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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"

28051 results found.

  1. GRB020127: Chandra Observations and Prospective Counterparts
  2. pre-SN2002ap (SN/GRB?) imaging of M74
  3. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  4. GRB020124, optical observations
  5. GRB 020127, I-band observations starting 3.14-hr after the event
  6. GRB010921 Optical Observations
  7. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  8. GRB020124: Optical observations
  9. GRB 020124: Optical observations
  10. GRB 020124: Optical afterglow
  11. GRB020124(=H1896): Localization of a Long GRB by HETE
  12. Possible optical counterpart to a GRB
  13. GRB011212, Optical Observations
  14. Optical polarization observations for GRB011211
  15. GRB 011211: Detection of the Probable Host Galaxy
  16. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  17. GRB 011130: Optical Observations of X-ray and Radio Sources
  18. GRB 011212: optical observation at Asiago
  19. GRB 011211: Evidence for an Optical Break
  20. GRB 011211: TNG Spectroscopic Observations
  21. optical follow-up of GRB(XRF) 011211
  22. GRB 011212: optical observation at Oslo (relayed)
  23. GRB 011211, Optical Observations
  24. GRB011212, BVRI field photometry
  25. GRB011211, BVRI field photometry
  26. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  27. Fading of the optical source associated of XRF 011211
  28. GRB 011211 Optical Observations: Likely Afterglow
  29. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  30. GRB011130 (XRF011130) Chandra Observations
  31. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  32. GRB 011130, K band observations
  33. GRB011130, optical observations
  34. GRB011130 (=XRF011130): Second Revised Localization by HETE
  35. GRB011130 (XRF011130) SDSS PT i-band observations
  36. XRF011130: Infrared Observations
  37. GRB 011121
  38. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  39. GRB 011121: J-band observations
  40. GRB 011121: NIR observations, host galaxy?
  41. GRB011121: UBRI Observations
  42. GRB 011121 J-Band Astrometry
  43. GRB 011121: Detection of Bright IR Counterpart
  44. GRB011121: possible redshift, continued decay
  45. GRB 011030: TNG K-band observation
  46. XRF011030: J and K band observations
  47. XRF011030: Chandra Observations
  48. GRB011030: Z-band observations
  49. GRB 011030 R band observations
  50. GRB 011030 I-band Observation
  51. The X-ray Flash 011030 ('GRB 011030')
  52. Non-triggered burst 011030 ("GRB 011030")
  53. The Radio Afterglow from the X-ray Rich GRB 011030
  54. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  55. GRB 970828: HST Observations of the Host Galaxy
  56. GRB 000131: HST Detection of the Host Galaxy
  57. GRB 970828: HST Observations of the Host Galaxy
  58. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  59. GRB011019: Subaru Optical Observations
  60. GRB 011030 I-band Observations
  61. GRB 011030 K-band Observations
  62. GRB010921, optical observations
  63. GRB011030 - further refinement WFC position
  64. GRB 011030, Radio observations
  65. GRB011030: radio search
  66. GRB 010921: Possible supernova component
  67. GRB010921, optical observation at early time
  68. GRB 010921, I-band observations
  69. GRB011019, optical observations
  70. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  71. GRB 010921: The afterglow of HETE #1761
  72. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  73. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  74. GRB010923 as seen by BeppoSAX GRBM
  75. GRB010928(=H1770): Localization of a Long GRB by HETE
  76. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  77. GRB010921, negative optical observations
  78. GRB010921 field photometry
  79. H1761: A Bright GRB Detected by HETE
  80. GRB000926, Host Galaxy Observations
  81. GRB001109, Host Galaxy Spectroscopic Observations
  82. Probable SGR or Short Duration GRB Detected by HETE
  83. GCN and HETE status
  84. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  85. GRB 010222 - WHT BVRI images
  86. SGR1900+14 burst seen by HETE: BeppoSAX data
  87. GRB 010629 Optical Observations
  88. SGR1900+14: High Fluence Burst Localized by HETE
  89. GRB010629, optical observations
  90. GRB010629: A Burst Localized by HETE
  91. SGR1900+14: Second Burst Localized by HETE
  92. SGR1900+14: A Burst Localized by HETE
  93. SGR1806-20: A Second, Intense Burst Localized by HETE
  94. SGR1806-20: Localization by HETE
  95. HETE Fully-Automated GCN Notices
  96. GRB000301C: Late-time HST/STIS observation
  97. GRB010518: a faint BeppoSAX detection
  98. GRB000418: HST/STIS Second-epoch Observations
  99. X-ray precursors to the large flare from SGR 1900+14
  100. GRB010427, Gamma Ray Observations

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