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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"

28057 results found.

  1. GRB020124 BVRI field photometry
  2. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  3. SN2002ap (SN/GRB?) Echelle spectra
  4. GRB020127 Optical Observations
  5. SN 2002ap in M74
  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?) Radio Observations
  10. GRB020124, optical observations
  11. GRB 020127, I-band observations starting 3.14-hr after the event
  12. GRB010921 Optical Observations
  13. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  14. GRB020124: Optical observations
  15. GRB 020124: Optical observations
  16. GRB 020124: Optical afterglow
  17. GRB020124(=H1896): Localization of a Long GRB by HETE
  18. Possible optical counterpart to a GRB
  19. GRB011212, Optical Observations
  20. Optical polarization observations for GRB011211
  21. GRB 011211: Detection of the Probable Host Galaxy
  22. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  23. GRB 011130: Optical Observations of X-ray and Radio Sources
  24. GRB 011212: optical observation at Asiago
  25. GRB 011211: Evidence for an Optical Break
  26. GRB 011211: TNG Spectroscopic Observations
  27. optical follow-up of GRB(XRF) 011211
  28. GRB 011212: optical observation at Oslo (relayed)
  29. GRB 011211, Optical Observations
  30. GRB011212, BVRI field photometry
  31. GRB011211, BVRI field photometry
  32. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  33. Fading of the optical source associated of XRF 011211
  34. GRB 011211 Optical Observations: Likely Afterglow
  35. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  36. GRB011130 (XRF011130) Chandra Observations
  37. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  38. GRB 011130, K band observations
  39. GRB011130, optical observations
  40. GRB011130 (=XRF011130): Second Revised Localization by HETE
  41. GRB011130 (XRF011130) SDSS PT i-band observations
  42. XRF011130: Infrared Observations
  43. GRB 011121
  44. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  45. GRB 011121: J-band observations
  46. GRB 011121: NIR observations, host galaxy?
  47. GRB011121: UBRI Observations
  48. GRB 011121 J-Band Astrometry
  49. GRB 011121: Detection of Bright IR Counterpart
  50. GRB011121: possible redshift, continued decay
  51. GRB 011030: TNG K-band observation
  52. XRF011030: J and K band observations
  53. XRF011030: Chandra Observations
  54. GRB011030: Z-band observations
  55. GRB 011030 R band observations
  56. GRB 011030 I-band Observation
  57. The X-ray Flash 011030 ('GRB 011030')
  58. Non-triggered burst 011030 ("GRB 011030")
  59. The Radio Afterglow from the X-ray Rich GRB 011030
  60. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  61. GRB 970828: HST Observations of the Host Galaxy
  62. GRB 000131: HST Detection of the Host Galaxy
  63. GRB 970828: HST Observations of the Host Galaxy
  64. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  65. GRB011019: Subaru Optical Observations
  66. GRB 011030 I-band Observations
  67. GRB 011030 K-band Observations
  68. GRB010921, optical observations
  69. GRB011030 - further refinement WFC position
  70. GRB 011030, Radio observations
  71. GRB011030: radio search
  72. GRB 010921: Possible supernova component
  73. GRB010921, optical observation at early time
  74. GRB 010921, I-band observations
  75. GRB011019, optical observations
  76. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  77. GRB 010921: The afterglow of HETE #1761
  78. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  79. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  80. GRB010923 as seen by BeppoSAX GRBM
  81. GRB010928(=H1770): Localization of a Long GRB by HETE
  82. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  83. GRB010921, negative optical observations
  84. GRB010921 field photometry
  85. H1761: A Bright GRB Detected by HETE
  86. GRB000926, Host Galaxy Observations
  87. GRB001109, Host Galaxy Spectroscopic Observations
  88. Probable SGR or Short Duration GRB Detected by HETE
  89. GCN and HETE status
  90. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  91. GRB 010222 - WHT BVRI images
  92. SGR1900+14 burst seen by HETE: BeppoSAX data
  93. GRB 010629 Optical Observations
  94. SGR1900+14: High Fluence Burst Localized by HETE
  95. GRB010629, optical observations
  96. GRB010629: A Burst Localized by HETE
  97. SGR1900+14: Second Burst Localized by HETE
  98. SGR1900+14: A Burst Localized by HETE
  99. SGR1806-20: A Second, Intense Burst Localized by HETE
  100. SGR1806-20: Localization by HETE

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