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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"

21812 results found.

  1. GRB 000131: HST Detection of the Host Galaxy
  2. GRB 970828: HST Observations of the Host Galaxy
  3. GRB010921, optical observation
  4. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  5. GRB011019: Subaru Optical Observations
  6. GRB 011030 I-band Observations
  7. GRB 011030 K-band Observations
  8. GRB010921, optical observations
  9. GRB 011030, WSRT radio observations
  10. GRB 011030, Radio observations
  11. GRB 011030, R-band observations
  12. GRB011019: NEAT Optical Observations
  13. GRB011019: ROTSE-III optical observations
  14. GRB 010921, I-band observations
  15. GRB011019: Optical observations
  16. GRB011019, optical observations -- correction
  17. GRB011019, optical observations
  18. GRB010921: Spectroscopy of the Host Galaxy
  19. GRB 010921: The afterglow of HETE #1761
  20. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  21. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  22. GRB010928(=H1770): Localization of a Long GRB by HETE
  23. GRB010921, negative optical observations
  24. GRB010921 Optical Observations
  25. HETE Trigger #1760 (GRB 010920B?): a new optical source
  26. HETE Trigger #1759 (GRB 010920?) optical observations
  27. GRB001109, Host Galaxy Astrometry
  28. GRB000926, Host Galaxy Observations
  29. GRB001109, Host Galaxy Spectroscopic Observations
  30. GRB000926 Host Galaxy Observations
  31. GRB 010222: HST observations -- host galaxy and late-time decay
  32. GRB 010222 - WHT BVRI images
  33. GRB 010629 Optical Observations
  34. GRB010629: Optical Observations
  35. SGR1900+14: High Fluence Burst Localized by HETE
  36. GRB010629, optical observations
  37. GRB010629: A Burst Localized by HETE
  38. SGR1900+14: Second Burst Localized by HETE
  39. SGR1900+14: A Burst Localized by HETE
  40. SGR1806-20: A Second, Intense Burst Localized by HETE
  41. GRB 00630: Host Galaxy
  42. SGR1806-20: Localization by HETE
  43. GRB000301C: Late-time HST/STIS observation
  44. GRB000418: HST/STIS Second-epoch Observations
  45. GRB010214, optical observations
  46. GRB010427, Gamma Ray Observations
  47. SGR 1900+14: No evidence of extended X-ray emission
  48. SGR 1900+14 : RXTE observations
  49. GRB 010222 /corrections to VBT data
  50. Millimeter observation of SGR 1900+14
  51. Chandra Observations of SGR 1900+14
  52. SGR 1900+14, Chandra observations
  53. Chandra Observations of SGR 1900+14
  54. SGR1900+14, I-band observations
  55. GRB 010326b Optical Observations
  56. GRB010412: Optical observations
  57. GRB010412: Optical observations
  58. GRB010412: BeppoSAX GRBM and WFC observations
  59. GRB Observation Report
  60. GRB 980326: Late-time HST/STIS observations
  61. Further Optical Observations of GRB 010324
  62. GRB010222, CXO X-ray observations
  63. GRB 010326A: Further optical observations
  64. GRB 010326B: Optical observations
  65. GRB010324, optical observations
  66. GRB010326B: Localization by HETE (2nd GRB for this date)
  67. GRB 010326: Optical observations
  68. GRB 010326 optical observations
  69. GRB010326: Refined Localization by HETE
  70. GRB010326: Localization by HETE
  71. Optical Observations of GRB 010324
  72. IPN TRIANGULATION OF GRB010324
  73. GRB990705, VLT-FORS1 observations of the host galaxy
  74. GRB010222, late-time optical observation
  75. GRB 010222 - HEGRA GeV/TeV Observations
  76. GRB010222: Sub-millimeter vanishing act
  77. GRB 010222, Optical Observations
  78. GRB 010222: High-Resolution Keck Spectroscopy
  79. GRB 010214, I-band data
  80. Sub-millimeter Excess/GRB 010222
  81. GRB 010222
  82. GRB 010222 HST/Chandra TOO
  83. GRB010222 further R-band photometry
  84. GRB010222 Optical observations
  85. GRB010222, field photometry
  86. GRB010222 further R-band photometry
  87. GRB010222, possible increase of optical decay slope
  88. GRB 010222 BV optical observations
  89. GRB010220, Optical Observations
  90. GRB010222 R-BAND OBSERVATION
  91. GRB 010220: Near-IR Observations
  92. GRB010214 follow-up from Hanle
  93. GRB 010222: Near-IR Observations
  94. GRB 010222: Optical Observations
  95. GRB010222: Optical decay slope
  96. GRB 010214, Optical Observations
  97. GRB010222: Sub-millimeter detection
  98. GRB010222: R-band fading behavior
  99. GRB010222: Optical Observations
  100. GRB010222, radio observations

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