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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. Optical/NIR observations of GRB001109
  2. GRB 001109: deep JHK upper limits
  3. GRB 001109 X-ray afterglow with BeppoSAX
  4. CORRECTION to XMM-Newton observation of GRB001025
  5. GRB001109: Optical observations
  6. GRB001109: BeppoSAX/NFI Observations
  7. GRB001109, R-band optical observations
  8. GRB001109, Radio observations
  9. GRB001109: BeppoSAX refined WFC position
  10. BeppoSAX ALERT: GRB001109
  11. GRB001105 BVRI field photometry correction
  12. GRB001105, BVRI field photometry
  13. GRB 001105, R-band observation
  14. IPN TRIANGULATION OF GRB001105
  15. GRB 001025B, Optical obervations
  16. GRB 991208: HST Imaging of the Host Galaxy
  17. GRB000926: R-image of the host galaxy
  18. GRB 001025B, I-band observations
  19. XMM-Newton observation of GRB001025
  20. GRB001025B, Radio observations
  21. GRB 001025 Optical Observations
  22. GRB 001025A, optical observation
  23. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  24. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  25. IPN triangulation of GRB001025
  26. GRB001007: Optical observations
  27. ASM Localization of GRB 001025
  28. GRB001007, Radio observations
  29. IPN TRIANGULATION OF GRB001020
  30. GRB001019, Optical Observations
  31. GRB 001018, Possible Radio Afterglow
  32. GRB001018, Gamma Ray Observations
  33. IPN TRIANGULATION OF GRB001019
  34. CORRECTION TO PEAK FLUX OF GRB001018
  35. IPN TRIANGULATION OF GRB001018
  36. IPN TRIANGULATION OF GRB 001017
  37. GRB 000926: Improved Absorber Redshift
  38. V,R,I band observations of GRB000926
  39. The Likely Optical/Infrared Afterglow of GRB 001011
  40. HETE positions added to GCN
  41. GRB001011 BeppoSAX/WFC refined position
  42. BeppoSAX ALERT: GRB001011
  43. GRB 001007, BVR-band observations
  44. GRB000926 - Amateur Optical Observations
  45. GRB001007: Optical observations
  46. CONCAM null result on GRB001005
  47. IPN triangulation of GRB001007
  48. GRB 000926 : the host galaxy
  49. HETE-2 Launches Successfully
  50. IPN triangulation of GRB001005
  51. HETE-2 48 hour Launch Delay
  52. GRB 000926 Chandra Observation
  53. IPN triangulation of GRB 001004
  54. Public availability of BeppoSAX data of GRB000926
  55. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  56. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  57. GRB000926 - Optical observations
  58. GRB000926 - Optical observations
  59. GRB 000926, Optical Decay
  60. GRB000911: VLT infrared observation
  61. GRB000926 - Optical observations
  62. GRB000926 - Optical observations
  63. GRB 000926: optical observations
  64. GRB 000926, Optical Observations
  65. GRB000926 - Optical observations
  66. GRB000911: optical VLT observations
  67. GRB000926 K'-band Observation
  68. GRB000926 : increasing optical decay slope
  69. GRB000926 optical observations
  70. GRB000926 - Optical observations
  71. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  72. J and K band observations of GRB 000926
  73. GRB000911 Optical Observations
  74. GRB 000926: Lightcurve Update and Predictions
  75. GRB 000926, optical observation by Oksanen (vsnet-grb)
  76. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  77. GRB000926: Optical observations
  78. CONCAM crude optical limits before and after GRB000926
  79. GRB 000926: Preliminary R-band Lightcurve
  80. GRB 000926 HST/Chandra TOO Status
  81. Spectroscopic Redshift of GRB 000926
  82. GRB 000926, Optical Observation
  83. GRB000926, radio observations
  84. GRB 000926: Optical candidate
  85. Optical candidate for GRB000926
  86. IPN triangulation of GRB000926
  87. IPN triangulation of GRB000926
  88. GRB 000911, BVRI field photometry
  89. GRB000911: Corrected coordinates
  90. GRB000911: Sub-millimeter observations
  91. IPN triangulation of GRB000925
  92. GRB000911: Optical Transient
  93. GRB000911, Radio and Optical observations
  94. GRB000911, Radio observations
  95. GRB000911: Optical observations
  96. IPN triangulation of GRB000911
  97. IPN triangulation of GRB000910
  98. False GRB alarm from RXTE/ASM on 8 Sept 2000
  99. GRB 000830: Optical observations
  100. GRB000830: Optical observations

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