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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. GRB020405: predicted break
  2. GRB 020409: Optical observations
  3. GRB 020409, No Optical Detection to R = 22
  4. GRB020410: second BeppoSAX NFI observation
  5. GRB 020409: No Evidence for an Optical Afterglow
  6. GRB 020409, 2nd epoch optical observations
  7. GRB 020331 Kyoto observation on March 31
  8. GRB 020409
  9. GRB 020409 SARA Observations
  10. GRB "020411"
  11. GRB 020409, No Optical Detection to R = 20
  12. GRB020410: BeppoSAX NFI observation
  13. GRB 020409: Optical observations
  14. April 11 BeppoSAX event (GRB020411) is likely not a GRB
  15. GRB 020410, optical observations
  16. BeppoSAX ALERT: possible GRB020411
  17. GRB 020409, optical observations
  18. GRB 020409: Optical Observations
  19. GRB020406(?), optical observations
  20. GRB020410, optical observations
  21. BeppoSAX ALERT: possible GRB020410
  22. X-ray afterglow of GRB020321
  23. BeppoSAX GRB : GRB020409
  24. GRB020331: Confirmation of Afterglow Candidate with Magellan
  25. GRB020405: VLT optical observations and V band decay slope
  26. GRB020331 optical observations with RIMOTS
  27. GRB020124 optical observations with RIBOTS/RIMOTS
  28. GRB 020321: Candidate X-ray Counterparts
  29. ASM GRB candidate 020406 refined error box
  30. GRB 020405: Moderate-resolution spectroscopy
  31. GRB020331: Optical Observations of Afterglow Candidate
  32. GRB020406(?), optical observations
  33. GRB020405: VLT optical observations
  34. Revised Photometry of the Optical Afterglow of GRB 020405
  35. GRB020405: OT observations
  36. GRB 020331: Candidate Optical Afterglow
  37. GRB 020405: Decay index
  38. Short RXTE/ASM transient 020406; may be a GRB
  39. GRB020405, Radio Observations
  40. GRB020405: VLT spectroscopy
  41. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  42. V band observations of GRB020405
  43. GRB 020405, U-band observations
  44. GRB 020405: Optical afterglow candidate
  45. IPN localization of GRB020405
  46. GRB011212: Optical Observations
  47. GRB 020331: NIR Observations
  48. GRB 020331: NIR Observations
  49. GRB020331 NIR observation at KPNO (re-submission)
  50. GRB02033 NIR observation at KPNO
  51. GRB020331 field photometry
  52. GRB 020331 Optical Observations
  53. GRB 020331, NIR observations
  54. GRB 020331: Optical observations
  55. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  56. GRB 020321: Infrared observations
  57. GRB 020322: BeppoSAX observations of the X-ray afterglow
  58. SN 2002ap - peak brightness date (SN/GRB?)
  59. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  60. GRB 020322, Radio observations
  61. Near-Infrared Observations of GRB020322 at TIRGO
  62. GRB 020321, Radio Observations
  63. GRB 020322: Optical Observations
  64. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  65. GRB 020321: Optical observations
  66. GRB020317 BVRI field photometry
  67. GRB011211 revised BVRI field photometry
  68. GRB020305 BVRI field photometry
  69. GRB020322 BVRI field photometry
  70. GRB 020322 optical observations
  71. GRB020322: Candidate Optical Afterglow
  72. GRB 020322 optical observation
  73. GRB020317 : Near IR Observations from Mt Abu Observatory
  74. GRB 020322: Optical Sources and Improved Astrometry
  75. GRB020322, optical observations
  76. GRB 020322: Optical candidate
  77. XMM-Newton observation of GRB020322
  78. GRB020322: Optical Observations
  79. GRB020322: BeppoSAX/NFI Observations
  80. Bepposax GRB020322 The second springtime BSAX GRB
  81. GRB 020321: Optical observations
  82. GRB 011121: Fourth Epoch of HST Imaging
  83. GRB020317: optical observations
  84. GRB020321 optical observations
  85. GRB020321: BeppoSAX/NFI Observations
  86. GRB020321: a faint BeppoSAX detection
  87. GRB020305: NIR observations
  88. GRB 020317 : KISO Optical Observations
  89. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  90. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  91. GRB 020305: Optical Observations
  92. GRB020317, optical observations
  93. GRB 020317: Optical observations
  94. GRB 011121: Third HST Epoch
  95. GRB020305: Properties of the Candidate Optical Afterglow
  96. GRB 011121: HST Observations reveal an intermediate-time multicolor
  97. GRB011121, possible supernova association
  98. GRB011130 (XRF011130) Second Epoch Chandra Observations
  99. GRB020305: Subaru Optical Observations
  100. GRB 020305: Optical observations

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