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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. Short RXTE/ASM transient 020406; may be a GRB
  2. GRB020405, Radio Observations
  3. GRB020405: VLT spectroscopy
  4. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  5. V band observations of GRB020405
  6. GRB 020405, U-band observations
  7. GRB 020405: Optical afterglow candidate
  8. IPN localization of GRB020405
  9. GRB011212: Optical Observations
  10. GRB 020331: NIR Observations
  11. GRB 020331: NIR Observations
  12. GRB020331 NIR observation at KPNO (re-submission)
  13. GRB02033 NIR observation at KPNO
  14. GRB020331 field photometry
  15. GRB 020331 Optical Observations
  16. GRB 020331, NIR observations
  17. GRB 020331: Optical observations
  18. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  19. GRB 020321: Infrared observations
  20. GRB 020322: BeppoSAX observations of the X-ray afterglow
  21. SN 2002ap - peak brightness date (SN/GRB?)
  22. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  23. GRB 020322, Radio observations
  24. Near-Infrared Observations of GRB020322 at TIRGO
  25. GRB 020321, Radio Observations
  26. GRB 020322: Optical Observations
  27. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  28. GRB 020321: Optical observations
  29. GRB020317 BVRI field photometry
  30. GRB011211 revised BVRI field photometry
  31. GRB020305 BVRI field photometry
  32. GRB020322 BVRI field photometry
  33. GRB 020322 optical observations
  34. GRB020322: Candidate Optical Afterglow
  35. GRB 020322 optical observation
  36. GRB020317 : Near IR Observations from Mt Abu Observatory
  37. GRB 020322: Optical Sources and Improved Astrometry
  38. GRB020322, optical observations
  39. GRB 020322: Optical candidate
  40. XMM-Newton observation of GRB020322
  41. GRB020322: Optical Observations
  42. GRB020322: BeppoSAX/NFI Observations
  43. Bepposax GRB020322 The second springtime BSAX GRB
  44. GRB 020321: Optical observations
  45. GRB 011121: Fourth Epoch of HST Imaging
  46. GRB020317: optical observations
  47. GRB020321 optical observations
  48. GRB020321: BeppoSAX/NFI Observations
  49. GRB020321: a faint BeppoSAX detection
  50. GRB020305: NIR observations
  51. GRB 020317 : KISO Optical Observations
  52. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  53. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  54. GRB 020305: Optical Observations
  55. GRB020317, optical observations
  56. GRB 020317: Optical observations
  57. GRB 011121: Third HST Epoch
  58. GRB020305: Properties of the Candidate Optical Afterglow
  59. GRB 011121: HST Observations reveal an intermediate-time multicolor
  60. GRB011121, possible supernova association
  61. GRB011130 (XRF011130) Second Epoch Chandra Observations
  62. GRB020305: Subaru Optical Observations
  63. GRB 020305: Optical observations
  64. XRF/GRB 011030 Images
  65. XRF/GRB 011030: Detection of the Probable Host Galaxy
  66. GRB 020305: Candidate optical afterglow
  67. Type Ic SN2002bl (SN/GRB?) Radio Observations
  68. GRB020305, optical observations
  69. GRB020305: Optical Observations
  70. IPN triangulation of GRB020305 (HETE 1939)
  71. GRB020305 (=H1939): Localization of a GRB by HETE
  72. GRB 020305: Optical observations
  73. HST Imaging of the afterglow and host of GRB 011121
  74. GRB 010921: HST Observations
  75. IPN detection and localization of Cygnus X-1 flares
  76. GRB020127: Further VLA Observations of Possible Counterparts
  77. RXTE Observations of SGR 1900+14
  78. IPN detection of further SGR1900+14 activity
  79. SGR1900+14 activity
  80. IPN/HETE Detection of Bursts from SGR1900+14
  81. IPN Upper Limits to a GRB Associated With SN2002ap
  82. GRB020124 BVRI field photometry
  83. GRB020127: Palomar and VLA Observations of Possible Counterparts
  84. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  85. SN2002ap (SN/GRB?) Echelle spectra
  86. SN2002ap (SN/GRB?) optical spectrographic observations
  87. GRB020127, WSRT radio observations
  88. GRB020127 Optical Observations
  89. SN 2002ap (SN/GRB?)
  90. SN 2002ap in M74
  91. SN2002ap (SN/GRB?) UBVRI Field Photometry
  92. GRB020127: Chandra Observations and Prospective Counterparts
  93. pre-SN2002ap (SN/GRB?) imaging of M74
  94. SN 2002ap (hypernova / GRB ??): special list on VSNET
  95. Type Ib/c SN2002ap (SN/GRB?)
  96. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  97. GRB020124, optical observations
  98. GRB020127: Optical observations
  99. GRB 020127, I-band observations starting 3.14-hr after the event
  100. IPN detection of further activity from SGR1806-20

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