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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"

24665 results found.

  1. GRB 020305: Candidate optical afterglow
  2. GRB020305, optical observations
  3. IPN triangulation of GRB020305 (HETE 1939)
  4. GRB020305 (=H1939): Localization of a GRB by HETE
  5. HST Imaging of the afterglow and host of GRB 011121
  6. IPN detection and localization of Cygnus X-1 flares
  7. SGR1900+14 activity
  8. IPN Upper Limits to a GRB Associated With SN2002ap
  9. GRB020124 BVRI field photometry
  10. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  11. SN2002ap (SN/GRB?) Echelle spectra
  12. GRB020127 Optical Observations
  13. SN 2002ap in M74
  14. SN2002ap (SN/GRB?) UBVRI Field Photometry
  15. GRB020127: Chandra Observations and Prospective Counterparts
  16. pre-SN2002ap (SN/GRB?) imaging of M74
  17. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  18. GRB020124, optical observations
  19. GRB 020127, I-band observations starting 3.14-hr after the event
  20. GRB010921 Optical Observations
  21. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  22. GRB020124: Optical observations
  23. GRB 020124: Optical observations
  24. GRB 020124: Optical afterglow
  25. GRB020124(=H1896): Localization of a Long GRB by HETE
  26. Possible optical counterpart to a GRB
  27. GRB011212, Optical Observations
  28. Optical polarization observations for GRB011211
  29. GRB 011211: Detection of the Probable Host Galaxy
  30. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  31. GRB 011130: Optical Observations of X-ray and Radio Sources
  32. GRB 011212: optical observation at Asiago
  33. GRB 011211: Evidence for an Optical Break
  34. GRB 011211: TNG Spectroscopic Observations
  35. optical follow-up of GRB(XRF) 011211
  36. GRB 011212: optical observation at Oslo (relayed)
  37. GRB 011211, Optical Observations
  38. GRB011212, BVRI field photometry
  39. GRB011211, BVRI field photometry
  40. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  41. Fading of the optical source associated of XRF 011211
  42. GRB 011211 Optical Observations: Likely Afterglow
  43. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  44. GRB011130 (XRF011130) Chandra Observations
  45. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  46. GRB 011130, K band observations
  47. GRB011130, optical observations
  48. GRB011130 (=XRF011130): Second Revised Localization by HETE
  49. GRB011130 (XRF011130) SDSS PT i-band observations
  50. XRF011130: Infrared Observations
  51. GRB 011121
  52. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  53. GRB 011121: J-band observations
  54. GRB 011121: NIR observations, host galaxy?
  55. GRB011121: UBRI Observations
  56. GRB 011121 J-Band Astrometry
  57. GRB 011121: Detection of Bright IR Counterpart
  58. GRB011121: possible redshift, continued decay
  59. GRB 011030: TNG K-band observation
  60. XRF011030: J and K band observations
  61. XRF011030: Chandra Observations
  62. GRB011030: Z-band observations
  63. GRB 011030 R band observations
  64. GRB 011030 I-band Observation
  65. The X-ray Flash 011030 ('GRB 011030')
  66. Non-triggered burst 011030 ("GRB 011030")
  67. The Radio Afterglow from the X-ray Rich GRB 011030
  68. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  69. GRB 970828: HST Observations of the Host Galaxy
  70. GRB 000131: HST Detection of the Host Galaxy
  71. GRB 970828: HST Observations of the Host Galaxy
  72. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  73. GRB011019: Subaru Optical Observations
  74. GRB 011030 I-band Observations
  75. GRB 011030 K-band Observations
  76. GRB010921, optical observations
  77. GRB011030 - further refinement WFC position
  78. GRB 011030, Radio observations
  79. GRB011030: radio search
  80. GRB 010921: Possible supernova component
  81. GRB010921, optical observation at early time
  82. GRB 010921, I-band observations
  83. GRB011019, optical observations
  84. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  85. GRB 010921: The afterglow of HETE #1761
  86. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  87. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  88. GRB010923 as seen by BeppoSAX GRBM
  89. GRB010928(=H1770): Localization of a Long GRB by HETE
  90. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  91. GRB010921, negative optical observations
  92. GRB010921 field photometry
  93. H1761: A Bright GRB Detected by HETE
  94. GRB000926, Host Galaxy Observations
  95. GRB001109, Host Galaxy Spectroscopic Observations
  96. Probable SGR or Short Duration GRB Detected by HETE
  97. GCN and HETE status
  98. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  99. GRB 010222 - WHT BVRI images
  100. SGR1900+14 burst seen by HETE: BeppoSAX data

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