/UVOT Upper Limits
  98. GRB 051022: SSO40 Optical Observations
  99. GRB051022,optical observation
  100. GRB 051022A: ROTSE-III Optical Limits

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