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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"

20960 results found.

  1. GRB 020317 : KISO Optical Observations
  2. GRB 020305: Optical Observations
  3. GRB020317, optical observations
  4. GRB 020317: Optical observations
  5. GRB 011121: Third HST Epoch
  6. GRB 011121: HST Observations reveal an intermediate-time multicolor
  7. GRB011121, possible supernova association
  8. GRB011130 (XRF011130) Second Epoch Chandra Observations
  9. GRB020305: Subaru Optical Observations
  10. GRB 020305: Optical observations
  11. XRF/GRB 011030: Detection of the Probable Host Galaxy
  12. GRB 020305: Candidate optical afterglow
  13. Type Ic SN2002bl (SN/GRB?) Radio Observations
  14. GRB020305, optical observations
  15. GRB020305: Optical Observations
  16. GRB 020305: Optical observations
  17. HST Imaging of the afterglow and host of GRB 011121
  18. GRB 010921: HST Observations
  19. GRB020127: Further VLA Observations of Possible Counterparts
  20. RXTE Observations of SGR 1900+14
  21. GRB020127: Palomar and VLA Observations of Possible Counterparts
  22. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  23. SN2002ap (SN/GRB?) Echelle spectra
  24. SN2002ap (SN/GRB?) optical spectrographic observations
  25. GRB020127, WSRT radio observations
  26. GRB020127 Optical Observations
  27. SN 2002ap in M74
  28. GRB020127: Chandra Observations and Prospective Counterparts
  29. Type Ib/c SN2002ap (SN/GRB?)
  30. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  31. GRB020124, optical observations
  32. GRB020127: Optical observations
  33. GRB 020127, I-band observations starting 3.14-hr after the event
  34. GRB020127 Optical Observations -- Erratum to GCN 1230
  35. GRB010921 Optical Observations
  36. GRB020124: Optical observations
  37. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  38. GRB020124: Optical observations
  39. GRB 020124: Optical observations
  40. GRB 020124 Optical Observations
  41. IPN observations of SGR1806-20
  42. GRB 020124: Optical afterglow
  43. HETE 1896: Optical observations
  44. GRB optical counterpart candidate in GCN 1217 is M dwarf
  45. Possible optical counterpart to a GRB
  46. GRB011212, Optical Observations
  47. Optical polarization observations for GRB011211
  48. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  49. GRB011212: Optical observations at Gunma
  50. GRB 011211, spectrum and optical photometry
  51. GRB 011130: Optical Observations of X-ray and Radio Sources
  52. GRB 011130, Radio/X-ray Comparison
  53. GRB011212: Optical observations
  54. GRB 011212: optical observation at Asiago
  55. GRB 011211: TNG Spectroscopic Observations
  56. GRB 011211, Optical Observations
  57. GRB011212: Optical observations
  58. GRB 011211 Optical Observations: Likely Afterglow
  59. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  60. GRB 011130: Optical Observations of Chandra Sources
  61. GRB 011130: Optical Observations of Chandra sources
  62. GRB011130 (XRF011130) Chandra Observations
  63. GRB 011130: Magellan spectroscopy
  64. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  65. GRB011130, optical observations
  66. GRB 011130, K band observations
  67. GRB011130, optical observations
  68. GRB011130 (XRF011130) optical observations
  69. GRB011130 (XRF011130) SDSS PT i-band observations
  70. XRF011130: Infrared Observations
  71. GRB011130, Radio Observations
  72. GRB011130 (=XRF011130), Optical Observations
  73. XRF011130: NEAT Optical Observations
  74. GRB001109, Radio Monitoring
  75. GRB 011121
  76. GRB 011121: J-band observations
  77. GRB 011121: NIR observations, host galaxy?
  78. GRB010921 - Milagro GeV/TeV Observations
  79. GRB 011121: HST Scheduled
  80. GRB011121: fainter still
  81. GRB011121: UBRI Observations
  82. GRB011121
  83. GRB 011121: Radio Observations
  84. GRB011121: continued decay
  85. GRB 011121: Detection of Bright IR Counterpart
  86. GRB011121: possible redshift, continued decay
  87. GRB011121: fading behavior
  88. GRB011121: possible optical counterpart
  89. XRF011030: J and K band observations
  90. XRF011030: Chandra Observations
  91. GRB 011030: K-band observations
  92. GRB011030: Z-band observations
  93. GRB 011030 R band observations
  94. The X-ray Flash 011030 ('GRB 011030')
  95. Non-triggered burst 011030 ("GRB 011030")
  96. The Radio Afterglow from the X-ray Rich GRB 011030
  97. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  98. GRB 970828: HST Observations of the Host Galaxy
  99. GRB 970828: HST Observations of the Host Galaxy
  100. GRB010921, optical observation

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