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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. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  2. V band observations of GRB020405
  3. GRB 020405, U-band observations
  4. GRB 020405: Optical afterglow candidate
  5. IPN localization of GRB020405
  6. GRB011212: Optical Observations
  7. GRB 020331: NIR Observations
  8. GRB 020331: NIR Observations
  9. GRB020331 NIR observation at KPNO (re-submission)
  10. GRB02033 NIR observation at KPNO
  11. GRB020331 field photometry
  12. GRB 020331 Optical Observations
  13. GRB 020331, NIR observations
  14. GRB 020331: Optical observations
  15. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  16. GRB 020321: Infrared observations
  17. GRB 020322: BeppoSAX observations of the X-ray afterglow
  18. SN 2002ap - peak brightness date (SN/GRB?)
  19. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  20. GRB 020322, Radio observations
  21. Near-Infrared Observations of GRB020322 at TIRGO
  22. GRB 020321, Radio Observations
  23. GRB 020322: Optical Observations
  24. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  25. GRB 020321: Optical observations
  26. GRB020317 BVRI field photometry
  27. GRB011211 revised BVRI field photometry
  28. GRB020305 BVRI field photometry
  29. GRB020322 BVRI field photometry
  30. GRB 020322 optical observations
  31. GRB020322: Candidate Optical Afterglow
  32. GRB 020322 optical observation
  33. GRB020317 : Near IR Observations from Mt Abu Observatory
  34. GRB 020322: Optical Sources and Improved Astrometry
  35. GRB020322, optical observations
  36. GRB 020322: Optical candidate
  37. XMM-Newton observation of GRB020322
  38. GRB020322: Optical Observations
  39. GRB020322: BeppoSAX/NFI Observations
  40. Bepposax GRB020322 The second springtime BSAX GRB
  41. GRB 020321: Optical observations
  42. GRB 011121: Fourth Epoch of HST Imaging
  43. GRB020317: optical observations
  44. GRB020321 optical observations
  45. GRB020321: BeppoSAX/NFI Observations
  46. GRB020321: a faint BeppoSAX detection
  47. GRB020305: NIR observations
  48. GRB 020317 : KISO Optical Observations
  49. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  50. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  51. GRB 020305: Optical Observations
  52. GRB020317, optical observations
  53. GRB 020317: Optical observations
  54. GRB 011121: Third HST Epoch
  55. GRB020305: Properties of the Candidate Optical Afterglow
  56. GRB 011121: HST Observations reveal an intermediate-time multicolor
  57. GRB011121, possible supernova association
  58. GRB011130 (XRF011130) Second Epoch Chandra Observations
  59. GRB020305: Subaru Optical Observations
  60. GRB 020305: Optical observations
  61. XRF/GRB 011030 Images
  62. XRF/GRB 011030: Detection of the Probable Host Galaxy
  63. GRB 020305: Candidate optical afterglow
  64. Type Ic SN2002bl (SN/GRB?) Radio Observations
  65. GRB020305, optical observations
  66. GRB020305: Optical Observations
  67. IPN triangulation of GRB020305 (HETE 1939)
  68. GRB020305 (=H1939): Localization of a GRB by HETE
  69. GRB 020305: Optical observations
  70. HST Imaging of the afterglow and host of GRB 011121
  71. GRB 010921: HST Observations
  72. IPN detection and localization of Cygnus X-1 flares
  73. GRB020127: Further VLA Observations of Possible Counterparts
  74. RXTE Observations of SGR 1900+14
  75. IPN detection of further SGR1900+14 activity
  76. SGR1900+14 activity
  77. IPN/HETE Detection of Bursts from SGR1900+14
  78. IPN Upper Limits to a GRB Associated With SN2002ap
  79. GRB020124 BVRI field photometry
  80. GRB020127: Palomar and VLA Observations of Possible Counterparts
  81. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  82. SN2002ap (SN/GRB?) Echelle spectra
  83. SN2002ap (SN/GRB?) optical spectrographic observations
  84. GRB020127, WSRT radio observations
  85. GRB020127 Optical Observations
  86. SN 2002ap (SN/GRB?)
  87. SN 2002ap in M74
  88. SN2002ap (SN/GRB?) UBVRI Field Photometry
  89. GRB020127: Chandra Observations and Prospective Counterparts
  90. pre-SN2002ap (SN/GRB?) imaging of M74
  91. SN 2002ap (hypernova / GRB ??): special list on VSNET
  92. Type Ib/c SN2002ap (SN/GRB?)
  93. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  94. GRB020124, optical observations
  95. GRB020127: Optical observations
  96. GRB 020127, I-band observations starting 3.14-hr after the event
  97. IPN detection of further activity from SGR1806-20
  98. IPN triangulation of GRB020127 (=H1902)
  99. GRB020127 Optical Observations -- Erratum to GCN 1230
  100. GRB010921 Optical Observations

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