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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"

32505 results found.

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

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