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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"

35946 results found.

  1. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  2. GRB 020405, U-band observations
  3. GRB 020405: Optical afterglow candidate
  4. IPN localization of GRB020405
  5. GRB011212: Optical Observations
  6. GRB 020331: NIR Observations
  7. GRB 020331: NIR Observations
  8. GRB020331 NIR observation at KPNO (re-submission)
  9. GRB02033 NIR observation at KPNO
  10. GRB020331 field photometry
  11. GRB 020331 Optical Observations
  12. GRB 020331, NIR observations
  13. GRB 020331: Optical observations
  14. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  15. GRB 020321: Infrared observations
  16. GRB 020322: BeppoSAX observations of the X-ray afterglow
  17. SN 2002ap - peak brightness date (SN/GRB?)
  18. GRB 020322, Radio observations
  19. Near-Infrared Observations of GRB020322 at TIRGO
  20. GRB 020321, Radio Observations
  21. GRB 020322: Optical Observations
  22. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  23. GRB 020321: Optical observations
  24. GRB020317 BVRI field photometry
  25. GRB011211 revised BVRI field photometry
  26. GRB020305 BVRI field photometry
  27. GRB020322 BVRI field photometry
  28. GRB 020322 optical observations
  29. GRB 020322 optical observation
  30. GRB020317 : Near IR Observations from Mt Abu Observatory
  31. GRB 020322: Optical Sources and Improved Astrometry
  32. GRB020322, optical observations
  33. GRB 020322: Optical candidate
  34. GRB020322: BeppoSAX/NFI Observations
  35. Bepposax GRB020322 The second springtime BSAX GRB
  36. GRB 020321: Optical observations
  37. GRB 011121: Fourth Epoch of HST Imaging
  38. GRB020317: optical observations
  39. GRB020321 optical observations
  40. GRB020321: BeppoSAX/NFI Observations
  41. GRB020321: a faint BeppoSAX detection
  42. GRB 020317 : KISO Optical Observations
  43. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  44. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  45. GRB 020305: Optical Observations
  46. GRB020317, optical observations
  47. GRB 020317: Optical observations
  48. GRB 011121: Third HST Epoch
  49. GRB020305: Properties of the Candidate Optical Afterglow
  50. GRB 011121: HST Observations reveal an intermediate-time multicolor
  51. GRB011121, possible supernova association
  52. GRB011130 (XRF011130) Second Epoch Chandra Observations
  53. GRB020305: Subaru Optical Observations
  54. GRB 020305: Optical observations
  55. XRF/GRB 011030 Images
  56. XRF/GRB 011030: Detection of the Probable Host Galaxy
  57. GRB 020305: Candidate optical afterglow
  58. Type Ic SN2002bl (SN/GRB?) Radio Observations
  59. GRB020305: Optical Observations
  60. IPN triangulation of GRB020305 (HETE 1939)
  61. GRB020305 (=H1939): Localization of a GRB by HETE
  62. GRB 020305: Optical observations
  63. HST Imaging of the afterglow and host of GRB 011121
  64. GRB 010921: HST Observations
  65. IPN detection and localization of Cygnus X-1 flares
  66. GRB020127: Further VLA Observations of Possible Counterparts
  67. IPN detection of further SGR1900+14 activity
  68. SGR1900+14 activity
  69. IPN/HETE Detection of Bursts from SGR1900+14
  70. IPN Upper Limits to a GRB Associated With SN2002ap
  71. GRB020124 BVRI field photometry
  72. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  73. SN2002ap (SN/GRB?) Echelle spectra
  74. SN2002ap (SN/GRB?) optical spectrographic observations
  75. GRB020127 Optical Observations
  76. SN 2002ap (SN/GRB?)
  77. SN2002ap (SN/GRB?) UBVRI Field Photometry
  78. GRB020127: Chandra Observations and Prospective Counterparts
  79. pre-SN2002ap (SN/GRB?) imaging of M74
  80. SN 2002ap (hypernova / GRB ??): special list on VSNET
  81. Type Ib/c SN2002ap (SN/GRB?)
  82. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  83. GRB020124, optical observations
  84. GRB020127: Optical observations
  85. GRB 020127, I-band observations starting 3.14-hr after the event
  86. IPN detection of further activity from SGR1806-20
  87. IPN triangulation of GRB020127 (=H1902)
  88. GRB010921 Optical Observations
  89. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  90. GRB020124: Optical observations
  91. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  92. GRB020124: Optical observations
  93. GRB 020124: Optical observations
  94. GRB 020124 Optical Observations
  95. IPN triangulation of GRB020124 (HETE 1896)
  96. IPN observations of SGR1806-20
  97. GRB 020124: Optical afterglow
  98. GRB020124(=H1896): Localization of a Long GRB by HETE
  99. GRB optical counterpart candidate in GCN 1217 is M dwarf
  100. Possible optical counterpart to a GRB

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