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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').
  1. GRB 020321: Infrared observations
  2. GRB 020322: BeppoSAX observations of the X-ray afterglow
  3. SN 2002ap - peak brightness date (SN/GRB?)
  4. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  5. GRB 020322, Radio observations
  6. Near-Infrared Observations of GRB020322 at TIRGO
  7. GRB 020321, Radio Observations
  8. GRB 020322: Optical Observations
  9. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  10. GRB 020321: Optical observations
  11. GRB020317 BVRI field photometry
  12. GRB011211 revised BVRI field photometry
  13. GRB020305 BVRI field photometry
  14. GRB020322 BVRI field photometry
  15. GRB 020322 optical observations
  16. GRB020322: Candidate Optical Afterglow
  17. GRB 020322 optical observation
  18. GRB020317 : Near IR Observations from Mt Abu Observatory
  19. GRB 020322: Optical Sources and Improved Astrometry
  20. GRB020322, optical observations
  21. GRB 020322: Optical candidate
  22. XMM-Newton observation of GRB020322
  23. GRB020322: Optical Observations
  24. GRB020322: BeppoSAX/NFI Observations
  25. Bepposax GRB020322 The second springtime BSAX GRB
  26. GRB 020321: Optical observations
  27. GRB 011121: Fourth Epoch of HST Imaging
  28. GRB020317: optical observations
  29. GRB020321 optical observations
  30. GRB020321: BeppoSAX/NFI Observations
  31. GRB020321: a faint BeppoSAX detection
  32. GRB020305: NIR observations
  33. GRB 020317 : KISO Optical Observations
  34. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  35. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  36. GRB 020305: Optical Observations
  37. GRB020317, optical observations
  38. GRB 020317: Optical observations
  39. GRB 011121: Third HST Epoch
  40. GRB020305: Properties of the Candidate Optical Afterglow
  41. GRB 011121: HST Observations reveal an intermediate-time multicolor
  42. GRB011121, possible supernova association
  43. GRB011130 (XRF011130) Second Epoch Chandra Observations
  44. GRB020305: Subaru Optical Observations
  45. GRB 020305: Optical observations
  46. XRF/GRB 011030 Images
  47. XRF/GRB 011030: Detection of the Probable Host Galaxy
  48. GRB 020305: Candidate optical afterglow
  49. Type Ic SN2002bl (SN/GRB?) Radio Observations
  50. GRB020305, optical 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. RXTE Observations of SGR 1900+14
  60. IPN detection of further SGR1900+14 activity
  61. SGR1900+14 activity
  62. IPN/HETE Detection of Bursts from SGR1900+14
  63. IPN Upper Limits to a GRB Associated With SN2002ap
  64. GRB020124 BVRI field photometry
  65. GRB020127: Palomar and VLA Observations of Possible Counterparts
  66. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  67. SN2002ap (SN/GRB?) Echelle spectra
  68. SN2002ap (SN/GRB?) optical spectrographic observations
  69. GRB020127, WSRT radio observations
  70. GRB020127 Optical Observations
  71. SN 2002ap (SN/GRB?)
  72. SN 2002ap in M74
  73. SN2002ap (SN/GRB?) UBVRI Field Photometry
  74. GRB020127: Chandra Observations and Prospective Counterparts
  75. pre-SN2002ap (SN/GRB?) imaging of M74
  76. SN 2002ap (hypernova / GRB ??): special list on VSNET
  77. Type Ib/c SN2002ap (SN/GRB?)
  78. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  79. GRB020124, optical observations
  80. GRB020127: Optical observations
  81. GRB 020127, I-band observations starting 3.14-hr after the event
  82. IPN detection of further activity from SGR1806-20
  83. IPN triangulation of GRB020127 (=H1902)
  84. GRB020127 Optical Observations -- Erratum to GCN 1230
  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. HETE 1896: Optical observations
  97. GRB optical counterpart candidate in GCN 1217 is M dwarf
  98. Possible optical counterpart to a GRB
  99. GRB011212, Optical Observations
  100. GRB011211: BeppoSAX/GRBM data

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