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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. The Likely Optical/Infrared Afterglow of GRB 001011
  2. HETE positions added to GCN
  3. GRB001011 BeppoSAX/WFC refined position
  4. BeppoSAX ALERT: GRB001011
  5. GRB 001007, BVR-band observations
  6. GRB000926 - Amateur Optical Observations
  7. GRB001007: Optical observations
  8. CONCAM null result on GRB001005
  9. IPN triangulation of GRB001007
  10. GRB 000926 : the host galaxy
  11. HETE-2 Launches Successfully
  12. IPN triangulation of GRB001005
  13. HETE-2 48 hour Launch Delay
  14. GRB 000926 Chandra Observation
  15. IPN triangulation of GRB 001004
  16. Public availability of BeppoSAX data of GRB000926
  17. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  18. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  19. GRB000926 - Optical observations
  20. GRB000926 - Optical observations
  21. GRB 000926, Optical Decay
  22. GRB000911: VLT infrared observation
  23. GRB000926 - Optical observations
  24. GRB000926 - Optical observations
  25. GRB 000926: optical observations
  26. GRB 000926, Optical Observations
  27. GRB000926 - Optical observations
  28. GRB000911: optical VLT observations
  29. GRB000926 K'-band Observation
  30. GRB000926 : increasing optical decay slope
  31. GRB000926 optical observations
  32. GRB000926 - Optical observations
  33. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  34. J and K band observations of GRB 000926
  35. GRB000911 Optical Observations
  36. GRB 000926: Lightcurve Update and Predictions
  37. GRB 000926, optical observation by Oksanen (vsnet-grb)
  38. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  39. GRB000926: Optical observations
  40. CONCAM crude optical limits before and after GRB000926
  41. GRB 000926: Preliminary R-band Lightcurve
  42. GRB 000926 HST/Chandra TOO Status
  43. Spectroscopic Redshift of GRB 000926
  44. GRB 000926, Optical Observation
  45. GRB000926, radio observations
  46. GRB 000926: Optical candidate
  47. Optical candidate for GRB000926
  48. IPN triangulation of GRB000926
  49. IPN triangulation of GRB000926
  50. GRB 000911, BVRI field photometry
  51. GRB000911: Corrected coordinates
  52. GRB000911: Sub-millimeter observations
  53. IPN triangulation of GRB000925
  54. GRB000911: Optical Transient
  55. GRB000911, Radio and Optical observations
  56. GRB000911, Radio observations
  57. GRB000911: Optical observations
  58. IPN triangulation of GRB000911
  59. IPN triangulation of GRB000910
  60. False GRB alarm from RXTE/ASM on 8 Sept 2000
  61. GRB 000830: Optical observations
  62. GRB000830: Optical observations
  63. GRB000830, TNG B-band observations
  64. GRB000830, BVRI field photometry
  65. GRB000830: Optical observations
  66. GRB000210, Optical observations
  67. Chandra Position of GRB000210
  68. "Snapshot" afterglow IDs and GRB 000830
  69. GRB000830: Optical observations
  70. IPN triangulation of GRB000830
  71. HST/STIS observations of the host galaxy of GRB 980329
  72. HST/STIS observations of the chaotic environment of GRB 980613
  73. IPN localization of GRB000820
  74. SGR 1806-20 burst activity
  75. GRB000812, TNG R-band observations
  76. GRB000801 & GRB000730, Gamma Ray Observations
  77. GRB000730, Gamma Ray Observations
  78. GRB000812, Radio observations
  79. IPN localization of GRB000812
  80. IPN localization of GRB000811
  81. GRB000801, Gamma Ray Observations
  82. GRB000801, VLT-Antu R-band observations
  83. GRB000301C, UBVI optical observations
  84. GRB000801, Radio Observations
  85. GRB 991208 Host Galaxy Imaging
  86. Updated IPN coordinates for GRB000801
  87. IPN localization of GRB000801
  88. IPN localization of GRB000801
  89. IPN localization of GRB000730B
  90. IPN localization of GRB000730B
  91. IPN localization of GRB000730
  92. GRB 990510: Possible detection of a host galaxy
  93. GRB 990510 Host Galaxy Discovery
  94. GRB 000727, optical observations
  95. IPN localization of GRB000727
  96. GRB 990705, HST/STIS observations of the host galaxy
  97. GRB 990712: Late time HST/STIS Observations
  98. GRB 991216, HST/STIS observations
  99. GRB000620, Radio Observations
  100. GRB981226, HST/STIS observations of the host galaxy

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