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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. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  2. GRB 011130: Magellan spectroscopy
  3. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  4. GRB011130, optical observations
  5. GRB 011130, K band observations
  6. GRB011130, optical observations
  7. GRB011130 (=XRF011130): Second Revised Localization by HETE
  8. GRB 011130 I-band Observation
  9. GRB011130 (XRF011130) optical observations
  10. GRB011130 (XRF011130) SDSS PT i-band observations
  11. XRF011130: Infrared Observations
  12. GRB011130, Radio Observations
  13. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  14. GRB011130 (=XRF011130), Optical Observations
  15. XRF011130: NEAT Optical Observations
  16. GRB011130 (=XRF011130): Revised Localization of an X-ray
  17. GRB001109, Radio Monitoring
  18. GRB 011121: Errata URL
  19. GRB 011121
  20. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  21. GRB 011121: J-band observations
  22. GRB 011121: NIR observations, host galaxy?
  23. GRB010921 - Milagro GeV/TeV Observations
  24. GRB 011121: HST Scheduled
  25. GRB011121: fainter still
  26. Correction: GCN1157 (GRB 011121)
  27. GRB011121: UBRI Observations
  28. GRB011121
  29. GRB 011121: Radio Observations
  30. GRB 011121 J-Band Astrometry
  31. GRB011121: continued decay
  32. GRB 011121: Detection of Bright IR Counterpart
  33. GRB011121: possible redshift, continued decay
  34. GRB011121: fading behavior
  35. GRB011121: possible optical counterpart
  36. GRB011121: BeppoSAX-WFC refined positions
  37. IPN triangulation of GRB011121
  38. BEPPOSAX GRB011121
  39. GRB 011030: TNG K-band observation
  40. XRF011030: J and K band observations
  41. GRB011030, optical observation
  42. XRF011030: Chandra Observations
  43. GRB 011030: K-band observations
  44. GRB011030: Z-band observations
  45. GRB 011030 R band observations
  46. GRB 011030 I-band Observation
  47. The X-ray Flash 011030 ('GRB 011030')
  48. Non-triggered burst 011030 ("GRB 011030")
  49. The Radio Afterglow from the X-ray Rich GRB 011030
  50. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  51. GRB 970828: HST Observations of the Host Galaxy
  52. GRB 000131: HST Detection of the Host Galaxy
  53. GRB 970828: HST Observations of the Host Galaxy
  54. GRB010921, optical observation
  55. GRB 011019 optical observation
  56. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  57. GRB011019: Subaru Optical Observations
  58. GRB 011030 I-band Observations
  59. GRB 011030 K-band Observations
  60. GRB010921, optical observations
  61. GRB 011030, WSRT radio observations
  62. GRB011030 - further refinement WFC position
  63. GRB 011030, Radio observations
  64. GRB011030: radio search
  65. GRB 011030, R-band observations
  66. X-ray rich GRB011030: BeppoSAX refined positions
  67. BeppoSAX ALERT: Possible X-ray rich GRB011030
  68. GRB 010921: Possible supernova component
  69. GRB011019: NEAT Optical Observations
  70. GRB011019: ROTSE-III optical observations
  71. GRB010921, optical observation at early time
  72. GRB 010921, I-band observations
  73. GRB011019: Optical observations
  74. GRB011019, optical observations -- correction
  75. GRB011019, optical observations
  76. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  77. GRB010921: Spectroscopy of the Host Galaxy
  78. GRB 010921: The afterglow of HETE #1761
  79. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  80. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  81. GRB010923 as seen by BeppoSAX GRBM
  82. GRB010928(=H1770): Localization of a Long GRB by HETE
  83. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  84. GRB010921, negative optical observations
  85. GRB010921 field photometry
  86. GRB010921 Optical Observations
  87. GRB 010921 DPOSS Images Available
  88. IPN triangulation of GRB010921 (=H1761)
  89. H1761: A Bright GRB Detected by HETE
  90. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  91. HETE Trigger #1760 (GRB 010920B?): a new optical source
  92. HETE Trigger #1759 (GRB 010920?) optical observations
  93. GRB001109, Host Galaxy Astrometry
  94. GRB000926, Host Galaxy Observations
  95. GRB001109, Host Galaxy Spectroscopic Observations
  96. Probable SGR or Short Duration GRB Detected by HETE
  97. GRB000926 Host Galaxy Observations
  98. GRB 010222: HST observations -- host galaxy and late-time decay
  99. BeppoSAX/GRBM detection of GRB 010801
  100. GCN and HETE status

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