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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"

36144 results found.

  1. GRB070208: optical observations
  2. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  3. GRB 070311, deep optical photometry
  4. Short-Hard GRB 070209: PROMPT Observations
  5. GRB 070318: Gemini + Magellan spectra
  6. GRB 070318: absorption-line redshift
  7. GRB070318: Swift-XRT refined analysis
  8. GRB 070318: Swift/UVOT Continued Observations
  9. GRB 070318, Swift-BAT refined analysis
  10. IBAS Alert n. 4176: not a GRB
  11. GRB 070318: Swift detection of a burst with an optical afterglow
  12. GRB 070311: Late Central Engine Activity Optical Flare??
  13. GRB 070311: MDM Optical Monitoring
  14. VLA observation of GRB 070311
  15. GRB 070311: Tautenburg sees afterglow fading
  16. IBAS Alert n. 4169: not a GRB
  17. GRB 070311: Optical observation.
  18. GRB 070311: Optical Brightening
  19. GRB 070306: possible emission-line redshift
  20. GRB 070311: SARA upper limit
  21. GRB 070309: variability of the XRT afterglow candidate
  22. GRB 070311: MDM Optical Follow-up
  23. GRB 070311: RAPTOR Detection of Optical Emission
  24. GRB070311: FRAM early follow-up limit
  25. GRB 070311: P60 Observations
  26. GRB 070311: MDM Optical Detection
  27. GRB 070311: Swift/UVOT Upper Limits
  28. GRB 070311: MITSuME Okayama Optical Observation
  29. GRB 070311: Swift-XRT refined analysis
  30. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  31. GRB 070311: REM candidate afterglow
  32. GRB 070311: a long GRB detected by INTEGRAL
  33. GRB060901: Candidate optical afterglow
  34. GRB070309: Swift/XRT possible afterglow detection
  35. GRB 070125: Chandra X-ray Confirmation of Jet Break
  36. GRB 070309: Swift/UVOT Upper Limits
  37. GRB 070306, optical observation
  38. Swift UVOT Finding Charts for GRB 070309
  39. GRB 070309: A long GRB detected by INTEGRAL
  40. GRB 070125: X-ray light curve analysis
  41. VLA observation of GRB 070306
  42. IBAS Alert 4162: Not a GRB
  43. GRB 070306: NOT observations
  44. GRB 070306 Swift/UVOT refined analysis
  45. GRB070306: confirmation of near infrared afterglow
  46. GRB 070306: ART-3 early optical and near infrared constraints
  47. GRB 070306: IR observations and candidate afterglow
  48. GRB 070306, Swift-BAT refined analysis
  49. GRB 070306: XRT Team Refined Analysis
  50. GRB 070306: Optical and IR observations with KANATA
  51. GRB070306 - SDSS Pre-burst Observations
  52. GRB 070306: Swift detection of a burst
  53. GRB 070223: NIR observations at WHT
  54. GRB070227: Swift-XRT refined analysis
  55. GRB 060605 new redshift
  56. GRB 070125, deep late-time optical observation
  57. VLA observation of GRB 070224
  58. GRB 070227: optical observations
  59. GRB 070223: Optical Observations
  60. GRB 070227: optical observations
  61. GRB 070227: Swift/UVOT Upper Limits
  62. GRB 070227: TAROT La Silla observatory optical observations
  63. GRB 070227, Swift-BAT refined analysis
  64. GRB070227: possible X-ray afterglow detection
  65. GRB 070227: Swift detection of a burst in ground analysis
  66. GRB 920925C: optical afterglow candidate
  67. GRB 070224: Optical afterglow confirmation
  68. IBAS Alert n. 4144: not a GRB
  69. GRB 070224: Swift/UVOT Upper Limits
  70. VLA observation of GRB 070223
  71. VLA observation of GRB 070220
  72. GRB070224: Magellan Imaging Observations
  73. GRB 070224: WHT K-band imaging
  74. GRB 070224: MDM Observations
  75. GRB 070224: SARA upper limit
  76. GRB070224: Swift-XRT Refined Analysis
  77. GRB 070224: optical afterglow candidate
  78. GRB 070224, Swift-BAT refined analysis
  79. GRB 070224: MASTER-Net refind analysis
  80. GRB 070224: MASTER-VWF-Kislovodsk observations
  81. GRB 070224: MASTER observations
  82. GRB 070224: Swift detection of a burst
  83. GRB 070223: Optical observations
  84. GRB070223: Swift/UVOT refined analysis
  85. GRB 070223: Optical-IR observation with KANATA
  86. GRB 070223, Swift-BAT refined analysis
  87. GRB 070223: Swift-XRT Refined Analysis
  88. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  89. GRB070223 - SDSS Pre-Burst Observations
  90. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  91. GRB 070223: MDM Observations
  92. GRB070223: Swift burst
  93. Konus-Wind and Konus-A observations of GRB 070220
  94. GRB 070220: MITSuME Okayama Optical Observation
  95. GRB 070220: ART-3 Optical and NIR limits
  96. GRB 070220 Swift-BAT Refined Analysis
  97. Swift/UVOT refined analysis of GRB070220
  98. GRB 070209: Swift XRT refined analysis
  99. GRB 070220: Swift-XRT Refined Analysis
  100. GRB 070220: Observation with the KANATA 1.5m telescope

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