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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"

37524 results found.

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

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