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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"

36063 results found.

  1. GRB020127: Optical observations
  2. GRB 020127, I-band observations starting 3.14-hr after the event
  3. IPN detection of further activity from SGR1806-20
  4. IPN triangulation of GRB020127 (=H1902)
  5. GRB010921 Optical Observations
  6. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  7. GRB020124: Optical observations
  8. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  9. GRB020124: Optical observations
  10. GRB 020124: Optical observations
  11. GRB 020124 Optical Observations
  12. IPN triangulation of GRB020124 (HETE 1896)
  13. IPN observations of SGR1806-20
  14. GRB 020124: Optical afterglow
  15. GRB020124(=H1896): Localization of a Long GRB by HETE
  16. GRB optical counterpart candidate in GCN 1217 is M dwarf
  17. Possible optical counterpart to a GRB
  18. GRB011212, Optical Observations
  19. GRB 011211: Detection of the Probable Host Galaxy
  20. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  21. GRB 011211, spectrum and optical photometry
  22. GRB 011130: Optical Observations of X-ray and Radio Sources
  23. GRB 011130, Radio/X-ray Comparison
  24. GRB 011212: optical observation at Asiago
  25. GRB 011211: Evidence for an Optical Break
  26. GRB 011211: TNG Spectroscopic Observations
  27. optical follow-up of GRB(XRF) 011211
  28. GRB 011212: optical observation at Oslo (relayed)
  29. GRB 011211: Optical Spectroscopy
  30. GRB 011211, Optical Observations
  31. GRB011212, BVRI field photometry
  32. GRB011211, BVRI field photometry
  33. GRB011212: Optical observations
  34. GRB 011211: BVRi-band photometry
  35. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  36. Fading of the optical source associated of XRF 011211
  37. GRB 011211 Optical Observations: Likely Afterglow
  38. BeppoSAX Alert: GRB011211(=XRF011211)
  39. GRB 011130: Optical Observations of Chandra Sources
  40. GRB 011130: Optical Observations of Chandra sources
  41. GRB 011130: Magellan spectroscopy
  42. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  43. GRB011130, optical observations
  44. GRB 011130, K band observations
  45. GRB011130, optical observations
  46. GRB 011130 I-band Observation
  47. GRB011130 (XRF011130) optical observations
  48. GRB011130 (XRF011130) SDSS PT i-band observations
  49. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  50. XRF011130: NEAT Optical Observations
  51. GRB011130 (=XRF011130): Revised Localization of an X-ray
  52. GRB001109, Radio Monitoring
  53. GRB 011121: Errata URL
  54. GRB 011121
  55. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  56. GRB 011121: J-band observations
  57. GRB 011121: NIR observations, host galaxy?
  58. GRB 011121: HST Scheduled
  59. GRB011121: fainter still
  60. Correction: GCN1157 (GRB 011121)
  61. GRB 011121: Radio Observations
  62. GRB 011121 J-Band Astrometry
  63. GRB011121: continued decay
  64. GRB 011121: Detection of Bright IR Counterpart
  65. GRB011121: possible redshift, continued decay
  66. IPN triangulation of GRB011121
  67. BEPPOSAX GRB011121
  68. GRB 011030: TNG K-band observation
  69. XRF011030: Chandra Observations
  70. GRB 011030: K-band observations
  71. GRB 011030 R band observations
  72. GRB 011030 I-band Observation
  73. The X-ray Flash 011030 ('GRB 011030')
  74. Non-triggered burst 011030 ("GRB 011030")
  75. The Radio Afterglow from the X-ray Rich GRB 011030
  76. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  77. GRB 970828: HST Observations of the Host Galaxy
  78. GRB 000131: HST Detection of the Host Galaxy
  79. GRB 970828: HST Observations of the Host Galaxy
  80. GRB010921, optical observation
  81. GRB 011019 optical observation
  82. GRB011019: Subaru Optical Observations
  83. GRB 011030 I-band Observations
  84. GRB 011030 K-band Observations
  85. GRB010921, optical observations
  86. GRB 011030, WSRT radio observations
  87. GRB011030 - further refinement WFC position
  88. GRB 011030, Radio observations
  89. GRB 011030, R-band observations
  90. BeppoSAX ALERT: Possible X-ray rich GRB011030
  91. GRB 010921: Possible supernova component
  92. GRB011019: NEAT Optical Observations
  93. GRB010921, optical observation at early time
  94. GRB 010921, I-band observations
  95. GRB011019: Optical observations
  96. GRB011019, optical observations
  97. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  98. GRB010921: Spectroscopy of the Host Galaxy
  99. GRB 010921: The afterglow of HETE #1761
  100. Optical Observations of the field of HETE trigger #1793/GRB 011012?

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