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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"

44330 results found.

  1. GRB 990510: optical observations
  2. GRB990510, VI observations
  3. GRB 990506 R band observations
  4. GRB990510: X-ray afterglow
  5. GRB 990510: optical observation
  6. VLT spectrum of GRB990510
  7. GRB 990510: Broad Band Break
  8. GRB 990510: BATSE Observations
  9. GRB990510: optical observation
  10. GRB 990510 Optical Observations
  11. GRB 990510, BVI photometry
  12. GRB 990510 optical observations
  13. GRB 990510: BeppoSAX/GRBM observations
  14. GRB990510 optical observations
  15. GRB990510
  16. GRB 990510 optical observations
  17. GRB 990510 optical observations
  18. Galactic extinction towards GRB 990510
  19. GRB990510: NFI X-ray source
  20. GRB 990510 optical observations
  21. IPN localization of GRB990510
  22. GRB 990506 Radio Observations
  23. GRB 990123, optical monitoring
  24. GRB 990506: BATSE Observations
  25. GRB 990506, optical observations
  26. GRB 990510: Final BeppoSAX-WFC Coordinates
  27. GRB 990506, Optical Observations
  28. GRB 990506 optical observations
  29. GRB 990506 optical observations
  30. GRB 990506, optical observations
  31. GRB990506 observation plan
  32. Refined IPN error box for GRB990506
  33. GRB 990506: Limits on the possible optical transient
  34. GRB 990506, armchair astronomy
  35. GRB 990506, optical observations from +1 to +3 hours
  36. GRB 990506, optical observations
  37. GRB990506 Optical observations
  38. New IPN/RXTE error box for GRB990506
  39. IPN localization for GRB990506
  40. GRB 970228: Redshift and properties of the host galaxy
  41. IPN localization of GRB990427
  42. GRB981220 VLBA observations
  43. GRB980425 Optical observations of exponential decline at late time
  44. GRB990321 REFINED IPN ANNULUS
  45. GRB990323 PRECISE IPN POSITION
  46. GRB990321 IPN TRIANGULATION
  47. GRB 990316 Optical Observations
  48. GRB 990316, Radio observations
  49. GRB 990316, Optical observations
  50. GRB990316, Optical observations
  51. GRB 990316 optical observations
  52. GRB990316: simultaneous optical observation
  53. GRB990316 - Optical null results
  54. ASM/IPN error box for GRB 990308 (BATSE #7457)
  55. GRB990308 not a new SGR
  56. GRB 990308a and GRB 990308b
  57. GRB990308 (Trig. 7457), optical observations
  58. GRB990308, Possible new SGR~0209+70
  59. GRB981220, IPN localization
  60. GRB 981220, radio observations
  61. GRB 990123, Field Photometry
  62. GRB 990217 Optical Observations
  63. GRB 990217, radio observations
  64. BATSE Resumes Normal Operations
  65. GRB990217: BeppoSAX/GRBM data
  66. Optical Observations of GRB990217
  67. GRB990123: Caltech STIS Photometry and Images
  68. GRB990123 observations
  69. GRB990217, WFC position
  70. GRB990123, Optical Observation
  71. GRB 990123: Discovery of the Probable Host Galaxy
  72. GRB 990123: Reduced HST Images
  73. For Immediate Posting to GCN - HST Data GRB 990123 Available
  74. GRB19990123 observations
  75. GRB 990123: BVRI standards in the field
  76. GRB 990123: Updated Keck Spectroscopy Results
  77. GRB981220, field photometry
  78. GRB 990123 NOT Spectrum Update
  79. GRB990123, Optical observation
  80. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  81. GRB 990123: Publicly available reduced HST images
  82. GRB990123, Upcoming HST Service Observations
  83. GRB990123, 15-GHz limits
  84. GRB 990123: New Constraints on Possible Foreground Galaxies
  85. GRB990123 Optical Observations
  86. GRB990123, Probability of gravitational lensing
  87. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  88. GRB 990123: Continued Radio Observations
  89. GRB990123, Preliminary Lens Search Results
  90. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  91. On the Lensing Interpretation of GRB 990123
  92. Search for Potential Images of GRB 990123
  93. Search for Potential Images of GRB 990123
  94. GRB990123, Optical BVRI Observations
  95. GRB 990123: near-infrared observations.
  96. GRB990123, OSSE observations
  97. GRB990123: NIR Observation
  98. GRB990123, ASCA X-ray observation of afterglow
  99. "GRB 990123: New BV Observations"
  100. GRB 990123 Optical Follow-Up

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