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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"

21322 results found.

  1. GRB 970228: Redshift and properties of the host galaxy
  2. GRB981220 VLBA observations
  3. GRB980425 Optical observations of exponential decline at late time
  4. GRB 990316 Optical Observations
  5. GRB 990316, Radio observations
  6. GRB 990316, Optical observations
  7. GRB990316, Optical observations
  8. GRB 990316 optical observations
  9. GRB990316: simultaneous optical observation
  10. GRB990308 not a new SGR
  11. GRB990308 (Trig. 7457), optical observations
  12. GRB990308, Possible new SGR~0209+70
  13. GRB 981220, radio observations
  14. GRB 990217 Optical Observations
  15. GRB 990217, radio observations
  16. Optical Observations of GRB990217
  17. GRB990123 observations
  18. GRB990123, Optical Observation
  19. GRB 990123: Discovery of the Probable Host Galaxy
  20. GRB 990123: Reduced HST Images
  21. For Immediate Posting to GCN - HST Data GRB 990123 Available
  22. GRB19990123 observations
  23. GRB 990123: Updated Keck Spectroscopy Results
  24. GRB981220, field photometry
  25. GRB 990123 NOT Spectrum Update
  26. GRB990123, Optical observation
  27. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  28. GRB 990123: Publicly available reduced HST images
  29. GRB990123, Upcoming HST Service Observations
  30. GRB990123, 15-GHz limits
  31. GRB 990123: New Constraints on Possible Foreground Galaxies
  32. GRB990123 Optical Observations
  33. GRB990123, Probability of gravitational lensing
  34. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  35. GRB 990123: Continued Radio Observations
  36. GRB990123, Preliminary Lens Search Results
  37. On the Lensing Interpretation of GRB 990123
  38. Search for Potential Images of GRB 990123
  39. GRB990123, Optical BVRI Observations
  40. GRB 990123: near-infrared observations.
  41. GRB990123, OSSE observations
  42. GRB990123: NIR Observation
  43. "GRB 990123: New BV Observations"
  44. GRB 990123 Optical Follow-Up
  45. GRB 990123; Addendum to GCN 223
  46. GRB 990123: BATSE Observations
  47. GRB 990123 Keck Spectrum update
  48. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  49. GRB990123 Optical Observations
  50. GRB 990123 Spectroscopic Redshifts
  51. GRB 990123: New Optical Observations, Decay Measure
  52. GRB 990123 Optical Follow-Up
  53. GRB 990123: Possible Gravitationally Lensed Burst?
  54. GRB990123, optical observation
  55. GRB 990123 optical observations
  56. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  57. GRB 990123 radio observations
  58. GRB 990123, new radio source
  59. GRB990123 optical observations
  60. GRB990123, Optical observation
  61. GRB 990123 Optical Follow-up
  62. GRB 990123: Bright New Source, Possible Optical Transient
  63. GRB 990123, Radio observations
  64. SN 1999E & GRB 980919
  65. Possible identification of SN1999E with GRB980910
  66. Optical Observations of GRB 981220
  67. GRB 981226: radio variable
  68. GRB981220
  69. GRB981220, Correction to GCN 179
  70. GRB981220, Optical Observations
  71. GRB 981220 Optical observations
  72. GRB 981226 Optical Observations
  73. GRB 980613: Spectroscopy of the host galaxy
  74. GRB981226, sub-millimeter observations
  75. GRB981220, sub-millimeter observations
  76. GRB 981220 and GRB 981226, optical observations
  77. GRB981226 Optical Observations
  78. GRB 981226 radio observations
  79. GRB 981226
  80. GRB 981226 optical observations
  81. radio observations of GRB 981226
  82. GRB981220 B, R and I band observations
  83. Optical Observations of GRB981226
  84. GRB 981220:Optical Observations
  85. GRB 981220 optical R and I observations
  86. GRB981226, BeppoSAX Christmas GRB
  87. GRB 981226 - Infrared Observations
  88. GRB 981226 optical observations
  89. GRB 981220
  90. GRB 981220, radio observations
  91. GRB 981220, radio observations
  92. GRB981220 I-band Observations
  93. GRB981220 Optical Observations
  94. GRB 981220
  95. GRB 981220 Optical Observations
  96. GRB 981220, optical observations
  97. GRB 980326/Host Galaxy
  98. GRB980329 R,I flux calibration and R,I,K upper limits
  99. GRB980425 Optical Follow-up
  100. GRB980425: X-ray revised positions

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