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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"

15987 results found.

  1. GRB 990506, optical observations
  2. GRB 990506, Optical Observations
  3. GRB 990506 optical observations
  4. GRB 990506 optical observations
  5. GRB 990506, optical observations
  6. GRB 990506: Limits on the possible optical transient
  7. GRB 990506, armchair astronomy
  8. GRB 990506, optical observations from +1 to +3 hours
  9. GRB 990506, optical observations
  10. GRB990506 Optical observations
  11. GRB980425 Optical observations of exponential decline at late time
  12. GRB 990316 Optical Observations
  13. GRB 990316, Radio observations
  14. GRB 990316, Optical observations
  15. GRB990316, Optical observations
  16. GRB 990316 optical observations
  17. GRB990316: simultaneous optical observation
  18. GRB990316 - Optical null results
  19. GRB990308 (Trig. 7457), optical observations
  20. GRB 990217 Optical Observations
  21. Optical Observations of GRB990217
  22. GRB990123 observations
  23. GRB990217 Optical observation
  24. GRB990123, Optical Observation
  25. GRB 990123: Discovery of the Probable Host Galaxy
  26. GRB 990123: Reduced HST Images
  27. GRB19990123 observations
  28. GRB 990123: Updated Keck Spectroscopy Results
  29. GRB990123, Optical observation
  30. GRB 990123: New Constraints on Possible Foreground Galaxies
  31. GRB990123 Optical Observations
  32. GRB990123, Probability of gravitational lensing
  33. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  34. GRB 990123: Continued Radio Observations
  35. GRB990123, Preliminary Lens Search Results
  36. On the Lensing Interpretation of GRB 990123
  37. Search for Potential Images of GRB 990123
  38. Search for Potential Images of GRB 990123
  39. GRB990123, Optical BVRI Observations
  40. GRB 990123: near-infrared observations.
  41. GRB990123: NIR Observation
  42. "GRB 990123: New BV Observations"
  43. GRB 990123 Optical Follow-Up
  44. GRB 990123: BATSE Observations
  45. GRB990123 IPN annulus
  46. GRB990123 Optical Observations
  47. GRB 990123 Spectroscopic Redshifts
  48. GRB 990123: New Optical Observations, Decay Measure
  49. GRB 990123 Optical Follow-Up
  50. GRB 990123: Possible Gravitationally Lensed Burst?
  51. GRB990123, optical observation
  52. GRB 990123 optical observations
  53. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  54. GRB 990123 radio observations
  55. GRB 990123, new radio source
  56. GRB990123 optical observations
  57. GRB990123, Optical observation
  58. GRB 990123: Optical Decay Slope
  59. GRB 990123 r-band photometry
  60. GRB 990123 Optical Follow-up
  61. GRB990123, early optical counterpart detection
  62. GRB990123 Optical Observation
  63. GRB 990123: Bright New Source, Possible Optical Transient
  64. Optical Observations of GRB 981220
  65. GRB 981226: radio variable
  66. GRB981220, Correction to GCN 179
  67. GRB981220, Optical Observations
  68. GRB 981220 Optical observations
  69. GRB 981226 Optical Observations
  70. GRB 981220 and GRB 981226, optical observations
  71. GRB981226 Optical Observations
  72. GRB 981226 radio observations
  73. GRB 981226
  74. GRB 981226 optical observations
  75. radio observations of GRB 981226
  76. GRB981220 B, R and I band observations
  77. Optical Observations of GRB981226
  78. GRB 981220:Optical Observations
  79. GRB 981220 optical R and I observations
  80. GRB 981226 optical observations
  81. GRB 981220, radio observations
  82. GRB981226 Optical Observation
  83. GRB981220 Optical Observations
  84. GRB 981220 Optical Observations
  85. GRB 981220, optical observations
  86. GRB 980326/Host Galaxy
  87. GRB980329 R,I flux calibration and R,I,K upper limits
  88. GRB980425 Optical Follow-up
  89. GRB970508 optical observations
  90. GRB971214, association with a Galactic star?
  91. Optical Observations of the Host Galaxy of GRB 980519
  92. GRB980519, Optical Observations
  93. GRB980703, Host galaxy multicolor photometry
  94. GRB980703 optical photometry
  95. GRB980703 optical observations
  96. GRB980703 H-band Observations
  97. GRB 980703: Spectrum of the proposed optical counterpart
  98. GRB980703: Spectrum of the proposed optical counterpart
  99. GRB980703 Transient Optical Follow-Up
  100. GRB980613 Optical Observations

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Download all Circulars as a .tar.gz archive (updated once a day):
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