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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"

41618 results found.

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

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