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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"

25906 results found.

  1. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  2. GRB020321 : Optical observations.
  3. GRB020331: Third Epoch and Revised Second Epoch Optical
  4. GRB 020418: Optical observations
  5. GRB 020124: Optical observations
  6. GRB 020418: Optical observations
  7. GRB020410: BeppoSAX NFI observations refined analysis
  8. GRB020405: predicted break
  9. GRB 020409: Optical observations
  10. GRB 020409: No Evidence for an Optical Afterglow
  11. GRB 020409, 2nd epoch optical observations
  12. GRB 020331 Kyoto observation on March 31
  13. GRB 020409
  14. GRB020406(?), optical observations
  15. X-ray afterglow of GRB020321
  16. GRB020331: Confirmation of Afterglow Candidate with Magellan
  17. GRB 020405: Moderate-resolution spectroscopy
  18. GRB020331: Optical Observations of Afterglow Candidate
  19. Revised Photometry of the Optical Afterglow of GRB 020405
  20. GRB 020331: Candidate Optical Afterglow
  21. GRB 020405: Decay index
  22. GRB020405, Radio Observations
  23. GRB020405: VLT spectroscopy
  24. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  25. GRB 020405: Optical afterglow candidate
  26. GRB 020331: NIR Observations
  27. GRB 020331: NIR Observations
  28. GRB020331 NIR observation at KPNO (re-submission)
  29. GRB02033 NIR observation at KPNO
  30. GRB020331 field photometry
  31. GRB 020331, NIR observations
  32. GRB 020331: Optical observations
  33. GRB 020322: BeppoSAX observations of the X-ray afterglow
  34. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  35. GRB 020322, Radio observations
  36. Near-Infrared Observations of GRB020322 at TIRGO
  37. GRB 020321, Radio Observations
  38. GRB 020322: Optical Observations
  39. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  40. GRB 020321: Optical observations
  41. GRB020317 BVRI field photometry
  42. GRB 020322 optical observations
  43. GRB020322: Candidate Optical Afterglow
  44. GRB020322, optical observations
  45. GRB 020322: Optical candidate
  46. GRB 020321: Optical observations
  47. GRB 011121: Fourth Epoch of HST Imaging
  48. GRB020305: NIR observations
  49. GRB 020305: Optical Observations
  50. GRB 020317: Optical observations
  51. GRB 011121: Third HST Epoch
  52. GRB020305: Properties of the Candidate Optical Afterglow
  53. GRB 011121: HST Observations reveal an intermediate-time multicolor
  54. GRB011121, possible supernova association
  55. GRB020305: Subaru Optical Observations
  56. GRB 020305: Optical observations
  57. GRB 020305: Candidate optical afterglow
  58. HST Imaging of the afterglow and host of GRB 011121
  59. GRB 010921: HST Observations
  60. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  61. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  62. GRB 020124 Optical Observations
  63. GRB 020124: Optical afterglow
  64. GRB 011211: Detection of the Probable Host Galaxy
  65. Color indices of the afterglow of GRB011211
  66. GRB011212: Optical observations at Gunma
  67. GRB 011211, spectrum and optical photometry
  68. GRB 011211: Evidence for an Optical Break
  69. optical follow-up of GRB(XRF) 011211
  70. GRB 011212: optical observation at Oslo (relayed)
  71. GRB 011211, Optical Observations
  72. GRB011212: Optical observations
  73. GRB 011211: BVRi-band photometry
  74. GRB 011211 Optical Observations: Likely Afterglow
  75. GRB 011130: Magellan spectroscopy
  76. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  77. GRB011130, optical observations
  78. GRB011130, optical observations
  79. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  80. GRB001109, Radio Monitoring
  81. GRB 011121
  82. GRB 011121: J-band observations
  83. GRB 011121: NIR observations, host galaxy?
  84. GRB010921 - Milagro GeV/TeV Observations
  85. GRB 011121: HST Scheduled
  86. GRB011121: fainter still
  87. GRB 011121: Radio Observations
  88. GRB011121: continued decay
  89. GRB 011121: Detection of Bright IR Counterpart
  90. GRB011121: possible redshift, continued decay
  91. GRB011121: fading behavior
  92. GRB011121: possible optical counterpart
  93. The X-ray Flash 011030 ('GRB 011030')
  94. The Radio Afterglow from the X-ray Rich GRB 011030
  95. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  96. GRB010921, optical observation
  97. GRB 011030 I-band Observations
  98. GRB 011030 K-band Observations
  99. GRB 010921: Possible supernova component
  100. GRB010921, optical observation at early time

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