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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"

32505 results found.

  1. GRB 070328: Suzaku WAM observation of the prompt emission
  2. INTEGRAL ToO Observation of SGR1806-20
  3. UVOT observations of GRB070330
  4. GRB 070330, Swift-BAT refined analysis
  5. GRB 070330, SMARTS optical/IR observations
  6. GRB 070330: Swift-XRT refined analysis
  7. GRB 070330 - Watcher Observations
  8. Konus-Wind observation of GRB 070328
  9. GRB 070328: Swift/UVOT Upper Limits
  10. long burst from SGR 1806-20 detected on March 26
  11. GRB 070328: Swift/XRT Refined Analysis
  12. GRB 070328 : Suzaku ToO follow up starts
  13. GRB 070328, Swift-BAT refined analysis
  14. GRB070220: optical observations
  15. GRB070208: optical observations
  16. GRB070223: confirmation of nIR and optical afterglow
  17. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  18. GRB 070311, deep optical photometry
  19. Short-Hard GRB 070209: PROMPT Observations
  20. GRB 070318: Gemini + Magellan spectra
  21. GRB 070318: absorption-line redshift
  22. GRB070318: Swift UVOT continuing observations
  23. GRB070318: Swift-XRT refined analysis
  24. GRB 070318: Swift/UVOT Continued Observations
  25. GRB 070318, Swift-BAT refined analysis
  26. GRB 070311: Late Central Engine Activity Optical Flare??
  27. GRB 070311: MDM Optical Monitoring
  28. VLA observation of GRB 070311
  29. GRB 070311: Tautenburg sees afterglow fading
  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. 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 070125: X-ray light curve analysis
  52. VLA observation of GRB 070306
  53. GRB 070306: NOT observations
  54. GRB 070306 Swift/UVOT refined analysis
  55. GRB070306: confirmation of near infrared afterglow
  56. GRB 070306: ART-3 early optical and near infrared constraints
  57. GRB 070306, Swift-BAT refined analysis
  58. GRB 070306: XRT Team Refined Analysis
  59. GRB 070306: Optical and IR observations with KANATA
  60. GRB 070223: NIR observations at WHT
  61. GRB070227: Swift-XRT refined analysis
  62. GRB 060605 new redshift
  63. GRB 070125, deep late-time optical observation
  64. VLA observation of GRB 070224
  65. GRB 070223: Optical Observations
  66. GRB 070227: optical observations
  67. GRB 070227: Swift/UVOT Upper Limits
  68. GRB 070227, Swift-BAT refined analysis
  69. GRB070227: possible X-ray afterglow detection
  70. GRB 070224: Optical afterglow confirmation
  71. GRB 070224: Swift/UVOT Upper Limits
  72. GRB070224: Swift-XRT Astrometrically Corrected Position
  73. VLA observation of GRB 070223
  74. VLA observation of GRB 070220
  75. GRB070224: Magellan Imaging Observations
  76. GRB 070224: WHT K-band imaging
  77. GRB 070224: MDM Observations
  78. GRB070224: Gemini Imaging Observations
  79. GRB070224: Swift-XRT Refined Analysis
  80. GRB 070224: optical afterglow candidate
  81. GRB 070224, Swift-BAT refined analysis
  82. GRB 070224: MASTER-Net refind analysis
  83. GRB 070224: MASTER-VWF-Kislovodsk observations
  84. GRB 070223: Optical observations
  85. RHESSI Spectrum of GRB070220
  86. GRB070223: Swift/UVOT refined analysis
  87. GRB 070223: Optical-IR observation with KANATA
  88. GRB 070223, Swift-BAT refined analysis
  89. GRB070223: MASTER-VWF-Kislovodsk observations
  90. GRB 070223: Swift-XRT Refined Analysis
  91. GRB070223 - SDSS Pre-Burst Observations
  92. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  93. GRB 070223: MDM Observations
  94. Konus-Wind and Konus-A observations of GRB 070220
  95. GRB 070220: MITSuME Okayama Optical Observation
  96. GRB 070220: ART-3 Optical and NIR limits
  97. GRB 070220 Swift-BAT Refined Analysis
  98. Swift/UVOT refined analysis of GRB070220
  99. GRB 070209: Swift XRT refined analysis
  100. GRB 070220: Swift-XRT Refined Analysis

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