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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"

20554 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 observations
  5. GRB990510, VI observations
  6. GRB 990506 R band observations
  7. GRB990510: X-ray afterglow
  8. GRB 990510: optical observation
  9. GRB 990510: Broad Band Break
  10. GRB 990510: BATSE Observations
  11. GRB 990510 Optical Observations
  12. GRB 990510, BVI photometry
  13. GRB 990510 optical observations
  14. GRB 990510: BeppoSAX/GRBM observations
  15. GRB990510 optical observations
  16. GRB990510
  17. GRB 990510 optical observations
  18. GRB 990510 optical observations
  19. GRB 990510 optical observations
  20. GRB 990506 Radio Observations
  21. GRB 990123, optical monitoring
  22. GRB 990506: BATSE Observations
  23. GRB 990506, optical observations
  24. GRB 990506, Optical Observations
  25. GRB 990506 optical observations
  26. GRB 990506 optical observations
  27. GRB 990506, optical observations
  28. GRB990506 observation plan
  29. GRB 990506: Limits on the possible optical transient
  30. GRB 990506, optical observations from +1 to +3 hours
  31. GRB 990506, optical observations
  32. GRB990506 Optical observations
  33. GRB 970228: Redshift and properties of the host galaxy
  34. GRB981220 VLBA observations
  35. GRB980425 Optical observations of exponential decline at late time
  36. GRB 990316 Optical Observations
  37. GRB 990316, Radio observations
  38. GRB 990316, Optical observations
  39. GRB990316, Optical observations
  40. GRB 990316 optical observations
  41. GRB990316: simultaneous optical observation
  42. GRB990308 not a new SGR
  43. GRB990308 (Trig. 7457), optical observations
  44. GRB990308, Possible new SGR~0209+70
  45. GRB 981220, radio observations
  46. GRB 990217 Optical Observations
  47. GRB 990217, radio observations
  48. Optical Observations of GRB990217
  49. GRB990123 observations
  50. GRB990123, Optical Observation
  51. GRB 990123: Discovery of the Probable Host Galaxy
  52. GRB 990123: Reduced HST Images
  53. For Immediate Posting to GCN - HST Data GRB 990123 Available
  54. GRB19990123 observations
  55. GRB 990123: Updated Keck Spectroscopy Results
  56. GRB981220, field photometry
  57. GRB 990123 NOT Spectrum Update
  58. GRB990123, Optical observation
  59. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  60. GRB 990123: Publicly available reduced HST images
  61. GRB990123, Upcoming HST Service Observations
  62. GRB990123, 15-GHz limits
  63. GRB 990123: New Constraints on Possible Foreground Galaxies
  64. GRB990123 Optical Observations
  65. GRB990123, Probability of gravitational lensing
  66. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  67. GRB 990123: Continued Radio Observations
  68. GRB990123, Preliminary Lens Search Results
  69. On the Lensing Interpretation of GRB 990123
  70. Search for Potential Images of GRB 990123
  71. GRB990123, Optical BVRI Observations
  72. GRB 990123: near-infrared observations.
  73. GRB990123, OSSE observations
  74. GRB990123: NIR Observation
  75. "GRB 990123: New BV Observations"
  76. GRB 990123 Optical Follow-Up
  77. GRB 990123; Addendum to GCN 223
  78. GRB 990123: BATSE Observations
  79. GRB 990123 Keck Spectrum update
  80. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  81. GRB990123 Optical Observations
  82. GRB 990123 Spectroscopic Redshifts
  83. GRB 990123: New Optical Observations, Decay Measure
  84. GRB 990123 Optical Follow-Up
  85. GRB 990123: Possible Gravitationally Lensed Burst?
  86. GRB990123, optical observation
  87. GRB 990123 optical observations
  88. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  89. GRB 990123 radio observations
  90. GRB 990123, new radio source
  91. GRB990123 optical observations
  92. GRB990123, Optical observation
  93. GRB 990123 Optical Follow-up
  94. GRB 990123: Bright New Source, Possible Optical Transient
  95. GRB 990123, Radio observations
  96. SN 1999E & GRB 980919
  97. Possible identification of SN1999E with GRB980910
  98. Optical Observations of GRB 981220
  99. GRB 981226: radio variable
  100. GRB981220

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