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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"

30663 results found.

  1. GRB 991216, optical observations
  2. GRB 991216 Optical Observations
  3. GRB 991216 Optical spectroscopy/imaging
  4. VLT spectra of GRB991216
  5. GRB991216 Optical and IR observations
  6. SAX J2303.2+0015 Optical observations
  7. IR observations of GRB991216
  8. GRB991216 radio observations
  9. GRB 991217 (SAX J2303.2+0015) Optical observations
  10. GRB991216 radio observations
  11. Lowell/Perkins observation of GRB 991216
  12. GRB991216, optical observations
  13. Refined IPN localization of GRB991216
  14. GRB 991216 Radio Observations
  15. GRB 991208 Keck Spectroscopy
  16. GRB 991208 Infrared Detection
  17. GRB991216
  18. GRB 991216--Summary of RXTE Observations
  19. GRB 991216 Optical Observations
  20. GRB 991216, optical observations
  21. GRB 991208 SAO-RAS Spectroscopy
  22. GRB 991216, Optical Transient
  23. GRB 991216, Optical Afterglow
  24. GRB991216 ('Beethoven Burst') B, R, and K Observations
  25. GRB 991216: Comparison with DPOSS images
  26. GRB 991208 optical observations
  27. Lowell/Perkins observation of GRB 991216
  28. GRB 991216 Optical Observation
  29. GRB 991208 Keck Spectroscopy
  30. R-band Observations of GRB991208 at TNG
  31. GRB991208, optical observations
  32. GRB 991208 Keck Spectroscopy
  33. GRB991208 - millimeter detection
  34. GRB 991208, Optical Observation
  35. GRB991208 15-GHz observations
  36. GRB991208, optical observations
  37. GRB 991208 - OVRO detection
  38. GRB 991208 Optical Decay
  39. GRB 991208 optical observations
  40. GRB 991208 optical observations
  41. GRB 991208: Radio Observations
  42. Optical Observations of GRB991105
  43. GRB991106: BeppoSAX/BATSE results
  44. GRB 991106, optical observations
  45. GRB991106, near-infrared observations
  46. BeppoSAX NFI Observation of GRB991106
  47. GRB 991106, radio observations
  48. GRB 991105: BATSE Observations
  49. IPN localization of GRB991105
  50. GRB 991106 Optical Observations
  51. GRB 991105, optical observations
  52. GRB991106, optical observation at SAO-RAS
  53. GRB 991106, LOTIS Optical Observations
  54. GRB 991106, optical observations
  55. Revised BeppoSAX WFC position of GRB991105
  56. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  57. GRB 991014, Optical Observations
  58. GRB 991014 - BeppoSAX NFI observations
  59. GRB 991014, Optical Observations
  60. GRB 991014, Optical Observations
  61. GRB 991014, optical observations
  62. Super-LOTIS optical observation of GRB991014
  63. IPN/NFI error box for GRB991014
  64. IPN localization of GRB991014 - CORRECTION
  65. IPN localization of GRB991014
  66. GRB 990915 optical observations
  67. GRB 990907 optical observations
  68. Optical Observations of GRB990907
  69. IPN error box for GRB990915 (=BATSE 7766)
  70. IPN localization of BATSE #7766 (GRB990915)
  71. GRB990907: BeppoSAX follow up and X-ray afterglow
  72. GRB990907 and 990908
  73. IPN localization of GRB990907
  74. GRB 990712 Late Optical Decay and Host Galaxy
  75. GRB 990712, Optical Observation
  76. GRB990806 BeppoSAX follow up
  77. GRB990806: BATSE Observations
  78. GRB 990806 Optical observations
  79. Optical Observations of GRB990806
  80. GRB 990806, Optical Observations
  81. GRB 990806, optical observations
  82. GRB 990806, Optical Observations
  83. GRB990806 UBVRIJHK observations
  84. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  85. VLT spectrum of GRB990712
  86. GRB 990712
  87. Late-time HST/STIS Observations of GRB 990510
  88. BeppoSAX NFI Observation of GRB990705
  89. BeppoSAX NFI Observation of GRB990705
  90. Updated Astrometry for the IR Counterpart of GRB990705
  91. GRB 990705, R-band observations
  92. Updated IPN localization of GRB990705
  93. IPN localization of GRB990704
  94. IPN localization of GRB990705
  95. Infrared and Optical Observations of GRB990705
  96. GRB 990705, radio observations
  97. GRB990704: SAX-NFI results summary
  98. GRB990704 radio and optical observations
  99. GRB 990704 X-ray Observations
  100. GRB 990704 Optical Observations

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