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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"

33774 results found.

  1. GRB020127: Chandra Observations and Prospective Counterparts
  2. pre-SN2002ap (SN/GRB?) imaging of M74
  3. SN 2002ap (hypernova / GRB ??): special list on VSNET
  4. Type Ib/c SN2002ap (SN/GRB?)
  5. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  6. GRB020124, optical observations
  7. GRB020127: Optical observations
  8. GRB 020127, I-band observations starting 3.14-hr after the event
  9. IPN detection of further activity from SGR1806-20
  10. IPN triangulation of GRB020127 (=H1902)
  11. GRB010921 Optical Observations
  12. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  13. GRB020124: Optical observations
  14. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  15. GRB020124: Optical observations
  16. GRB 020124: Optical observations
  17. GRB 020124 Optical Observations
  18. IPN triangulation of GRB020124 (HETE 1896)
  19. IPN observations of SGR1806-20
  20. GRB 020124: Optical afterglow
  21. GRB020124(=H1896): Localization of a Long GRB by HETE
  22. GRB optical counterpart candidate in GCN 1217 is M dwarf
  23. Possible optical counterpart to a GRB
  24. GRB011212, Optical Observations
  25. Optical polarization observations for GRB011211
  26. GRB 011211: Detection of the Probable Host Galaxy
  27. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  28. GRB 011211, spectrum and optical photometry
  29. GRB 011130: Optical Observations of X-ray and Radio Sources
  30. GRB 011130, Radio/X-ray Comparison
  31. GRB 011212: optical observation at Asiago
  32. GRB 011211: Evidence for an Optical Break
  33. GRB 011211: TNG Spectroscopic Observations
  34. optical follow-up of GRB(XRF) 011211
  35. GRB 011212: optical observation at Oslo (relayed)
  36. GRB 011211: Optical Spectroscopy
  37. GRB 011211, Optical Observations
  38. GRB011212, BVRI field photometry
  39. GRB011211, BVRI field photometry
  40. GRB011212: Optical observations
  41. GRB 011211: BVRi-band photometry
  42. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  43. Fading of the optical source associated of XRF 011211
  44. GRB 011211 Optical Observations: Likely Afterglow
  45. BeppoSAX Alert: GRB011211(=XRF011211)
  46. GRB 011130: Optical Observations of Chandra Sources
  47. GRB 011130: Optical Observations of Chandra sources
  48. GRB 011130: Magellan spectroscopy
  49. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  50. GRB011130, optical observations
  51. GRB 011130, K band observations
  52. GRB011130, optical observations
  53. GRB 011130 I-band Observation
  54. GRB011130 (XRF011130) optical observations
  55. GRB011130 (XRF011130) SDSS PT i-band observations
  56. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  57. XRF011130: NEAT Optical Observations
  58. GRB011130 (=XRF011130): Revised Localization of an X-ray
  59. GRB001109, Radio Monitoring
  60. GRB 011121: Errata URL
  61. GRB 011121
  62. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  63. GRB 011121: J-band observations
  64. GRB 011121: NIR observations, host galaxy?
  65. GRB 011121: HST Scheduled
  66. GRB011121: fainter still
  67. Correction: GCN1157 (GRB 011121)
  68. GRB 011121: Radio Observations
  69. GRB 011121 J-Band Astrometry
  70. GRB011121: continued decay
  71. GRB 011121: Detection of Bright IR Counterpart
  72. GRB011121: possible redshift, continued decay
  73. IPN triangulation of GRB011121
  74. BEPPOSAX GRB011121
  75. GRB 011030: TNG K-band observation
  76. XRF011030: Chandra Observations
  77. GRB 011030: K-band observations
  78. GRB 011030 R band observations
  79. GRB 011030 I-band Observation
  80. The X-ray Flash 011030 ('GRB 011030')
  81. Non-triggered burst 011030 ("GRB 011030")
  82. The Radio Afterglow from the X-ray Rich GRB 011030
  83. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  84. GRB 970828: HST Observations of the Host Galaxy
  85. GRB 000131: HST Detection of the Host Galaxy
  86. GRB 970828: HST Observations of the Host Galaxy
  87. GRB010921, optical observation
  88. GRB 011019 optical observation
  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. GRB 011030, R-band observations
  97. BeppoSAX ALERT: Possible X-ray rich GRB011030
  98. GRB 010921: Possible supernova component
  99. GRB011019: NEAT Optical Observations
  100. GRB010921, optical observation at early time

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