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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"

26364 results found.

  1. GRB020305, optical observations
  2. IPN triangulation of GRB020305 (HETE 1939)
  3. GRB020305 (=H1939): Localization of a GRB by HETE
  4. HST Imaging of the afterglow and host of GRB 011121
  5. IPN detection and localization of Cygnus X-1 flares
  6. SGR1900+14 activity
  7. IPN Upper Limits to a GRB Associated With SN2002ap
  8. GRB020124 BVRI field photometry
  9. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  10. SN2002ap (SN/GRB?) Echelle spectra
  11. GRB020127 Optical Observations
  12. SN 2002ap in M74
  13. SN2002ap (SN/GRB?) UBVRI Field Photometry
  14. GRB020127: Chandra Observations and Prospective Counterparts
  15. pre-SN2002ap (SN/GRB?) imaging of M74
  16. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  17. GRB020124, optical observations
  18. GRB 020127, I-band observations starting 3.14-hr after the event
  19. GRB010921 Optical Observations
  20. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  21. GRB020124: Optical observations
  22. GRB 020124: Optical observations
  23. GRB 020124: Optical afterglow
  24. GRB020124(=H1896): Localization of a Long GRB by HETE
  25. Possible optical counterpart to a GRB
  26. GRB011212, Optical Observations
  27. Optical polarization observations for GRB011211
  28. GRB 011211: Detection of the Probable Host Galaxy
  29. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  30. GRB 011130: Optical Observations of X-ray and Radio Sources
  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 Observations
  37. GRB011212, BVRI field photometry
  38. GRB011211, BVRI field photometry
  39. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  40. Fading of the optical source associated of XRF 011211
  41. GRB 011211 Optical Observations: Likely Afterglow
  42. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  43. GRB011130 (XRF011130) Chandra Observations
  44. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  45. GRB 011130, K band observations
  46. GRB011130, optical observations
  47. GRB011130 (=XRF011130): Second Revised Localization by HETE
  48. GRB011130 (XRF011130) SDSS PT i-band observations
  49. XRF011130: Infrared Observations
  50. GRB 011121
  51. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  52. GRB 011121: J-band observations
  53. GRB 011121: NIR observations, host galaxy?
  54. GRB011121: UBRI Observations
  55. GRB 011121 J-Band Astrometry
  56. GRB 011121: Detection of Bright IR Counterpart
  57. GRB011121: possible redshift, continued decay
  58. GRB 011030: TNG K-band observation
  59. XRF011030: J and K band observations
  60. XRF011030: Chandra Observations
  61. GRB011030: Z-band observations
  62. GRB 011030 R band observations
  63. GRB 011030 I-band Observation
  64. The X-ray Flash 011030 ('GRB 011030')
  65. Non-triggered burst 011030 ("GRB 011030")
  66. The Radio Afterglow from the X-ray Rich GRB 011030
  67. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  68. GRB 970828: HST Observations of the Host Galaxy
  69. GRB 000131: HST Detection of the Host Galaxy
  70. GRB 970828: HST Observations of the Host Galaxy
  71. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  72. GRB011019: Subaru Optical Observations
  73. GRB 011030 I-band Observations
  74. GRB 011030 K-band Observations
  75. GRB010921, optical observations
  76. GRB011030 - further refinement WFC position
  77. GRB 011030, Radio observations
  78. GRB011030: radio search
  79. GRB 010921: Possible supernova component
  80. GRB010921, optical observation at early time
  81. GRB 010921, I-band observations
  82. GRB011019, optical observations
  83. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  84. GRB 010921: The afterglow of HETE #1761
  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. GRB010923 as seen by BeppoSAX GRBM
  88. GRB010928(=H1770): Localization of a Long GRB by HETE
  89. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  90. GRB010921, negative optical observations
  91. GRB010921 field photometry
  92. H1761: A Bright GRB Detected by HETE
  93. GRB000926, Host Galaxy Observations
  94. GRB001109, Host Galaxy Spectroscopic Observations
  95. Probable SGR or Short Duration GRB Detected by HETE
  96. GCN and HETE status
  97. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  98. GRB 010222 - WHT BVRI images
  99. SGR1900+14 burst seen by HETE: BeppoSAX data
  100. GRB 010629 Optical Observations

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