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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"

35957 results found.

  1. GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
  2. Konus-Wind and Konus-A observations of GRB 070402
  3. IPN triangulation of GRB070402
  4. GRB 070328: Suzaku WAM observation of the prompt emission
  5. GRB 070330, Swift-BAT refined analysis
  6. GRB 070330, SMARTS optical/IR observations
  7. GRB 070330: TAROT La Silla observatory optical observations
  8. GRB 070330: Swift-XRT refined analysis
  9. GRB 070330 - Watcher Observations
  10. GRB 070330: Swift detection of a burst
  11. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  12. Konus-Wind observation of GRB 070328
  13. GRB 070328: Swift/UVOT Upper Limits
  14. long burst from SGR 1806-20 detected on March 26
  15. GRB 070328: Swift/XRT Refined Analysis
  16. GRB 070328 : Suzaku ToO follow up starts
  17. GRB 070328, Swift-BAT refined analysis
  18. GRB 070328: Swift detection of a burst
  19. GRB070220: optical observations
  20. GRB070208: optical observations
  21. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  22. GRB 070311, deep optical photometry
  23. Short-Hard GRB 070209: PROMPT Observations
  24. GRB 070318: Gemini + Magellan spectra
  25. GRB 070318: absorption-line redshift
  26. GRB070318: Swift-XRT refined analysis
  27. GRB 070318: Swift/UVOT Continued Observations
  28. GRB 070318, Swift-BAT refined analysis
  29. IBAS Alert n. 4176: not a GRB
  30. GRB 070318: Swift detection of a burst with an optical afterglow
  31. GRB 070311: Late Central Engine Activity Optical Flare??
  32. GRB 070311: MDM Optical Monitoring
  33. VLA observation of GRB 070311
  34. GRB 070311: Tautenburg sees afterglow fading
  35. IBAS Alert n. 4169: not a GRB
  36. GRB 070311: Optical observation.
  37. GRB 070311: Optical Brightening
  38. GRB 070306: possible emission-line redshift
  39. GRB 070311: SARA upper limit
  40. GRB 070309: variability of the XRT afterglow candidate
  41. GRB 070311: MDM Optical Follow-up
  42. GRB 070311: RAPTOR Detection of Optical Emission
  43. GRB070311: FRAM early follow-up limit
  44. GRB 070311: P60 Observations
  45. GRB 070311: MDM Optical Detection
  46. GRB 070311: Swift/UVOT Upper Limits
  47. GRB 070311: MITSuME Okayama Optical Observation
  48. GRB 070311: Swift-XRT refined analysis
  49. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  50. GRB 070311: REM candidate afterglow
  51. GRB 070311: a long GRB detected by INTEGRAL
  52. GRB060901: Candidate optical afterglow
  53. GRB070309: Swift/XRT possible afterglow detection
  54. GRB 070125: Chandra X-ray Confirmation of Jet Break
  55. GRB 070309: Swift/UVOT Upper Limits
  56. GRB 070306, optical observation
  57. Swift UVOT Finding Charts for GRB 070309
  58. GRB 070309: A long GRB detected by INTEGRAL
  59. GRB 070125: X-ray light curve analysis
  60. VLA observation of GRB 070306
  61. IBAS Alert 4162: Not a GRB
  62. GRB 070306: NOT observations
  63. GRB 070306 Swift/UVOT refined analysis
  64. GRB070306: confirmation of near infrared afterglow
  65. GRB 070306: ART-3 early optical and near infrared constraints
  66. GRB 070306: IR observations and candidate afterglow
  67. GRB 070306, Swift-BAT refined analysis
  68. GRB 070306: XRT Team Refined Analysis
  69. GRB 070306: Optical and IR observations with KANATA
  70. GRB070306 - SDSS Pre-burst Observations
  71. GRB 070306: Swift detection of a burst
  72. GRB 070223: NIR observations at WHT
  73. GRB070227: Swift-XRT refined analysis
  74. GRB 060605 new redshift
  75. GRB 070125, deep late-time optical observation
  76. VLA observation of GRB 070224
  77. GRB 070227: optical observations
  78. GRB 070223: Optical Observations
  79. GRB 070227: optical observations
  80. GRB 070227: Swift/UVOT Upper Limits
  81. GRB 070227: TAROT La Silla observatory optical observations
  82. GRB 070227, Swift-BAT refined analysis
  83. GRB070227: possible X-ray afterglow detection
  84. GRB 070227: Swift detection of a burst in ground analysis
  85. GRB 920925C: optical afterglow candidate
  86. GRB 070224: Optical afterglow confirmation
  87. IBAS Alert n. 4144: not a GRB
  88. GRB 070224: Swift/UVOT Upper Limits
  89. VLA observation of GRB 070223
  90. VLA observation of GRB 070220
  91. GRB070224: Magellan Imaging Observations
  92. GRB 070224: WHT K-band imaging
  93. GRB 070224: MDM Observations
  94. GRB 070224: SARA upper limit
  95. GRB070224: Swift-XRT Refined Analysis
  96. GRB 070224: optical afterglow candidate
  97. GRB 070224, Swift-BAT refined analysis
  98. GRB 070224: MASTER-Net refind analysis
  99. GRB 070224: MASTER-VWF-Kislovodsk observations
  100. GRB 070224: MASTER observations

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