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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"

36319 results found.

  1. GRB070220: optical observations
  2. GRB070208: optical observations
  3. GRB070223: confirmation of nIR and optical afterglow
  4. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  5. GRB 070311, deep optical photometry
  6. Short-Hard GRB 070209: PROMPT Observations
  7. GRB 070318: Gemini + Magellan spectra
  8. GRB 070318: absorption-line redshift
  9. GRB070318: Swift UVOT continuing observations
  10. GRB070318: Swift-XRT refined analysis
  11. GRB 070318: Swift/UVOT Continued Observations
  12. GRB 070318, Swift-BAT refined analysis
  13. IBAS Alert n. 4176: not a GRB
  14. GRB 070318: Swift detection of a burst with an optical afterglow
  15. GRB 070311: Late Central Engine Activity Optical Flare??
  16. GRB 070311: MDM Optical Monitoring
  17. VLA observation of GRB 070311
  18. GRB 070311: Tautenburg sees afterglow fading
  19. IBAS Alert n. 4169: not a GRB
  20. GRB 070311: Optical observation.
  21. GRB 070311: Optical Brightening
  22. GRB 070306: possible emission-line redshift
  23. GRB 070311: SARA upper limit
  24. GRB 070309: variability of the XRT afterglow candidate
  25. GRB 070311: MDM Optical Follow-up
  26. GRB 070311: RAPTOR Detection of Optical Emission
  27. GRB070311: FRAM early follow-up limit
  28. GRB 070311: P60 Observations
  29. GRB 070311: MDM Optical Detection
  30. GRB 070311: Swift/UVOT Upper Limits
  31. GRB 070311: MITSuME Okayama Optical Observation
  32. GRB 070311: Swift-XRT refined analysis
  33. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  34. GRB 070311: REM candidate afterglow
  35. GRB 070311: a long GRB detected by INTEGRAL
  36. GRB060901: Candidate optical afterglow
  37. GRB070309: Swift/XRT possible afterglow detection
  38. GRB 070125: Chandra X-ray Confirmation of Jet Break
  39. GRB 070309: Swift/UVOT Upper Limits
  40. GRB 070306, optical observation
  41. Swift UVOT Finding Charts for GRB 070309
  42. GRB 070309: A long GRB detected by INTEGRAL
  43. GRB 070125: X-ray light curve analysis
  44. VLA observation of GRB 070306
  45. IBAS Alert 4162: Not a GRB
  46. GRB 070306: NOT observations
  47. GRB 070306 Swift/UVOT refined analysis
  48. GRB070306: confirmation of near infrared afterglow
  49. GRB 070306: ART-3 early optical and near infrared constraints
  50. GRB 070306: IR observations and candidate afterglow
  51. GRB 070306, Swift-BAT refined analysis
  52. GRB 070306: XRT Team Refined Analysis
  53. GRB 070306: Optical and IR observations with KANATA
  54. GRB070306 - SDSS Pre-burst Observations
  55. GRB 070306: Swift detection of a burst
  56. GRB 070223: NIR observations at WHT
  57. GRB070227: Swift-XRT refined analysis
  58. GRB 060605 new redshift
  59. GRB 070125, deep late-time optical observation
  60. VLA observation of GRB 070224
  61. GRB 070227: optical observations
  62. GRB 070223: Optical Observations
  63. GRB 070227: optical observations
  64. GRB 070227: Swift/UVOT Upper Limits
  65. GRB 070227: TAROT La Silla observatory optical observations
  66. GRB 070227, Swift-BAT refined analysis
  67. GRB070227: possible X-ray afterglow detection
  68. GRB 070227: Swift detection of a burst in ground analysis
  69. GRB 920925C: optical afterglow candidate
  70. GRB 070224: Optical afterglow confirmation
  71. IBAS Alert n. 4144: not a GRB
  72. GRB 070224: Swift/UVOT Upper Limits
  73. GRB070224: Swift-XRT Astrometrically Corrected Position
  74. VLA observation of GRB 070223
  75. VLA observation of GRB 070220
  76. GRB070224: Magellan Imaging Observations
  77. GRB 070224: WHT K-band imaging
  78. GRB 070224: MDM Observations
  79. GRB070224: Gemini Imaging Observations
  80. GRB 070224: SARA upper limit
  81. GRB070224: Swift-XRT Refined Analysis
  82. GRB 070224: optical afterglow candidate
  83. GRB 070224, Swift-BAT refined analysis
  84. GRB 070224: MASTER-Net refind analysis
  85. GRB 070224: MASTER-VWF-Kislovodsk observations
  86. GRB 070224: MASTER observations
  87. GRB 070224: Swift detection of a burst
  88. GRB 070223: Optical observations
  89. GRB070223: Swift/UVOT refined analysis
  90. GRB 070223: Optical-IR observation with KANATA
  91. GRB 070223, Swift-BAT refined analysis
  92. GRB 070223: Swift-XRT Refined Analysis
  93. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  94. GRB070223 - SDSS Pre-Burst Observations
  95. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  96. GRB 070223: MDM Observations
  97. GRB070223: Swift burst
  98. Konus-Wind and Konus-A observations of GRB 070220
  99. GRB 070220: MITSuME Okayama Optical Observation
  100. GRB 070220: ART-3 Optical and NIR limits

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