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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"

25048 results found.

  1. GRB020124, optical observations
  2. GRB 020127, I-band observations starting 3.14-hr after the event
  3. GRB010921 Optical Observations
  4. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  5. GRB020124: Optical observations
  6. GRB 020124: Optical observations
  7. GRB 020124: Optical afterglow
  8. GRB020124(=H1896): Localization of a Long GRB by HETE
  9. Possible optical counterpart to a GRB
  10. GRB011212, Optical Observations
  11. Optical polarization observations for GRB011211
  12. GRB 011211: Detection of the Probable Host Galaxy
  13. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  14. GRB 011130: Optical Observations of X-ray and Radio Sources
  15. GRB 011212: optical observation at Asiago
  16. GRB 011211: Evidence for an Optical Break
  17. GRB 011211: TNG Spectroscopic Observations
  18. optical follow-up of GRB(XRF) 011211
  19. GRB 011212: optical observation at Oslo (relayed)
  20. GRB 011211, Optical Observations
  21. GRB011212, BVRI field photometry
  22. GRB011211, BVRI field photometry
  23. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  24. Fading of the optical source associated of XRF 011211
  25. GRB 011211 Optical Observations: Likely Afterglow
  26. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  27. GRB011130 (XRF011130) Chandra Observations
  28. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  29. GRB 011130, K band observations
  30. GRB011130, optical observations
  31. GRB011130 (=XRF011130): Second Revised Localization by HETE
  32. GRB011130 (XRF011130) SDSS PT i-band observations
  33. XRF011130: Infrared Observations
  34. GRB 011121
  35. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  36. GRB 011121: J-band observations
  37. GRB 011121: NIR observations, host galaxy?
  38. GRB011121: UBRI Observations
  39. GRB 011121 J-Band Astrometry
  40. GRB 011121: Detection of Bright IR Counterpart
  41. GRB011121: possible redshift, continued decay
  42. GRB 011030: TNG K-band observation
  43. XRF011030: J and K band observations
  44. XRF011030: Chandra Observations
  45. GRB011030: Z-band observations
  46. GRB 011030 R band observations
  47. GRB 011030 I-band Observation
  48. The X-ray Flash 011030 ('GRB 011030')
  49. Non-triggered burst 011030 ("GRB 011030")
  50. The Radio Afterglow from the X-ray Rich GRB 011030
  51. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  52. GRB 970828: HST Observations of the Host Galaxy
  53. GRB 000131: HST Detection of the Host Galaxy
  54. GRB 970828: HST Observations of the Host Galaxy
  55. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  56. GRB011019: Subaru Optical Observations
  57. GRB 011030 I-band Observations
  58. GRB 011030 K-band Observations
  59. GRB010921, optical observations
  60. GRB011030 - further refinement WFC position
  61. GRB 011030, Radio observations
  62. GRB011030: radio search
  63. GRB 010921: Possible supernova component
  64. GRB010921, optical observation at early time
  65. GRB 010921, I-band observations
  66. GRB011019, optical observations
  67. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  68. GRB 010921: The afterglow of HETE #1761
  69. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  70. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  71. GRB010923 as seen by BeppoSAX GRBM
  72. GRB010928(=H1770): Localization of a Long GRB by HETE
  73. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  74. GRB010921, negative optical observations
  75. GRB010921 field photometry
  76. H1761: A Bright GRB Detected by HETE
  77. GRB000926, Host Galaxy Observations
  78. GRB001109, Host Galaxy Spectroscopic Observations
  79. Probable SGR or Short Duration GRB Detected by HETE
  80. GCN and HETE status
  81. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  82. GRB 010222 - WHT BVRI images
  83. SGR1900+14 burst seen by HETE: BeppoSAX data
  84. GRB 010629 Optical Observations
  85. SGR1900+14: High Fluence Burst Localized by HETE
  86. GRB010629, optical observations
  87. GRB010629: A Burst Localized by HETE
  88. SGR1900+14: Second Burst Localized by HETE
  89. SGR1900+14: A Burst Localized by HETE
  90. SGR1806-20: A Second, Intense Burst Localized by HETE
  91. SGR1806-20: Localization by HETE
  92. HETE Fully-Automated GCN Notices
  93. GRB000301C: Late-time HST/STIS observation
  94. GRB010518: a faint BeppoSAX detection
  95. GRB000418: HST/STIS Second-epoch Observations
  96. X-ray precursors to the large flare from SGR 1900+14
  97. GRB010427, Gamma Ray Observations
  98. SGR 1900+14: No evidence of extended X-ray emission
  99. SGR 1900+14 : RXTE observations
  100. BeppoSAX/NFI Follow-up Observation of SGR 1900+14

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