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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"
  1. GRB 070810: Swift-XRT Team Refined Analysis
  2. GRB 070809: Swift-XRT refined analysis
  3. GRB 070810: enhanced Swift-XRT position
  4. GRB 070810: Swift/UVOT Optical Counterpart
  5. GRB 070810: ROTSE-III Detection of Optical Counterpart
  6. GRB 070810: Swift detection of a burst
  7. GRB 070809, Swift-BAT refined analysis
  8. GRB 070809: Optical Pre-imaging from Palomar
  9. GRB 070808: Swift/UVOT upper limits
  10. GRB 070809: ROTSE-III Optical Limits
  11. GRB 070809: Swift detection of a short burst
  12. GRB 070808 : Faulkes Telescope South Observations
  13. GCN Swift XRT update position notices and enhanced position circulars
  14. GRB 070808: Swift XRT refined analysis
  15. GRB 070808, Swift-BAT refined analysis
  16. GRB 070808: OPTIMA-Burst optical upper limit
  17. GRB 070808: Xinglong TNT optical Upper Limit
  18. GRB070808: Optical observations with KANATA
  19. GRB070808 - SDSS Pre-Burst Observations
  20. GRB 070808: ROTSE-III Optical Limits
  21. GRB 070808: Swift detection of a burst
  22. GRB061121A: PROMPT Observations
  23. GRB070805 XRT and UVOT afterglow candidate
  24. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  25. GRB070612A: Radio upper limit from GMRT
  26. GRB 070721B: correct afterglow position
  27. Swift/UVOT observations of GRB070805
  28. GRB 070805, Swift-BAT refined analysis
  29. GRB 070805: Swift XRT initial analysis.
  30. GRB 070805: Swift/UVOT initial analysis
  31. GRB 070805: Swift detection of a burst
  32. UVOT observations of SAXJ1810.8-2609
  33. Swift detection of a outburst from SAX J1810.8-2609
  34. VLA non-detection of GRB 070721B
  35. GRB 070802: REM optical observations
  36. GRB 070724B: Swift-XRT afterglow confirmation
  37. GRB 070802: Swift-XRT refined analysis
  38. GRB070802: Swift/UVOT upper limits
  39. GRB 070802: Confirmation of the optical afterglow
  40. GRB 070802, Swift-BAT refined analysis
  41. GRB 070802: VLT redshift
  42. GRB 070802: refined Swift XRT position
  43. GRB 070802: V-band detection of the candidate afterglow
  44. GRB 070802: LCO I-band candidate
  45. GRB 070802: GROND J band candidate
  46. GRB 070802: LCO optical observations
  47. GRB 070802: Swift detection of a burst
  48. GRB 070731, Swift-BAT refined analysis
  49. Konus-A observation of GRB 070729
  50. Swift/UVOT detection of GRB070714B
  51. AGILE-ACS position for the SGR 1806-20 July 27 burst
  52. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  53. GRB 070729: LCO optical imaging
  54. VLA upper limit on short hard burst GRB 070714B
  55. Intense burst from SGR 1806-20 detected on July 27
  56. GRB070729: Swift/UVOT upper limits
  57. GRB 070729: Swift-XRT refined analysis
  58. GRB 070729, Swift-BAT refined analysis
  59. GRB 070729: Magellan NIR Observations
  60. GRB 070724B: P60 Observations
  61. GRB 070729: Swift detection of a short hard burst
  62. GRB 070724B: Swift/UVOT Upper limits
  63. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  64. GRB 070724B: Swift-XRT afterglow likely candidate
  65. GRB 070721A: optical observations
  66. GRB 070724A: further VLT observations
  67. GRB 070724B: Suzaku WAM observation of the prompt emission
  68. Konus-Wind observation of GRB 070724B
  69. GRB 070724B: Analysis of AGILE gamma-ray data
  70. GRB 070724B: Swift-XRT afterglow candidates
  71. GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard
  72. Four radio sources in Swift-XRT error box of GRB 070724
  73. GRB 070724: optical observations
  74. GRB070724: Host galaxy redshift
  75. GRB 070724: P60 and Gemini Observations
  76. GRB 060814 - Keck host detection and redshift
  77. GRB 070724: IR observations
  78. GRB 070724: Closer association with DSS source
  79. Swift/UVOT refined analysis of GRB070724
  80. GRB 070724: Swift-XRT Team refined analysis
  81. GRB 070724: Pre-Imaging Shows a Source in the XRT Error Circle
  82. Short-Hard GRB070714B: PROMPT Observations
  83. GRB 070724, Swift-BAT refined analysis of a short burst
  84. GRB 070721B: further observations and analysis
  85. GRB 070724: Swift detection of a burst
  86. GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
  87. GRB 070714B: Keck observations
  88. GRB 070721B: optical observations and proposed redshift
  89. Swift/UVOT observations of GRB070721B optical afterglow.
  90. GRB 070721B, Further Swift-BAT refined analysis
  91. Swift/UVOT Observations of GRB070721A
  92. GRB 070721B : Faulkes Telescope South observations
  93. GRB 070721B: Swift-XRT refined analysis
  94. GRB 070721A : Faulkes Telescope South optical limit
  95. GRB 070721A: Swift/XRT refined analysis
  96. GRB 070721B, Swift-BAT refined analysis
  97. GRB 070721A, Swift-BAT refined analysis
  98. GRB070721B: A bright UVOT candidate
  99. GRB 070721B: Swift detection of a burst
  100. GRB 070721: Swift detection of a possible burst

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