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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 070824 - Combined SuperAGILE/IPN Localization
  2. Konus-Wind observation of very bright GRB 070821
  3. GRB 070731: Swift/UVOT Upper Limit
  4. IPN Localization of GRB 070821 (long, very bright)
  5. GRB 070805: UVOT afterglow candidate retraction
  6. GRB070810b: optical candidate
  7. GRB 070810A: ROTSE-III Refined Analysis
  8. Swift observatory off line
  9. GRB 061110A: redshift confirmed
  10. GRB 070810B : Faulkes Telescope South Observations
  11. GRB 070810A: Continued Keck Imaging
  12. GRB 070810B: Keck spectroscopy of possible host galaxies
  13. GRB070810B: Swift/UVOT Upper Limits
  14. GRB 070810B: XRT refined analysis
  15. GRB 070810B, Swift-BAT refined analysis
  16. GRB 070810: MASTER optical observation
  17. GRB 070809: Swift/UVOT Corrected Photometry
  18. Swift Alert 070810.8: MASTER optical observation
  19. Swift Trigger 287421: False trigger due to star tracker loss
  20. GRB 070810A: Swift-BAT refined analysis
  21. GRB 070810B: Xinglong TNT optical Upper Limit
  22. GRB070810B: Optical observations with KANATA
  23. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  24. GRB 070809: Swift/UVOT Upper Limits
  25. GRB 070810B: Swift detection of a short burst
  26. VLA upper limit on the short hard burst GRB 070729
  27. GRB 070810: Keck redshift and photometry
  28. No radio detection in superAGILE burst 070724B
  29. GRB 070809: Keck Imaging
  30. GRB 070810: Swift-XRT Team Refined Analysis
  31. GRB 070809: Swift-XRT refined analysis
  32. GRB 070810: enhanced Swift-XRT position
  33. GRB 070810: Swift/UVOT Optical Counterpart
  34. GRB 070810: ROTSE-III Detection of Optical Counterpart
  35. GRB 070810: Swift detection of a burst
  36. GRB 070809, Swift-BAT refined analysis
  37. GRB 070809: Optical Pre-imaging from Palomar
  38. GRB 070808: Swift/UVOT upper limits
  39. GRB 070809: ROTSE-III Optical Limits
  40. GRB 070809: Swift detection of a short burst
  41. GRB 070808 : Faulkes Telescope South Observations
  42. GCN Swift XRT update position notices and enhanced position circulars
  43. GRB 070808: Swift XRT refined analysis
  44. GRB 070808, Swift-BAT refined analysis
  45. GRB 070808: OPTIMA-Burst optical upper limit
  46. GRB 070808: Xinglong TNT optical Upper Limit
  47. GRB070808: Optical observations with KANATA
  48. GRB070808 - SDSS Pre-Burst Observations
  49. GRB 070808: ROTSE-III Optical Limits
  50. GRB 070808: Swift detection of a burst
  51. GRB061121A: PROMPT Observations
  52. GRB070805 XRT and UVOT afterglow candidate
  53. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  54. GRB070612A: Radio upper limit from GMRT
  55. GRB 070721B: correct afterglow position
  56. Swift/UVOT observations of GRB070805
  57. GRB 070805, Swift-BAT refined analysis
  58. GRB 070805: Swift XRT initial analysis.
  59. GRB 070805: Swift/UVOT initial analysis
  60. GRB 070805: Swift detection of a burst
  61. UVOT observations of SAXJ1810.8-2609
  62. Swift detection of a outburst from SAX J1810.8-2609
  63. VLA non-detection of GRB 070721B
  64. GRB 070802: REM optical observations
  65. GRB 070724B: Swift-XRT afterglow confirmation
  66. GRB 070802: Swift-XRT refined analysis
  67. GRB070802: Swift/UVOT upper limits
  68. GRB 070802: Confirmation of the optical afterglow
  69. GRB 070802, Swift-BAT refined analysis
  70. GRB 070802: VLT redshift
  71. GRB 070802: refined Swift XRT position
  72. GRB 070802: V-band detection of the candidate afterglow
  73. GRB 070802: LCO I-band candidate
  74. GRB 070802: GROND J band candidate
  75. GRB 070802: LCO optical observations
  76. GRB 070802: Swift detection of a burst
  77. GRB 070731, Swift-BAT refined analysis
  78. Konus-A observation of GRB 070729
  79. Swift/UVOT detection of GRB070714B
  80. AGILE-ACS position for the SGR 1806-20 July 27 burst
  81. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  82. GRB 070729: LCO optical imaging
  83. VLA upper limit on short hard burst GRB 070714B
  84. Intense burst from SGR 1806-20 detected on July 27
  85. GRB070729: Swift/UVOT upper limits
  86. GRB 070729: Swift-XRT refined analysis
  87. GRB 070729, Swift-BAT refined analysis
  88. GRB 070729: Magellan NIR Observations
  89. GRB 070724B: P60 Observations
  90. GRB 070729: Swift detection of a short hard burst
  91. GRB 070724B: Swift/UVOT Upper limits
  92. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  93. GRB 070724B: Swift-XRT afterglow likely candidate
  94. GRB 070721A: optical observations
  95. GRB 070724A: further VLT observations
  96. GRB 070724B: Suzaku WAM observation of the prompt emission
  97. Konus-Wind observation of GRB 070724B
  98. GRB 070724B: Analysis of AGILE gamma-ray data
  99. GRB 070724B: Swift-XRT afterglow candidates
  100. GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard

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