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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"

41200 results found.

  1. Type Ib/c SN2002ap (SN/GRB?)
  2. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  3. GRB020124, optical observations
  4. GRB020127: Optical observations
  5. GRB 020127, I-band observations starting 3.14-hr after the event
  6. IPN detection of further activity from SGR1806-20
  7. IPN triangulation of GRB020127 (=H1902)
  8. GRB020127 Optical Observations -- Erratum to GCN 1230
  9. GRB010921 Optical Observations
  10. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  11. GRB020124: Optical observations
  12. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  13. GRB020124: Optical observations
  14. GRB 020124: Optical observations
  15. GRB 020124 Optical Observations
  16. IPN triangulation of GRB020124 (HETE 1896)
  17. IPN observations of SGR1806-20
  18. GRB 020124: Optical afterglow
  19. GRB020124(=H1896): Localization of a Long GRB by HETE
  20. HETE 1896: Optical observations
  21. GRB optical counterpart candidate in GCN 1217 is M dwarf
  22. Possible optical counterpart to a GRB
  23. GRB011212, Optical Observations
  24. GRB011211: BeppoSAX/GRBM data
  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. Color indices of the afterglow of GRB011211
  29. GRB011212: Optical observations at Gunma
  30. GRB 011211, spectrum and optical photometry
  31. GRB 011130: Optical Observations of X-ray and Radio Sources
  32. GRB 011130, Radio/X-ray Comparison
  33. GRB011212: Optical observations
  34. GRB 011212: optical observation at Asiago
  35. GRB 011211: Evidence for an Optical Break
  36. GRB 011211: TNG Spectroscopic Observations
  37. optical follow-up of GRB(XRF) 011211
  38. GRB 011212: optical observation at Oslo (relayed)
  39. GRB 011211: Optical Spectroscopy
  40. GRB 011211, Optical Observations
  41. GRB011212, BVRI field photometry
  42. GRB011211, BVRI field photometry
  43. GRB011212: Optical observations
  44. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  45. Fading of the optical source associated of XRF 011211
  46. XMM-Newton observation of GRB011211
  47. GRB 011211 Optical Observations: Likely Afterglow
  48. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  49. BeppoSAX Alert: GRB011211(=XRF011211)
  50. GRB 011130: Optical Observations of Chandra Sources
  51. GRB 011130: Optical Observations of Chandra sources
  52. GRB011130 (XRF011130) Chandra Observations
  53. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  54. GRB 011130: Magellan spectroscopy
  55. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  56. GRB011130, optical observations
  57. GRB 011130, K band observations
  58. GRB011130, optical observations
  59. GRB011130 (=XRF011130): Second Revised Localization by HETE
  60. GRB 011130 I-band Observation
  61. GRB011130 (XRF011130) optical observations
  62. GRB011130 (XRF011130) SDSS PT i-band observations
  63. XRF011130: Infrared Observations
  64. GRB011130, Radio Observations
  65. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  66. GRB011130 (=XRF011130), Optical Observations
  67. XRF011130: NEAT Optical Observations
  68. GRB011130 (=XRF011130): Revised Localization of an X-ray
  69. GRB001109, Radio Monitoring
  70. GRB 011121
  71. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  72. GRB 011121: J-band observations
  73. GRB 011121: NIR observations, host galaxy?
  74. GRB010921 - Milagro GeV/TeV Observations
  75. GRB 011121: HST Scheduled
  76. GRB011121: fainter still
  77. GRB011121: UBRI Observations
  78. GRB011121
  79. GRB 011121: Radio Observations
  80. GRB 011121 J-Band Astrometry
  81. GRB011121: continued decay
  82. GRB 011121: Detection of Bright IR Counterpart
  83. GRB011121: possible redshift, continued decay
  84. GRB011121: fading behavior
  85. GRB011121: possible optical counterpart
  86. GRB 011030: TNG K-band observation
  87. XRF011030: J and K band observations
  88. GRB011030, optical observation
  89. XRF011030: Chandra Observations
  90. GRB 011030: K-band observations
  91. GRB011030: Z-band observations
  92. GRB 011030 R band observations
  93. GRB 011030 I-band Observation
  94. The X-ray Flash 011030 ('GRB 011030')
  95. Non-triggered burst 011030 ("GRB 011030")
  96. The Radio Afterglow from the X-ray Rich GRB 011030
  97. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  98. GRB 970828: HST Observations of the Host Galaxy
  99. GRB 000131: HST Detection of the Host Galaxy
  100. GRB 970828: HST Observations of the Host Galaxy

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