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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').
  1. "GRB 990123: New BV Observations"
  2. GRB 990123 Optical Follow-Up
  3. GRB 990123; Addendum to GCN 223
  4. GRB 990123: BATSE Observations
  5. GRB 990123 Keck Spectrum update
  6. GRB990123 IPN annulus
  7. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  8. GRB990123 Optical Observations
  9. GRB 990123 Spectroscopic Redshifts
  10. GRB 990123: New Optical Observations, Decay Measure
  11. GRB 990123 Optical Follow-Up
  12. GRB 990123: Possible Gravitationally Lensed Burst?
  13. GRB990123, optical observation
  14. GRB 990123 optical observations
  15. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  16. GRB 990123 radio observations
  17. GRB 990123, new radio source
  18. GRB990123 optical observations
  19. GRB990123, Optical observation
  20. GRB 990123: Optical Decay Slope
  21. GRB 990123 r-band photometry
  22. GRB 990123 Optical Follow-up
  23. GRB990123, early optical counterpart detection
  24. GRB990123 Optical Observation
  25. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  26. GRB990123, refined SAX-WFC position
  27. GRB 990123: Bright New Source, Possible Optical Transient
  28. GRB 990123, Radio observations
  29. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  30. SN 1999E & GRB 980919
  31. Possible identification of SN1999E with GRB980910
  32. Optical Observations of GRB 981220
  33. GRB 981226: radio variable
  34. GRB981220
  35. GRB981220, Correction to GCN 179
  36. GRB981220, Optical Observations
  37. GRB 981220 Optical observations
  38. GRB 981226 Optical Observations
  39. GRB 980613: Spectroscopy of the host galaxy
  40. GRB981226, sub-millimeter observations
  41. GRB981220, sub-millimeter observations
  42. GRB 981220 and GRB 981226, optical observations
  43. GRB981226 Optical Observations
  44. GRB981226 BeppoSAX follow up
  45. GRB 981226 radio observations
  46. GRB 981226
  47. GRB 981226 optical observations
  48. radio observations of GRB 981226
  49. GRB981220 B, R and I band observations
  50. GRB981226, BeppoSAX-NFI follow-up
  51. Optical Observations of GRB981226
  52. GRB 981220:Optical Observations
  53. GRB 981220 optical R and I observations
  54. GRB981226, BeppoSAX Christmas GRB
  55. GRB 981226 - Infrared Observations
  56. GRB 981226 optical observations
  57. GRB 981220
  58. GRB 981220, radio observations
  59. GRB981226 Optical Observation
  60. GRB 981220, radio observations
  61. GRB 981220: BeppoSAX/GRBM results
  62. GRB981220 I-band Observations
  63. GRB981220 Optical Observations
  64. GRB 981220
  65. GRB 981220 Optical Observations
  66. GRB 981220, optical observations
  67. GRB 980326/Host Galaxy
  68. GRB981220 IPN error box
  69. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  70. BeppoSAX NFI Observation of GRB980425
  71. GRB980329 R,I flux calibration and R,I,K upper limits
  72. GRB980425 Optical Follow-up
  73. GRB980425: X-ray revised positions
  74. GRB 980923 BATSE Observations
  75. SGR1900+14, BeppoSAX-GRBM observations
  76. GRB980703 Very Long Baseline Interferometry
  77. GRB970508 optical observations
  78. GRB971214, association with a Galactic star?
  79. Optical Observations of the Host Galaxy of GRB 980519
  80. GRB980519, Optical Observations
  81. GRB980703, Host galaxy multicolor photometry
  82. GRB980703 - BeppoSAX/GRBM detection
  83. GRB 980703 (NFI observations)
  84. GRB980703 optical photometry
  85. GRB 980703: BATSE Observations
  86. GRB980703 optical observations
  87. GRB980703: Radio transient
  88. GRB980703 H-band Observations
  89. GRB 980703: Spectrum of the proposed optical counterpart
  90. RXTE Observation of GRB 980706
  91. GRB980703: Spectrum of the proposed optical counterpart
  92. GRB980703 Transient Optical Follow-Up
  93. GRB980703: LOTIS observation at early times
  94. GRB980613 Optical Observations
  95. GRB 980703
  96. GRB980703 (I band observations)
  97. GRB 980703 H-band Observations
  98. GRB980703 (optical R observations)
  99. GRB980706
  100. GRB980703: radio source/optical transient

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