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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"

36790 results found.

  1. GRB990527 Optical Observations
  2. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  3. IPN error box for GRB990527
  4. Late Afterglows of GRBs 990510, 990123
  5. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  6. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  7. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  8. GRB 990506 optical observation
  9. X-ray/GRB 1SAX J0835.9+5118, 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. radio observations of X-ray/GRB transient field
  14. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  15. Optical report on X-ray/GRB transient
  16. radio detection of X-ray/GRB transient
  17. BeppoSAX: A new fast X-ray transient
  18. GRB 990510: optical observations
  19. GRB990510: photometric and spectroscopic observations with the VLT
  20. GRB 990510: optical linear polarization
  21. GRB 990510: optical observations
  22. GRB990510, VI observations
  23. GRB 990506 R band observations
  24. GRB990510: X-ray afterglow
  25. GRB 990510: optical observation
  26. VLT spectrum of GRB990510
  27. GRB 990510: Broad Band Break
  28. GRB 990510: BATSE Observations
  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. Galactic extinction towards GRB 990510
  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 990506, optical observations
  43. GRB 990510: Final BeppoSAX-WFC Coordinates
  44. GRB 990506, Optical Observations
  45. GRB 990506 optical observations
  46. GRB 990506 optical observations
  47. GRB 990506, optical observations
  48. GRB990506 observation plan
  49. Refined IPN error box for GRB990506
  50. GRB 990506: Limits on the possible optical transient
  51. GRB 990506, armchair astronomy
  52. GRB 990506, optical observations from +1 to +3 hours
  53. GRB 990506, optical observations
  54. GRB990506 observation plan
  55. New IPN/RXTE error box for GRB990506
  56. IPN localization for GRB990506
  57. GRB 970228: Redshift and properties of the host galaxy
  58. IPN localization of GRB990427
  59. GRB981220 VLBA observations
  60. GRB990321 REFINED IPN ANNULUS
  61. GRB990323 PRECISE IPN POSITION
  62. GRB990321 IPN TRIANGULATION
  63. GRB 990316 Optical Observations
  64. GRB 990316, Radio observations
  65. GRB 990316, Optical observations
  66. GRB990316, Optical observations
  67. GRB 990316 optical observations
  68. GRB990316: simultaneous optical observation
  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. GRB981220, IPN localization
  74. GRB 981220, radio observations
  75. GRB 990123, Field Photometry
  76. GRB 990217 Optical Observations
  77. GRB 990217, radio observations
  78. Optical Observations of GRB990217
  79. GRB990123: Caltech STIS Photometry and Images
  80. GRB990123 observations
  81. GRB990123, Optical Observation
  82. GRB 990123: Discovery of the Probable Host Galaxy
  83. GRB 990123: Reduced HST Images
  84. For Immediate Posting to GCN - HST Data GRB 990123 Available
  85. GRB19990123 observations
  86. GRB 990123: BVRI standards in the field
  87. GRB 990123: Updated Keck Spectroscopy Results
  88. GRB981220, field photometry
  89. GRB 990123 NOT Spectrum Update
  90. GRB990123, Optical observation
  91. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  92. GRB 990123: Publicly available reduced HST images
  93. GRB990123, Upcoming HST Service Observations
  94. GRB 990123: New Constraints on Possible Foreground Galaxies
  95. GRB990123 Optical Observations
  96. GRB990123, Probability of gravitational lensing
  97. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  98. GRB 990123: Continued Radio Observations
  99. GRB990123, Preliminary Lens Search Results
  100. GRB 990123: Correction to GCN 230 - C.A. Young added to author list

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