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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"
  1. GRB020305 (=H1939): Localization of a GRB by HETE
  2. GRB 020305: Optical observations
  3. HST Imaging of the afterglow and host of GRB 011121
  4. GRB 010921: HST Observations
  5. IPN detection and localization of Cygnus X-1 flares
  6. GRB020127: Further VLA Observations of Possible Counterparts
  7. RXTE Observations of SGR 1900+14
  8. IPN detection of further SGR1900+14 activity
  9. SGR1900+14 activity
  10. IPN/HETE Detection of Bursts from SGR1900+14
  11. IPN Upper Limits to a GRB Associated With SN2002ap
  12. GRB020124 BVRI field photometry
  13. GRB020127: Palomar and VLA Observations of Possible Counterparts
  14. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  15. SN2002ap (SN/GRB?) Echelle spectra
  16. SN2002ap (SN/GRB?) optical spectrographic observations
  17. GRB020127, WSRT radio observations
  18. GRB020127 Optical Observations
  19. SN 2002ap (SN/GRB?)
  20. SN 2002ap in M74
  21. SN2002ap (SN/GRB?) UBVRI Field Photometry
  22. GRB020127: Chandra Observations and Prospective Counterparts
  23. pre-SN2002ap (SN/GRB?) imaging of M74
  24. SN 2002ap (hypernova / GRB ??): special list on VSNET
  25. Type Ib/c SN2002ap (SN/GRB?)
  26. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  27. GRB020124, optical observations
  28. GRB020127: Optical observations
  29. GRB 020127, I-band observations starting 3.14-hr after the event
  30. IPN detection of further activity from SGR1806-20
  31. IPN triangulation of GRB020127 (=H1902)
  32. GRB020127 Optical Observations -- Erratum to GCN 1230
  33. GRB010921 Optical Observations
  34. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  35. GRB020124: Optical observations
  36. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  37. GRB020124: Optical observations
  38. GRB 020124: Optical observations
  39. GRB 020124 Optical Observations
  40. IPN triangulation of GRB020124 (HETE 1896)
  41. IPN observations of SGR1806-20
  42. GRB 020124: Optical afterglow
  43. GRB020124(=H1896): Localization of a Long GRB by HETE
  44. HETE 1896: Optical observations
  45. GRB optical counterpart candidate in GCN 1217 is M dwarf
  46. Possible optical counterpart to a GRB
  47. GRB011212, Optical Observations
  48. GRB011211: BeppoSAX/GRBM data
  49. Optical polarization observations for GRB011211
  50. GRB 011211: Detection of the Probable Host Galaxy
  51. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  52. Color indices of the afterglow of GRB011211
  53. GRB011212: Optical observations at Gunma
  54. GRB 011211, spectrum and optical photometry
  55. GRB 011130: Optical Observations of X-ray and Radio Sources
  56. GRB 011130, Radio/X-ray Comparison
  57. GRB011212: Optical observations
  58. GRB 011212: optical observation at Asiago
  59. GRB 011211: Evidence for an Optical Break
  60. GRB 011211: TNG Spectroscopic Observations
  61. optical follow-up of GRB(XRF) 011211
  62. GRB 011212: optical observation at Oslo (relayed)
  63. GRB 011211: Optical Spectroscopy
  64. GRB 011211, Optical Observations
  65. GRB011212, BVRI field photometry
  66. GRB011211, BVRI field photometry
  67. GRB011212: Optical observations
  68. GRB 011211: BVRi-band photometry
  69. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  70. Fading of the optical source associated of XRF 011211
  71. XMM-Newton observation of GRB011211
  72. GRB 011211 Optical Observations: Likely Afterglow
  73. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  74. GRB011211(=XRF011211): BeppoSAX refined positions
  75. BeppoSAX Alert: GRB011211(=XRF011211)
  76. GRB 011130: Optical Observations of Chandra Sources
  77. GRB 011130: Optical Observations of Chandra sources
  78. GRB011130 (XRF011130) Chandra Observations
  79. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  80. GRB 011130: Magellan spectroscopy
  81. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  82. GRB011130, optical observations
  83. GRB 011130, K band observations
  84. GRB011130, optical observations
  85. GRB011130 (=XRF011130): Second Revised Localization by HETE
  86. GRB 011130 I-band Observation
  87. GRB011130 (XRF011130) optical observations
  88. GRB011130 (XRF011130) SDSS PT i-band observations
  89. XRF011130: Infrared Observations
  90. GRB011130, Radio Observations
  91. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  92. GRB011130 (=XRF011130), Optical Observations
  93. XRF011130: NEAT Optical Observations
  94. GRB011130 (=XRF011130): Revised Localization of an X-ray
  95. GRB001109, Radio Monitoring
  96. GRB 011121: Errata URL
  97. GRB 011121
  98. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  99. GRB 011121: J-band observations
  100. GRB 011121: NIR observations, host galaxy?

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