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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.

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

36146 results found.

  1. GRB 011130: Optical Observations of X-ray and Radio Sources
  2. GRB 011130, Radio/X-ray Comparison
  3. GRB 011212: optical observation at Asiago
  4. GRB 011211: Evidence for an Optical Break
  5. GRB 011211: TNG Spectroscopic Observations
  6. optical follow-up of GRB(XRF) 011211
  7. GRB 011212: optical observation at Oslo (relayed)
  8. GRB 011211: Optical Spectroscopy
  9. GRB 011211, Optical Observations
  10. GRB011212, BVRI field photometry
  11. GRB011211, BVRI field photometry
  12. GRB011212: Optical observations
  13. GRB 011211: BVRi-band photometry
  14. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  15. Fading of the optical source associated of XRF 011211
  16. GRB 011211 Optical Observations: Likely Afterglow
  17. BeppoSAX Alert: GRB011211(=XRF011211)
  18. GRB 011130: Optical Observations of Chandra Sources
  19. GRB 011130: Optical Observations of Chandra sources
  20. GRB 011130: Magellan spectroscopy
  21. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  22. GRB011130, optical observations
  23. GRB 011130, K band observations
  24. GRB011130, optical observations
  25. GRB 011130 I-band Observation
  26. GRB011130 (XRF011130) optical observations
  27. GRB011130 (XRF011130) SDSS PT i-band observations
  28. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  29. XRF011130: NEAT Optical Observations
  30. GRB011130 (=XRF011130): Revised Localization of an X-ray
  31. GRB001109, Radio Monitoring
  32. GRB 011121: Errata URL
  33. GRB 011121
  34. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  35. GRB 011121: J-band observations
  36. GRB 011121: NIR observations, host galaxy?
  37. GRB 011121: HST Scheduled
  38. GRB011121: fainter still
  39. Correction: GCN1157 (GRB 011121)
  40. GRB 011121: Radio Observations
  41. GRB 011121 J-Band Astrometry
  42. GRB011121: continued decay
  43. GRB 011121: Detection of Bright IR Counterpart
  44. GRB011121: possible redshift, continued decay
  45. IPN triangulation of GRB011121
  46. BEPPOSAX GRB011121
  47. GRB 011030: TNG K-band observation
  48. XRF011030: Chandra Observations
  49. GRB 011030: K-band observations
  50. GRB 011030 R band observations
  51. GRB 011030 I-band Observation
  52. The X-ray Flash 011030 ('GRB 011030')
  53. Non-triggered burst 011030 ("GRB 011030")
  54. The Radio Afterglow from the X-ray Rich GRB 011030
  55. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  56. GRB 970828: HST Observations of the Host Galaxy
  57. GRB 000131: HST Detection of the Host Galaxy
  58. GRB 970828: HST Observations of the Host Galaxy
  59. GRB010921, optical observation
  60. GRB 011019 optical observation
  61. GRB011019: Subaru Optical Observations
  62. GRB 011030 I-band Observations
  63. GRB 011030 K-band Observations
  64. GRB010921, optical observations
  65. GRB 011030, WSRT radio observations
  66. GRB011030 - further refinement WFC position
  67. GRB 011030, Radio observations
  68. GRB 011030, R-band observations
  69. BeppoSAX ALERT: Possible X-ray rich GRB011030
  70. GRB 010921: Possible supernova component
  71. GRB011019: NEAT Optical Observations
  72. GRB010921, optical observation at early time
  73. GRB 010921, I-band observations
  74. GRB011019: Optical observations
  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. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE

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