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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"

26368 results found.

  1. GRB011130 (XRF011130) Second Epoch Chandra Observations
  2. GRB020305: Subaru Optical Observations
  3. XRF/GRB 011030: Detection of the Probable Host Galaxy
  4. GRB 020305: Candidate optical afterglow
  5. GRB020305, optical observations
  6. IPN triangulation of GRB020305 (HETE 1939)
  7. GRB020305 (=H1939): Localization of a GRB by HETE
  8. HST Imaging of the afterglow and host of GRB 011121
  9. IPN detection and localization of Cygnus X-1 flares
  10. SGR1900+14 activity
  11. IPN Upper Limits to a GRB Associated With SN2002ap
  12. GRB020124 BVRI field photometry
  13. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  14. SN2002ap (SN/GRB?) Echelle spectra
  15. GRB020127 Optical Observations
  16. SN 2002ap in M74
  17. SN2002ap (SN/GRB?) UBVRI Field Photometry
  18. GRB020127: Chandra Observations and Prospective Counterparts
  19. pre-SN2002ap (SN/GRB?) imaging of M74
  20. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  21. GRB020124, optical observations
  22. GRB 020127, I-band observations starting 3.14-hr after the event
  23. GRB010921 Optical Observations
  24. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  25. GRB020124: Optical observations
  26. GRB 020124: Optical observations
  27. GRB 020124: Optical afterglow
  28. GRB020124(=H1896): Localization of a Long GRB by HETE
  29. Possible optical counterpart to a GRB
  30. GRB011212, Optical Observations
  31. Optical polarization observations for GRB011211
  32. GRB 011211: Detection of the Probable Host Galaxy
  33. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  34. GRB 011130: Optical Observations of X-ray and Radio Sources
  35. GRB 011212: optical observation at Asiago
  36. GRB 011211: Evidence for an Optical Break
  37. GRB 011211: TNG Spectroscopic Observations
  38. optical follow-up of GRB(XRF) 011211
  39. GRB 011212: optical observation at Oslo (relayed)
  40. GRB 011211, Optical Observations
  41. GRB011212, BVRI field photometry
  42. GRB011211, BVRI field photometry
  43. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  44. Fading of the optical source associated of XRF 011211
  45. GRB 011211 Optical Observations: Likely Afterglow
  46. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  47. GRB011130 (XRF011130) Chandra Observations
  48. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  49. GRB 011130, K band observations
  50. GRB011130, optical observations
  51. GRB011130 (=XRF011130): Second Revised Localization by HETE
  52. GRB011130 (XRF011130) SDSS PT i-band observations
  53. XRF011130: Infrared Observations
  54. GRB 011121
  55. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  56. GRB 011121: J-band observations
  57. GRB 011121: NIR observations, host galaxy?
  58. GRB011121: UBRI Observations
  59. GRB 011121 J-Band Astrometry
  60. GRB 011121: Detection of Bright IR Counterpart
  61. GRB011121: possible redshift, continued decay
  62. GRB 011030: TNG K-band observation
  63. XRF011030: J and K band observations
  64. XRF011030: Chandra Observations
  65. GRB011030: Z-band observations
  66. GRB 011030 R band observations
  67. GRB 011030 I-band Observation
  68. The X-ray Flash 011030 ('GRB 011030')
  69. Non-triggered burst 011030 ("GRB 011030")
  70. The Radio Afterglow from the X-ray Rich GRB 011030
  71. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  72. GRB 970828: HST Observations of the Host Galaxy
  73. GRB 000131: HST Detection of the Host Galaxy
  74. GRB 970828: HST Observations of the Host Galaxy
  75. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  76. GRB011019: Subaru Optical Observations
  77. GRB 011030 I-band Observations
  78. GRB 011030 K-band Observations
  79. GRB010921, optical observations
  80. GRB011030 - further refinement WFC position
  81. GRB 011030, Radio observations
  82. GRB011030: radio search
  83. GRB 010921: Possible supernova component
  84. GRB010921, optical observation at early time
  85. GRB 010921, I-band observations
  86. GRB011019, optical observations
  87. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  88. GRB 010921: The afterglow of HETE #1761
  89. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  90. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  91. GRB010923 as seen by BeppoSAX GRBM
  92. GRB010928(=H1770): Localization of a Long GRB by HETE
  93. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  94. GRB010921, negative optical observations
  95. GRB010921 field photometry
  96. H1761: A Bright GRB Detected by HETE
  97. GRB000926, Host Galaxy Observations
  98. GRB001109, Host Galaxy Spectroscopic Observations
  99. Probable SGR or Short Duration GRB Detected by HETE
  100. GCN and HETE status

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