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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"

41209 results found.

  1. GRB 070318: Swift/UVOT Continued Observations
  2. GRB 070318, Swift-BAT refined analysis
  3. GRB 070318: Swift detection of a burst with an optical afterglow
  4. GRB 070311: Late Central Engine Activity Optical Flare??
  5. GRB 070311: MDM Optical Monitoring
  6. GRB 070311: Tautenburg sees afterglow fading
  7. GRB 070311: Optical observation.
  8. GRB 070311: Optical Brightening
  9. GRB 070306: possible emission-line redshift
  10. GRB 070309: variability of the XRT afterglow candidate
  11. GRB 070311: MDM Optical Follow-up
  12. GRB 070311: RAPTOR Detection of Optical Emission
  13. GRB 070311: P60 Observations
  14. GRB 070311: MDM Optical Detection
  15. GRB 070311: MITSuME Okayama Optical Observation
  16. GRB 070311: Swift-XRT refined analysis
  17. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  18. GRB 070311: REM candidate afterglow
  19. GRB 070311: a long GRB detected by INTEGRAL
  20. GRB060901: Candidate optical afterglow
  21. GRB070309: Swift/XRT possible afterglow detection
  22. GRB 070125: Chandra X-ray Confirmation of Jet Break
  23. GRB 070306, optical observation
  24. GRB 070309: A long GRB detected by INTEGRAL
  25. GRB 070125: X-ray light curve analysis
  26. GRB 070306: NOT observations
  27. GRB 070306 Swift/UVOT refined analysis
  28. GRB070306: confirmation of near infrared afterglow
  29. GRB 070306: ART-3 early optical and near infrared constraints
  30. GRB 070306: IR observations and candidate afterglow
  31. GRB 070306, Swift-BAT refined analysis
  32. GRB 070306: XRT Team Refined Analysis
  33. GRB 070306: Optical and IR observations with KANATA
  34. GRB070306 - SDSS Pre-burst Observations
  35. GRB 070306: Swift detection of a burst
  36. GRB 070223: NIR observations at WHT
  37. GRB070227: Swift-XRT refined analysis
  38. GRB 060605 new redshift
  39. GRB 070125, deep late-time optical observation
  40. GRB 070227: optical observations
  41. GRB 070223: Optical Observations
  42. GRB 070227: optical observations
  43. GRB 070227: Swift/UVOT Upper Limits
  44. GRB 070227: TAROT La Silla observatory optical observations
  45. GRB 070227, Swift-BAT refined analysis
  46. GRB070227: possible X-ray afterglow detection
  47. GRB 070227: Swift detection of a burst in ground analysis
  48. GRB 920925C: optical afterglow candidate
  49. GRB 070224: Optical afterglow confirmation
  50. GRB070224: Swift-XRT Astrometrically Corrected Position
  51. GRB070224: Magellan Imaging Observations
  52. GRB 070224: WHT K-band imaging
  53. GRB 070224: MDM Observations
  54. GRB070224: Gemini Imaging Observations
  55. GRB070224: Swift-XRT Refined Analysis
  56. GRB 070224: optical afterglow candidate
  57. GRB 070224, Swift-BAT refined analysis
  58. GRB 070224: Swift detection of a burst
  59. GRB 070223: Optical observations
  60. RHESSI Spectrum of GRB070220
  61. GRB070223: Swift/UVOT refined analysis
  62. GRB 070223: Optical-IR observation with KANATA
  63. GRB 070223, Swift-BAT refined analysis
  64. GRB 070223: Swift-XRT Refined Analysis
  65. GRB070223 - SDSS Pre-Burst Observations
  66. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  67. GRB 070223: MDM Observations
  68. GRB070223: Swift burst
  69. Konus-Wind and Konus-A observations of GRB 070220
  70. GRB 070220: MITSuME Okayama Optical Observation
  71. GRB 070220: ART-3 Optical and NIR limits
  72. GRB 070220 Swift-BAT Refined Analysis
  73. Swift/UVOT refined analysis of GRB070220
  74. GRB 070209: Swift XRT refined analysis
  75. GRB 070220: Swift-XRT Refined Analysis
  76. GRB 070220: Observation with the KANATA 1.5m telescope
  77. GRB 070219: Gemini Observations
  78. GRB 070220 : Faulkes Telescope North optical limit
  79. GRB 070220: Swift detection of a burst
  80. GRB 070219: XRT Refined Analysis
  81. GRB 070219: I-band observations
  82. GRB 070219, Swift-BAT refined analysis
  83. GRB 070219: optical TNG observations
  84. GRB 070219: Liverpool Telescope Observations
  85. GRB 070219: ROTSE-III Optical Limits
  86. GRB070219 - SDSS Pre-Burst Observations
  87. GRB 070219: Swift detection of a burst
  88. GRB 070125 observations with the GMRT
  89. GRB 070209: Redshift of a galaxy in the error circle of XRT source
  90. GRB 060927: PROMPT Observations
  91. GRB 070129: MDM I-band Detection
  92. GRB 070125: Break in Optical Decay
  93. GRB 070209: Swift XRT analysis
  94. GRB 070201: clarification on localization and Konus-Wind spectra
  95. GRB070208: optical observations
  96. GRB 070201: Proximity of IPN annulus to M31
  97. GRB 070208: MARGE Optical Observations
  98. IPN localization of very bright long hard GRB 070207
  99. IPN localization of very intense short GRB 070201
  100. GRB 070209, Swift-BAT refined analysis of the short hard burst

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