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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"

38258 results found.

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

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