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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. IPN TRIANGULATION OF GRB010115
  2. IPN TRIANGULATION OF GRB010109
  3. IPN TRIANGULATION OF GRB010109
  4. GRB010103, optical observations
  5. IPN triangulation of GRB010104
  6. IPN triangulation of GRB010103
  7. GRB 001204: Ks observations
  8. H band observation of GRB 001212
  9. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  10. IPN triangulation of GRB001219
  11. GRB 001212 Optical Observation
  12. GRB 001212 Optical Observation
  13. GRB 001212 optical observation
  14. GRB 001212 possible OA in 2MASS
  15. GRB 001212 possible OA
  16. IPN triangulation of GRB001212
  17. GRB001204: Optical observations
  18. Confirmation of IPN position for GRB001204
  19. GRB001204, Radio observations
  20. IPN triangulation of GRB001204 (short/hard)
  21. GRB 001105, further optical observations
  22. GRB001120: Gunn-i observations
  23. GRB001120: Optical observations
  24. GRB001109, optical observations
  25. GRB001120, optical observations
  26. WSRT 4.8 GHz observations of GRB001109
  27. IPN triangulation of GRB001120
  28. Optical/NIR observations of GRB001109
  29. GRB 001109: deep JHK upper limits
  30. GRB 001109 X-ray afterglow with BeppoSAX
  31. CORRECTION to XMM-Newton observation of GRB001025
  32. GRB001109: Optical observations
  33. GRB001109: BeppoSAX/NFI Observations
  34. GRB001109, R-band optical observations
  35. GRB001109, Radio observations
  36. GRB001109: BeppoSAX refined WFC position
  37. BeppoSAX ALERT: GRB001109
  38. GRB001105 BVRI field photometry correction
  39. GRB001105, BVRI field photometry
  40. GRB 001105, R-band observation
  41. IPN TRIANGULATION OF GRB001105
  42. GRB 001025B, Optical obervations
  43. GRB 991208: HST Imaging of the Host Galaxy
  44. GRB000926: R-image of the host galaxy
  45. GRB 001025B, I-band observations
  46. XMM-Newton observation of GRB001025
  47. GRB001025B, Radio observations
  48. GRB 001025 Optical Observations
  49. GRB 001025A, optical observation
  50. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  51. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  52. IPN triangulation of GRB001025
  53. GRB001007: Optical observations
  54. ASM Localization of GRB 001025
  55. GRB001007, Radio observations
  56. IPN TRIANGULATION OF GRB001020
  57. GRB001019, Optical Observations
  58. GRB 001018, Possible Radio Afterglow
  59. GRB001018, Gamma Ray Observations
  60. IPN TRIANGULATION OF GRB001019
  61. CORRECTION TO PEAK FLUX OF GRB001018
  62. IPN TRIANGULATION OF GRB001018
  63. IPN TRIANGULATION OF GRB 001017
  64. GRB 000926: Improved Absorber Redshift
  65. V,R,I band observations of GRB000926
  66. The Likely Optical/Infrared Afterglow of GRB 001011
  67. HETE positions added to GCN
  68. GRB001011 BeppoSAX/WFC refined position
  69. BeppoSAX ALERT: GRB001011
  70. GRB 001007, BVR-band observations
  71. GRB000926 - Amateur Optical Observations
  72. GRB001007: Optical observations
  73. CONCAM null result on GRB001005
  74. IPN triangulation of GRB001007
  75. GRB 000926 : the host galaxy
  76. HETE-2 Launches Successfully
  77. IPN triangulation of GRB001005
  78. HETE-2 48 hour Launch Delay
  79. GRB 000926 Chandra Observation
  80. IPN triangulation of GRB 001004
  81. Public availability of BeppoSAX data of GRB000926
  82. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  83. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  84. GRB000926 - Optical observations
  85. GRB000926 - Optical observations
  86. GRB 000926, Optical Decay
  87. GRB000911: VLT infrared observation
  88. GRB000926 - Optical observations
  89. GRB000926 - Optical observations
  90. GRB 000926: optical observations
  91. GRB 000926, Optical Observations
  92. GRB000926 - Optical observations
  93. GRB000911: optical VLT observations
  94. GRB000926 K'-band Observation
  95. GRB000926 : increasing optical decay slope
  96. GRB000926 optical observations
  97. GRB000926 - Optical observations
  98. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  99. J and K band observations of GRB 000926
  100. GRB000911 Optical Observations

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