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

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