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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"

27774 results found.

  1. GRB 011211: Detection of the Probable Host Galaxy
  2. GRB 011211: Evidence for an Optical Break
  3. GRB 011211: TNG Spectroscopic Observations
  4. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  5. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  6. GRB 011130, K band observations
  7. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  8. GRB011130 (=XRF011130): Revised Localization of an X-ray
  9. GRB 011121: J-band observations
  10. GRB 011121: Detection of Bright IR Counterpart
  11. GRB 011030 I-band Observation
  12. The X-ray Flash 011030 ('GRB 011030')
  13. The Radio Afterglow from the X-ray Rich GRB 011030
  14. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  15. GRB 000131: HST Detection of the Host Galaxy
  16. GRB 011030 K-band Observations
  17. GRB011019: ROTSE-III optical observations
  18. GRB010928(=H1770): Localization of a Long GRB by HETE
  19. BeppoSAX/GRBM detection of GRB 010801
  20. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  21. BeppoSAX/GRBM detection of GRB010728
  22. SGR1900+14: High Fluence Burst Localized by HETE
  23. GRB010629: A Burst Localized by HETE
  24. SGR1900+14: Second Burst Localized by HETE
  25. SGR1900+14: A Burst Localized by HETE
  26. IPN detection of SGR1900+14
  27. SGR1806-20: A Second, Intense Burst Localized by HETE
  28. SGR1806-20: Localization by HETE
  29. GRB000301C: Late-time HST/STIS observation
  30. GRB010518: a faint BeppoSAX detection
  31. GRB000418: HST/STIS Second-epoch Observations
  32. SGR 1900+14: No evidence of extended X-ray emission
  33. SGR 1900+14: Detection of extended X-ray emission
  34. GRB 010222: High-Resolution Keck Spectroscopy
  35. GRB 010214, I-band data
  36. GRB 010222 Kyoto optical observation
  37. GRB010214 follow-up from Hanle
  38. GRB010222: Sub-millimeter detection
  39. GRB010222: Optical Observations
  40. GRB010222: possible optical counterpart
  41. GRB010220, Radio and Optical Observations
  42. GRB010213 Optical Observation
  43. GRB010213, Radio Observations
  44. GRB010214 Optical Observation
  45. IPN Status Report
  46. HETE Status
  47. GRB010126 opt. obs.
  48. GRB010126: CONCAM crude optical limits during GRB
  49. GRB010126 optical observations
  50. Optical Observations of GRB 001018 at Keck
  51. GRB 001212 Optical Observation
  52. Confirmation of IPN position for GRB001204
  53. WSRT 4.8 GHz observations of GRB001109
  54. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  55. GRB001007: Optical observations
  56. GRB000926 - Amateur Optical Observations
  57. CONCAM null result on GRB001005
  58. CONCAM crude optical limits before and after GRB000926
  59. GRB 990510: Possible detection of a host galaxy
  60. GRB 000630: Detection of the Optical Afterglow
  61. GRB000620: BeppoSAX WFC and GRBM detection
  62. GRB000615, R-band photometry
  63. GRB980425, HST/STIS observations of the host galaxy
  64. GRB000604 optical non-detection
  65. GRB000604, optical observations
  66. GRB 000418: Detection of the Host Galaxy
  67. X-ray Afterglow of GRB 000529
  68. Possible GRB-related phenomenon
  69. GRB000424, optical observations
  70. GRB000418, Radio detection
  71. GRB000418, K'-band photometry
  72. GRB 000418, Optical Observation
  73. GRB000424, optical observations
  74. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  75. GRB 000301C: A Precise Redshift Determination
  76. GRB 000301C: HST/STIS CCD Imaging of the field
  77. GRB000301C - Host galaxy not detected in R (?)
  78. GRB000301C 250 GHz detection
  79. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  80. GRB000214: BeppoSAX GRBM and WFC Detection
  81. Optical observations of the Chandra X-ray source for GRB000210
  82. GRB000210: possible afterglow detection with BeppoSAX NFI
  83. GRB000210: BeppoSAX GRBM and WFC Detection
  84. GRB 000131 Optical Observations
  85. GRB000126, optical observations
  86. Second RXTE Observation of GRB 000115
  87. GRB 991216 VLBA Observations
  88. GRB 991216: Detection of the Host and/or Absorber Galaxy
  89. GRB 991216 RXTE ASM Observations
  90. GRB 991216 Optical spectroscopy/imaging
  91. GRB 991208 Infrared Detection
  92. GRB 991216--Summary of RXTE Observations
  93. GRB991216 Optical Observations
  94. GRB991208 - millimeter detection
  95. GRB 991208 - OVRO detection
  96. GRB 991208 optical observations
  97. GRB991106: BeppoSAX/BATSE results
  98. GRB 991106, optical observations
  99. GRB991106: the first BeppoSAX short GRB detection?
  100. GRB991105: SAX-GRBM/-WFC detection

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