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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"

15685 results found.

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

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