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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"

28052 results found.

  1. SN2002ap (SN/GRB?) UBVRI Field Photometry
  2. GRB020127: Chandra Observations and Prospective Counterparts
  3. pre-SN2002ap (SN/GRB?) imaging of M74
  4. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  5. GRB020124, optical observations
  6. GRB 020127, I-band observations starting 3.14-hr after the event
  7. GRB010921 Optical Observations
  8. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  9. GRB020124: Optical observations
  10. GRB 020124: Optical observations
  11. GRB 020124: Optical afterglow
  12. GRB020124(=H1896): Localization of a Long GRB by HETE
  13. Possible optical counterpart to a GRB
  14. GRB011212, Optical Observations
  15. Optical polarization observations for GRB011211
  16. GRB 011211: Detection of the Probable Host Galaxy
  17. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  18. GRB 011130: Optical Observations of X-ray and Radio Sources
  19. GRB 011212: optical observation at Asiago
  20. GRB 011211: Evidence for an Optical Break
  21. GRB 011211: TNG Spectroscopic Observations
  22. optical follow-up of GRB(XRF) 011211
  23. GRB 011212: optical observation at Oslo (relayed)
  24. GRB 011211, Optical Observations
  25. GRB011212, BVRI field photometry
  26. GRB011211, BVRI field photometry
  27. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  28. Fading of the optical source associated of XRF 011211
  29. GRB 011211 Optical Observations: Likely Afterglow
  30. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  31. GRB011130 (XRF011130) Chandra Observations
  32. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  33. GRB 011130, K band observations
  34. GRB011130, optical observations
  35. GRB011130 (=XRF011130): Second Revised Localization by HETE
  36. GRB011130 (XRF011130) SDSS PT i-band observations
  37. XRF011130: Infrared Observations
  38. GRB 011121
  39. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  40. GRB 011121: J-band observations
  41. GRB 011121: NIR observations, host galaxy?
  42. GRB011121: UBRI Observations
  43. GRB 011121 J-Band Astrometry
  44. GRB 011121: Detection of Bright IR Counterpart
  45. GRB011121: possible redshift, continued decay
  46. GRB 011030: TNG K-band observation
  47. XRF011030: J and K band observations
  48. XRF011030: Chandra Observations
  49. GRB011030: Z-band observations
  50. GRB 011030 R band observations
  51. GRB 011030 I-band Observation
  52. The X-ray Flash 011030 ('GRB 011030')
  53. Non-triggered burst 011030 ("GRB 011030")
  54. The Radio Afterglow from the X-ray Rich GRB 011030
  55. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  56. GRB 970828: HST Observations of the Host Galaxy
  57. GRB 000131: HST Detection of the Host Galaxy
  58. GRB 970828: HST Observations of the Host Galaxy
  59. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  60. GRB011019: Subaru Optical Observations
  61. GRB 011030 I-band Observations
  62. GRB 011030 K-band Observations
  63. GRB010921, optical observations
  64. GRB011030 - further refinement WFC position
  65. GRB 011030, Radio observations
  66. GRB011030: radio search
  67. GRB 010921: Possible supernova component
  68. GRB010921, optical observation at early time
  69. GRB 010921, I-band observations
  70. GRB011019, optical observations
  71. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  72. GRB 010921: The afterglow of HETE #1761
  73. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  74. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  75. GRB010923 as seen by BeppoSAX GRBM
  76. GRB010928(=H1770): Localization of a Long GRB by HETE
  77. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  78. GRB010921, negative optical observations
  79. GRB010921 field photometry
  80. H1761: A Bright GRB Detected by HETE
  81. GRB000926, Host Galaxy Observations
  82. GRB001109, Host Galaxy Spectroscopic Observations
  83. Probable SGR or Short Duration GRB Detected by HETE
  84. GCN and HETE status
  85. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  86. GRB 010222 - WHT BVRI images
  87. SGR1900+14 burst seen by HETE: BeppoSAX data
  88. GRB 010629 Optical Observations
  89. SGR1900+14: High Fluence Burst Localized by HETE
  90. GRB010629, optical observations
  91. GRB010629: A Burst Localized by HETE
  92. SGR1900+14: Second Burst Localized by HETE
  93. SGR1900+14: A Burst Localized by HETE
  94. SGR1806-20: A Second, Intense Burst Localized by HETE
  95. SGR1806-20: Localization by HETE
  96. HETE Fully-Automated GCN Notices
  97. GRB000301C: Late-time HST/STIS observation
  98. GRB010518: a faint BeppoSAX detection
  99. GRB000418: HST/STIS Second-epoch Observations
  100. X-ray precursors to the large flare from SGR 1900+14

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