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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').
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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.

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

37517 results found.

  1. GRB011130 (XRF011130) optical observations
  2. GRB011130 (XRF011130) SDSS PT i-band observations
  3. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  4. XRF011130: NEAT Optical Observations
  5. GRB011130 (=XRF011130): Revised Localization of an X-ray
  6. GRB001109, Radio Monitoring
  7. GRB 011121: Errata URL
  8. GRB 011121
  9. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  10. GRB 011121: J-band observations
  11. GRB 011121: NIR observations, host galaxy?
  12. GRB 011121: HST Scheduled
  13. GRB011121: fainter still
  14. Correction: GCN1157 (GRB 011121)
  15. GRB 011121: Radio Observations
  16. GRB 011121 J-Band Astrometry
  17. GRB011121: continued decay
  18. GRB 011121: Detection of Bright IR Counterpart
  19. GRB011121: possible redshift, continued decay
  20. IPN triangulation of GRB011121
  21. BEPPOSAX GRB011121
  22. GRB 011030: TNG K-band observation
  23. XRF011030: Chandra Observations
  24. GRB 011030: K-band observations
  25. GRB 011030 R band observations
  26. GRB 011030 I-band Observation
  27. The X-ray Flash 011030 ('GRB 011030')
  28. Non-triggered burst 011030 ("GRB 011030")
  29. The Radio Afterglow from the X-ray Rich GRB 011030
  30. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  31. GRB 970828: HST Observations of the Host Galaxy
  32. GRB 000131: HST Detection of the Host Galaxy
  33. GRB 970828: HST Observations of the Host Galaxy
  34. GRB010921, optical observation
  35. GRB 011019 optical observation
  36. GRB011019: Subaru Optical Observations
  37. GRB 011030 I-band Observations
  38. GRB 011030 K-band Observations
  39. GRB010921, optical observations
  40. GRB 011030, WSRT radio observations
  41. GRB011030 - further refinement WFC position
  42. GRB 011030, Radio observations
  43. GRB 011030, R-band observations
  44. BeppoSAX ALERT: Possible X-ray rich GRB011030
  45. GRB 010921: Possible supernova component
  46. GRB011019: NEAT Optical Observations
  47. GRB010921, optical observation at early time
  48. GRB 010921, I-band observations
  49. GRB011019: Optical observations
  50. GRB011019, optical observations
  51. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  52. GRB010921: Spectroscopy of the Host Galaxy
  53. GRB 010921: The afterglow of HETE #1761
  54. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  55. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  56. GRB010923 as seen by BeppoSAX GRBM
  57. GRB010928(=H1770): Localization of a Long GRB by HETE
  58. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  59. GRB010921, negative optical observations
  60. GRB010921 field photometry
  61. GRB010921 Optical Observations
  62. GRB 010921 DPOSS Images Available
  63. IPN triangulation of GRB010921 (=H1761)
  64. H1761: A Bright GRB Detected by HETE
  65. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  66. HETE Trigger #1760 (GRB 010920B?): a new optical source
  67. HETE Trigger #1759 (GRB 010920?) optical observations
  68. GRB001109, Host Galaxy Astrometry
  69. GRB000926, Host Galaxy Observations
  70. GRB001109, Host Galaxy Spectroscopic Observations
  71. Probable SGR or Short Duration GRB Detected by HETE
  72. GRB000926 Host Galaxy Observations
  73. GRB 010222: HST observations -- host galaxy and late-time decay
  74. BeppoSAX/GRBM detection of GRB 010801
  75. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  76. GRB 010222 - WHT BVRI images
  77. GRB 010629 Optical Observations
  78. GRB010629: Optical Observations
  79. GRB010629, optical observations
  80. IPN triangulation of GRB010629
  81. GRB010629: A Burst Localized by HETE
  82. Possible burst from SGR1806-20
  83. IPN detection of SGR1900+14
  84. GRB 00630: Host Galaxy
  85. IPN triangulation of GRB010613
  86. IPN triangulation of GRB010612
  87. HETE Fully-Automated GCN Notices
  88. GRB000301C: Late-time HST/STIS observation
  89. GRB010518: a faint BeppoSAX detection
  90. GRB000418: HST/STIS Second-epoch Observations
  91. GRB010427, Gamma Ray Observations
  92. SGR1900+14
  93. GRB 010222 /corrections to VBT data
  94. Possible precursor to the SGR1900+14 giant burst
  95. IPN Triangulation of the Giant Flare from SGR1900+14
  96. GRB010412, field photometry
  97. GRB 010326b Optical Observations
  98. GRB010412: Optical observations
  99. GRB010412: Optical observations
  100. IPN Triangulation of GRB010412

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