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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"

35348 results found.

  1. IPN localization of GRB020405
  2. GRB011212: Optical Observations
  3. GRB 020331: NIR Observations
  4. GRB 020331: NIR Observations
  5. GRB020331 NIR observation at KPNO (re-submission)
  6. GRB02033 NIR observation at KPNO
  7. GRB020331 field photometry
  8. GRB 020331 Optical Observations
  9. GRB 020331, NIR observations
  10. GRB 020331: Optical observations
  11. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  12. GRB 020321: Infrared observations
  13. GRB 020322: BeppoSAX observations of the X-ray afterglow
  14. SN 2002ap - peak brightness date (SN/GRB?)
  15. GRB 020322, Radio observations
  16. Near-Infrared Observations of GRB020322 at TIRGO
  17. GRB 020321, Radio Observations
  18. GRB 020322: Optical Observations
  19. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  20. GRB 020321: Optical observations
  21. GRB020317 BVRI field photometry
  22. GRB011211 revised BVRI field photometry
  23. GRB020305 BVRI field photometry
  24. GRB020322 BVRI field photometry
  25. GRB 020322 optical observations
  26. GRB 020322 optical observation
  27. GRB020317 : Near IR Observations from Mt Abu Observatory
  28. GRB 020322: Optical Sources and Improved Astrometry
  29. GRB020322, optical observations
  30. GRB 020322: Optical candidate
  31. GRB020322: BeppoSAX/NFI Observations
  32. Bepposax GRB020322 The second springtime BSAX GRB
  33. GRB 020321: Optical observations
  34. GRB 011121: Fourth Epoch of HST Imaging
  35. GRB020317: optical observations
  36. GRB020321 optical observations
  37. GRB020321: BeppoSAX/NFI Observations
  38. GRB020321: a faint BeppoSAX detection
  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. IPN triangulation of GRB020305 (HETE 1939)
  58. GRB020305 (=H1939): Localization of a GRB by HETE
  59. GRB 020305: Optical observations
  60. HST Imaging of the afterglow and host of GRB 011121
  61. GRB 010921: HST Observations
  62. IPN detection and localization of Cygnus X-1 flares
  63. GRB020127: Further VLA Observations of Possible Counterparts
  64. IPN detection of further SGR1900+14 activity
  65. SGR1900+14 activity
  66. IPN/HETE Detection of Bursts from SGR1900+14
  67. IPN Upper Limits to a GRB Associated With SN2002ap
  68. GRB020124 BVRI field photometry
  69. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  70. SN2002ap (SN/GRB?) Echelle spectra
  71. SN2002ap (SN/GRB?) optical spectrographic observations
  72. GRB020127 Optical Observations
  73. SN 2002ap (SN/GRB?)
  74. SN2002ap (SN/GRB?) UBVRI Field Photometry
  75. GRB020127: Chandra Observations and Prospective Counterparts
  76. pre-SN2002ap (SN/GRB?) imaging of M74
  77. SN 2002ap (hypernova / GRB ??): special list on VSNET
  78. Type Ib/c SN2002ap (SN/GRB?)
  79. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  80. GRB020124, optical observations
  81. GRB020127: Optical observations
  82. GRB 020127, I-band observations starting 3.14-hr after the event
  83. IPN detection of further activity from SGR1806-20
  84. IPN triangulation of GRB020127 (=H1902)
  85. GRB010921 Optical Observations
  86. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  87. GRB020124: Optical observations
  88. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  89. GRB020124: Optical observations
  90. GRB 020124: Optical observations
  91. GRB 020124 Optical Observations
  92. IPN triangulation of GRB020124 (HETE 1896)
  93. IPN observations of SGR1806-20
  94. GRB 020124: Optical afterglow
  95. GRB020124(=H1896): Localization of a Long GRB by HETE
  96. GRB optical counterpart candidate in GCN 1217 is M dwarf
  97. Possible optical counterpart to a GRB
  98. GRB011212, Optical Observations
  99. Optical polarization observations for GRB011211
  100. GRB 011211: Detection of the Probable Host Galaxy

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