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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"

28082 results found.

  1. GRB 070406: Correction to the optical candidate in GCN6253
  2. GRB 070406: Gemini South Imaging and XRT analysis
  3. GRB070406: Swift UVOT observations
  4. GRB 070406: further analysis of NOT images.
  5. Short GRB 070406 - Possible Bright Host Galaxy
  6. GRB 070406: NOT observations
  7. GRB 070406: Optical candidate
  8. GRB 070406: SARA upper limit
  9. GRB 070406: Xinglong TNT optical Upper Limit
  10. GRB 070402: Suzaku WAM observation of the prompt emission
  11. GRB 070328: Suzaku WAM observation of the prompt emission
  12. UVOT observations of GRB070330
  13. GRB 070330, Swift-BAT refined analysis
  14. GRB 070330: TAROT La Silla observatory optical observations
  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: Swift/XRT Refined Analysis
  20. GRB 070328 : Suzaku ToO follow up starts
  21. GRB 070328, Swift-BAT refined analysis
  22. GRB 070328: Swift detection of a burst
  23. GRB 070311, deep optical photometry
  24. Short-Hard GRB 070209: PROMPT Observations
  25. GRB 070318: absorption-line redshift
  26. GRB070318: Swift UVOT continuing observations
  27. GRB 070318, Swift-BAT refined analysis
  28. GRB 070318: Swift detection of a burst with an optical afterglow
  29. GRB 070311: Late Central Engine Activity Optical Flare??
  30. VLA observation of GRB 070311
  31. GRB 070311: Optical observation.
  32. GRB 070306: possible emission-line redshift
  33. GRB 070311: SARA upper limit
  34. GRB 070309: variability of the XRT afterglow candidate
  35. GRB070311: FRAM early follow-up limit
  36. GRB 070311: P60 Observations
  37. GRB 070311: Swift/UVOT Upper Limits
  38. GRB 070311: MITSuME Okayama Optical Observation
  39. GRB 070311: Swift-XRT refined analysis
  40. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  41. GRB 070311: REM candidate afterglow
  42. GRB 070311: a long GRB detected by INTEGRAL
  43. GRB060901: Candidate optical afterglow
  44. GRB 070125: Chandra X-ray Confirmation of Jet Break
  45. GRB 070309: Swift/UVOT Upper Limits
  46. GRB 070306, optical observation
  47. Swift UVOT Finding Charts for GRB 070309
  48. GRB 070309: A long GRB detected by INTEGRAL
  49. GRB 070125: X-ray light curve analysis
  50. VLA observation of GRB 070306
  51. GRB 070306: NOT observations
  52. GRB 070306 Swift/UVOT refined analysis
  53. GRB 070306: IR observations and candidate afterglow
  54. GRB 070306, Swift-BAT refined analysis
  55. GRB 070306: XRT Team Refined Analysis
  56. GRB 070306: Optical and IR observations with KANATA
  57. GRB070306 - SDSS Pre-burst Observations
  58. GRB 070306: Swift detection of a burst
  59. GRB070227: Swift-XRT refined analysis
  60. GRB 060605 new redshift
  61. GRB 070125, deep late-time optical observation
  62. VLA observation of GRB 070224
  63. GRB 070227: Swift/UVOT Upper Limits
  64. GRB 070227: TAROT La Silla observatory optical observations
  65. GRB 070227, Swift-BAT refined analysis
  66. GRB 070227: Swift detection of a burst in ground analysis
  67. GRB 070224: Swift/UVOT Upper Limits
  68. VLA observation of GRB 070223
  69. VLA observation of GRB 070220
  70. GRB070224: Magellan Imaging Observations
  71. GRB 070224: WHT K-band imaging
  72. GRB 070224: MDM Observations
  73. GRB070224: Gemini Imaging Observations
  74. GRB 070224: SARA upper limit
  75. GRB070224: Swift-XRT Refined Analysis
  76. GRB 070224: optical afterglow candidate
  77. GRB 070224, Swift-BAT refined analysis
  78. GRB 070224: MASTER-Net refind analysis
  79. GRB 070224: MASTER-VWF-Kislovodsk observations
  80. GRB 070224: Swift detection of a burst
  81. GRB 070223: Optical observations
  82. GRB070223: Swift/UVOT refined analysis
  83. GRB 070223: Optical-IR observation with KANATA
  84. GRB 070223, Swift-BAT refined analysis
  85. GRB070223: MASTER-VWF-Kislovodsk observations
  86. GRB 070223: Swift-XRT Refined Analysis
  87. GRB070223 - SDSS Pre-Burst Observations
  88. GRB 070223: MDM Observations
  89. GRB070223: Swift burst
  90. GRB 070220: MITSuME Okayama Optical Observation
  91. GRB 070220 Swift-BAT Refined Analysis
  92. Swift/UVOT refined analysis of GRB070220
  93. GRB 070209: Swift XRT refined analysis
  94. GRB 070220: Swift-XRT Refined Analysis
  95. GRB 070220: Observation with the KANATA 1.5m telescope
  96. GRB 070219: Gemini Observations
  97. GRB 070220: Swift detection of a burst
  98. GRB070219: MASTER-VWF-Kislovodsk observations
  99. GRB 070219: Swift/UVOT Upper limits
  100. GRB 070219: I-band observations

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