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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"

36188 results found.

  1. HST Imaging of the afterglow and host of GRB 011121
  2. GRB 010921: HST Observations
  3. IPN detection and localization of Cygnus X-1 flares
  4. GRB020127: Further VLA Observations of Possible Counterparts
  5. IPN detection of further SGR1900+14 activity
  6. SGR1900+14 activity
  7. IPN/HETE Detection of Bursts from SGR1900+14
  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. SN2002ap (SN/GRB?) optical spectrographic observations
  13. GRB020127 Optical Observations
  14. SN 2002ap (SN/GRB?)
  15. SN2002ap (SN/GRB?) UBVRI Field Photometry
  16. GRB020127: Chandra Observations and Prospective Counterparts
  17. pre-SN2002ap (SN/GRB?) imaging of M74
  18. SN 2002ap (hypernova / GRB ??): special list on VSNET
  19. Type Ib/c SN2002ap (SN/GRB?)
  20. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  21. GRB020124, optical observations
  22. GRB020127: Optical observations
  23. GRB 020127, I-band observations starting 3.14-hr after the event
  24. IPN detection of further activity from SGR1806-20
  25. IPN triangulation of GRB020127 (=H1902)
  26. GRB010921 Optical Observations
  27. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  28. GRB020124: Optical observations
  29. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  30. GRB020124: Optical observations
  31. GRB 020124: Optical observations
  32. GRB 020124 Optical Observations
  33. IPN triangulation of GRB020124 (HETE 1896)
  34. IPN observations of SGR1806-20
  35. GRB 020124: Optical afterglow
  36. GRB020124(=H1896): Localization of a Long GRB by HETE
  37. GRB optical counterpart candidate in GCN 1217 is M dwarf
  38. Possible optical counterpart to a GRB
  39. GRB011212, Optical Observations
  40. GRB 011211: Detection of the Probable Host Galaxy
  41. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  42. GRB 011211, spectrum and optical photometry
  43. GRB 011130: Optical Observations of X-ray and Radio Sources
  44. GRB 011130, Radio/X-ray Comparison
  45. GRB 011212: optical observation at Asiago
  46. GRB 011211: Evidence for an Optical Break
  47. GRB 011211: TNG Spectroscopic Observations
  48. optical follow-up of GRB(XRF) 011211
  49. GRB 011212: optical observation at Oslo (relayed)
  50. GRB 011211: Optical Spectroscopy
  51. GRB 011211, Optical Observations
  52. GRB011212, BVRI field photometry
  53. GRB011211, BVRI field photometry
  54. GRB011212: Optical observations
  55. GRB 011211: BVRi-band photometry
  56. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  57. Fading of the optical source associated of XRF 011211
  58. GRB 011211 Optical Observations: Likely Afterglow
  59. BeppoSAX Alert: GRB011211(=XRF011211)
  60. GRB 011130: Optical Observations of Chandra Sources
  61. GRB 011130: Optical Observations of Chandra sources
  62. GRB 011130: Magellan spectroscopy
  63. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  64. GRB011130, optical observations
  65. GRB 011130, K band observations
  66. GRB011130, optical observations
  67. GRB 011130 I-band Observation
  68. GRB011130 (XRF011130) optical observations
  69. GRB011130 (XRF011130) SDSS PT i-band observations
  70. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  71. XRF011130: NEAT Optical Observations
  72. GRB011130 (=XRF011130): Revised Localization of an X-ray
  73. GRB001109, Radio Monitoring
  74. GRB 011121: Errata URL
  75. GRB 011121
  76. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  77. GRB 011121: J-band observations
  78. GRB 011121: NIR observations, host galaxy?
  79. GRB 011121: HST Scheduled
  80. GRB011121: fainter still
  81. Correction: GCN1157 (GRB 011121)
  82. GRB 011121: Radio Observations
  83. GRB 011121 J-Band Astrometry
  84. GRB011121: continued decay
  85. GRB 011121: Detection of Bright IR Counterpart
  86. GRB011121: possible redshift, continued decay
  87. IPN triangulation of GRB011121
  88. BEPPOSAX GRB011121
  89. GRB 011030: TNG K-band observation
  90. XRF011030: Chandra Observations
  91. GRB 011030: K-band observations
  92. GRB 011030 R band observations
  93. GRB 011030 I-band Observation
  94. The X-ray Flash 011030 ('GRB 011030')
  95. Non-triggered burst 011030 ("GRB 011030")
  96. The Radio Afterglow from the X-ray Rich GRB 011030
  97. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  98. GRB 970828: HST Observations of the Host Galaxy
  99. GRB 000131: HST Detection of the Host Galaxy
  100. GRB 970828: HST Observations of the Host Galaxy

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