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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"

35429 results found.

  1. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  2. GRB 020321: Optical observations
  3. GRB020317 BVRI field photometry
  4. GRB011211 revised BVRI field photometry
  5. GRB020305 BVRI field photometry
  6. GRB020322 BVRI field photometry
  7. GRB 020322 optical observations
  8. GRB 020322 optical observation
  9. GRB020317 : Near IR Observations from Mt Abu Observatory
  10. GRB 020322: Optical Sources and Improved Astrometry
  11. GRB020322, optical observations
  12. GRB 020322: Optical candidate
  13. GRB020322: BeppoSAX/NFI Observations
  14. Bepposax GRB020322 The second springtime BSAX GRB
  15. GRB 020321: Optical observations
  16. GRB 011121: Fourth Epoch of HST Imaging
  17. GRB020317: optical observations
  18. GRB020321 optical observations
  19. GRB020321: BeppoSAX/NFI Observations
  20. GRB020321: a faint BeppoSAX detection
  21. GRB 020317 : KISO Optical Observations
  22. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  23. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  24. GRB 020305: Optical Observations
  25. GRB020317, optical observations
  26. GRB 020317: Optical observations
  27. GRB 011121: Third HST Epoch
  28. GRB020305: Properties of the Candidate Optical Afterglow
  29. GRB 011121: HST Observations reveal an intermediate-time multicolor
  30. GRB011121, possible supernova association
  31. GRB011130 (XRF011130) Second Epoch Chandra Observations
  32. GRB020305: Subaru Optical Observations
  33. GRB 020305: Optical observations
  34. XRF/GRB 011030 Images
  35. XRF/GRB 011030: Detection of the Probable Host Galaxy
  36. GRB 020305: Candidate optical afterglow
  37. Type Ic SN2002bl (SN/GRB?) Radio Observations
  38. GRB020305: Optical Observations
  39. IPN triangulation of GRB020305 (HETE 1939)
  40. GRB020305 (=H1939): Localization of a GRB by HETE
  41. GRB 020305: Optical observations
  42. HST Imaging of the afterglow and host of GRB 011121
  43. GRB 010921: HST Observations
  44. IPN detection and localization of Cygnus X-1 flares
  45. GRB020127: Further VLA Observations of Possible Counterparts
  46. IPN detection of further SGR1900+14 activity
  47. SGR1900+14 activity
  48. IPN/HETE Detection of Bursts from SGR1900+14
  49. IPN Upper Limits to a GRB Associated With SN2002ap
  50. GRB020124 BVRI field photometry
  51. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  52. SN2002ap (SN/GRB?) Echelle spectra
  53. SN2002ap (SN/GRB?) optical spectrographic observations
  54. GRB020127 Optical Observations
  55. SN 2002ap (SN/GRB?)
  56. SN2002ap (SN/GRB?) UBVRI Field Photometry
  57. GRB020127: Chandra Observations and Prospective Counterparts
  58. pre-SN2002ap (SN/GRB?) imaging of M74
  59. SN 2002ap (hypernova / GRB ??): special list on VSNET
  60. Type Ib/c SN2002ap (SN/GRB?)
  61. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  62. GRB020124, optical observations
  63. GRB020127: Optical observations
  64. GRB 020127, I-band observations starting 3.14-hr after the event
  65. IPN detection of further activity from SGR1806-20
  66. IPN triangulation of GRB020127 (=H1902)
  67. GRB010921 Optical Observations
  68. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  69. GRB020124: Optical observations
  70. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  71. GRB020124: Optical observations
  72. GRB 020124: Optical observations
  73. GRB 020124 Optical Observations
  74. IPN triangulation of GRB020124 (HETE 1896)
  75. IPN observations of SGR1806-20
  76. GRB 020124: Optical afterglow
  77. GRB020124(=H1896): Localization of a Long GRB by HETE
  78. GRB optical counterpart candidate in GCN 1217 is M dwarf
  79. Possible optical counterpart to a GRB
  80. GRB011212, Optical Observations
  81. GRB 011211: Detection of the Probable Host Galaxy
  82. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  83. GRB 011211, spectrum and optical photometry
  84. GRB 011130: Optical Observations of X-ray and Radio Sources
  85. GRB 011130, Radio/X-ray Comparison
  86. GRB 011212: optical observation at Asiago
  87. GRB 011211: Evidence for an Optical Break
  88. GRB 011211: TNG Spectroscopic Observations
  89. optical follow-up of GRB(XRF) 011211
  90. GRB 011212: optical observation at Oslo (relayed)
  91. GRB 011211: Optical Spectroscopy
  92. GRB 011211, Optical Observations
  93. GRB011212, BVRI field photometry
  94. GRB011211, BVRI field photometry
  95. GRB011212: Optical observations
  96. GRB 011211: BVRi-band photometry
  97. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  98. Fading of the optical source associated of XRF 011211
  99. GRB 011211 Optical Observations: Likely Afterglow
  100. BeppoSAX Alert: GRB011211(=XRF011211)

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