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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. GRB010126 optical observations
  2. GRB010126: Optical observations
  3. IPN TRIANGULATION OF GRB010126
  4. IPN/RXTE TRIANGULATION OF GRB010126
  5. GRB 010119, optical observations
  6. GRB010119: Optical observations
  7. Optical Observations of GRB 001018 at Keck
  8. GRB010119, Radio observations
  9. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  10. Optical observations of GRB 001018 with JCAM
  11. IPN TRIANGULATION OF GRB010115
  12. IPN TRIANGULATION OF GRB010109
  13. IPN TRIANGULATION OF GRB010109
  14. GRB010103, optical observations
  15. IPN triangulation of GRB010104
  16. IPN triangulation of GRB010103
  17. GRB 001204: Ks observations
  18. H band observation of GRB 001212
  19. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  20. IPN triangulation of GRB001219
  21. GRB 001212 Optical Observation
  22. GRB 001212 Optical Observation
  23. GRB 001212 optical observation
  24. GRB 001212 possible OA in 2MASS
  25. GRB 001212 possible OA
  26. IPN triangulation of GRB001212
  27. GRB001204: Optical observations
  28. Confirmation of IPN position for GRB001204
  29. GRB001204, Radio observations
  30. IPN triangulation of GRB001204 (short/hard)
  31. GRB 001105, further optical observations
  32. GRB001120: Gunn-i observations
  33. GRB001120: Optical observations
  34. GRB001109, optical observations
  35. GRB001120, optical observations
  36. WSRT 4.8 GHz observations of GRB001109
  37. IPN triangulation of GRB001120
  38. Optical/NIR observations of GRB001109
  39. GRB 001109: deep JHK upper limits
  40. GRB 001109 X-ray afterglow with BeppoSAX
  41. CORRECTION to XMM-Newton observation of GRB001025
  42. GRB001109: Optical observations
  43. GRB001109: BeppoSAX/NFI Observations
  44. GRB001109, R-band optical observations
  45. GRB001109, Radio observations
  46. GRB001109: BeppoSAX refined WFC position
  47. BeppoSAX ALERT: GRB001109
  48. GRB001105 BVRI field photometry correction
  49. GRB001105, BVRI field photometry
  50. GRB 001105, R-band observation
  51. IPN TRIANGULATION OF GRB001105
  52. GRB 001025B, Optical obervations
  53. GRB 991208: HST Imaging of the Host Galaxy
  54. GRB000926: R-image of the host galaxy
  55. GRB 001025B, I-band observations
  56. XMM-Newton observation of GRB001025
  57. GRB001025B, Radio observations
  58. GRB 001025 Optical Observations
  59. GRB 001025A, optical observation
  60. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  61. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  62. IPN triangulation of GRB001025
  63. GRB001007: Optical observations
  64. ASM Localization of GRB 001025
  65. GRB001007, Radio observations
  66. IPN TRIANGULATION OF GRB001020
  67. GRB001019, Optical Observations
  68. GRB 001018, Possible Radio Afterglow
  69. GRB001018, Gamma Ray Observations
  70. IPN TRIANGULATION OF GRB001019
  71. CORRECTION TO PEAK FLUX OF GRB001018
  72. IPN TRIANGULATION OF GRB001018
  73. IPN TRIANGULATION OF GRB 001017
  74. GRB 000926: Improved Absorber Redshift
  75. V,R,I band observations of GRB000926
  76. The Likely Optical/Infrared Afterglow of GRB 001011
  77. HETE positions added to GCN
  78. GRB001011 BeppoSAX/WFC refined position
  79. BeppoSAX ALERT: GRB001011
  80. GRB 001007, BVR-band observations
  81. GRB000926 - Amateur Optical Observations
  82. GRB001007: Optical observations
  83. CONCAM null result on GRB001005
  84. IPN triangulation of GRB001007
  85. GRB 000926 : the host galaxy
  86. HETE-2 Launches Successfully
  87. IPN triangulation of GRB001005
  88. HETE-2 48 hour Launch Delay
  89. GRB 000926 Chandra Observation
  90. IPN triangulation of GRB 001004
  91. Public availability of BeppoSAX data of GRB000926
  92. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  93. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  94. GRB000926 - Optical observations
  95. GRB000926 - Optical observations
  96. GRB 000926, Optical Decay
  97. GRB000911: VLT infrared observation
  98. GRB000926 - Optical observations
  99. GRB000926 - Optical observations
  100. GRB 000926: optical observations

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