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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

21326 results found.

  1. GRB 011121: Detection of Bright IR Counterpart
  2. GRB011121: possible redshift, continued decay
  3. GRB011121: fading behavior
  4. GRB011121: possible optical counterpart
  5. XRF011030: J and K band observations
  6. XRF011030: Chandra Observations
  7. GRB 011030: K-band observations
  8. GRB011030: Z-band observations
  9. GRB 011030 R band observations
  10. The X-ray Flash 011030 ('GRB 011030')
  11. Non-triggered burst 011030 ("GRB 011030")
  12. The Radio Afterglow from the X-ray Rich GRB 011030
  13. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  14. GRB 970828: HST Observations of the Host Galaxy
  15. GRB 000131: HST Detection of the Host Galaxy
  16. GRB 970828: HST Observations of the Host Galaxy
  17. GRB010921, optical observation
  18. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  19. GRB011019: Subaru Optical Observations
  20. GRB 011030 I-band Observations
  21. GRB 011030 K-band Observations
  22. GRB010921, optical observations
  23. GRB 011030, WSRT radio observations
  24. GRB 011030, Radio observations
  25. GRB 011030, R-band observations
  26. GRB011019: NEAT Optical Observations
  27. GRB011019: ROTSE-III optical observations
  28. GRB 010921, I-band observations
  29. GRB011019: Optical observations
  30. GRB011019, optical observations -- correction
  31. GRB011019, optical observations
  32. GRB010921: Spectroscopy of the Host Galaxy
  33. GRB 010921: The afterglow of HETE #1761
  34. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  35. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  36. GRB010928(=H1770): Localization of a Long GRB by HETE
  37. GRB010921, negative optical observations
  38. GRB010921 Optical Observations
  39. HETE Trigger #1760 (GRB 010920B?): a new optical source
  40. HETE Trigger #1759 (GRB 010920?) optical observations
  41. GRB001109, Host Galaxy Astrometry
  42. GRB000926, Host Galaxy Observations
  43. GRB001109, Host Galaxy Spectroscopic Observations
  44. GRB000926 Host Galaxy Observations
  45. GRB 010222: HST observations -- host galaxy and late-time decay
  46. GRB 010222 - WHT BVRI images
  47. GRB 010629 Optical Observations
  48. GRB010629: Optical Observations
  49. SGR1900+14: High Fluence Burst Localized by HETE
  50. GRB010629, optical observations
  51. GRB010629: A Burst Localized by HETE
  52. SGR1900+14: Second Burst Localized by HETE
  53. SGR1900+14: A Burst Localized by HETE
  54. SGR1806-20: A Second, Intense Burst Localized by HETE
  55. GRB 00630: Host Galaxy
  56. SGR1806-20: Localization by HETE
  57. GRB000301C: Late-time HST/STIS observation
  58. GRB000418: HST/STIS Second-epoch Observations
  59. GRB010214, optical observations
  60. GRB010427, Gamma Ray Observations
  61. SGR 1900+14: No evidence of extended X-ray emission
  62. SGR 1900+14 : RXTE observations
  63. GRB 010222 /corrections to VBT data
  64. Millimeter observation of SGR 1900+14
  65. Chandra Observations of SGR 1900+14
  66. SGR 1900+14, Chandra observations
  67. Chandra Observations of SGR 1900+14
  68. SGR1900+14, I-band observations
  69. GRB 010326b Optical Observations
  70. GRB010412: Optical observations
  71. GRB010412: Optical observations
  72. GRB010412: BeppoSAX GRBM and WFC observations
  73. GRB Observation Report
  74. GRB 980326: Late-time HST/STIS observations
  75. Further Optical Observations of GRB 010324
  76. GRB010222, CXO X-ray observations
  77. GRB 010326A: Further optical observations
  78. GRB 010326B: Optical observations
  79. GRB010324, optical observations
  80. GRB010326B: Localization by HETE (2nd GRB for this date)
  81. GRB 010326: Optical observations
  82. GRB 010326 optical observations
  83. GRB010326: Refined Localization by HETE
  84. GRB010326: Localization by HETE
  85. Optical Observations of GRB 010324
  86. IPN TRIANGULATION OF GRB010324
  87. GRB990705, VLT-FORS1 observations of the host galaxy
  88. GRB010222, late-time optical observation
  89. GRB 010222 - HEGRA GeV/TeV Observations
  90. GRB010222: Sub-millimeter vanishing act
  91. GRB 010222, Optical Observations
  92. GRB 010222: High-Resolution Keck Spectroscopy
  93. GRB 010214, I-band data
  94. Sub-millimeter Excess/GRB 010222
  95. GRB 010222
  96. GRB 010222 HST/Chandra TOO
  97. GRB010222 further R-band photometry
  98. GRB010222 Optical observations
  99. GRB010222, field photometry
  100. GRB010222 further R-band photometry

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