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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. GRB070810b: optical candidate
  2. GRB 070810A: ROTSE-III Refined Analysis
  3. Swift observatory off line
  4. GRB 061110A: redshift confirmed
  5. GRB 070810B : Faulkes Telescope South Observations
  6. GRB 070810A: Continued Keck Imaging
  7. GRB 070810B: Keck spectroscopy of possible host galaxies
  8. GRB070810B: Swift/UVOT Upper Limits
  9. GRB 070810B: XRT refined analysis
  10. GRB 070810B, Swift-BAT refined analysis
  11. GRB 070810: MASTER optical observation
  12. GRB 070809: Swift/UVOT Corrected Photometry
  13. Swift Alert 070810.8: MASTER optical observation
  14. Swift Trigger 287421: False trigger due to star tracker loss
  15. GRB 070810A: Swift-BAT refined analysis
  16. GRB 070810B: Xinglong TNT optical Upper Limit
  17. GRB070810B: Optical observations with KANATA
  18. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  19. GRB 070809: Swift/UVOT Upper Limits
  20. GRB 070810B: Swift detection of a short burst
  21. VLA upper limit on the short hard burst GRB 070729
  22. GRB 070810: Keck redshift and photometry
  23. No radio detection in superAGILE burst 070724B
  24. GRB 070809: Keck Imaging
  25. GRB 070810: Swift-XRT Team Refined Analysis
  26. GRB 070809: Swift-XRT refined analysis
  27. GRB 070810: enhanced Swift-XRT position
  28. GRB 070810: Swift/UVOT Optical Counterpart
  29. GRB 070810: ROTSE-III Detection of Optical Counterpart
  30. GRB 070810: Swift detection of a burst
  31. GRB 070809, Swift-BAT refined analysis
  32. GRB 070809: Optical Pre-imaging from Palomar
  33. GRB 070808: Swift/UVOT upper limits
  34. GRB 070809: ROTSE-III Optical Limits
  35. GRB 070809: Swift detection of a short burst
  36. GRB 070808 : Faulkes Telescope South Observations
  37. GCN Swift XRT update position notices and enhanced position circulars
  38. GRB 070808: Swift XRT refined analysis
  39. GRB 070808, Swift-BAT refined analysis
  40. GRB 070808: OPTIMA-Burst optical upper limit
  41. GRB 070808: Xinglong TNT optical Upper Limit
  42. GRB070808: Optical observations with KANATA
  43. GRB070808 - SDSS Pre-Burst Observations
  44. GRB 070808: ROTSE-III Optical Limits
  45. GRB 070808: Swift detection of a burst
  46. GRB061121A: PROMPT Observations
  47. GRB070805 XRT and UVOT afterglow candidate
  48. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  49. GRB070612A: Radio upper limit from GMRT
  50. GRB 070721B: correct afterglow position
  51. Swift/UVOT observations of GRB070805
  52. GRB 070805, Swift-BAT refined analysis
  53. GRB 070805: Swift XRT initial analysis.
  54. GRB 070805: Swift/UVOT initial analysis
  55. GRB 070805: Swift detection of a burst
  56. UVOT observations of SAXJ1810.8-2609
  57. Swift detection of a outburst from SAX J1810.8-2609
  58. VLA non-detection of GRB 070721B
  59. GRB 070802: REM optical observations
  60. GRB 070724B: Swift-XRT afterglow confirmation
  61. GRB 070802: Swift-XRT refined analysis
  62. GRB070802: Swift/UVOT upper limits
  63. GRB 070802: Confirmation of the optical afterglow
  64. GRB 070802, Swift-BAT refined analysis
  65. GRB 070802: VLT redshift
  66. GRB 070802: refined Swift XRT position
  67. GRB 070802: V-band detection of the candidate afterglow
  68. GRB 070802: LCO I-band candidate
  69. GRB 070802: GROND J band candidate
  70. GRB 070802: LCO optical observations
  71. GRB 070802: Swift detection of a burst
  72. GRB 070731, Swift-BAT refined analysis
  73. Konus-A observation of GRB 070729
  74. Swift/UVOT detection of GRB070714B
  75. AGILE-ACS position for the SGR 1806-20 July 27 burst
  76. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  77. GRB 070729: LCO optical imaging
  78. VLA upper limit on short hard burst GRB 070714B
  79. Intense burst from SGR 1806-20 detected on July 27
  80. GRB070729: Swift/UVOT upper limits
  81. GRB 070729: Swift-XRT refined analysis
  82. GRB 070729, Swift-BAT refined analysis
  83. GRB 070729: Magellan NIR Observations
  84. GRB 070724B: P60 Observations
  85. GRB 070729: Swift detection of a short hard burst
  86. GRB 070724B: Swift/UVOT Upper limits
  87. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  88. GRB 070724B: Swift-XRT afterglow likely candidate
  89. GRB 070721A: optical observations
  90. GRB 070724A: further VLT observations
  91. GRB 070724B: Suzaku WAM observation of the prompt emission
  92. Konus-Wind observation of GRB 070724B
  93. GRB 070724B: Analysis of AGILE gamma-ray data
  94. GRB 070724B: Swift-XRT afterglow candidates
  95. GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard
  96. Four radio sources in Swift-XRT error box of GRB 070724
  97. GRB 070724: optical observations
  98. GRB070724: Host galaxy redshift
  99. GRB 070724: P60 and Gemini Observations
  100. GRB 060814 - Keck host detection and redshift

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