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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"

35938 results found.

  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. GRB 020322, Radio observations
  11. Near-Infrared Observations of GRB020322 at TIRGO
  12. GRB 020321, Radio Observations
  13. GRB 020322: Optical Observations
  14. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  15. GRB 020321: Optical observations
  16. GRB020317 BVRI field photometry
  17. GRB011211 revised BVRI field photometry
  18. GRB020305 BVRI field photometry
  19. GRB020322 BVRI field photometry
  20. GRB 020322 optical observations
  21. GRB 020322 optical observation
  22. GRB020317 : Near IR Observations from Mt Abu Observatory
  23. GRB 020322: Optical Sources and Improved Astrometry
  24. GRB020322, optical observations
  25. GRB 020322: Optical candidate
  26. GRB020322: BeppoSAX/NFI Observations
  27. Bepposax GRB020322 The second springtime BSAX GRB
  28. GRB 020321: Optical observations
  29. GRB 011121: Fourth Epoch of HST Imaging
  30. GRB020317: optical observations
  31. GRB020321 optical observations
  32. GRB020321: BeppoSAX/NFI Observations
  33. GRB020321: a faint BeppoSAX detection
  34. GRB 020317 : KISO Optical Observations
  35. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  36. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  37. GRB 020305: Optical Observations
  38. GRB020317, optical observations
  39. GRB 020317: Optical observations
  40. GRB 011121: Third HST Epoch
  41. GRB020305: Properties of the Candidate Optical Afterglow
  42. GRB 011121: HST Observations reveal an intermediate-time multicolor
  43. GRB011121, possible supernova association
  44. GRB011130 (XRF011130) Second Epoch Chandra Observations
  45. GRB020305: Subaru Optical Observations
  46. GRB 020305: Optical observations
  47. XRF/GRB 011030 Images
  48. XRF/GRB 011030: Detection of the Probable Host Galaxy
  49. GRB 020305: Candidate optical afterglow
  50. Type Ic SN2002bl (SN/GRB?) Radio Observations
  51. GRB020305: Optical Observations
  52. IPN triangulation of GRB020305 (HETE 1939)
  53. GRB020305 (=H1939): Localization of a GRB by HETE
  54. GRB 020305: Optical observations
  55. HST Imaging of the afterglow and host of GRB 011121
  56. GRB 010921: HST Observations
  57. IPN detection and localization of Cygnus X-1 flares
  58. GRB020127: Further VLA Observations of Possible Counterparts
  59. IPN detection of further SGR1900+14 activity
  60. SGR1900+14 activity
  61. IPN/HETE Detection of Bursts from SGR1900+14
  62. IPN Upper Limits to a GRB Associated With SN2002ap
  63. GRB020124 BVRI field photometry
  64. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  65. SN2002ap (SN/GRB?) Echelle spectra
  66. SN2002ap (SN/GRB?) optical spectrographic observations
  67. GRB020127 Optical Observations
  68. SN 2002ap (SN/GRB?)
  69. SN2002ap (SN/GRB?) UBVRI Field Photometry
  70. GRB020127: Chandra Observations and Prospective Counterparts
  71. pre-SN2002ap (SN/GRB?) imaging of M74
  72. SN 2002ap (hypernova / GRB ??): special list on VSNET
  73. Type Ib/c SN2002ap (SN/GRB?)
  74. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  75. GRB020124, optical observations
  76. GRB020127: Optical observations
  77. GRB 020127, I-band observations starting 3.14-hr after the event
  78. IPN detection of further activity from SGR1806-20
  79. IPN triangulation of GRB020127 (=H1902)
  80. GRB010921 Optical Observations
  81. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  82. GRB020124: Optical observations
  83. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  84. GRB020124: Optical observations
  85. GRB 020124: Optical observations
  86. GRB 020124 Optical Observations
  87. IPN triangulation of GRB020124 (HETE 1896)
  88. IPN observations of SGR1806-20
  89. GRB 020124: Optical afterglow
  90. GRB020124(=H1896): Localization of a Long GRB by HETE
  91. GRB optical counterpart candidate in GCN 1217 is M dwarf
  92. Possible optical counterpart to a GRB
  93. GRB011212, Optical Observations
  94. GRB 011211: Detection of the Probable Host Galaxy
  95. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  96. GRB 011211, spectrum and optical photometry
  97. GRB 011130: Optical Observations of X-ray and Radio Sources
  98. GRB 011130, Radio/X-ray Comparison
  99. GRB 011212: optical observation at Asiago
  100. GRB 011211: Evidence for an Optical Break

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