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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"

41612 results found.

  1. BeppoSAX: A new fast X-ray transient
  2. GRB 990510: optical observations
  3. GRB990510: photometric and spectroscopic observations with the VLT
  4. GRB 990510: optical linear polarization
  5. GRB 990510: optical observations
  6. GRB990510, VI observations
  7. GRB 990506 R band observations
  8. GRB990510: X-ray afterglow
  9. GRB 990510: optical observation
  10. VLT spectrum of GRB990510
  11. GRB 990510: Broad Band Break
  12. GRB 990510: BATSE Observations
  13. GRB990510: optical observation
  14. GRB 990510 Optical Observations
  15. GRB 990510, BVI photometry
  16. GRB 990510 optical observations
  17. GRB 990510: BeppoSAX/GRBM observations
  18. GRB990510 optical observations
  19. GRB990510
  20. GRB 990510 optical observations
  21. GRB 990510 optical observations
  22. GRB 990510 optical observations
  23. GRB 990506 Radio Observations
  24. GRB 990123, optical monitoring
  25. GRB 990506: BATSE Observations
  26. GRB 990506, optical observations
  27. GRB 990510: Final BeppoSAX-WFC Coordinates
  28. GRB 990506, Optical Observations
  29. GRB 990506 optical observations
  30. GRB 990506 optical observations
  31. GRB 990506, optical observations
  32. GRB990506 observation plan
  33. Refined IPN error box for GRB990506
  34. GRB 990506: Limits on the possible optical transient
  35. GRB 990506, armchair astronomy
  36. GRB 990506, optical observations from +1 to +3 hours
  37. GRB 990506, optical observations
  38. GRB990506 Optical observations
  39. GRB990506 observation plan
  40. IPN localization for GRB990506
  41. GRB 970228: Redshift and properties of the host galaxy
  42. GRB981220 VLBA observations
  43. GRB980425 Optical observations of exponential decline at late time
  44. GRB990323 PRECISE IPN POSITION
  45. GRB990321 IPN TRIANGULATION
  46. GRB 990316 Optical Observations
  47. GRB 990316, Radio observations
  48. GRB 990316, Optical observations
  49. GRB990316, Optical observations
  50. GRB 990316 optical observations
  51. GRB990316: simultaneous optical observation
  52. ASM/IPN error box for GRB 990308 (BATSE #7457)
  53. GRB990308 not a new SGR
  54. GRB 990308a and GRB 990308b
  55. GRB990308 (Trig. 7457), optical observations
  56. GRB990308, Possible new SGR~0209+70
  57. GRB981220, IPN localization
  58. GRB 981220, radio observations
  59. GRB 990123, Field Photometry
  60. GRB 990217 Optical Observations
  61. GRB 990217, radio observations
  62. BATSE Resumes Normal Operations
  63. GRB990217: BeppoSAX/GRBM data
  64. Optical Observations of GRB990217
  65. GRB990123 observations
  66. GRB990217 Optical observation
  67. GRB990217, WFC position
  68. GRB990123, Optical Observation
  69. GRB 990123: Discovery of the Probable Host Galaxy
  70. GRB 990123: Reduced HST Images
  71. For Immediate Posting to GCN - HST Data GRB 990123 Available
  72. GRB19990123 observations
  73. GRB 990123: BVRI standards in the field
  74. GRB 990123: Updated Keck Spectroscopy Results
  75. GRB981220, field photometry
  76. GRB 990123 NOT Spectrum Update
  77. GRB990123, Optical observation
  78. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  79. GRB 990123: Publicly available reduced HST images
  80. GRB990123, Upcoming HST Service Observations
  81. GRB990123, 15-GHz limits
  82. GRB 990123: New Constraints on Possible Foreground Galaxies
  83. GRB990123 Optical Observations
  84. GRB990123, Probability of gravitational lensing
  85. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  86. GRB 990123: Continued Radio Observations
  87. GRB990123, Preliminary Lens Search Results
  88. On the Lensing Interpretation of GRB 990123
  89. Search for Potential Images of GRB 990123
  90. Search for Potential Images of GRB 990123
  91. GRB990123, Optical BVRI Observations
  92. GRB 990123: near-infrared observations.
  93. GRB990123, OSSE observations
  94. GRB990123: NIR Observation
  95. GRB990123, ASCA X-ray observation of afterglow
  96. "GRB 990123: New BV Observations"
  97. GRB 990123 Optical Follow-Up
  98. GRB 990123; Addendum to GCN 223
  99. GRB 990123: BATSE Observations
  100. GRB 990123 Keck Spectrum update

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