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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"

28091 results found.

  1. GRB 051210: Magellan Imaging
  2. GRB 051211: TAROT optical limits
  3. GRB 051211B: a possible optical detection by TAROT
  4. GRB 051211:IAC80 optical observations
  5. GRB 051210: SALT detection limit
  6. GRB 051210: Swift XRT refined analysis
  7. GRB 051210: FRAM early limit
  8. GRB 051210: Swift-BAT refined analysis of a short burst
  9. GRB051210: Swift UVOT Observation
  10. GRB 051210: Swift detection of a burst
  11. An extraordinary long burst on December 3 from SGR1806-20
  12. Possible resuming of the SGR 1806-20 activity
  13. GRB051117B: Swift XRT refined analysis
  14. GRB051117b: No Swift/UVOT Detection
  15. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  16. GRB 051117A: Swift/UVOT Detection of an Afterglow
  17. GRB051111: Suzaku WAM observation of the prompt emission
  18. GRB051008: Suzaku WAM observation of the prompt emission
  19. GRB 051117B: R and I observations of possible host galaxy
  20. GRB 051117A: Refined analysis of the Swift-BAT burst
  21. GRB 051117B: Refined analysis of the Swift-BAT burst
  22. GRB 051117B,optical observation
  23. GRB 051117B: Lulin R and I band observation
  24. GRB051114: results of the Swift-XRT observation
  25. GRB 051109B : Nainital upper limits
  26. GRB 051114: Radio Observations
  27. GRB 051114: Swift-BAT refined analysis
  28. GRB050925: analysis of the XMM-Newton observation
  29. GRB 051114: Swift-BAT detection of a short burst
  30. GRB 051111: Further spectroscopic analysis
  31. GRB 051111: Radio afterglow
  32. GRB 051113: Swift-BAT refined analysis
  33. GRB051103: Radio Observations
  34. GRB/SGR 050925: XMM-Newton ToO observation
  35. GRB051111: Swift/UVOT Observations
  36. GRB051111: XRT preliminary analysis
  37. GRB 051111: Swift-BAT refined analysis
  38. GRB 051109A Optical Observations
  39. GRB 051111A : Lulin BVRI multi band afterglow observation
  40. GRB051111a: SARA Observations
  41. GRB 051111a: IR photometry
  42. GRB 051109B. Radio Observations
  43. GRB 051109A
  44. GRB051109A - radio observations
  45. GRB 051109B: Swift-BAT refined analysis
  46. GRB 051109A: Swift-UVOT Observations
  47. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  48. GRB051109B: no UVOT source detected
  49. GRB051109B: XRT refined analysis
  50. GRB 051109B : Lulin Optical Observations
  51. GRB 051109A : Lulin BVRI Optical afterglow observation
  52. GRB051109A: further steepening in the X-ray light curve
  53. GRB051109A: XRT refined analysis
  54. GRB 051109B: Super-LOTIS Observations
  55. GRB051105B: REM Optical observation
  56. GRB 051109B: Swift detection of a burst
  57. GRB 051109: Rc and Ic observations
  58. GRB 051109: Swift-BAT refined analysis
  59. GRB 051109a: IR Photometry and Astrometry
  60. GRB051109: Swift detection of a burst
  61. GRB 051109a: IR Detections
  62. GRB051105B: Swift/XRT upper limit
  63. GRB051105B: Swift/UVOT upper limit
  64. GRB051103: MASTER: OT limit and host galaxy candidates
  65. GRB051028: Swift-XRT refined analysis
  66. GRB 051105a, observation from Naini Tal and OSN
  67. GRB 051105a: MDM Observations
  68. GRB 051105A: TNG optical observations
  69. GRB051105A: Swift/UVOT Observations
  70. GRB 051105A, radio observations
  71. GRB051103:_MASTER_optical_observations
  72. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  73. GRB 051105A, optical observations
  74. XRT observations of GRB 051105A
  75. GRB 051105b: ART optical limits
  76. GRB 051105B (INTEGRAL 2701): Optical observation
  77. GRB 051105: Swift detection of a short burst
  78. Recent GRB UBVRcIc field photometry
  79. GRB051028 SARA Observation
  80. GRB051028: optical observations
  81. GRB051028: Swift/UVOT upper limits
  82. GRB051028: Swift XRT Position
  83. GRB051028:MASTER observations
  84. GRB051021B: Swift/UVOT Upper limits
  85. GRB 051021, Optical Observations
  86. GRB 051022: XRT Refined Spectral and Temporal Analysis
  87. GRB051012: Swift-XRT analysis
  88. GRB051021B: Swift XRT refined analysis
  89. GRB 051022, mm counterpart
  90. GRB 051022: Swift/UVOT Upper Limits
  91. GRB051022: Radio Counterpart
  92. GRB051022: IR observations
  93. GRB051021A: Swift XRT refined analysis
  94. GRB051022: Optical Observations
  95. GRB051021b: Magellan IR Imaging
  96. GRB 051021, SMARTS optical/IR observations
  97. GRB051022: Swift XRT Position
  98. GRB 051021: P200 Ks Observations
  99. GRB 051022 (=H3950): SXC Flight Localization is Valid
  100. GRB051021: Swift/UVOT Upper Limits

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