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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"

24663 results found.

  1. IPN triangulation of GRB020305 (HETE 1939)
  2. GRB020305 (=H1939): Localization of a GRB by HETE
  3. HST Imaging of the afterglow and host of GRB 011121
  4. IPN detection and localization of Cygnus X-1 flares
  5. SGR1900+14 activity
  6. IPN Upper Limits to a GRB Associated With SN2002ap
  7. GRB020124 BVRI field photometry
  8. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  9. SN2002ap (SN/GRB?) Echelle spectra
  10. GRB020127 Optical Observations
  11. SN 2002ap in M74
  12. SN2002ap (SN/GRB?) UBVRI Field Photometry
  13. GRB020127: Chandra Observations and Prospective Counterparts
  14. pre-SN2002ap (SN/GRB?) imaging of M74
  15. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  16. GRB020124, optical observations
  17. GRB 020127, I-band observations starting 3.14-hr after the event
  18. GRB010921 Optical Observations
  19. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  20. GRB020124: Optical observations
  21. GRB 020124: Optical observations
  22. GRB 020124: Optical afterglow
  23. GRB020124(=H1896): Localization of a Long GRB by HETE
  24. Possible optical counterpart to a GRB
  25. GRB011212, Optical Observations
  26. Optical polarization observations for GRB011211
  27. GRB 011211: Detection of the Probable Host Galaxy
  28. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  29. GRB 011130: Optical Observations of X-ray and Radio Sources
  30. GRB 011212: optical observation at Asiago
  31. GRB 011211: Evidence for an Optical Break
  32. GRB 011211: TNG Spectroscopic Observations
  33. optical follow-up of GRB(XRF) 011211
  34. GRB 011212: optical observation at Oslo (relayed)
  35. GRB 011211, Optical Observations
  36. GRB011212, BVRI field photometry
  37. GRB011211, BVRI field photometry
  38. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  39. Fading of the optical source associated of XRF 011211
  40. GRB 011211 Optical Observations: Likely Afterglow
  41. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  42. GRB011130 (XRF011130) Chandra Observations
  43. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  44. GRB 011130, K band observations
  45. GRB011130, optical observations
  46. GRB011130 (=XRF011130): Second Revised Localization by HETE
  47. GRB011130 (XRF011130) SDSS PT i-band observations
  48. XRF011130: Infrared Observations
  49. GRB 011121
  50. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  51. GRB 011121: J-band observations
  52. GRB 011121: NIR observations, host galaxy?
  53. GRB011121: UBRI Observations
  54. GRB 011121 J-Band Astrometry
  55. GRB 011121: Detection of Bright IR Counterpart
  56. GRB011121: possible redshift, continued decay
  57. GRB 011030: TNG K-band observation
  58. XRF011030: J and K band observations
  59. XRF011030: Chandra Observations
  60. GRB011030: Z-band observations
  61. GRB 011030 R band observations
  62. GRB 011030 I-band Observation
  63. The X-ray Flash 011030 ('GRB 011030')
  64. Non-triggered burst 011030 ("GRB 011030")
  65. The Radio Afterglow from the X-ray Rich GRB 011030
  66. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  67. GRB 970828: HST Observations of the Host Galaxy
  68. GRB 000131: HST Detection of the Host Galaxy
  69. GRB 970828: HST Observations of the Host Galaxy
  70. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  71. GRB011019: Subaru Optical Observations
  72. GRB 011030 I-band Observations
  73. GRB 011030 K-band Observations
  74. GRB010921, optical observations
  75. GRB011030 - further refinement WFC position
  76. GRB 011030, Radio observations
  77. GRB011030: radio search
  78. GRB 010921: Possible supernova component
  79. GRB010921, optical observation at early time
  80. GRB 010921, I-band observations
  81. GRB011019, optical observations
  82. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  83. GRB 010921: The afterglow of HETE #1761
  84. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  85. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  86. GRB010923 as seen by BeppoSAX GRBM
  87. GRB010928(=H1770): Localization of a Long GRB by HETE
  88. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  89. GRB010921, negative optical observations
  90. GRB010921 field photometry
  91. H1761: A Bright GRB Detected by HETE
  92. GRB000926, Host Galaxy Observations
  93. GRB001109, Host Galaxy Spectroscopic Observations
  94. Probable SGR or Short Duration GRB Detected by HETE
  95. GCN and HETE status
  96. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  97. GRB 010222 - WHT BVRI images
  98. SGR1900+14 burst seen by HETE: BeppoSAX data
  99. GRB 010629 Optical Observations
  100. SGR1900+14: High Fluence Burst Localized by HETE

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