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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"

37551 results found.

  1. GRB 070330: TAROT La Silla observatory optical observations
  2. GRB 070330: Swift-XRT refined analysis
  3. GRB 070330 - Watcher Observations
  4. GRB 070330: Swift detection of a burst
  5. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  6. Konus-Wind observation of GRB 070328
  7. GRB 070328: Swift/UVOT Upper Limits
  8. long burst from SGR 1806-20 detected on March 26
  9. GRB 070328: Swift/XRT Refined Analysis
  10. GRB 070328 : Suzaku ToO follow up starts
  11. GRB 070328, Swift-BAT refined analysis
  12. GRB 070328: Swift detection of a burst
  13. GRB070220: optical observations
  14. GRB070208: optical observations
  15. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  16. GRB 070311, deep optical photometry
  17. Short-Hard GRB 070209: PROMPT Observations
  18. GRB 070318: Gemini + Magellan spectra
  19. GRB 070318: absorption-line redshift
  20. GRB070318: Swift-XRT refined analysis
  21. GRB 070318: Swift/UVOT Continued Observations
  22. GRB 070318, Swift-BAT refined analysis
  23. IBAS Alert n. 4176: not a GRB
  24. GRB 070318: Swift detection of a burst with an optical afterglow
  25. GRB 070311: Late Central Engine Activity Optical Flare??
  26. GRB 070311: MDM Optical Monitoring
  27. VLA observation of GRB 070311
  28. GRB 070311: Tautenburg sees afterglow fading
  29. IBAS Alert n. 4169: not a GRB
  30. GRB 070311: Optical observation.
  31. GRB 070311: Optical Brightening
  32. GRB 070306: possible emission-line redshift
  33. GRB 070311: SARA upper limit
  34. GRB 070309: variability of the XRT afterglow candidate
  35. GRB 070311: MDM Optical Follow-up
  36. GRB 070311: RAPTOR Detection of Optical Emission
  37. GRB070311: FRAM early follow-up limit
  38. GRB 070311: P60 Observations
  39. GRB 070311: MDM Optical Detection
  40. GRB 070311: Swift/UVOT Upper Limits
  41. GRB 070311: MITSuME Okayama Optical Observation
  42. GRB 070311: Swift-XRT refined analysis
  43. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  44. GRB 070311: REM candidate afterglow
  45. GRB 070311: a long GRB detected by INTEGRAL
  46. GRB060901: Candidate optical afterglow
  47. GRB070309: Swift/XRT possible afterglow detection
  48. GRB 070125: Chandra X-ray Confirmation of Jet Break
  49. GRB 070309: Swift/UVOT Upper Limits
  50. GRB 070306, optical observation
  51. Swift UVOT Finding Charts for GRB 070309
  52. GRB 070309: A long GRB detected by INTEGRAL
  53. GRB 070125: X-ray light curve analysis
  54. VLA observation of GRB 070306
  55. IBAS Alert 4162: Not a GRB
  56. GRB 070306: NOT observations
  57. GRB 070306 Swift/UVOT refined analysis
  58. GRB070306: confirmation of near infrared afterglow
  59. GRB 070306: ART-3 early optical and near infrared constraints
  60. GRB 070306: IR observations and candidate afterglow
  61. GRB 070306, Swift-BAT refined analysis
  62. GRB 070306: XRT Team Refined Analysis
  63. GRB 070306: Optical and IR observations with KANATA
  64. GRB070306 - SDSS Pre-burst Observations
  65. GRB 070306: Swift detection of a burst
  66. GRB 070223: NIR observations at WHT
  67. GRB070227: Swift-XRT refined analysis
  68. GRB 060605 new redshift
  69. GRB 070125, deep late-time optical observation
  70. VLA observation of GRB 070224
  71. GRB 070227: optical observations
  72. GRB 070223: Optical Observations
  73. GRB 070227: optical observations
  74. GRB 070227: Swift/UVOT Upper Limits
  75. GRB 070227: TAROT La Silla observatory optical observations
  76. GRB 070227, Swift-BAT refined analysis
  77. GRB070227: possible X-ray afterglow detection
  78. GRB 070227: Swift detection of a burst in ground analysis
  79. GRB 920925C: optical afterglow candidate
  80. GRB 070224: Optical afterglow confirmation
  81. IBAS Alert n. 4144: not a GRB
  82. GRB 070224: Swift/UVOT Upper Limits
  83. VLA observation of GRB 070223
  84. VLA observation of GRB 070220
  85. GRB070224: Magellan Imaging Observations
  86. GRB 070224: WHT K-band imaging
  87. GRB 070224: MDM Observations
  88. GRB 070224: SARA upper limit
  89. GRB070224: Swift-XRT Refined Analysis
  90. GRB 070224: optical afterglow candidate
  91. GRB 070224, Swift-BAT refined analysis
  92. GRB 070224: MASTER-Net refind analysis
  93. GRB 070224: MASTER-VWF-Kislovodsk observations
  94. GRB 070224: MASTER observations
  95. GRB 070224: Swift detection of a burst
  96. GRB 070223: Optical observations
  97. GRB070223: Swift/UVOT refined analysis
  98. GRB 070223: Optical-IR observation with KANATA
  99. GRB 070223, Swift-BAT refined analysis
  100. GRB 070223: Swift-XRT Refined Analysis

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