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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"

37423 results found.

  1. GRB 990506 - Optical Observations
  2. Optical Observations of GRB 990506
  3. GRB990527 Optical Observations
  4. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  5. IPN error box for GRB990527
  6. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  7. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  8. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  9. GRB 990506 optical observation
  10. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  11. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  12. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  13. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  14. radio observations of X-ray/GRB transient field
  15. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  16. Optical report on X-ray/GRB transient
  17. radio detection of X-ray/GRB transient
  18. BeppoSAX: A new fast X-ray transient
  19. GRB 990510: optical observations
  20. GRB990510: photometric and spectroscopic observations with the VLT
  21. GRB 990510: optical linear polarization
  22. GRB990510, VI observations
  23. GRB 990506 R band observations
  24. GRB990510: X-ray afterglow
  25. VLT spectrum of GRB990510
  26. GRB 990510: Broad Band Break
  27. GRB 990510: BATSE Observations
  28. GRB990510: optical observation
  29. GRB 990510 Optical Observations
  30. GRB 990510, BVI photometry
  31. GRB 990510 optical observations
  32. GRB 990510: BeppoSAX/GRBM observations
  33. GRB990510 optical observations
  34. GRB 990510 optical observations
  35. GRB 990510 optical observations
  36. GRB990510: NFI X-ray source
  37. GRB 990510 optical observations
  38. IPN localization of GRB990510
  39. GRB 990506 Radio Observations
  40. GRB 990123, optical monitoring
  41. GRB 990506: BATSE Observations
  42. GRB 990510: Final BeppoSAX-WFC Coordinates
  43. GRB 990506, Optical Observations
  44. GRB 990506 optical observations
  45. GRB 990506 optical observations
  46. GRB 990506, optical observations
  47. Refined IPN error box for GRB990506
  48. GRB 990506: Limits on the possible optical transient
  49. GRB 990506, armchair astronomy
  50. GRB 990506, optical observations from +1 to +3 hours
  51. GRB 990506, optical observations
  52. GRB990506 Optical observations
  53. New IPN/RXTE error box for GRB990506
  54. IPN localization for GRB990506
  55. GRB 970228: Redshift and properties of the host galaxy
  56. IPN localization of GRB990427
  57. GRB981220 VLBA observations
  58. GRB980425 Optical observations of exponential decline at late time
  59. GRB990321 REFINED IPN ANNULUS
  60. GRB990323 PRECISE IPN POSITION
  61. GRB990321 IPN TRIANGULATION
  62. GRB 990316 Optical Observations
  63. GRB 990316, Radio observations
  64. GRB 990316, Optical observations
  65. GRB990316, Optical observations
  66. GRB 990316 optical observations
  67. GRB990316: simultaneous optical observation
  68. GRB990316 - Optical null results
  69. ASM/IPN error box for GRB 990308 (BATSE #7457)
  70. GRB990308 not a new SGR
  71. GRB 990308a and GRB 990308b
  72. GRB990308 (Trig. 7457), optical observations
  73. GRB990308, Possible new SGR~0209+70
  74. GRB981220, IPN localization
  75. GRB 981220, radio observations
  76. GRB 990217 Optical Observations
  77. GRB 990217, radio observations
  78. BATSE Flight Anomaly
  79. GRB990217: BeppoSAX/GRBM data
  80. Optical Observations of GRB990217
  81. GRB990123: Caltech STIS Photometry and Images
  82. GRB990123 observations
  83. GRB990217 Optical observation
  84. GRB990217, WFC position
  85. GRB990123, Optical Observation
  86. GRB 990123: Discovery of the Probable Host Galaxy
  87. GRB 990123: Reduced HST Images
  88. GRB19990123 observations
  89. GRB 990123: Updated Keck Spectroscopy Results
  90. GRB981220, field photometry
  91. GRB 990123 NOT Spectrum Update
  92. GRB990123, Optical observation
  93. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  94. GRB 990123: Publicly available reduced HST images
  95. GRB990123, Upcoming HST Service Observations
  96. GRB 990123: New Constraints on Possible Foreground Galaxies
  97. GRB990123 Optical Observations
  98. GRB990123, Probability of gravitational lensing
  99. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  100. GRB 990123: Continued Radio Observations

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