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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"

27391 results found.

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

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