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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"

18357 results found.

  1. GRB 051221: Possible nearby cluster
  2. GRB 051221: No variability in Gemini data
  3. GRB 051221: Improved astrometry of the IR counterpart
  4. GRB 051221: Swift detection of a bright short burst
  5. Swift detection of an RS CVn flare star
  6. GRB051211A: possible optical candidate
  7. GRB 051215: near-infrared observations
  8. GRB051215 - SDSS pre-burst observations
  9. GRB 051215: Swift detection of a possible burst
  10. GRB 051211B, optical observation
  11. GRB 051213: Swift-BAT detection of a burst
  12. GRB 051211A: Swift/UVOT upper limits
  13. GRB 051211B: Swift/UVOT upper limits
  14. GRB 051211A,optical observation
  15. GRB 051211B: Swift XRT confirmation of the afterglow
  16. GRB051211B: Liverpool Telescope observation
  17. GRB051211b: P60 Observations
  18. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  19. GRB 051210: Swift/UVOT upper limits
  20. GRB 051210: Magellan Imaging
  21. GRB 051211: TAROT optical limits
  22. GRB 051211B: a possible optical detection by TAROT
  23. GRB 051211:IAC80 optical observations
  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. GRB 051109A : GAO 150cm telescope Rc-band detection
  33. GRB 051117B: R and I observations of possible host galaxy
  34. GRB 051117B,optical observation
  35. GRB 051117B: Lulin R and I band observation
  36. GRB051114: results of the Swift-XRT observation
  37. GRB 051109B : Nainital upper limits
  38. GRB 051114: Radio Observations
  39. GRB050925: analysis of the XMM-Newton observation
  40. GRB051109A optical observations
  41. GRB 051111: Radio afterglow
  42. GRB051103: Radio Observations
  43. GRB051111: Swift/UVOT Observations
  44. GRB051111: XRT preliminary analysis
  45. GRB 051109A Optical Observations
  46. GRB 051111a: IR photometry
  47. GRB 051109B. Radio Observations
  48. GRB 051109A
  49. GRB051109A - radio observations
  50. Early RAPTOR measurements of GRB 051109a - the movie.
  51. GRB 051109A: Swift-UVOT Observations
  52. GRB051109B: no UVOT source detected
  53. GRB 051109B: Super-LOTIS Observations
  54. GRB051105B: REM Optical observation
  55. GRB 051109: HET Optical Spectrum and Absorption Redshift
  56. GRB 051109: Rc and Ic observations
  57. GRB 051109: Swift-BAT refined analysis
  58. GRB 051109a: IR Photometry and Astrometry
  59. GRB051109: Swift detection of a burst
  60. GRB 051109a: IR Detections
  61. GRB051105B: Swift/XRT upper limit
  62. GRB051105B: Swift/UVOT upper limit
  63. GRB051103: optical observations
  64. GRB051103: MASTER: OT limit and host galaxy candidates
  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. XRT observations of GRB 051105A
  71. GRB 051105: Swift detection of a short burst
  72. Recent GRB UBVRcIc field photometry
  73. GRB051028 SARA Observation
  74. GRB051028: Swift/UVOT upper limits
  75. GRB051028: Swift XRT Position
  76. GRB051028:MASTER observations
  77. GRB051021B: Swift/UVOT Upper limits
  78. GRB 051021, Optical Observations
  79. GRB051012: Swift-XRT analysis
  80. GRB 051022: Swift/UVOT Upper Limits
  81. GRB051022: Radio Counterpart
  82. GRB051022: IR observations
  83. GRB051021A: Swift XRT refined analysis
  84. GRB051022: Optical Observations
  85. GRB051021b: Magellan IR Imaging
  86. GRB 051021, SMARTS optical/IR observations
  87. GRB051022: Swift XRT Position
  88. GRB 051021: P200 Ks Observations
  89. GRB 051022 (=H3950): SXC Flight Localization is Valid
  90. GRB051021: Swift/UVOT Upper Limits
  91. GRB 051022: SSO40 Optical Observations
  92. GRB051022,optical observation
  93. GRB 051021,optical observation
  94. GRB 051021B: Swift detection of a burst
  95. GRB 051021: Optical observations and candidate afterglow
  96. Swift-BAT triggered on a posible CR Shower or possible GRB
  97. Afterglow candidate of GRB 051016B observed at Lulin
  98. GRB 051016A: Swift/UVOT upper limits
  99. GRB 051016B: Swift/UVOT detection
  100. GRB 051016B,optical observation

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