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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"

23445 results found.

  1. GRB070406: Swift UVOT observations
  2. Short GRB 070406 - Possible Bright Host Galaxy
  3. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  4. GRB 070406: NOT observations
  5. GRB 070406: SARA upper limit
  6. GRB 070406: Xinglong TNT optical Upper Limit
  7. GRB 070406: Swift detection of a burst
  8. GRB 070402: Suzaku WAM observation of the prompt emission
  9. Konus-Wind and Konus-A observations of GRB 070402
  10. IPN triangulation of GRB070402
  11. GRB 070328: Suzaku WAM observation of the prompt emission
  12. UVOT observations of GRB070330
  13. GRB 070330: TAROT La Silla observatory optical observations
  14. GRB 070330: Swift-XRT refined analysis
  15. GRB 070330 - Watcher Observations
  16. GRB 070330: Swift detection of a burst
  17. GRB 070328: Swift/UVOT Upper Limits
  18. long burst from SGR 1806-20 detected on March 26
  19. GRB 070328 : Suzaku ToO follow up starts
  20. GRB 070328: Swift detection of a burst
  21. GRB 070311, deep optical photometry
  22. Short-Hard GRB 070209: PROMPT Observations
  23. GRB 070318: absorption-line redshift
  24. GRB070318: Swift UVOT continuing observations
  25. GRB070318: Swift-XRT refined analysis
  26. GRB 070318, Swift-BAT refined analysis
  27. GRB 070318: Swift detection of a burst with an optical afterglow
  28. VLA observation of GRB 070311
  29. GRB 070311: Optical observation.
  30. GRB 070306: possible emission-line redshift
  31. GRB 070311: SARA upper limit
  32. GRB 070311: RAPTOR Detection of Optical Emission
  33. GRB070311: FRAM early follow-up limit
  34. GRB 070311: P60 Observations
  35. GRB 070311: Swift/UVOT Upper Limits
  36. GRB 070311: MITSuME Okayama Optical Observation
  37. GRB 070311: Swift-XRT refined analysis
  38. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  39. GRB 070311: REM candidate afterglow
  40. GRB060901: Candidate optical afterglow
  41. GRB070309: Swift/XRT possible afterglow detection
  42. GRB 070125: Chandra X-ray Confirmation of Jet Break
  43. GRB 070309: Swift/UVOT Upper Limits
  44. GRB 070306, optical observation
  45. Swift UVOT Finding Charts for GRB 070309
  46. VLA observation of GRB 070306
  47. GRB 070306: NOT observations
  48. GRB 070306 Swift/UVOT refined analysis
  49. GRB 070306: ART-3 early optical and near infrared constraints
  50. GRB 070306: IR observations and candidate afterglow
  51. GRB 070306: Optical and IR observations with KANATA
  52. GRB070306 - SDSS Pre-burst Observations
  53. GRB 070306: Swift detection of a burst
  54. GRB 060605 new redshift
  55. GRB 070125, deep late-time optical observation
  56. VLA observation of GRB 070224
  57. GRB 070227: Swift/UVOT Upper Limits
  58. GRB 070227: TAROT La Silla observatory optical observations
  59. GRB 070227, Swift-BAT refined analysis
  60. GRB 070227: Swift detection of a burst in ground analysis
  61. GRB 920925C: optical afterglow candidate
  62. GRB 070224: Swift/UVOT Upper Limits
  63. VLA observation of GRB 070223
  64. VLA observation of GRB 070220
  65. GRB070224: Magellan Imaging Observations
  66. GRB 070224: WHT K-band imaging
  67. GRB 070224: MDM Observations
  68. GRB070224: Gemini Imaging Observations
  69. GRB 070224: SARA upper limit
  70. GRB070224: Swift-XRT Refined Analysis
  71. GRB 070224: optical afterglow candidate
  72. GRB 070224: MASTER-Net refind analysis
  73. GRB 070224: MASTER-VWF-Kislovodsk observations
  74. GRB 070224: Swift detection of a burst
  75. GRB 070223: Optical observations
  76. GRB070223: Swift/UVOT refined analysis
  77. GRB 070223: Optical-IR observation with KANATA
  78. GRB070223: MASTER-VWF-Kislovodsk observations
  79. GRB070223 - SDSS Pre-Burst Observations
  80. GRB070223: Swift burst
  81. GRB 070220: MITSuME Okayama Optical Observation
  82. GRB 070220: ART-3 Optical and NIR limits
  83. Swift/UVOT refined analysis of GRB070220
  84. GRB 070209: Swift XRT refined analysis
  85. GRB 070220: Observation with the KANATA 1.5m telescope
  86. GRB 070219: Gemini Observations
  87. GRB 070220: Swift detection of a burst
  88. GRB070219: MASTER-VWF-Kislovodsk observations
  89. GRB 070219: Swift/UVOT Upper limits
  90. GRB 070219: I-band observations
  91. GRB 070219: optical TNG observations
  92. GRB 070219: ROTSE-III Optical Limits
  93. GRB070219 - SDSS Pre-Burst Observations
  94. GRB 070219: Swift detection of a burst
  95. GRB 070125 observations with the GMRT
  96. GRB 060927: PROMPT Observations
  97. GRB 070129: MDM I-band Detection
  98. GRB 070209: Swift XRT analysis
  99. IPN localization of very bright long hard GRB 070207
  100. IPN localization of very intense short GRB 070201

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