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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"

21788 results found.

  1. GRB020127 Optical Observations
  2. SN 2002ap in M74
  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. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  8. GRB020124, optical observations
  9. GRB020127: Optical observations
  10. GRB 020127, I-band observations starting 3.14-hr after the event
  11. GRB020127 Optical Observations -- Erratum to GCN 1230
  12. GRB010921 Optical Observations
  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 observations of SGR1806-20
  19. GRB 020124: Optical afterglow
  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. Optical polarization observations for GRB011211
  25. GRB 011211: Detection of the Probable Host Galaxy
  26. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  27. Color indices of the afterglow of GRB011211
  28. GRB011212: Optical observations at Gunma
  29. GRB 011130: Optical Observations of X-ray and Radio Sources
  30. GRB 011130, Radio/X-ray Comparison
  31. GRB011212: Optical observations
  32. GRB 011212: optical observation at Asiago
  33. GRB 011211: TNG Spectroscopic Observations
  34. GRB 011211, Optical Observations
  35. GRB011212: Optical observations
  36. GRB 011211 Optical Observations: Likely Afterglow
  37. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  38. GRB 011130: Optical Observations of Chandra Sources
  39. GRB 011130: Optical Observations of Chandra sources
  40. GRB011130 (XRF011130) Chandra Observations
  41. GRB 011130: Magellan spectroscopy
  42. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  43. GRB011130, optical observations
  44. GRB 011130, K band observations
  45. GRB011130, optical observations
  46. GRB011130 (XRF011130) optical observations
  47. GRB011130 (XRF011130) SDSS PT i-band observations
  48. XRF011130: Infrared Observations
  49. GRB011130, Radio Observations
  50. GRB011130 (=XRF011130), Optical Observations
  51. XRF011130: NEAT Optical Observations
  52. GRB001109, Radio Monitoring
  53. GRB 011121
  54. GRB 011121: J-band observations
  55. GRB 011121: NIR observations, host galaxy?
  56. GRB010921 - Milagro GeV/TeV Observations
  57. GRB 011121: HST Scheduled
  58. GRB011121: fainter still
  59. GRB011121: UBRI Observations
  60. GRB011121
  61. GRB 011121: Radio Observations
  62. GRB011121: continued decay
  63. GRB 011121: Detection of Bright IR Counterpart
  64. GRB011121: possible redshift, continued decay
  65. GRB011121: fading behavior
  66. GRB011121: possible optical counterpart
  67. XRF011030: J and K band observations
  68. XRF011030: Chandra Observations
  69. GRB 011030: K-band observations
  70. GRB011030: Z-band observations
  71. GRB 011030 R band observations
  72. The X-ray Flash 011030 ('GRB 011030')
  73. Non-triggered burst 011030 ("GRB 011030")
  74. The Radio Afterglow from the X-ray Rich GRB 011030
  75. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  76. GRB 970828: HST Observations of the Host Galaxy
  77. GRB 000131: HST Detection of the Host Galaxy
  78. GRB 970828: HST Observations of the Host Galaxy
  79. GRB010921, optical observation
  80. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  81. GRB011019: Subaru Optical Observations
  82. GRB 011030 I-band Observations
  83. GRB 011030 K-band Observations
  84. GRB010921, optical observations
  85. GRB 011030, WSRT radio observations
  86. GRB 011030, Radio observations
  87. GRB 011030, R-band observations
  88. GRB011019: NEAT Optical Observations
  89. GRB011019: ROTSE-III optical observations
  90. GRB 010921, I-band observations
  91. GRB011019: Optical observations
  92. GRB011019, optical observations -- correction
  93. GRB011019, optical observations
  94. GRB010921: Spectroscopy of the Host Galaxy
  95. GRB 010921: The afterglow of HETE #1761
  96. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  97. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  98. GRB010928(=H1770): Localization of a Long GRB by HETE
  99. GRB010921, negative optical observations
  100. GRB010921 Optical Observations

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