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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"

45442 results found.

  1. HST Imaging of the afterglow and host of GRB 011121
  2. GRB 010921: HST Observations
  3. IPN detection and localization of Cygnus X-1 flares
  4. GRB020127: Further VLA Observations of Possible Counterparts
  5. RXTE Observations of SGR 1900+14
  6. IPN detection of further SGR1900+14 activity
  7. SGR1900+14 activity
  8. IPN/HETE Detection of Bursts from SGR1900+14
  9. IPN Upper Limits to a GRB Associated With SN2002ap
  10. GRB020124 BVRI field photometry
  11. GRB020127: Palomar and VLA Observations of Possible Counterparts
  12. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  13. SN2002ap (SN/GRB?) Echelle spectra
  14. SN2002ap (SN/GRB?) optical spectrographic observations
  15. GRB020127, WSRT radio observations
  16. GRB020127 Optical Observations
  17. SN 2002ap (SN/GRB?)
  18. SN 2002ap in M74
  19. SN2002ap (SN/GRB?) UBVRI Field Photometry
  20. GRB020127: Chandra Observations and Prospective Counterparts
  21. pre-SN2002ap (SN/GRB?) imaging of M74
  22. SN 2002ap (hypernova / GRB ??): special list on VSNET
  23. Type Ib/c SN2002ap (SN/GRB?)
  24. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  25. GRB020124, optical observations
  26. GRB020127: Optical observations
  27. GRB 020127, I-band observations starting 3.14-hr after the event
  28. IPN detection of further activity from SGR1806-20
  29. IPN triangulation of GRB020127 (=H1902)
  30. GRB020127 Optical Observations -- Erratum to GCN 1230
  31. GRB010921 Optical Observations
  32. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  33. GRB020124: Optical observations
  34. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  35. GRB020124: Optical observations
  36. GRB 020124: Optical observations
  37. GRB 020124 Optical Observations
  38. IPN triangulation of GRB020124 (HETE 1896)
  39. IPN observations of SGR1806-20
  40. GRB 020124: Optical afterglow
  41. GRB020124(=H1896): Localization of a Long GRB by HETE
  42. HETE 1896: Optical observations
  43. GRB optical counterpart candidate in GCN 1217 is M dwarf
  44. Possible optical counterpart to a GRB
  45. GRB011212, Optical Observations
  46. GRB011211: BeppoSAX/GRBM data
  47. Optical polarization observations for GRB011211
  48. GRB 011211: Detection of the Probable Host Galaxy
  49. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  50. Color indices of the afterglow of GRB011211
  51. GRB011212: Optical observations at Gunma
  52. GRB 011211, spectrum and optical photometry
  53. GRB 011130: Optical Observations of X-ray and Radio Sources
  54. GRB 011130, Radio/X-ray Comparison
  55. GRB011212: Optical observations
  56. GRB 011212: optical observation at Asiago
  57. GRB 011211: Evidence for an Optical Break
  58. GRB 011211: TNG Spectroscopic Observations
  59. optical follow-up of GRB(XRF) 011211
  60. GRB 011212: optical observation at Oslo (relayed)
  61. GRB 011211: Optical Spectroscopy
  62. GRB 011211, Optical Observations
  63. GRB011212, BVRI field photometry
  64. GRB011211, BVRI field photometry
  65. GRB011212: Optical observations
  66. GRB 011211: BVRi-band photometry
  67. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  68. Fading of the optical source associated of XRF 011211
  69. XMM-Newton observation of GRB011211
  70. GRB 011211 Optical Observations: Likely Afterglow
  71. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  72. GRB011211(=XRF011211): BeppoSAX refined positions
  73. BeppoSAX Alert: GRB011211(=XRF011211)
  74. GRB 011130: Optical Observations of Chandra Sources
  75. GRB 011130: Optical Observations of Chandra sources
  76. GRB011130 (XRF011130) Chandra Observations
  77. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  78. GRB 011130: Magellan spectroscopy
  79. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  80. GRB011130, optical observations
  81. GRB 011130, K band observations
  82. GRB011130, optical observations
  83. GRB011130 (=XRF011130): Second Revised Localization by HETE
  84. GRB 011130 I-band Observation
  85. GRB011130 (XRF011130) optical observations
  86. GRB011130 (XRF011130) SDSS PT i-band observations
  87. XRF011130: Infrared Observations
  88. GRB011130, Radio Observations
  89. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  90. GRB011130 (=XRF011130), Optical Observations
  91. XRF011130: NEAT Optical Observations
  92. GRB011130 (=XRF011130): Revised Localization of an X-ray
  93. GRB001109, Radio Monitoring
  94. GRB 011121
  95. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  96. GRB 011121: J-band observations
  97. GRB 011121: NIR observations, host galaxy?
  98. GRB010921 - Milagro GeV/TeV Observations
  99. GRB 011121: HST Scheduled
  100. GRB011121: fainter still

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