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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"

37493 results found.

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

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