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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"

28050 results found.

  1. pre-SN2002ap (SN/GRB?) imaging of M74
  2. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  3. GRB020124, optical observations
  4. GRB 020127, I-band observations starting 3.14-hr after the event
  5. GRB010921 Optical Observations
  6. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  7. GRB020124: Optical observations
  8. GRB 020124: Optical observations
  9. GRB 020124: Optical afterglow
  10. GRB020124(=H1896): Localization of a Long GRB by HETE
  11. Possible optical counterpart to a GRB
  12. GRB011212, Optical Observations
  13. Optical polarization observations for GRB011211
  14. GRB 011211: Detection of the Probable Host Galaxy
  15. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  16. GRB 011130: Optical Observations of X-ray and Radio Sources
  17. GRB 011212: optical observation at Asiago
  18. GRB 011211: Evidence for an Optical Break
  19. GRB 011211: TNG Spectroscopic Observations
  20. optical follow-up of GRB(XRF) 011211
  21. GRB 011212: optical observation at Oslo (relayed)
  22. GRB 011211, Optical Observations
  23. GRB011212, BVRI field photometry
  24. GRB011211, BVRI field photometry
  25. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  26. Fading of the optical source associated of XRF 011211
  27. GRB 011211 Optical Observations: Likely Afterglow
  28. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  29. GRB011130 (XRF011130) Chandra Observations
  30. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  31. GRB 011130, K band observations
  32. GRB011130, optical observations
  33. GRB011130 (=XRF011130): Second Revised Localization by HETE
  34. GRB011130 (XRF011130) SDSS PT i-band observations
  35. XRF011130: Infrared Observations
  36. GRB 011121
  37. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  38. GRB 011121: J-band observations
  39. GRB 011121: NIR observations, host galaxy?
  40. GRB011121: UBRI Observations
  41. GRB 011121 J-Band Astrometry
  42. GRB 011121: Detection of Bright IR Counterpart
  43. GRB011121: possible redshift, continued decay
  44. GRB 011030: TNG K-band observation
  45. XRF011030: J and K band observations
  46. XRF011030: Chandra Observations
  47. GRB011030: Z-band observations
  48. GRB 011030 R band observations
  49. GRB 011030 I-band Observation
  50. The X-ray Flash 011030 ('GRB 011030')
  51. Non-triggered burst 011030 ("GRB 011030")
  52. The Radio Afterglow from the X-ray Rich GRB 011030
  53. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  54. GRB 970828: HST Observations of the Host Galaxy
  55. GRB 000131: HST Detection of the Host Galaxy
  56. GRB 970828: HST Observations of the Host Galaxy
  57. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  58. GRB011019: Subaru Optical Observations
  59. GRB 011030 I-band Observations
  60. GRB 011030 K-band Observations
  61. GRB010921, optical observations
  62. GRB011030 - further refinement WFC position
  63. GRB 011030, Radio observations
  64. GRB011030: radio search
  65. GRB 010921: Possible supernova component
  66. GRB010921, optical observation at early time
  67. GRB 010921, I-band observations
  68. GRB011019, optical observations
  69. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  70. GRB 010921: The afterglow of HETE #1761
  71. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  72. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  73. GRB010923 as seen by BeppoSAX GRBM
  74. GRB010928(=H1770): Localization of a Long GRB by HETE
  75. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  76. GRB010921, negative optical observations
  77. GRB010921 field photometry
  78. H1761: A Bright GRB Detected by HETE
  79. GRB000926, Host Galaxy Observations
  80. GRB001109, Host Galaxy Spectroscopic Observations
  81. Probable SGR or Short Duration GRB Detected by HETE
  82. GCN and HETE status
  83. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  84. GRB 010222 - WHT BVRI images
  85. SGR1900+14 burst seen by HETE: BeppoSAX data
  86. GRB 010629 Optical Observations
  87. SGR1900+14: High Fluence Burst Localized by HETE
  88. GRB010629, optical observations
  89. GRB010629: A Burst Localized by HETE
  90. SGR1900+14: Second Burst Localized by HETE
  91. SGR1900+14: A Burst Localized by HETE
  92. SGR1806-20: A Second, Intense Burst Localized by HETE
  93. SGR1806-20: Localization by HETE
  94. HETE Fully-Automated GCN Notices
  95. GRB000301C: Late-time HST/STIS observation
  96. GRB010518: a faint BeppoSAX detection
  97. GRB000418: HST/STIS Second-epoch Observations
  98. X-ray precursors to the large flare from SGR 1900+14
  99. GRB010427, Gamma Ray Observations
  100. SGR 1900+14: No evidence of extended X-ray emission

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