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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"

32501 results found.

  1. pre-SN2002ap (SN/GRB?) imaging of M74
  2. Type Ib/c SN2002ap (SN/GRB?)
  3. GRB020127: Optical observations
  4. GRB 020127, I-band observations starting 3.14-hr after the event
  5. IPN triangulation of GRB020127 (=H1902)
  6. GRB020127 Optical Observations -- Erratum to GCN 1230
  7. GRB010921 Optical Observations
  8. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  9. GRB020124: Optical observations
  10. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  11. GRB020124: Optical observations
  12. GRB 020124: Optical observations
  13. GRB 020124 Optical Observations
  14. IPN triangulation of GRB020124 (HETE 1896)
  15. GRB 020124: Optical afterglow
  16. GRB020124(=H1896): Localization of a Long GRB by HETE
  17. GRB optical counterpart candidate in GCN 1217 is M dwarf
  18. GRB011212, Optical Observations
  19. GRB011211: BeppoSAX/GRBM data
  20. Optical polarization observations for GRB011211
  21. Color indices of the afterglow of GRB011211
  22. GRB011212: Optical observations at Gunma
  23. GRB 011211, spectrum and optical photometry
  24. GRB 011130: Optical Observations of X-ray and Radio Sources
  25. GRB 011130, Radio/X-ray Comparison
  26. GRB011212: Optical observations
  27. GRB 011212: optical observation at Asiago
  28. GRB 011211: Evidence for an Optical Break
  29. GRB 011211: TNG Spectroscopic Observations
  30. optical follow-up of GRB(XRF) 011211
  31. GRB 011212: optical observation at Oslo (relayed)
  32. GRB 011211: Optical Spectroscopy
  33. GRB 011211, Optical Observations
  34. GRB011212, BVRI field photometry
  35. GRB011211, BVRI field photometry
  36. GRB011212: Optical observations
  37. GRB 011211: BVRi-band photometry
  38. Fading of the optical source associated of XRF 011211
  39. XMM-Newton observation of GRB011211
  40. GRB 011211 Optical Observations: Likely Afterglow
  41. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  42. GRB 011130: Optical Observations of Chandra Sources
  43. GRB 011130: Optical Observations of Chandra sources
  44. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  45. GRB 011130: Magellan spectroscopy
  46. GRB011130, optical observations
  47. GRB011130, optical observations
  48. GRB011130 (=XRF011130): Second Revised Localization by HETE
  49. GRB 011130 I-band Observation
  50. GRB011130 (XRF011130) optical observations
  51. GRB011130 (XRF011130) SDSS PT i-band observations
  52. XRF011130: Infrared Observations
  53. GRB011130, Radio Observations
  54. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  55. GRB011130 (=XRF011130), Optical Observations
  56. XRF011130: NEAT Optical Observations
  57. GRB011130 (=XRF011130): Revised Localization of an X-ray
  58. GRB001109, Radio Monitoring
  59. GRB 011121: Errata URL
  60. GRB 011121
  61. GRB 011121: J-band observations
  62. GRB 011121: NIR observations, host galaxy?
  63. GRB010921 - Milagro GeV/TeV Observations
  64. GRB 011121: HST Scheduled
  65. GRB011121: fainter still
  66. Correction: GCN1157 (GRB 011121)
  67. GRB011121: UBRI Observations
  68. GRB011121
  69. GRB 011121: Radio Observations
  70. GRB 011121 J-Band Astrometry
  71. GRB011121: continued decay
  72. GRB 011121: Detection of Bright IR Counterpart
  73. GRB011121: possible redshift, continued decay
  74. GRB011121: fading behavior
  75. GRB011121: possible optical counterpart
  76. IPN triangulation of GRB011121
  77. GRB 011030: TNG K-band observation
  78. XRF011030: J and K band observations
  79. XRF011030: Chandra Observations
  80. GRB 011030: K-band observations
  81. GRB011030: Z-band observations
  82. GRB 011030 I-band Observation
  83. The X-ray Flash 011030 ('GRB 011030')
  84. The Radio Afterglow from the X-ray Rich GRB 011030
  85. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  86. GRB 000131: HST Detection of the Host Galaxy
  87. GRB 011019 optical observation
  88. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  89. GRB011019: Subaru Optical Observations
  90. GRB 011030 I-band Observations
  91. GRB 011030 K-band Observations
  92. GRB010921, optical observations
  93. GRB 011030, WSRT radio observations
  94. GRB011030 - further refinement WFC position
  95. GRB 011030, Radio observations
  96. GRB011030: radio search
  97. GRB 011030, R-band observations
  98. BeppoSAX ALERT: Possible X-ray rich GRB011030
  99. GRB 010921: Possible supernova component
  100. GRB011019: ROTSE-III optical observations

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