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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"

45650 results found.

  1. SN2002ap (SN/GRB?) Echelle spectra
  2. SN2002ap (SN/GRB?) optical spectrographic observations
  3. GRB020127, WSRT radio observations
  4. GRB020127 Optical Observations
  5. SN 2002ap (SN/GRB?)
  6. SN 2002ap in M74
  7. SN2002ap (SN/GRB?) UBVRI Field Photometry
  8. GRB020127: Chandra Observations and Prospective Counterparts
  9. pre-SN2002ap (SN/GRB?) imaging of M74
  10. SN 2002ap (hypernova / GRB ??): special list on VSNET
  11. Type Ib/c SN2002ap (SN/GRB?)
  12. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  13. GRB020124, optical observations
  14. GRB020127: Optical observations
  15. GRB 020127, I-band observations starting 3.14-hr after the event
  16. IPN detection of further activity from SGR1806-20
  17. IPN triangulation of GRB020127 (=H1902)
  18. GRB020127 Optical Observations -- Erratum to GCN 1230
  19. GRB010921 Optical Observations
  20. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  21. GRB020124: Optical observations
  22. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  23. GRB020124: Optical observations
  24. GRB 020124: Optical observations
  25. GRB 020124 Optical Observations
  26. IPN triangulation of GRB020124 (HETE 1896)
  27. IPN observations of SGR1806-20
  28. GRB 020124: Optical afterglow
  29. GRB020124(=H1896): Localization of a Long GRB by HETE
  30. HETE 1896: Optical observations
  31. GRB optical counterpart candidate in GCN 1217 is M dwarf
  32. Possible optical counterpart to a GRB
  33. GRB011212, Optical Observations
  34. GRB011211: BeppoSAX/GRBM data
  35. Optical polarization observations for GRB011211
  36. GRB 011211: Detection of the Probable Host Galaxy
  37. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  38. Color indices of the afterglow of GRB011211
  39. GRB011212: Optical observations at Gunma
  40. GRB 011211, spectrum and optical photometry
  41. GRB 011130: Optical Observations of X-ray and Radio Sources
  42. GRB 011130, Radio/X-ray Comparison
  43. GRB011212: Optical observations
  44. GRB 011212: optical observation at Asiago
  45. GRB 011211: Evidence for an Optical Break
  46. GRB 011211: TNG Spectroscopic Observations
  47. optical follow-up of GRB(XRF) 011211
  48. GRB 011212: optical observation at Oslo (relayed)
  49. GRB 011211: Optical Spectroscopy
  50. GRB 011211, Optical Observations
  51. GRB011212, BVRI field photometry
  52. GRB011211, BVRI field photometry
  53. GRB011212: Optical observations
  54. GRB 011211: BVRi-band photometry
  55. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  56. Fading of the optical source associated of XRF 011211
  57. XMM-Newton observation of GRB011211
  58. GRB 011211 Optical Observations: Likely Afterglow
  59. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  60. GRB011211(=XRF011211): BeppoSAX refined positions
  61. BeppoSAX Alert: GRB011211(=XRF011211)
  62. GRB 011130: Optical Observations of Chandra Sources
  63. GRB 011130: Optical Observations of Chandra sources
  64. GRB011130 (XRF011130) Chandra Observations
  65. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  66. GRB 011130: Magellan spectroscopy
  67. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  68. GRB011130, optical observations
  69. GRB 011130, K band observations
  70. GRB011130, optical observations
  71. GRB011130 (=XRF011130): Second Revised Localization by HETE
  72. GRB 011130 I-band Observation
  73. GRB011130 (XRF011130) optical observations
  74. GRB011130 (XRF011130) SDSS PT i-band observations
  75. XRF011130: Infrared Observations
  76. GRB011130, Radio Observations
  77. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  78. GRB011130 (=XRF011130), Optical Observations
  79. XRF011130: NEAT Optical Observations
  80. GRB011130 (=XRF011130): Revised Localization of an X-ray
  81. GRB001109, Radio Monitoring
  82. GRB 011121: Errata URL
  83. GRB 011121
  84. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  85. GRB 011121: J-band observations
  86. GRB 011121: NIR observations, host galaxy?
  87. GRB010921 - Milagro GeV/TeV Observations
  88. GRB 011121: HST Scheduled
  89. GRB011121: fainter still
  90. Correction: GCN1157 (GRB 011121)
  91. GRB011121: UBRI Observations
  92. GRB011121
  93. GRB 011121: Radio Observations
  94. GRB 011121 J-Band Astrometry
  95. GRB011121: continued decay
  96. GRB 011121: Detection of Bright IR Counterpart
  97. GRB011121: possible redshift, continued decay
  98. GRB011121: fading behavior
  99. GRB011121: possible optical counterpart
  100. GRB011121: BeppoSAX-WFC refined positions

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