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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"

42241 results found.

  1. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  2. GRB 020305: Optical Observations
  3. GRB020317, optical observations
  4. GRB 020317: Optical observations
  5. GRB 011121: Third HST Epoch
  6. GRB020305: Properties of the Candidate Optical Afterglow
  7. GRB 011121: HST Observations reveal an intermediate-time multicolor
  8. GRB011121, possible supernova association
  9. GRB011130 (XRF011130) Second Epoch Chandra Observations
  10. GRB020305: Subaru Optical Observations
  11. GRB 020305: Optical observations
  12. XRF/GRB 011030: Detection of the Probable Host Galaxy
  13. GRB 020305: Candidate optical afterglow
  14. Type Ic SN2002bl (SN/GRB?) Radio Observations
  15. GRB020305, optical observations
  16. GRB020305: Optical Observations
  17. IPN triangulation of GRB020305 (HETE 1939)
  18. GRB020305 (=H1939): Localization of a GRB by HETE
  19. GRB 020305: Optical observations
  20. HST Imaging of the afterglow and host of GRB 011121
  21. GRB 010921: HST Observations
  22. IPN detection and localization of Cygnus X-1 flares
  23. GRB020127: Further VLA Observations of Possible Counterparts
  24. RXTE Observations of SGR 1900+14
  25. IPN detection of further SGR1900+14 activity
  26. SGR1900+14 activity
  27. IPN/HETE Detection of Bursts from SGR1900+14
  28. IPN Upper Limits to a GRB Associated With SN2002ap
  29. GRB020124 BVRI field photometry
  30. GRB020127: Palomar and VLA Observations of Possible Counterparts
  31. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  32. SN2002ap (SN/GRB?) Echelle spectra
  33. SN2002ap (SN/GRB?) optical spectrographic observations
  34. GRB020127, WSRT radio observations
  35. GRB020127 Optical Observations
  36. SN 2002ap (SN/GRB?)
  37. SN 2002ap in M74
  38. SN2002ap (SN/GRB?) UBVRI Field Photometry
  39. GRB020127: Chandra Observations and Prospective Counterparts
  40. pre-SN2002ap (SN/GRB?) imaging of M74
  41. SN 2002ap (hypernova / GRB ??): special list on VSNET
  42. Type Ib/c SN2002ap (SN/GRB?)
  43. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  44. GRB020124, optical observations
  45. GRB020127: Optical observations
  46. GRB 020127, I-band observations starting 3.14-hr after the event
  47. IPN detection of further activity from SGR1806-20
  48. IPN triangulation of GRB020127 (=H1902)
  49. GRB020127 Optical Observations -- Erratum to GCN 1230
  50. GRB010921 Optical Observations
  51. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  52. GRB020124: Optical observations
  53. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  54. GRB020124: Optical observations
  55. GRB 020124: Optical observations
  56. GRB 020124 Optical Observations
  57. IPN triangulation of GRB020124 (HETE 1896)
  58. IPN observations of SGR1806-20
  59. GRB 020124: Optical afterglow
  60. GRB020124(=H1896): Localization of a Long GRB by HETE
  61. HETE 1896: Optical observations
  62. GRB optical counterpart candidate in GCN 1217 is M dwarf
  63. Possible optical counterpart to a GRB
  64. GRB011212, Optical Observations
  65. GRB011211: BeppoSAX/GRBM data
  66. Optical polarization observations for GRB011211
  67. GRB 011211: Detection of the Probable Host Galaxy
  68. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  69. Color indices of the afterglow of GRB011211
  70. GRB011212: Optical observations at Gunma
  71. GRB 011211, spectrum and optical photometry
  72. GRB 011130: Optical Observations of X-ray and Radio Sources
  73. GRB 011130, Radio/X-ray Comparison
  74. GRB011212: Optical observations
  75. GRB 011212: optical observation at Asiago
  76. GRB 011211: Evidence for an Optical Break
  77. GRB 011211: TNG Spectroscopic Observations
  78. optical follow-up of GRB(XRF) 011211
  79. GRB 011212: optical observation at Oslo (relayed)
  80. GRB 011211: Optical Spectroscopy
  81. GRB 011211, Optical Observations
  82. GRB011212, BVRI field photometry
  83. GRB011211, BVRI field photometry
  84. GRB011212: Optical observations
  85. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  86. Fading of the optical source associated of XRF 011211
  87. XMM-Newton observation of GRB011211
  88. GRB 011211 Optical Observations: Likely Afterglow
  89. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  90. BeppoSAX Alert: GRB011211(=XRF011211)
  91. GRB 011130: Optical Observations of Chandra Sources
  92. GRB 011130: Optical Observations of Chandra sources
  93. GRB011130 (XRF011130) Chandra Observations
  94. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  95. GRB 011130: Magellan spectroscopy
  96. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  97. GRB011130, optical observations
  98. GRB 011130, K band observations
  99. GRB011130, optical observations
  100. GRB011130 (=XRF011130): Second Revised Localization by HETE

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