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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"

32541 results found.

  1. GRB 020322 optical observations
  2. GRB020322: Candidate Optical Afterglow
  3. GRB 020322 optical observation
  4. GRB 020322: Optical Sources and Improved Astrometry
  5. GRB020322, optical observations
  6. GRB 020322: Optical candidate
  7. XMM-Newton observation of GRB020322
  8. GRB020322: Optical Observations
  9. GRB 020321: Optical observations
  10. GRB 011121: Fourth Epoch of HST Imaging
  11. GRB020317: optical observations
  12. GRB020321 optical observations
  13. GRB020305: NIR observations
  14. GRB 020317 : KISO Optical Observations
  15. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  16. GRB 020305: Optical Observations
  17. GRB020317, optical observations
  18. GRB 011121: Third HST Epoch
  19. GRB020305: Properties of the Candidate Optical Afterglow
  20. GRB 011121: HST Observations reveal an intermediate-time multicolor
  21. GRB011121, possible supernova association
  22. GRB011130 (XRF011130) Second Epoch Chandra Observations
  23. GRB020305: Subaru Optical Observations
  24. GRB 020305: Optical observations
  25. XRF/GRB 011030 Images
  26. XRF/GRB 011030: Detection of the Probable Host Galaxy
  27. GRB 020305: Candidate optical afterglow
  28. Type Ic SN2002bl (SN/GRB?) Radio Observations
  29. GRB020305 (=H1939): Localization of a GRB by HETE
  30. HST Imaging of the afterglow and host of GRB 011121
  31. GRB 010921: HST Observations
  32. GRB020127: Further VLA Observations of Possible Counterparts
  33. IPN detection of further SGR1900+14 activity
  34. SGR1900+14 activity
  35. GRB020124 BVRI field photometry
  36. GRB020127: Palomar and VLA Observations of Possible Counterparts
  37. GRB020127, WSRT radio observations
  38. GRB020127 Optical Observations
  39. SN2002ap (SN/GRB?) UBVRI Field Photometry
  40. GRB020127: Chandra Observations and Prospective Counterparts
  41. pre-SN2002ap (SN/GRB?) imaging of M74
  42. Type Ib/c SN2002ap (SN/GRB?)
  43. GRB020127: Optical observations
  44. GRB 020127, I-band observations starting 3.14-hr after the event
  45. IPN triangulation of GRB020127 (=H1902)
  46. GRB020127 Optical Observations -- Erratum to GCN 1230
  47. GRB010921 Optical Observations
  48. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  49. GRB020124: Optical observations
  50. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  51. GRB020124: Optical observations
  52. GRB 020124: Optical observations
  53. GRB 020124 Optical Observations
  54. IPN triangulation of GRB020124 (HETE 1896)
  55. GRB 020124: Optical afterglow
  56. GRB020124(=H1896): Localization of a Long GRB by HETE
  57. GRB optical counterpart candidate in GCN 1217 is M dwarf
  58. GRB011212, Optical Observations
  59. GRB011211: BeppoSAX/GRBM data
  60. Optical polarization observations for GRB011211
  61. Color indices of the afterglow of GRB011211
  62. GRB011212: Optical observations at Gunma
  63. GRB 011211, spectrum and optical photometry
  64. GRB 011130: Optical Observations of X-ray and Radio Sources
  65. GRB 011130, Radio/X-ray Comparison
  66. GRB011212: Optical observations
  67. GRB 011212: optical observation at Asiago
  68. GRB 011211: Evidence for an Optical Break
  69. GRB 011211: TNG Spectroscopic Observations
  70. optical follow-up of GRB(XRF) 011211
  71. GRB 011212: optical observation at Oslo (relayed)
  72. GRB 011211: Optical Spectroscopy
  73. GRB 011211, Optical Observations
  74. GRB011212, BVRI field photometry
  75. GRB011211, BVRI field photometry
  76. GRB011212: Optical observations
  77. GRB 011211: BVRi-band photometry
  78. Fading of the optical source associated of XRF 011211
  79. XMM-Newton observation of GRB011211
  80. GRB 011211 Optical Observations: Likely Afterglow
  81. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  82. GRB 011130: Optical Observations of Chandra Sources
  83. GRB 011130: Optical Observations of Chandra sources
  84. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  85. GRB 011130: Magellan spectroscopy
  86. GRB011130, optical observations
  87. GRB011130, optical observations
  88. GRB011130 (=XRF011130): Second Revised Localization by HETE
  89. GRB 011130 I-band Observation
  90. GRB011130 (XRF011130) optical observations
  91. GRB011130 (XRF011130) SDSS PT i-band observations
  92. XRF011130: Infrared Observations
  93. GRB011130, Radio Observations
  94. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  95. GRB011130 (=XRF011130), Optical Observations
  96. XRF011130: NEAT Optical Observations
  97. GRB011130 (=XRF011130): Revised Localization of an X-ray
  98. GRB001109, Radio Monitoring
  99. GRB 011121: Errata URL
  100. GRB 011121

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