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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"

17798 results found.

  1. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  2. Near-Infrared Observations of GRB020322 at TIRGO
  3. GRB 020322: Optical Observations
  4. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  5. GRB 020321: Optical observations
  6. GRB020317 BVRI field photometry
  7. GRB011211 revised BVRI field photometry
  8. GRB020305 BVRI field photometry
  9. GRB020322 BVRI field photometry
  10. GRB020322: Candidate Optical Afterglow
  11. GRB 020322: Optical Sources and Improved Astrometry
  12. GRB020317: optical observations
  13. GRB020321 optical observations
  14. GRB020321: a faint BeppoSAX detection
  15. GRB 020317 : KISO Optical Observations
  16. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  17. GRB 020305: Optical Observations
  18. GRB020317, optical observations
  19. GRB 020317: Optical observations
  20. GRB020305: Properties of the Candidate Optical Afterglow
  21. GRB011130 (XRF011130) Second Epoch Chandra Observations
  22. GRB 020305: Optical observations
  23. XRF/GRB 011030: Detection of the Probable Host Galaxy
  24. GRB 020305: Candidate optical afterglow
  25. GRB020305, optical observations
  26. HST Imaging of the afterglow and host of GRB 011121
  27. GRB 010921: HST Observations
  28. SGR1900+14 activity
  29. GRB020124 BVRI field photometry
  30. GRB020127 Optical Observations
  31. SN2002ap (SN/GRB?) UBVRI Field Photometry
  32. GRB020127: Chandra Observations and Prospective Counterparts
  33. pre-SN2002ap (SN/GRB?) imaging of M74
  34. GRB020124, optical observations
  35. GRB 020127, I-band observations starting 3.14-hr after the event
  36. GRB010921 Optical Observations
  37. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  38. GRB020124: Optical observations
  39. GRB020124: Optical observations
  40. GRB 020124: Optical observations
  41. GRB 020124: Optical afterglow
  42. GRB020124(=H1896): Localization of a Long GRB by HETE
  43. Possible optical counterpart to a GRB
  44. GRB011212, Optical Observations
  45. Optical polarization observations for GRB011211
  46. GRB 011130: Optical Observations of X-ray and Radio Sources
  47. GRB 011130, Radio/X-ray Comparison
  48. GRB 011212: optical observation at Asiago
  49. GRB 011211: Evidence for an Optical Break
  50. GRB 011212: optical observation at Oslo (relayed)
  51. GRB 011211, Optical Observations
  52. GRB011212, BVRI field photometry
  53. GRB011211, BVRI field photometry
  54. Fading of the optical source associated of XRF 011211
  55. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  56. GRB011130 (XRF011130) Chandra Observations
  57. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  58. GRB 011130, K band observations
  59. GRB011130 (XRF011130) SDSS PT i-band observations
  60. XRF011130: Infrared Observations
  61. GRB 011121: J-band observations
  62. GRB 011121: NIR observations, host galaxy?
  63. GRB011121: UBRI Observations
  64. GRB 011121 J-Band Astrometry
  65. GRB 011121: Detection of Bright IR Counterpart
  66. GRB011121: possible redshift, continued decay
  67. GRB 011030: TNG K-band observation
  68. XRF011030: J and K band observations
  69. XRF011030: Chandra Observations
  70. GRB011030: Z-band observations
  71. Non-triggered burst 011030 ("GRB 011030")
  72. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  73. GRB 970828: HST Observations of the Host Galaxy
  74. GRB 000131: HST Detection of the Host Galaxy
  75. GRB 970828: HST Observations of the Host Galaxy
  76. GRB010921, optical observation
  77. GRB011019: Subaru Optical Observations
  78. GRB011030 - further refinement WFC position
  79. GRB011030: radio search
  80. GRB 010921: Possible supernova component
  81. GRB010921, optical observation at early time
  82. GRB 010921, I-band observations
  83. GRB011019, optical observations
  84. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  85. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  86. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  87. GRB010928(=H1770): Localization of a Long GRB by HETE
  88. GRB010921, negative optical observations
  89. GRB010921 field photometry
  90. GRB000926, Host Galaxy Observations
  91. GRB001109, Host Galaxy Spectroscopic Observations
  92. Probable SGR or Short Duration GRB Detected by HETE
  93. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  94. GRB 010222 - WHT BVRI images
  95. GRB 010629 Optical Observations
  96. SGR1900+14: High Fluence Burst Localized by HETE
  97. GRB010629, optical observations
  98. IPN triangulation of GRB010629
  99. GRB010629: A Burst Localized by HETE
  100. SGR1900+14: Second Burst Localized by HETE

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