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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"

35275 results found.

  1. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  2. SN2002ap (SN/GRB?) Echelle spectra
  3. SN2002ap (SN/GRB?) optical spectrographic observations
  4. GRB020127 Optical Observations
  5. SN 2002ap (SN/GRB?)
  6. SN2002ap (SN/GRB?) UBVRI Field Photometry
  7. GRB020127: Chandra Observations and Prospective Counterparts
  8. pre-SN2002ap (SN/GRB?) imaging of M74
  9. SN 2002ap (hypernova / GRB ??): special list on VSNET
  10. Type Ib/c SN2002ap (SN/GRB?)
  11. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  12. GRB020124, optical observations
  13. GRB020127: Optical observations
  14. GRB 020127, I-band observations starting 3.14-hr after the event
  15. IPN detection of further activity from SGR1806-20
  16. IPN triangulation of GRB020127 (=H1902)
  17. GRB010921 Optical Observations
  18. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  19. GRB020124: Optical observations
  20. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  21. GRB020124: Optical observations
  22. GRB 020124: Optical observations
  23. GRB 020124 Optical Observations
  24. IPN triangulation of GRB020124 (HETE 1896)
  25. IPN observations of SGR1806-20
  26. GRB 020124: Optical afterglow
  27. GRB020124(=H1896): Localization of a Long GRB by HETE
  28. GRB optical counterpart candidate in GCN 1217 is M dwarf
  29. Possible optical counterpart to a GRB
  30. GRB011212, Optical Observations
  31. GRB 011211: Detection of the Probable Host Galaxy
  32. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  33. GRB 011211, spectrum and optical photometry
  34. GRB 011130: Optical Observations of X-ray and Radio Sources
  35. GRB 011130, Radio/X-ray Comparison
  36. GRB 011212: optical observation at Asiago
  37. GRB 011211: Evidence for an Optical Break
  38. GRB 011211: TNG Spectroscopic Observations
  39. optical follow-up of GRB(XRF) 011211
  40. GRB 011212: optical observation at Oslo (relayed)
  41. GRB 011211: Optical Spectroscopy
  42. GRB 011211, Optical Observations
  43. GRB011212, BVRI field photometry
  44. GRB011211, BVRI field photometry
  45. GRB011212: Optical observations
  46. GRB 011211: BVRi-band photometry
  47. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  48. Fading of the optical source associated of XRF 011211
  49. GRB 011211 Optical Observations: Likely Afterglow
  50. BeppoSAX Alert: GRB011211(=XRF011211)
  51. GRB 011130: Optical Observations of Chandra Sources
  52. GRB 011130: Optical Observations of Chandra sources
  53. GRB 011130: Magellan spectroscopy
  54. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  55. GRB011130, optical observations
  56. GRB 011130, K band observations
  57. GRB011130, optical observations
  58. GRB 011130 I-band Observation
  59. GRB011130 (XRF011130) optical observations
  60. GRB011130 (XRF011130) SDSS PT i-band observations
  61. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  62. XRF011130: NEAT Optical Observations
  63. GRB011130 (=XRF011130): Revised Localization of an X-ray
  64. GRB001109, Radio Monitoring
  65. GRB 011121: Errata URL
  66. GRB 011121
  67. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  68. GRB 011121: J-band observations
  69. GRB 011121: NIR observations, host galaxy?
  70. GRB 011121: HST Scheduled
  71. GRB011121: fainter still
  72. Correction: GCN1157 (GRB 011121)
  73. GRB 011121: Radio Observations
  74. GRB 011121 J-Band Astrometry
  75. GRB011121: continued decay
  76. GRB 011121: Detection of Bright IR Counterpart
  77. GRB011121: possible redshift, continued decay
  78. IPN triangulation of GRB011121
  79. BEPPOSAX GRB011121
  80. GRB 011030: TNG K-band observation
  81. XRF011030: Chandra Observations
  82. GRB 011030: K-band observations
  83. GRB 011030 R band observations
  84. GRB 011030 I-band Observation
  85. The X-ray Flash 011030 ('GRB 011030')
  86. Non-triggered burst 011030 ("GRB 011030")
  87. The Radio Afterglow from the X-ray Rich GRB 011030
  88. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  89. GRB 970828: HST Observations of the Host Galaxy
  90. GRB 000131: HST Detection of the Host Galaxy
  91. GRB 970828: HST Observations of the Host Galaxy
  92. GRB010921, optical observation
  93. GRB 011019 optical observation
  94. GRB011019: Subaru Optical Observations
  95. GRB 011030 I-band Observations
  96. GRB 011030 K-band Observations
  97. GRB010921, optical observations
  98. GRB 011030, WSRT radio observations
  99. GRB011030 - further refinement WFC position
  100. GRB 011030, Radio observations

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