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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"

19426 results found.

  1. GRB060105: Swift detection of a bright long burst
  2. GRB 060102: MDM Observation
  3. Swift-BAT trigger 175653 is probably not a GRB
  4. GRB 051221B: Optical Observations with Kuiper 1.54m
  5. GRB 051227: optical observation
  6. GRB 051227: optical afterglow
  7. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  8. GRB 051227: Magellan r'-band Imaging/Astrometry
  9. GRB 051227: refined analysis of VLT images
  10. GRB 051227: P60 Observations
  11. GRB 051227: MDM Observation
  12. GRB 051227: R-band object in the XRT error circle
  13. GRB051227: SDSS pre-burst observations
  14. GRB 051227, optical observation
  15. GRB 051227: Swift detection of a burst
  16. GRB051117B: optical observation
  17. Konus-Wind observation of GRB 051221A
  18. GRB051221A: Suzaku WAM observation of the prompt emission
  19. GRB 051221A: MDM Optical Observations
  20. GRB 051221B: ROTSE-III Optical Limits
  21. GRB 051221B: TAROT optical limits
  22. GRB 051221A: RAPTOR Fading Counterpart Constraint
  23. GRB 051221B: BOOTES optical observations.
  24. Swift-BAT detection of a possible burst
  25. GRB 051221: Swift/UVOT upper limits
  26. GRB 051221: Improved astrometry of the IR counterpart
  27. GRB 051221: Swift detection of a bright short burst
  28. Swift-BAT discovery of hard x-ray transient SWIFT J1626.6-5156
  29. Swift detection of an RS CVn flare star
  30. GRB051211A: possible optical candidate
  31. GRB 051215: near-infrared observations
  32. GRB051215 - SDSS pre-burst observations
  33. GRB 051215: Swift detection of a possible burst
  34. GRB051105: optical observations
  35. GRB 051213: Swift-BAT refined analysis
  36. GRB 051211B, optical observation
  37. GRB 051211A: Swift/UVOT upper limits
  38. GRB 051211B: Swift/UVOT upper limits
  39. GRB 051211A,optical observation
  40. GRB051211B: Liverpool Telescope observation
  41. GRB051211b: P60 Observations
  42. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  43. GRB 051210: Swift/UVOT upper limits
  44. GRB 051210: Magellan Imaging
  45. GRB 051211: TAROT optical limits
  46. GRB 051211B: a possible optical detection by TAROT
  47. GRB 051211:IAC80 optical observations
  48. GRB 051210: Optical imaging from Las Campanas
  49. GRB 051210: SALT detection limit
  50. GRB 051210: FRAM early limit
  51. GRB051210: Swift UVOT Observation
  52. GRB 051210: Swift detection of a burst
  53. An extraordinary long burst on December 3 from SGR1806-20
  54. Possible resuming of the SGR 1806-20 activity
  55. GRB051117b: No Swift/UVOT Detection
  56. GRB 051117A: Swift/UVOT Detection of an Afterglow
  57. GRB051111: Suzaku WAM observation of the prompt emission
  58. GRB051008: Suzaku WAM observation of the prompt emission
  59. GRB 051109B: GAO 150cm telescope Optical limit
  60. GRB 051117B: R and I observations of possible host galaxy
  61. GRB 051117B,optical observation
  62. GRB 051117B: ROTSE-III Optical Limits
  63. GRB051114: results of the Swift-XRT observation
  64. GRB 051109B : Nainital upper limits
  65. GRB 051114: Radio Observations
  66. GRB050925: analysis of the XMM-Newton observation
  67. GRB 051111: Radio afterglow
  68. GRB051103: Radio Observations
  69. GRB051111: Swift/UVOT Observations
  70. GRB051111: XRT preliminary analysis
  71. GRB 051109A Optical Observations
  72. GRB 051111a: IR photometry
  73. GRB 051109B. Radio Observations
  74. GRB 051109A
  75. GRB051109A - radio observations
  76. Early RAPTOR measurements of GRB 051109a - the movie.
  77. GRB 051109B: ROTSE-III Optical Limits
  78. GRB 051109A: Swift-UVOT Observations
  79. GRB051109B: no UVOT source detected
  80. GRB 051109B: Super-LOTIS Observations
  81. GRB051105B: REM Optical observation
  82. GRB 051109: PROMPT Detections
  83. GRB 051109: Rc and Ic observations
  84. GRB 051109: Swift-BAT refined analysis
  85. GRB 051109a: IR Photometry and Astrometry
  86. GRB051109: Swift detection of a burst
  87. GRB 051109a: IR Detections
  88. GRB051105B: Swift/XRT upper limit
  89. GRB051105B: Swift/UVOT upper limit
  90. GRB 051105a, observation from Naini Tal and OSN
  91. GRB 051105a: MDM Observations
  92. GRB 051105A: TNG optical observations
  93. GRB051105A: Swift/UVOT Observations
  94. GRB 051105A, radio observations
  95. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  96. XRT observations of GRB 051105A
  97. GRB 051105b: ART optical limits
  98. GRB051105B - A long GRB detected by INTEGRAL
  99. GRB 051105: Optical limit
  100. GRB 051105: Swift detection of a short burst

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