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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"

21263 results found.

  1. GRB 070419A: SARA observations
  2. GRB 070419A: NAYUTA Optical Observation
  3. GRB 070419A: Optical and IR observations with KANATA
  4. GRB070419A, optical observation
  5. Infrared detection of GRB070419A with UKIRT
  6. GRB 070419A: Kiso Optical observation
  7. GRB 070419: P60 Confirmation of Optical Afterglow
  8. GRB 070419B: Swift detection of a burst
  9. GRB 070419A: ROTSE-III Optical Limits
  10. GRB 070419: Swift detection of a burst
  11. GRB 070418: Optical and IR observations with KANATA
  12. Trigger 276045: Swift detection of a possible burst
  13. GRB 070406: Swift XRT refined analysis
  14. GRB070412: UKIRT-WFCAM JHK upper limits
  15. GRB070412: Swift UVOT observations
  16. GRB 070411: Swift/UVOT observations
  17. GRB 070412, Swift-BAT refined analysis
  18. GRB 070412 Liverpool Telescope optical limit
  19. GRB 070412: Optical observations at Crni Vrh
  20. GRB 070412: further NOT observations
  21. GRB 070412: IAC80 optical afterglow candidate
  22. GRB 070412: NOT observations
  23. GRB 070411, Swift-BAT refined analysis
  24. GRB 070412: Swift detection of a burst
  25. GRB 070411: IAC80 optical observations
  26. GRB 070411 : Liverpool Telescope Observations
  27. GRB 070411: Tautenburg RRM Afterglow Confirmation
  28. GRB 070411: Swift detection of a burst with optical afterglow
  29. GRB 070406: Swift XRT team further analysis
  30. Suzaku ToO observation of SGR 1806-20
  31. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  32. GRB 070406: Correction to the optical candidate in GCN6253
  33. GRB 070406: Gemini South Imaging and XRT analysis
  34. GRB070406: Swift UVOT observations
  35. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  36. GRB 070406: NOT observations
  37. GRB 070406: SARA upper limit
  38. GRB 070406: Xinglong TNT optical Upper Limit
  39. GRB 070402: Suzaku WAM observation of the prompt emission
  40. Konus-Wind and Konus-A observations of GRB 070402
  41. IPN triangulation of GRB070402
  42. GRB 070328: Suzaku WAM observation of the prompt emission
  43. UVOT observations of GRB070330
  44. GRB 070330: TAROT La Silla observatory optical observations
  45. GRB 070330 - Watcher Observations
  46. Konus-Wind observation of GRB 070328
  47. GRB 070328: Swift/UVOT Upper Limits
  48. long burst from SGR 1806-20 detected on March 26
  49. GRB 070328 : Suzaku ToO follow up starts
  50. GRB 070328, Swift-BAT refined analysis
  51. GRB 070328: Swift detection of a burst
  52. GRB 070311, deep optical photometry
  53. Short-Hard GRB 070209: PROMPT Observations
  54. GRB 070318: absorption-line redshift
  55. GRB070318: Swift UVOT continuing observations
  56. GRB 070318: Swift detection of a burst with an optical afterglow
  57. VLA observation of GRB 070311
  58. GRB 070311: Optical observation.
  59. GRB 070306: possible emission-line redshift
  60. GRB 070311: SARA upper limit
  61. GRB 070309: variability of the XRT afterglow candidate
  62. GRB070311: FRAM early follow-up limit
  63. GRB 070311: P60 Observations
  64. GRB 070311: Swift/UVOT Upper Limits
  65. GRB 070311: MITSuME Okayama Optical Observation
  66. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  67. GRB 070311: REM candidate afterglow
  68. GRB060901: Candidate optical afterglow
  69. GRB070309: Swift/XRT possible afterglow detection
  70. GRB 070125: Chandra X-ray Confirmation of Jet Break
  71. GRB 070309: Swift/UVOT Upper Limits
  72. GRB 070306, optical observation
  73. Swift UVOT Finding Charts for GRB 070309
  74. VLA observation of GRB 070306
  75. GRB 070306: NOT observations
  76. GRB 070306 Swift/UVOT refined analysis
  77. GRB 070306: IR observations and candidate afterglow
  78. GRB 070306: Optical and IR observations with KANATA
  79. GRB070306 - SDSS Pre-burst Observations
  80. GRB 070306: Swift detection of a burst
  81. GRB 060605 new redshift
  82. GRB 070125, deep late-time optical observation
  83. VLA observation of GRB 070224
  84. GRB 070227: Swift/UVOT Upper Limits
  85. GRB 070227: TAROT La Silla observatory optical observations
  86. GRB 070227: Swift detection of a burst in ground analysis
  87. GRB 070224: Swift/UVOT Upper Limits
  88. VLA observation of GRB 070223
  89. VLA observation of GRB 070220
  90. GRB070224: Magellan Imaging Observations
  91. GRB 070224: WHT K-band imaging
  92. GRB 070224: MDM Observations
  93. GRB070224: Gemini Imaging Observations
  94. GRB 070224: SARA upper limit
  95. GRB 070224: optical afterglow candidate
  96. GRB 070224: MASTER-Net refind analysis
  97. GRB 070224: MASTER-VWF-Kislovodsk observations
  98. GRB 070224: Swift detection of a burst
  99. GRB 070223: Optical observations
  100. RHESSI Spectrum of GRB070220

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