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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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

37101 results found.

  1. GRB020124, optical observations
  2. GRB020127: Optical observations
  3. GRB 020127, I-band observations starting 3.14-hr after the event
  4. IPN detection of further activity from SGR1806-20
  5. IPN triangulation of GRB020127 (=H1902)
  6. GRB010921 Optical Observations
  7. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  8. GRB020124: Optical observations
  9. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  10. GRB020124: Optical observations
  11. GRB 020124: Optical observations
  12. GRB 020124 Optical Observations
  13. IPN triangulation of GRB020124 (HETE 1896)
  14. IPN observations of SGR1806-20
  15. GRB 020124: Optical afterglow
  16. GRB020124(=H1896): Localization of a Long GRB by HETE
  17. GRB optical counterpart candidate in GCN 1217 is M dwarf
  18. Possible optical counterpart to a GRB
  19. GRB011212, Optical Observations
  20. GRB 011211: Detection of the Probable Host Galaxy
  21. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  22. GRB 011211, spectrum and optical photometry
  23. GRB 011130: Optical Observations of X-ray and Radio Sources
  24. GRB 011130, Radio/X-ray Comparison
  25. GRB 011212: optical observation at Asiago
  26. GRB 011211: Evidence for an Optical Break
  27. GRB 011211: TNG Spectroscopic Observations
  28. optical follow-up of GRB(XRF) 011211
  29. GRB 011212: optical observation at Oslo (relayed)
  30. GRB 011211: Optical Spectroscopy
  31. GRB 011211, Optical Observations
  32. GRB011212, BVRI field photometry
  33. GRB011211, BVRI field photometry
  34. GRB011212: Optical observations
  35. GRB 011211: BVRi-band photometry
  36. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  37. Fading of the optical source associated of XRF 011211
  38. GRB 011211 Optical Observations: Likely Afterglow
  39. BeppoSAX Alert: GRB011211(=XRF011211)
  40. GRB 011130: Optical Observations of Chandra Sources
  41. GRB 011130: Optical Observations of Chandra sources
  42. GRB 011130: Magellan spectroscopy
  43. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  44. GRB011130, optical observations
  45. GRB 011130, K band observations
  46. GRB011130, optical observations
  47. GRB 011130 I-band Observation
  48. GRB011130 (XRF011130) optical observations
  49. GRB011130 (XRF011130) SDSS PT i-band observations
  50. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  51. XRF011130: NEAT Optical Observations
  52. GRB011130 (=XRF011130): Revised Localization of an X-ray
  53. GRB001109, Radio Monitoring
  54. GRB 011121: Errata URL
  55. GRB 011121
  56. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  57. GRB 011121: J-band observations
  58. GRB 011121: NIR observations, host galaxy?
  59. GRB 011121: HST Scheduled
  60. GRB011121: fainter still
  61. Correction: GCN1157 (GRB 011121)
  62. GRB 011121: Radio Observations
  63. GRB 011121 J-Band Astrometry
  64. GRB011121: continued decay
  65. GRB 011121: Detection of Bright IR Counterpart
  66. GRB011121: possible redshift, continued decay
  67. IPN triangulation of GRB011121
  68. BEPPOSAX GRB011121
  69. GRB 011030: TNG K-band observation
  70. XRF011030: Chandra Observations
  71. GRB 011030: K-band observations
  72. GRB 011030 R band observations
  73. GRB 011030 I-band Observation
  74. The X-ray Flash 011030 ('GRB 011030')
  75. Non-triggered burst 011030 ("GRB 011030")
  76. The Radio Afterglow from the X-ray Rich GRB 011030
  77. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  78. GRB 970828: HST Observations of the Host Galaxy
  79. GRB 000131: HST Detection of the Host Galaxy
  80. GRB 970828: HST Observations of the Host Galaxy
  81. GRB010921, optical observation
  82. GRB 011019 optical observation
  83. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  84. GRB011019: Subaru Optical Observations
  85. GRB 011030 I-band Observations
  86. GRB 011030 K-band Observations
  87. GRB010921, optical observations
  88. GRB 011030, WSRT radio observations
  89. GRB011030 - further refinement WFC position
  90. GRB 011030, Radio observations
  91. GRB 011030, R-band observations
  92. BeppoSAX ALERT: Possible X-ray rich GRB011030
  93. GRB 010921: Possible supernova component
  94. GRB011019: NEAT Optical Observations
  95. GRB010921, optical observation at early time
  96. GRB 010921, I-band observations
  97. GRB011019: Optical observations
  98. GRB011019, optical observations
  99. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  100. GRB010921: Spectroscopy of the Host Galaxy

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