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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"

20510 results found.

  1. GRB "020411"
  2. GRB 020409: Optical observations
  3. GRB 020410, optical observations
  4. GRB 020409, optical observations
  5. GRB 020409: Optical Observations
  6. GRB020406(?), optical observations
  7. GRB020410, optical observations
  8. GRB020331: Confirmation of Afterglow Candidate with Magellan
  9. GRB020405: VLT optical observations and V band decay slope
  10. GRB020331 optical observations with RIMOTS
  11. GRB020124 optical observations with RIBOTS/RIMOTS
  12. GRB 020405: Moderate-resolution spectroscopy
  13. GRB020331: Optical Observations of Afterglow Candidate
  14. GRB020406(?), optical observations
  15. GRB020405: VLT optical observations
  16. Revised Photometry of the Optical Afterglow of GRB 020405
  17. GRB020405: OT observations
  18. GRB 020331: Candidate Optical Afterglow
  19. GRB 020405: Decay index
  20. Short RXTE/ASM transient 020406; may be a GRB
  21. GRB020405, Radio Observations
  22. V band observations of GRB020405
  23. GRB 020405, U-band observations
  24. GRB011212: Optical Observations
  25. GRB 020331: NIR Observations
  26. GRB 020331: NIR Observations
  27. GRB020331 NIR observation at KPNO (re-submission)
  28. GRB02033 NIR observation at KPNO
  29. GRB 020331 Optical Observations
  30. GRB 020331, NIR observations
  31. GRB 020331: Optical observations
  32. GRB 020321: Infrared 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. GRB 020321: Optical observations
  40. GRB 020322 optical observations
  41. GRB020317 : Near IR Observations from Mt Abu Observatory
  42. GRB020322, optical observations
  43. GRB020322: Optical Observations
  44. GRB020322: BeppoSAX/NFI Observations
  45. GRB 020321: Optical observations
  46. GRB 011121: Fourth Epoch of HST Imaging
  47. GRB020317: optical observations
  48. GRB020321 optical observations
  49. GRB020321: BeppoSAX/NFI Observations
  50. GRB020305: NIR observations
  51. GRB 020317 : KISO Optical Observations
  52. GRB 020305: Optical Observations
  53. GRB020317, optical observations
  54. GRB 020317: Optical observations
  55. GRB 011121: Third HST Epoch
  56. GRB 011121: HST Observations reveal an intermediate-time multicolor
  57. GRB011121, possible supernova association
  58. GRB011130 (XRF011130) Second Epoch Chandra Observations
  59. GRB020305: Subaru Optical Observations
  60. GRB 020305: Optical observations
  61. XRF/GRB 011030: Detection of the Probable Host Galaxy
  62. GRB 020305: Candidate optical afterglow
  63. Type Ic SN2002bl (SN/GRB?) Radio Observations
  64. GRB020305, optical observations
  65. GRB020305: Optical Observations
  66. GRB 020305: Optical observations
  67. HST Imaging of the afterglow and host of GRB 011121
  68. GRB 010921: HST Observations
  69. GRB020127: Further VLA Observations of Possible Counterparts
  70. RXTE Observations of SGR 1900+14
  71. GRB020127: Palomar and VLA Observations of Possible Counterparts
  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, WSRT radio observations
  76. GRB020127 Optical Observations
  77. SN 2002ap in M74
  78. GRB020127: Chandra Observations and Prospective Counterparts
  79. Type Ib/c SN2002ap (SN/GRB?)
  80. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  81. GRB020124, optical observations
  82. GRB020127: Optical observations
  83. GRB 020127, I-band observations starting 3.14-hr after the event
  84. GRB020127 Optical Observations -- Erratum to GCN 1230
  85. GRB010921 Optical Observations
  86. GRB020124: Optical observations
  87. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  88. GRB020124: Optical observations
  89. GRB 020124: Optical observations
  90. GRB 020124 Optical Observations
  91. IPN observations of SGR1806-20
  92. GRB 020124: Optical afterglow
  93. HETE 1896: Optical observations
  94. GRB optical counterpart candidate in GCN 1217 is M dwarf
  95. Possible optical counterpart to a GRB
  96. GRB011212, Optical Observations
  97. Optical polarization observations for GRB011211
  98. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  99. GRB011212: Optical observations at Gunma
  100. GRB 011211, spectrum and optical photometry

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