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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"

16159 results found.

  1. GRB011212: Optical Observations
  2. GRB 020331 Optical Observations
  3. GRB 020331: Optical observations
  4. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  5. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  6. GRB 020322, Radio observations
  7. Near-Infrared Observations of GRB020322 at TIRGO
  8. GRB 020322: Optical Observations
  9. GRB 020321: Optical observations
  10. GRB020317 BVRI field photometry
  11. GRB011211 revised BVRI field photometry
  12. GRB020305 BVRI field photometry
  13. GRB020322 BVRI field photometry
  14. GRB 020322 optical observations
  15. GRB020322: Candidate Optical Afterglow
  16. GRB 020322 optical observation
  17. GRB 020322: Optical Sources and Improved Astrometry
  18. GRB020322, optical observations
  19. GRB 020322: Optical candidate
  20. GRB020322: Optical Observations
  21. GRB 020321: Optical observations
  22. GRB 011121: Fourth Epoch of HST Imaging
  23. GRB020317: optical observations
  24. GRB020321 optical observations
  25. GRB 020317 : KISO Optical Observations
  26. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  27. GRB 020305: Optical Observations
  28. GRB020317, optical observations
  29. GRB 020317: Optical observations
  30. GRB020305: Properties of the Candidate Optical Afterglow
  31. GRB 011121: HST Observations reveal an intermediate-time multicolor
  32. GRB020305: Subaru Optical Observations
  33. GRB 020305: Optical observations
  34. XRF/GRB 011030: Detection of the Probable Host Galaxy
  35. GRB 020305: Candidate optical afterglow
  36. Type Ic SN2002bl (SN/GRB?) Radio Observations
  37. GRB020305, optical observations
  38. GRB020305: Optical Observations
  39. IPN triangulation of GRB020305 (HETE 1939)
  40. GRB020305 (=H1939): Localization of a GRB by HETE
  41. GRB 020305: Optical observations
  42. HST Imaging of the afterglow and host of GRB 011121
  43. GRB020124 BVRI field photometry
  44. GRB020127: Palomar and VLA Observations of Possible Counterparts
  45. SN2002ap (SN/GRB?) optical spectrographic observations
  46. GRB020127 Optical Observations
  47. Type Ib/c SN2002ap (SN/GRB?)
  48. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  49. GRB020124, optical observations
  50. GRB020127: Optical observations
  51. IPN triangulation of GRB020127 (=H1902)
  52. GRB020127 Optical Observations -- Erratum to GCN 1230
  53. GRB010921 Optical Observations
  54. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  55. GRB020124: Optical observations
  56. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  57. GRB020124: Optical observations
  58. GRB 020124: Optical observations
  59. GRB 020124 Optical Observations
  60. IPN triangulation of GRB020124 (HETE 1896)
  61. GRB 020124: Optical afterglow
  62. GRB020124(=H1896): Localization of a Long GRB by HETE
  63. HETE 1896: Optical observations
  64. GRB optical counterpart candidate in GCN 1217 is M dwarf
  65. Possible optical counterpart to a GRB
  66. GRB011212, Optical Observations
  67. Optical polarization observations for GRB011211
  68. Color indices of the afterglow of GRB011211
  69. GRB011212: Optical observations at Gunma
  70. GRB 011211, spectrum and optical photometry
  71. GRB 011130: Optical Observations of X-ray and Radio Sources
  72. GRB 011130, Radio/X-ray Comparison
  73. GRB011212: Optical observations
  74. GRB 011212: optical observation at Asiago
  75. GRB 011211: Evidence for an Optical Break
  76. optical follow-up of GRB(XRF) 011211
  77. GRB 011212: optical observation at Oslo (relayed)
  78. GRB 011211: Optical Spectroscopy
  79. GRB 011211, Optical Observations
  80. GRB011212, BVRI field photometry
  81. GRB011211, BVRI field photometry
  82. GRB011212: Optical observations
  83. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  84. Fading of the optical source associated of XRF 011211
  85. GRB 011211 Optical Observations: Likely Afterglow
  86. GRB 011130: Optical Observations of Chandra Sources
  87. GRB 011130: Optical Observations of Chandra sources
  88. GRB 011130: Magellan spectroscopy
  89. GRB011130, optical observations
  90. GRB 011130, K band observations
  91. GRB011130, optical observations
  92. GRB011130 (=XRF011130): Second Revised Localization by HETE
  93. GRB 011130 I-band Observation
  94. GRB011130 (XRF011130) optical observations
  95. XRF011130: Infrared Observations
  96. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  97. GRB011130 (=XRF011130), Optical Observations
  98. XRF011130: NEAT Optical Observations
  99. GRB011130 (=XRF011130): Revised Localization of an X-ray
  100. GRB001109, Radio Monitoring

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