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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"

37557 results found.

  1. GRB 020321: Candidate X-ray Counterparts
  2. ASM GRB candidate 020406 refined error box
  3. GRB 020405: Moderate-resolution spectroscopy
  4. GRB020406(?), optical observations
  5. GRB020405: VLT optical observations
  6. Revised Photometry of the Optical Afterglow of GRB 020405
  7. GRB020405: OT observations
  8. GRB 020331: Candidate Optical Afterglow
  9. GRB 020405: Decay index
  10. Short RXTE/ASM transient 020406; may be a GRB
  11. GRB020405, Radio Observations
  12. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  13. GRB 020405, U-band observations
  14. GRB 020405: Optical afterglow candidate
  15. IPN localization of GRB020405
  16. GRB011212: Optical Observations
  17. GRB 020331: NIR Observations
  18. GRB 020331: NIR Observations
  19. GRB020331 NIR observation at KPNO (re-submission)
  20. GRB02033 NIR observation at KPNO
  21. GRB020331 field photometry
  22. GRB 020331 Optical Observations
  23. GRB 020331, NIR observations
  24. GRB 020331: Optical observations
  25. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  26. GRB 020321: Infrared observations
  27. GRB 020322: BeppoSAX observations of the X-ray afterglow
  28. SN 2002ap - peak brightness date (SN/GRB?)
  29. GRB 020322, Radio observations
  30. Near-Infrared Observations of GRB020322 at TIRGO
  31. GRB 020321, Radio Observations
  32. GRB 020322: Optical Observations
  33. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  34. GRB 020321: Optical observations
  35. GRB020317 BVRI field photometry
  36. GRB011211 revised BVRI field photometry
  37. GRB020305 BVRI field photometry
  38. GRB020322 BVRI field photometry
  39. GRB 020322 optical observations
  40. GRB 020322 optical observation
  41. GRB020317 : Near IR Observations from Mt Abu Observatory
  42. GRB 020322: Optical Sources and Improved Astrometry
  43. GRB020322, optical observations
  44. GRB 020322: Optical candidate
  45. GRB020322: BeppoSAX/NFI Observations
  46. Bepposax GRB020322 The second springtime BSAX GRB
  47. GRB 020321: Optical observations
  48. GRB 011121: Fourth Epoch of HST Imaging
  49. GRB020317: optical observations
  50. GRB020321 optical observations
  51. GRB020321: BeppoSAX/NFI Observations
  52. GRB020321: a faint BeppoSAX detection
  53. GRB 020317 : KISO Optical Observations
  54. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  55. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  56. GRB 020305: Optical Observations
  57. GRB020317, optical observations
  58. GRB 020317: Optical observations
  59. GRB 011121: Third HST Epoch
  60. GRB020305: Properties of the Candidate Optical Afterglow
  61. GRB 011121: HST Observations reveal an intermediate-time multicolor
  62. GRB011121, possible supernova association
  63. GRB011130 (XRF011130) Second Epoch Chandra Observations
  64. GRB020305: Subaru Optical Observations
  65. GRB 020305: Optical observations
  66. XRF/GRB 011030 Images
  67. XRF/GRB 011030: Detection of the Probable Host Galaxy
  68. GRB 020305: Candidate optical afterglow
  69. Type Ic SN2002bl (SN/GRB?) Radio Observations
  70. GRB020305: Optical Observations
  71. IPN triangulation of GRB020305 (HETE 1939)
  72. GRB020305 (=H1939): Localization of a GRB by HETE
  73. GRB 020305: Optical observations
  74. HST Imaging of the afterglow and host of GRB 011121
  75. GRB 010921: HST Observations
  76. IPN detection and localization of Cygnus X-1 flares
  77. GRB020127: Further VLA Observations of Possible Counterparts
  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: Comparison of Chandra Epochs and Identification of Possible Counterparts
  84. SN2002ap (SN/GRB?) Echelle spectra
  85. SN2002ap (SN/GRB?) optical spectrographic observations
  86. GRB020127 Optical Observations
  87. SN 2002ap (SN/GRB?)
  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. GRB010921 Optical Observations
  100. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE

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