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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"

32796 results found.

  1. Late-time HST/STIS Observation of GRB 990123
  2. GRB 990506 - clarification to GCN 352
  3. GRB 990506 - Optical Observations
  4. Optical Observations of GRB 990506
  5. GRB 990506 Radio Transient
  6. GRB990527 Optical Observations
  7. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  8. IPN error box for GRB990527
  9. Late Afterglows of GRBs 990510, 990123
  10. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  11. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  12. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  13. GRB 990506 optical observation
  14. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  15. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  16. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  17. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  18. radio observations of X-ray/GRB transient field
  19. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  20. Optical report on X-ray/GRB transient
  21. radio detection of X-ray/GRB transient
  22. BeppoSAX: A new fast X-ray transient
  23. GRB 990510: optical observations
  24. GRB990510: photometric and spectroscopic observations with the VLT
  25. GRB 990510: optical linear polarization
  26. GRB 990510: optical observations
  27. GRB990510, VI observations
  28. GRB 990506 R band observations
  29. GRB990510: X-ray afterglow
  30. GRB 990510: optical observation
  31. VLT spectrum of GRB990510
  32. GRB 990510: Broad Band Break
  33. GRB 990510: BATSE Observations
  34. GRB 990510 Optical Observations
  35. GRB 990510, BVI photometry
  36. GRB 990510 optical observations
  37. GRB 990510: BeppoSAX/GRBM observations
  38. GRB990510 optical observations
  39. GRB 990510 optical observations
  40. GRB 990510 optical observations
  41. Galactic extinction towards GRB 990510
  42. GRB 990510 optical observations
  43. IPN localization of GRB990510
  44. GRB 990506 Radio Observations
  45. GRB 990123, optical monitoring
  46. GRB 990506: BATSE Observations
  47. GRB 990506, optical observations
  48. GRB 990510: Final BeppoSAX-WFC Coordinates
  49. GRB 990506, Optical Observations
  50. GRB 990506 optical observations
  51. GRB 990506 optical observations
  52. GRB 990506, optical observations
  53. GRB990506 observation plan
  54. Refined IPN error box for GRB990506
  55. GRB 990506: Limits on the possible optical transient
  56. GRB 990506, armchair astronomy
  57. GRB 990506, optical observations from +1 to +3 hours
  58. GRB 990506, optical observations
  59. GRB990506 observation plan
  60. New IPN/RXTE error box for GRB990506
  61. IPN localization for GRB990506
  62. GRB 970228: Redshift and properties of the host galaxy
  63. IPN localization of GRB990427
  64. GRB981220 VLBA observations
  65. GRB990321 REFINED IPN ANNULUS
  66. GRB990323 PRECISE IPN POSITION
  67. GRB990321 IPN TRIANGULATION
  68. GRB 990316 Optical Observations
  69. GRB 990316, Radio observations
  70. GRB 990316, Optical observations
  71. GRB990316, Optical observations
  72. GRB 990316 optical observations
  73. GRB990316: simultaneous optical observation
  74. ASM/IPN error box for GRB 990308 (BATSE #7457)
  75. GRB990308 not a new SGR
  76. GRB 990308a and GRB 990308b
  77. GRB990308 (Trig. 7457), optical observations
  78. GRB981220, IPN localization
  79. GRB 981220, radio observations
  80. GRB 990123, Field Photometry
  81. GRB 990217 Optical Observations
  82. GRB 990217, radio observations
  83. Optical Observations of GRB990217
  84. GRB990123: Caltech STIS Photometry and Images
  85. GRB990123 observations
  86. GRB990123, Optical Observation
  87. GRB 990123: Discovery of the Probable Host Galaxy
  88. GRB 990123: Reduced HST Images
  89. For Immediate Posting to GCN - HST Data GRB 990123 Available
  90. GRB19990123 observations
  91. GRB 990123: BVRI standards in the field
  92. GRB 990123: Updated Keck Spectroscopy Results
  93. GRB981220, field photometry
  94. GRB 990123 NOT Spectrum Update
  95. GRB990123, Optical observation
  96. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  97. GRB 990123: Publicly available reduced HST images
  98. GRB990123, Upcoming HST Service Observations
  99. GRB 990123: New Constraints on Possible Foreground Galaxies
  100. GRB990123 Optical Observations

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