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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"

32508 results found.

  1. SGR1900+14 activity
  2. GRB020124 BVRI field photometry
  3. GRB020127: Palomar and VLA Observations of Possible Counterparts
  4. GRB020127, WSRT radio observations
  5. GRB020127 Optical Observations
  6. SN2002ap (SN/GRB?) UBVRI Field Photometry
  7. GRB020127: Chandra Observations and Prospective Counterparts
  8. pre-SN2002ap (SN/GRB?) imaging of M74
  9. Type Ib/c SN2002ap (SN/GRB?)
  10. GRB020127: Optical observations
  11. GRB 020127, I-band observations starting 3.14-hr after the event
  12. IPN triangulation of GRB020127 (=H1902)
  13. GRB020127 Optical Observations -- Erratum to GCN 1230
  14. GRB010921 Optical Observations
  15. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  16. GRB020124: Optical observations
  17. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  18. GRB020124: Optical observations
  19. GRB 020124: Optical observations
  20. GRB 020124 Optical Observations
  21. IPN triangulation of GRB020124 (HETE 1896)
  22. GRB 020124: Optical afterglow
  23. GRB020124(=H1896): Localization of a Long GRB by HETE
  24. GRB optical counterpart candidate in GCN 1217 is M dwarf
  25. GRB011212, Optical Observations
  26. GRB011211: BeppoSAX/GRBM data
  27. Optical polarization observations for GRB011211
  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. GRB 011211: BVRi-band photometry
  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. GRB 011130: Optical Observations of Chandra Sources
  50. GRB 011130: Optical Observations of Chandra sources
  51. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  52. GRB 011130: Magellan spectroscopy
  53. GRB011130, optical observations
  54. GRB011130, optical observations
  55. GRB011130 (=XRF011130): Second Revised Localization by HETE
  56. GRB 011130 I-band Observation
  57. GRB011130 (XRF011130) optical observations
  58. GRB011130 (XRF011130) SDSS PT i-band observations
  59. XRF011130: Infrared Observations
  60. GRB011130, Radio Observations
  61. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  62. GRB011130 (=XRF011130), Optical Observations
  63. XRF011130: NEAT Optical Observations
  64. GRB011130 (=XRF011130): Revised Localization of an X-ray
  65. GRB001109, Radio Monitoring
  66. GRB 011121: Errata URL
  67. GRB 011121
  68. GRB 011121: J-band observations
  69. GRB 011121: NIR observations, host galaxy?
  70. GRB010921 - Milagro GeV/TeV Observations
  71. GRB 011121: HST Scheduled
  72. GRB011121: fainter still
  73. Correction: GCN1157 (GRB 011121)
  74. GRB011121: UBRI Observations
  75. GRB011121
  76. GRB 011121: Radio Observations
  77. GRB 011121 J-Band Astrometry
  78. GRB011121: continued decay
  79. GRB 011121: Detection of Bright IR Counterpart
  80. GRB011121: possible redshift, continued decay
  81. GRB011121: fading behavior
  82. GRB011121: possible optical counterpart
  83. IPN triangulation of GRB011121
  84. GRB 011030: TNG K-band observation
  85. XRF011030: J and K band observations
  86. XRF011030: Chandra Observations
  87. GRB 011030: K-band observations
  88. GRB011030: Z-band observations
  89. GRB 011030 I-band Observation
  90. The X-ray Flash 011030 ('GRB 011030')
  91. The Radio Afterglow from the X-ray Rich GRB 011030
  92. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  93. GRB 000131: HST Detection of the Host Galaxy
  94. GRB 011019 optical observation
  95. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  96. GRB011019: Subaru Optical Observations
  97. GRB 011030 I-band Observations
  98. GRB 011030 K-band Observations
  99. GRB010921, optical observations
  100. GRB 011030, WSRT radio observations

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