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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"

35155 results found.

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

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