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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"

26191 results found.

  1. GRB021004: Optical Afterglow
  2. GRB 020903: Optical observations at RIKEN
  3. XRF 020903: Supernova
  4. IPN triangulation of GRB020914
  5. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  6. INTEGRAL GRBs added to GCN
  7. GRB020812: optical observation
  8. Second epoch K band imaging of GRB 020819
  9. K band observation of GRB 020819
  10. HETE 2275: Optical observations
  11. Polarimetry of GRB020813: evidence for variability
  12. GRB020812: optical observations
  13. GRB020813: Early Time Magnitude
  14. GRB020813, optical observations
  15. Early Time Limits for GRB020813
  16. GRB 020813 Afterglow Observations; Possible break
  17. GRB 020813 multiband optical observations
  18. GRB020813: optical afterglow
  19. GRB020813: Fading of Candidate OT
  20. GRB020813: Candidate Optical Afterglow
  21. GRB 020812 optical observation
  22. GRB020801, optical afterglow candidate
  23. GRB020625 (=H2081): A Long Burst Localized by HETE
  24. HETE #2081: Optical observations
  25. GRB 020531, simultaneous optical observations
  26. GRB020321 : Optical observations.
  27. XRF 020427
  28. GRB 020410, optical observations
  29. GRB 020331: Candidate Optical Afterglow
  30. GRB 020322: BeppoSAX observations of the X-ray afterglow
  31. SN 2002ap - peak brightness date (SN/GRB?)
  32. GRB020321: a faint BeppoSAX detection
  33. GRB020317, optical observations
  34. GRB020305, optical observations
  35. GRB020124, optical observations
  36. HETE 1896: Optical observations
  37. GRB 011130, Radio/X-ray Comparison
  38. GRB011130 (=XRF011130), Optical Observations
  39. GRB001109, Radio Monitoring
  40. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  41. GRB 011030: K-band observations
  42. The X-ray Flash 011030 ('GRB 011030')
  43. The Radio Afterglow from the X-ray Rich GRB 011030
  44. GRB 011019 optical observation
  45. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  46. GRB 010921: The afterglow of HETE #1761
  47. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  48. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  49. GRB010921 Optical Observations
  50. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  51. HETE Trigger #1760 (GRB 010920B?): a new optical source
  52. HETE Trigger #1759 (GRB 010920?) optical observations
  53. BeppoSAX/GRBM detection of GRB 010801
  54. GCN and HETE status
  55. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  56. BeppoSAX/GRBM detection of GRB010728
  57. SGR1900+14 burst seen by HETE: BeppoSAX data
  58. GRB 010629 Optical Observations
  59. SGR1900+14: High Fluence Burst Localized by HETE
  60. GRB010629: A Burst Localized by HETE
  61. SGR1900+14: Second Burst Localized by HETE
  62. SGR1900+14: A Burst Localized by HETE
  63. SGR1806-20: A Second, Intense Burst Localized by HETE
  64. SGR1806-20: Localization by HETE
  65. IPN triangulation of GRB010613
  66. IPN triangulation of GRB010612
  67. GRB010518: a faint BeppoSAX detection
  68. Giant flare from SGR1900+14
  69. GRB010412: BeppoSAX GRBM and WFC observations
  70. GRB010324: BeppoSAX/GRBM data
  71. GRB010326B: Localization by HETE (2nd GRB for this date)
  72. GRB010326: Refined Localization by HETE
  73. GRB010326: Localization by HETE
  74. Sub-millimeter Excess/GRB 010222
  75. GRB010220: BeppoSAX WFC and GRBM preliminary data
  76. GRB010214: BeppoSAX WFC and GRBM preliminary data
  77. GRB 010214: X-Ray afterglow
  78. GRB010213, optical observations
  79. GRB010213 detected by HETE
  80. HETE Status
  81. GRB010126: CONCAM crude optical limits during GRB
  82. ASM Localization of GRB 001025
  83. HETE positions added to GCN
  84. CONCAM null result on GRB001005
  85. CONCAM crude optical limits before and after GRB000926
  86. GRB000812, Radio observations
  87. GRB000620: BeppoSAX WFC and GRBM detection
  88. GRB000607, optical observations
  89. GRB 000615: NIR observations
  90. GRB 000528 - WFC measurements
  91. IPN triangulation of GRB000519
  92. RXTE/ASM and IPN localization of GRB 000508B
  93. GRB000418, Radio detection
  94. BeppoSAX GRB000424
  95. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  96. GRB000408, lotis optical observations
  97. GRB000326, Radio observations
  98. GRB 000313 - optical transient in the BATSE error box
  99. GRB 000301C, Optical Observation
  100. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation

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