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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. GRB001105 BVRI field photometry correction
  2. GRB001105, BVRI field photometry
  3. GRB 001105, R-band observation
  4. IPN TRIANGULATION OF GRB001105
  5. GRB 001025B, Optical obervations
  6. GRB 991208: HST Imaging of the Host Galaxy
  7. GRB000926: R-image of the host galaxy
  8. GRB 001025B, I-band observations
  9. XMM-Newton observation of GRB001025
  10. GRB001025B, Radio observations
  11. GRB 001025 Optical Observations
  12. GRB 001025A, optical observation
  13. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  14. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  15. IPN triangulation of GRB001025
  16. GRB001007: Optical observations
  17. ASM Localization of GRB 001025
  18. GRB001007, Radio observations
  19. IPN TRIANGULATION OF GRB001020
  20. GRB001019, Optical Observations
  21. GRB 001018, Possible Radio Afterglow
  22. GRB001018, Gamma Ray Observations
  23. IPN TRIANGULATION OF GRB001019
  24. CORRECTION TO PEAK FLUX OF GRB001018
  25. IPN TRIANGULATION OF GRB001018
  26. IPN TRIANGULATION OF GRB 001017
  27. GRB 000926: Improved Absorber Redshift
  28. V,R,I band observations of GRB000926
  29. The Likely Optical/Infrared Afterglow of GRB 001011
  30. HETE positions added to GCN
  31. GRB001011 BeppoSAX/WFC refined position
  32. BeppoSAX ALERT: GRB001011
  33. GRB 001007, BVR-band observations
  34. GRB000926 - Amateur Optical Observations
  35. GRB001007: Optical observations
  36. CONCAM null result on GRB001005
  37. IPN triangulation of GRB001007
  38. GRB 000926 : the host galaxy
  39. HETE-2 Launches Successfully
  40. IPN triangulation of GRB001005
  41. HETE-2 48 hour Launch Delay
  42. GRB 000926 Chandra Observation
  43. IPN triangulation of GRB 001004
  44. Public availability of BeppoSAX data of GRB000926
  45. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  46. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  47. GRB000926 - Optical observations
  48. GRB000926 - Optical observations
  49. GRB 000926, Optical Decay
  50. GRB000911: VLT infrared observation
  51. GRB000926 - Optical observations
  52. GRB000926 - Optical observations
  53. GRB 000926: optical observations
  54. GRB 000926, Optical Observations
  55. GRB000926 - Optical observations
  56. GRB000911: optical VLT observations
  57. GRB000926 K'-band Observation
  58. GRB000926 : increasing optical decay slope
  59. GRB000926 optical observations
  60. GRB000926 - Optical observations
  61. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  62. J and K band observations of GRB 000926
  63. GRB000911 Optical Observations
  64. GRB 000926: Lightcurve Update and Predictions
  65. GRB 000926, optical observation by Oksanen (vsnet-grb)
  66. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  67. GRB000926: Optical observations
  68. CONCAM crude optical limits before and after GRB000926
  69. GRB 000926: Preliminary R-band Lightcurve
  70. GRB 000926 HST/Chandra TOO Status
  71. Spectroscopic Redshift of GRB 000926
  72. GRB 000926, Optical Observation
  73. GRB000926, radio observations
  74. GRB 000926: Optical candidate
  75. Optical candidate for GRB000926
  76. IPN triangulation of GRB000926
  77. IPN triangulation of GRB000926
  78. GRB 000911, BVRI field photometry
  79. GRB000911: Corrected coordinates
  80. GRB000911: Sub-millimeter observations
  81. IPN triangulation of GRB000925
  82. GRB000911: Optical Transient
  83. GRB000911, Radio and Optical observations
  84. GRB000911, Radio observations
  85. GRB000911: Optical observations
  86. IPN triangulation of GRB000911
  87. IPN triangulation of GRB000910
  88. False GRB alarm from RXTE/ASM on 8 Sept 2000
  89. GRB 000830: Optical observations
  90. GRB000830: Optical observations
  91. GRB000830, TNG B-band observations
  92. GRB000830, BVRI field photometry
  93. GRB000830: Optical observations
  94. GRB000210, Optical observations
  95. Chandra Position of GRB000210
  96. "Snapshot" afterglow IDs and GRB 000830
  97. GRB000830: Optical observations
  98. IPN triangulation of GRB000830
  99. HST/STIS observations of the host galaxy of GRB 980329
  100. HST/STIS observations of the chaotic environment of GRB 980613

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