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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. GRB 020405: Moderate-resolution spectroscopy
  2. GRB020331: Optical Observations of Afterglow Candidate
  3. GRB020406(?), optical observations
  4. GRB020405: VLT optical observations
  5. Revised Photometry of the Optical Afterglow of GRB 020405
  6. GRB020405: OT observations
  7. GRB 020331: Candidate Optical Afterglow
  8. GRB 020405: Decay index
  9. Short RXTE/ASM transient 020406; may be a GRB
  10. GRB020405, Radio Observations
  11. GRB020405: VLT spectroscopy
  12. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  13. V band observations of GRB020405
  14. GRB 020405, U-band observations
  15. GRB 020405: Optical afterglow candidate
  16. IPN localization of GRB020405
  17. GRB011212: Optical Observations
  18. GRB 020331: NIR Observations
  19. GRB 020331: NIR Observations
  20. GRB020331 NIR observation at KPNO (re-submission)
  21. GRB02033 NIR observation at KPNO
  22. GRB020331 field photometry
  23. GRB 020331 Optical Observations
  24. GRB 020331, NIR observations
  25. GRB 020331: Optical observations
  26. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  27. GRB 020321: Infrared observations
  28. GRB 020322: BeppoSAX observations of the X-ray afterglow
  29. SN 2002ap - peak brightness date (SN/GRB?)
  30. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  31. GRB 020322, Radio observations
  32. Near-Infrared Observations of GRB020322 at TIRGO
  33. GRB 020321, Radio Observations
  34. GRB 020322: Optical Observations
  35. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  36. GRB 020321: Optical observations
  37. GRB020317 BVRI field photometry
  38. GRB011211 revised BVRI field photometry
  39. GRB020305 BVRI field photometry
  40. GRB020322 BVRI field photometry
  41. GRB 020322 optical observations
  42. GRB020322: Candidate Optical Afterglow
  43. GRB 020322 optical observation
  44. GRB020317 : Near IR Observations from Mt Abu Observatory
  45. GRB 020322: Optical Sources and Improved Astrometry
  46. GRB020322, optical observations
  47. GRB 020322: Optical candidate
  48. XMM-Newton observation of GRB020322
  49. GRB020322: Optical Observations
  50. GRB020322: BeppoSAX/NFI Observations
  51. Bepposax GRB020322 The second springtime BSAX GRB
  52. GRB 020321: Optical observations
  53. GRB 011121: Fourth Epoch of HST Imaging
  54. GRB020317: optical observations
  55. GRB020321 optical observations
  56. GRB020321: BeppoSAX/NFI Observations
  57. GRB020321: a faint BeppoSAX detection
  58. GRB020305: NIR observations
  59. GRB 020317 : KISO Optical Observations
  60. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  61. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  62. GRB 020305: Optical Observations
  63. GRB020317, optical observations
  64. GRB 020317: Optical observations
  65. GRB 011121: Third HST Epoch
  66. GRB020305: Properties of the Candidate Optical Afterglow
  67. GRB 011121: HST Observations reveal an intermediate-time multicolor
  68. GRB011121, possible supernova association
  69. GRB011130 (XRF011130) Second Epoch Chandra Observations
  70. GRB020305: Subaru Optical Observations
  71. GRB 020305: Optical observations
  72. XRF/GRB 011030 Images
  73. XRF/GRB 011030: Detection of the Probable Host Galaxy
  74. GRB 020305: Candidate optical afterglow
  75. Type Ic SN2002bl (SN/GRB?) Radio Observations
  76. GRB020305, optical observations
  77. GRB020305: Optical Observations
  78. IPN triangulation of GRB020305 (HETE 1939)
  79. GRB020305 (=H1939): Localization of a GRB by HETE
  80. GRB 020305: Optical observations
  81. HST Imaging of the afterglow and host of GRB 011121
  82. GRB 010921: HST Observations
  83. IPN detection and localization of Cygnus X-1 flares
  84. GRB020127: Further VLA Observations of Possible Counterparts
  85. RXTE Observations of SGR 1900+14
  86. IPN detection of further SGR1900+14 activity
  87. SGR1900+14 activity
  88. IPN/HETE Detection of Bursts from SGR1900+14
  89. IPN Upper Limits to a GRB Associated With SN2002ap
  90. GRB020124 BVRI field photometry
  91. GRB020127: Palomar and VLA Observations of Possible Counterparts
  92. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  93. SN2002ap (SN/GRB?) Echelle spectra
  94. SN2002ap (SN/GRB?) optical spectrographic observations
  95. GRB020127, WSRT radio observations
  96. GRB020127 Optical Observations
  97. SN 2002ap (SN/GRB?)
  98. SN 2002ap in M74
  99. SN2002ap (SN/GRB?) UBVRI Field Photometry
  100. GRB020127: Chandra Observations and Prospective Counterparts

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