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

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