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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"

45632 results found.

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

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