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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"

24673 results found.

  1. GRB020317, optical observations
  2. GRB 020317: Optical observations
  3. GRB 011121: Third HST Epoch
  4. GRB020305: Properties of the Candidate Optical Afterglow
  5. GRB 011121: HST Observations reveal an intermediate-time multicolor
  6. GRB011130 (XRF011130) Second Epoch Chandra Observations
  7. GRB020305: Subaru Optical Observations
  8. XRF/GRB 011030: Detection of the Probable Host Galaxy
  9. GRB 020305: Candidate optical afterglow
  10. GRB020305, optical observations
  11. IPN triangulation of GRB020305 (HETE 1939)
  12. GRB020305 (=H1939): Localization of a GRB by HETE
  13. HST Imaging of the afterglow and host of GRB 011121
  14. IPN detection and localization of Cygnus X-1 flares
  15. SGR1900+14 activity
  16. IPN Upper Limits to a GRB Associated With SN2002ap
  17. GRB020124 BVRI field photometry
  18. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  19. SN2002ap (SN/GRB?) Echelle spectra
  20. GRB020127 Optical Observations
  21. SN 2002ap in M74
  22. SN2002ap (SN/GRB?) UBVRI Field Photometry
  23. GRB020127: Chandra Observations and Prospective Counterparts
  24. pre-SN2002ap (SN/GRB?) imaging of M74
  25. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  26. GRB020124, optical observations
  27. GRB 020127, I-band observations starting 3.14-hr after the event
  28. GRB010921 Optical Observations
  29. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  30. GRB020124: Optical observations
  31. GRB 020124: Optical observations
  32. GRB 020124: Optical afterglow
  33. GRB020124(=H1896): Localization of a Long GRB by HETE
  34. Possible optical counterpart to a GRB
  35. GRB011212, Optical Observations
  36. Optical polarization observations for GRB011211
  37. GRB 011211: Detection of the Probable Host Galaxy
  38. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  39. GRB 011130: Optical Observations of X-ray and Radio Sources
  40. GRB 011212: optical observation at Asiago
  41. GRB 011211: Evidence for an Optical Break
  42. GRB 011211: TNG Spectroscopic Observations
  43. optical follow-up of GRB(XRF) 011211
  44. GRB 011212: optical observation at Oslo (relayed)
  45. GRB 011211, Optical Observations
  46. GRB011212, BVRI field photometry
  47. GRB011211, BVRI field photometry
  48. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  49. Fading of the optical source associated of XRF 011211
  50. GRB 011211 Optical Observations: Likely Afterglow
  51. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  52. GRB011130 (XRF011130) Chandra Observations
  53. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  54. GRB 011130, K band observations
  55. GRB011130, optical observations
  56. GRB011130 (=XRF011130): Second Revised Localization by HETE
  57. GRB011130 (XRF011130) SDSS PT i-band observations
  58. XRF011130: Infrared Observations
  59. GRB 011121
  60. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  61. GRB 011121: J-band observations
  62. GRB 011121: NIR observations, host galaxy?
  63. GRB011121: UBRI Observations
  64. GRB 011121 J-Band Astrometry
  65. GRB 011121: Detection of Bright IR Counterpart
  66. GRB011121: possible redshift, continued decay
  67. GRB 011030: TNG K-band observation
  68. XRF011030: J and K band observations
  69. XRF011030: Chandra Observations
  70. GRB011030: Z-band observations
  71. GRB 011030 R band observations
  72. GRB 011030 I-band Observation
  73. The X-ray Flash 011030 ('GRB 011030')
  74. Non-triggered burst 011030 ("GRB 011030")
  75. The Radio Afterglow from the X-ray Rich GRB 011030
  76. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  77. GRB 970828: HST Observations of the Host Galaxy
  78. GRB 000131: HST Detection of the Host Galaxy
  79. GRB 970828: HST Observations of the Host Galaxy
  80. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  81. GRB011019: Subaru Optical Observations
  82. GRB 011030 I-band Observations
  83. GRB 011030 K-band Observations
  84. GRB010921, optical observations
  85. GRB011030 - further refinement WFC position
  86. GRB 011030, Radio observations
  87. GRB011030: radio search
  88. GRB 010921: Possible supernova component
  89. GRB010921, optical observation at early time
  90. GRB 010921, I-band observations
  91. GRB011019, optical observations
  92. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  93. GRB 010921: The afterglow of HETE #1761
  94. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  95. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  96. GRB010923 as seen by BeppoSAX GRBM
  97. GRB010928(=H1770): Localization of a Long GRB by HETE
  98. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  99. GRB010921, negative optical observations
  100. GRB010921 field photometry

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