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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. GRB02033 NIR observation at KPNO
  2. GRB020331 field photometry
  3. GRB 020331 Optical Observations
  4. GRB 020331, NIR observations
  5. GRB 020331: Optical observations
  6. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  7. GRB 020321: Infrared observations
  8. GRB 020322: BeppoSAX observations of the X-ray afterglow
  9. SN 2002ap - peak brightness date (SN/GRB?)
  10. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  11. GRB 020322, Radio observations
  12. Near-Infrared Observations of GRB020322 at TIRGO
  13. GRB 020321, Radio Observations
  14. GRB 020322: Optical Observations
  15. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  16. GRB 020321: Optical observations
  17. GRB020317 BVRI field photometry
  18. GRB011211 revised BVRI field photometry
  19. GRB020305 BVRI field photometry
  20. GRB020322 BVRI field photometry
  21. GRB 020322 optical observations
  22. GRB020322: Candidate Optical Afterglow
  23. GRB 020322 optical observation
  24. GRB020317 : Near IR Observations from Mt Abu Observatory
  25. GRB 020322: Optical Sources and Improved Astrometry
  26. GRB020322, optical observations
  27. GRB 020322: Optical candidate
  28. XMM-Newton observation of GRB020322
  29. GRB020322: Optical Observations
  30. GRB020322: BeppoSAX/NFI Observations
  31. Bepposax GRB020322 The second springtime BSAX GRB
  32. GRB 020321: Optical observations
  33. GRB 011121: Fourth Epoch of HST Imaging
  34. GRB020317: optical observations
  35. GRB020321 optical observations
  36. GRB020321: BeppoSAX/NFI Observations
  37. GRB020321: a faint BeppoSAX detection
  38. GRB020305: NIR observations
  39. GRB 020317 : KISO Optical Observations
  40. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  41. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  42. GRB 020305: Optical Observations
  43. GRB020317, optical observations
  44. GRB 020317: Optical observations
  45. GRB 011121: Third HST Epoch
  46. GRB020305: Properties of the Candidate Optical Afterglow
  47. GRB 011121: HST Observations reveal an intermediate-time multicolor
  48. GRB011121, possible supernova association
  49. GRB011130 (XRF011130) Second Epoch Chandra Observations
  50. GRB020305: Subaru Optical Observations
  51. GRB 020305: Optical observations
  52. XRF/GRB 011030 Images
  53. XRF/GRB 011030: Detection of the Probable Host Galaxy
  54. GRB 020305: Candidate optical afterglow
  55. Type Ic SN2002bl (SN/GRB?) Radio Observations
  56. GRB020305, optical observations
  57. GRB020305: Optical Observations
  58. IPN triangulation of GRB020305 (HETE 1939)
  59. GRB020305 (=H1939): Localization of a GRB by HETE
  60. GRB 020305: Optical observations
  61. HST Imaging of the afterglow and host of GRB 011121
  62. GRB 010921: HST Observations
  63. IPN detection and localization of Cygnus X-1 flares
  64. GRB020127: Further VLA Observations of Possible Counterparts
  65. RXTE Observations of SGR 1900+14
  66. IPN detection of further SGR1900+14 activity
  67. SGR1900+14 activity
  68. IPN/HETE Detection of Bursts from SGR1900+14
  69. IPN Upper Limits to a GRB Associated With SN2002ap
  70. GRB020124 BVRI field photometry
  71. GRB020127: Palomar and VLA Observations of Possible Counterparts
  72. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  73. SN2002ap (SN/GRB?) Echelle spectra
  74. SN2002ap (SN/GRB?) optical spectrographic observations
  75. GRB020127, WSRT radio observations
  76. GRB020127 Optical Observations
  77. SN 2002ap (SN/GRB?)
  78. SN 2002ap in M74
  79. SN2002ap (SN/GRB?) UBVRI Field Photometry
  80. GRB020127: Chandra Observations and Prospective Counterparts
  81. pre-SN2002ap (SN/GRB?) imaging of M74
  82. SN 2002ap (hypernova / GRB ??): special list on VSNET
  83. Type Ib/c SN2002ap (SN/GRB?)
  84. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  85. GRB020124, optical observations
  86. GRB020127: Optical observations
  87. GRB 020127, I-band observations starting 3.14-hr after the event
  88. IPN detection of further activity from SGR1806-20
  89. IPN triangulation of GRB020127 (=H1902)
  90. GRB020127 Optical Observations -- Erratum to GCN 1230
  91. GRB010921 Optical Observations
  92. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  93. GRB020124: Optical observations
  94. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  95. GRB020124: Optical observations
  96. GRB 020124: Optical observations
  97. GRB 020124 Optical Observations
  98. IPN triangulation of GRB020124 (HETE 1896)
  99. IPN observations of SGR1806-20
  100. GRB 020124: Optical afterglow

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