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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"

35952 results found.

  1. IPN triangulation of GRB020124 (HETE 1896)
  2. IPN observations of SGR1806-20
  3. GRB 020124: Optical afterglow
  4. GRB020124(=H1896): Localization of a Long GRB by HETE
  5. GRB optical counterpart candidate in GCN 1217 is M dwarf
  6. Possible optical counterpart to a GRB
  7. GRB011212, Optical Observations
  8. GRB 011211: Detection of the Probable Host Galaxy
  9. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  10. GRB 011211, spectrum and optical photometry
  11. GRB 011130: Optical Observations of X-ray and Radio Sources
  12. GRB 011130, Radio/X-ray Comparison
  13. GRB 011212: optical observation at Asiago
  14. GRB 011211: Evidence for an Optical Break
  15. GRB 011211: TNG Spectroscopic Observations
  16. optical follow-up of GRB(XRF) 011211
  17. GRB 011212: optical observation at Oslo (relayed)
  18. GRB 011211: Optical Spectroscopy
  19. GRB 011211, Optical Observations
  20. GRB011212, BVRI field photometry
  21. GRB011211, BVRI field photometry
  22. GRB011212: Optical observations
  23. GRB 011211: BVRi-band photometry
  24. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  25. Fading of the optical source associated of XRF 011211
  26. GRB 011211 Optical Observations: Likely Afterglow
  27. BeppoSAX Alert: GRB011211(=XRF011211)
  28. GRB 011130: Optical Observations of Chandra Sources
  29. GRB 011130: Optical Observations of Chandra sources
  30. GRB 011130: Magellan spectroscopy
  31. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  32. GRB011130, optical observations
  33. GRB 011130, K band observations
  34. GRB011130, optical observations
  35. GRB 011130 I-band Observation
  36. GRB011130 (XRF011130) optical observations
  37. GRB011130 (XRF011130) SDSS PT i-band observations
  38. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  39. XRF011130: NEAT Optical Observations
  40. GRB011130 (=XRF011130): Revised Localization of an X-ray
  41. GRB001109, Radio Monitoring
  42. GRB 011121: Errata URL
  43. GRB 011121
  44. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  45. GRB 011121: J-band observations
  46. GRB 011121: NIR observations, host galaxy?
  47. GRB 011121: HST Scheduled
  48. GRB011121: fainter still
  49. Correction: GCN1157 (GRB 011121)
  50. GRB 011121: Radio Observations
  51. GRB 011121 J-Band Astrometry
  52. GRB011121: continued decay
  53. GRB 011121: Detection of Bright IR Counterpart
  54. GRB011121: possible redshift, continued decay
  55. IPN triangulation of GRB011121
  56. BEPPOSAX GRB011121
  57. GRB 011030: TNG K-band observation
  58. XRF011030: Chandra Observations
  59. GRB 011030: K-band observations
  60. GRB 011030 R band observations
  61. GRB 011030 I-band Observation
  62. The X-ray Flash 011030 ('GRB 011030')
  63. Non-triggered burst 011030 ("GRB 011030")
  64. The Radio Afterglow from the X-ray Rich GRB 011030
  65. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  66. GRB 970828: HST Observations of the Host Galaxy
  67. GRB 000131: HST Detection of the Host Galaxy
  68. GRB 970828: HST Observations of the Host Galaxy
  69. GRB010921, optical observation
  70. GRB 011019 optical observation
  71. GRB011019: Subaru Optical Observations
  72. GRB 011030 I-band Observations
  73. GRB 011030 K-band Observations
  74. GRB010921, optical observations
  75. GRB 011030, WSRT radio observations
  76. GRB011030 - further refinement WFC position
  77. GRB 011030, Radio observations
  78. GRB 011030, R-band observations
  79. BeppoSAX ALERT: Possible X-ray rich GRB011030
  80. GRB 010921: Possible supernova component
  81. GRB011019: NEAT Optical Observations
  82. GRB010921, optical observation at early time
  83. GRB 010921, I-band observations
  84. GRB011019: Optical observations
  85. GRB011019, optical observations
  86. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  87. GRB010921: Spectroscopy of the Host Galaxy
  88. GRB 010921: The afterglow of HETE #1761
  89. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  90. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  91. GRB010923 as seen by BeppoSAX GRBM
  92. GRB010928(=H1770): Localization of a Long GRB by HETE
  93. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  94. GRB010921, negative optical observations
  95. GRB010921 field photometry
  96. GRB010921 Optical Observations
  97. GRB 010921 DPOSS Images Available
  98. IPN triangulation of GRB010921 (=H1761)
  99. H1761: A Bright GRB Detected by HETE
  100. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid

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