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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"

27393 results found.

  1. GRB 070412: IAC80 optical afterglow candidate
  2. GRB 070412: NOT observations
  3. GRB 070411, Swift-BAT refined analysis
  4. GRB 070412: Swift detection of a burst
  5. GRB 070411: IAC80 optical observations
  6. GRB 070411 : Liverpool Telescope Observations
  7. GRB 070411: Swift detection of a burst with optical afterglow
  8. GRB 070406: Swift XRT team further analysis
  9. Suzaku ToO observation of SGR 1806-20
  10. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  11. GRB 070406, Swift-BAT refined analysis
  12. GRB 070406: Correction to the optical candidate in GCN6253
  13. GRB 070406: Gemini South Imaging and XRT analysis
  14. GRB070406: Swift UVOT observations
  15. GRB 070406: further analysis of NOT images.
  16. Short GRB 070406 - Possible Bright Host Galaxy
  17. GRB 070406: NOT observations
  18. GRB 070406: Optical candidate
  19. GRB 070406: SARA upper limit
  20. GRB 070406: Xinglong TNT optical Upper Limit
  21. GRB 070402: Suzaku WAM observation of the prompt emission
  22. GRB 070328: Suzaku WAM observation of the prompt emission
  23. UVOT observations of GRB070330
  24. GRB 070330, Swift-BAT refined analysis
  25. GRB 070330: TAROT La Silla observatory optical observations
  26. GRB 070330 - Watcher Observations
  27. GRB 070330: Swift detection of a burst
  28. GRB 070328: Swift/UVOT Upper Limits
  29. long burst from SGR 1806-20 detected on March 26
  30. GRB 070328: Swift/XRT Refined Analysis
  31. GRB 070328 : Suzaku ToO follow up starts
  32. GRB 070328, Swift-BAT refined analysis
  33. GRB 070328: Swift detection of a burst
  34. GRB 070311, deep optical photometry
  35. Short-Hard GRB 070209: PROMPT Observations
  36. GRB 070318: absorption-line redshift
  37. GRB070318: Swift UVOT continuing observations
  38. GRB 070318, Swift-BAT refined analysis
  39. GRB 070318: Swift detection of a burst with an optical afterglow
  40. GRB 070311: Late Central Engine Activity Optical Flare??
  41. VLA observation of GRB 070311
  42. GRB 070311: Optical observation.
  43. GRB 070306: possible emission-line redshift
  44. GRB 070311: SARA upper limit
  45. GRB 070309: variability of the XRT afterglow candidate
  46. GRB070311: FRAM early follow-up limit
  47. GRB 070311: P60 Observations
  48. GRB 070311: Swift/UVOT Upper Limits
  49. GRB 070311: MITSuME Okayama Optical Observation
  50. GRB 070311: Swift-XRT refined analysis
  51. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  52. GRB 070311: REM candidate afterglow
  53. GRB 070311: a long GRB detected by INTEGRAL
  54. GRB060901: Candidate optical afterglow
  55. GRB 070125: Chandra X-ray Confirmation of Jet Break
  56. GRB 070309: Swift/UVOT Upper Limits
  57. GRB 070306, optical observation
  58. Swift UVOT Finding Charts for GRB 070309
  59. GRB 070309: A long GRB detected by INTEGRAL
  60. GRB 070125: X-ray light curve analysis
  61. VLA observation of GRB 070306
  62. GRB 070306: NOT observations
  63. GRB 070306 Swift/UVOT refined analysis
  64. GRB 070306: IR observations and candidate afterglow
  65. GRB 070306, Swift-BAT refined analysis
  66. GRB 070306: XRT Team Refined Analysis
  67. GRB 070306: Optical and IR observations with KANATA
  68. GRB070306 - SDSS Pre-burst Observations
  69. GRB 070306: Swift detection of a burst
  70. GRB070227: Swift-XRT refined analysis
  71. GRB 060605 new redshift
  72. GRB 070125, deep late-time optical observation
  73. VLA observation of GRB 070224
  74. GRB 070227: Swift/UVOT Upper Limits
  75. GRB 070227: TAROT La Silla observatory optical observations
  76. GRB 070227, Swift-BAT refined analysis
  77. GRB 070227: Swift detection of a burst in ground analysis
  78. GRB 070224: Swift/UVOT Upper Limits
  79. VLA observation of GRB 070223
  80. VLA observation of GRB 070220
  81. GRB070224: Magellan Imaging Observations
  82. GRB 070224: WHT K-band imaging
  83. GRB 070224: MDM Observations
  84. GRB070224: Gemini Imaging Observations
  85. GRB 070224: SARA upper limit
  86. GRB070224: Swift-XRT Refined Analysis
  87. GRB 070224: optical afterglow candidate
  88. GRB 070224, Swift-BAT refined analysis
  89. GRB 070224: MASTER-Net refind analysis
  90. GRB 070224: MASTER-VWF-Kislovodsk observations
  91. GRB 070224: Swift detection of a burst
  92. GRB 070223: Optical observations
  93. GRB070223: Swift/UVOT refined analysis
  94. GRB 070223: Optical-IR observation with KANATA
  95. GRB 070223, Swift-BAT refined analysis
  96. GRB070223: MASTER-VWF-Kislovodsk observations
  97. GRB 070223: Swift-XRT Refined Analysis
  98. GRB070223 - SDSS Pre-Burst Observations
  99. GRB 070223: MDM Observations
  100. GRB070223: Swift burst

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