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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 polarization observations for GRB011211
  2. GRB 011211: Detection of the Probable Host Galaxy
  3. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  4. Color indices of the afterglow of GRB011211
  5. GRB011212: Optical observations at Gunma
  6. GRB 011211, spectrum and optical photometry
  7. GRB 011130: Optical Observations of X-ray and Radio Sources
  8. GRB 011130, Radio/X-ray Comparison
  9. GRB011212: Optical observations
  10. GRB 011212: optical observation at Asiago
  11. GRB 011211: Evidence for an Optical Break
  12. GRB 011211: TNG Spectroscopic Observations
  13. optical follow-up of GRB(XRF) 011211
  14. GRB 011212: optical observation at Oslo (relayed)
  15. GRB 011211: Optical Spectroscopy
  16. GRB 011211, Optical Observations
  17. GRB011212, BVRI field photometry
  18. GRB011211, BVRI field photometry
  19. GRB011212: Optical observations
  20. GRB 011211: BVRi-band photometry
  21. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  22. Fading of the optical source associated of XRF 011211
  23. XMM-Newton observation of GRB011211
  24. GRB 011211 Optical Observations: Likely Afterglow
  25. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  26. GRB011211(=XRF011211): BeppoSAX refined positions
  27. BeppoSAX Alert: GRB011211(=XRF011211)
  28. GRB 011130: Optical Observations of Chandra Sources
  29. GRB 011130: Optical Observations of Chandra sources
  30. GRB011130 (XRF011130) Chandra Observations
  31. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  32. GRB 011130: Magellan spectroscopy
  33. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  34. GRB011130, optical observations
  35. GRB 011130, K band observations
  36. GRB011130, optical observations
  37. GRB011130 (=XRF011130): Second Revised Localization by HETE
  38. GRB 011130 I-band Observation
  39. GRB011130 (XRF011130) optical observations
  40. GRB011130 (XRF011130) SDSS PT i-band observations
  41. XRF011130: Infrared Observations
  42. GRB011130, Radio Observations
  43. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  44. GRB011130 (=XRF011130), Optical Observations
  45. XRF011130: NEAT Optical Observations
  46. GRB011130 (=XRF011130): Revised Localization of an X-ray
  47. GRB001109, Radio Monitoring
  48. GRB 011121: Errata URL
  49. GRB 011121
  50. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  51. GRB 011121: J-band observations
  52. GRB 011121: NIR observations, host galaxy?
  53. GRB010921 - Milagro GeV/TeV Observations
  54. GRB 011121: HST Scheduled
  55. GRB011121: fainter still
  56. Correction: GCN1157 (GRB 011121)
  57. GRB011121: UBRI Observations
  58. GRB011121
  59. GRB 011121: Radio Observations
  60. GRB 011121 J-Band Astrometry
  61. GRB011121: continued decay
  62. GRB 011121: Detection of Bright IR Counterpart
  63. GRB011121: possible redshift, continued decay
  64. GRB011121: fading behavior
  65. GRB011121: possible optical counterpart
  66. GRB011121: BeppoSAX-WFC refined positions
  67. IPN triangulation of GRB011121
  68. BEPPOSAX GRB011121
  69. GRB 011030: TNG K-band observation
  70. XRF011030: J and K band observations
  71. GRB011030, optical observation
  72. XRF011030: Chandra Observations
  73. GRB 011030: K-band observations
  74. GRB011030: Z-band observations
  75. GRB 011030 R band observations
  76. GRB 011030 I-band Observation
  77. The X-ray Flash 011030 ('GRB 011030')
  78. Non-triggered burst 011030 ("GRB 011030")
  79. The Radio Afterglow from the X-ray Rich GRB 011030
  80. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  81. GRB 970828: HST Observations of the Host Galaxy
  82. GRB 000131: HST Detection of the Host Galaxy
  83. GRB 970828: HST Observations of the Host Galaxy
  84. GRB010921, optical observation
  85. GRB 011019 optical observation
  86. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  87. GRB011019: Subaru Optical Observations
  88. GRB 011030 I-band Observations
  89. GRB 011030 K-band Observations
  90. GRB010921, optical observations
  91. GRB 011030, WSRT radio observations
  92. GRB011030 - further refinement WFC position
  93. GRB 011030, Radio observations
  94. GRB011030: radio search
  95. GRB 011030, R-band observations
  96. X-ray rich GRB011030: BeppoSAX refined positions
  97. BeppoSAX ALERT: Possible X-ray rich GRB011030
  98. GRB 010921: Possible supernova component
  99. GRB011019: NEAT Optical Observations
  100. GRB011019: ROTSE-III optical observations

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