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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"

27032 results found.

  1. 030302: NOT A GRB
  2. 030228: NOT A GRB
  3. GRB 030228, optical observations
  4. GRB 030226: R band polarimetric observations
  5. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  6. GRB 030226 simultaneous optical observations
  7. GRB030226: Candidate optical afterglow
  8. IPN triangulation of GRB030215C (annulus)
  9. GRB 020819: afterglow candidate
  10. Publicizing GRB Discoveries - A Message from NASA HQ
  11. GRB 030115, simultaneous observations by BOOTES-1
  12. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  13. Distribution of INTEGRAL SPI-ACS triggers
  14. GRB030115: TAROT optical observations
  15. GRB 030115, no optical candidate
  16. IPN triangulation of GRB030101 (two large error boxes)
  17. GRB 021219: OSN optical observations
  18. GRB021211: Measurement of Early Time Afterglow
  19. GRB021204: Kiso Observations
  20. GRB 021201 (short/hard), NOT observations
  21. GRB 021211, R- and I-band observations
  22. GRB021211, OT at 108 s
  23. HETE 2493: Optical observations
  24. HETE 2493: Optical candidate
  25. GRB 021204: Optical Observations at RIKEN
  26. GRB 021201: BOOTES simultaneous optical observations
  27. GRB 021112: RAPTOR Observations
  28. GRB021104: Optical Observations
  29. SGR1900+14 activity, November 2-4, 2002
  30. GRB021104: possible optical afterglow
  31. GRB 021016, optical observations
  32. GRB 021004: VRI observations at TNG: possible break
  33. GRB 021008, optical observations
  34. IPN triangulation of GRB021014 (large error box)
  35. GRB 021004: Additional V-band Polarimetric Observations
  36. GRB 021004 - Unusual Radio-to-Submm Spectrum
  37. GRB 021004: V-band Polarimetric Observations
  38. IRAM Millimeter detection of GRB 021004
  39. GRB 021004: Optical observations at RIKEN
  40. GRB 021004, SPM optical observations
  41. GRB021004: optical observations at Nyrola
  42. GRB021004: Optical Afterglow
  43. GRB 020903: Optical observations at RIKEN
  44. XRF 020903: Supernova
  45. IPN triangulation of GRB020914
  46. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  47. INTEGRAL GRBs added to GCN
  48. GRB020812: optical observation
  49. Second epoch K band imaging of GRB 020819
  50. K band observation of GRB 020819
  51. HETE 2275: Optical observations
  52. Polarimetry of GRB020813: evidence for variability
  53. GRB020812: optical observations
  54. GRB020813: Early Time Magnitude
  55. GRB020813, optical observations
  56. Early Time Limits for GRB020813
  57. GRB 020813 Afterglow Observations; Possible break
  58. GRB 020813 multiband optical observations
  59. GRB020813: optical afterglow
  60. GRB020813: Fading of Candidate OT
  61. GRB020813: Candidate Optical Afterglow
  62. GRB 020812 optical observation
  63. GRB020801, optical afterglow candidate
  64. GRB020625 (=H2081): A Long Burst Localized by HETE
  65. HETE #2081: Optical observations
  66. GRB 020531, simultaneous optical observations
  67. GRB020321 : Optical observations.
  68. XRF 020427
  69. GRB 020410, optical observations
  70. GRB 020331: Candidate Optical Afterglow
  71. GRB 020322: BeppoSAX observations of the X-ray afterglow
  72. SN 2002ap - peak brightness date (SN/GRB?)
  73. GRB020321: a faint BeppoSAX detection
  74. GRB020317, optical observations
  75. GRB020305, optical observations
  76. GRB020124, optical observations
  77. HETE 1896: Optical observations
  78. GRB 011130, Radio/X-ray Comparison
  79. GRB011130 (=XRF011130), Optical Observations
  80. GRB001109, Radio Monitoring
  81. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  82. GRB 011030: K-band observations
  83. The X-ray Flash 011030 ('GRB 011030')
  84. The Radio Afterglow from the X-ray Rich GRB 011030
  85. GRB 011019 optical observation
  86. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  87. GRB 010921: The afterglow of HETE #1761
  88. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  89. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  90. GRB010921 Optical Observations
  91. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  92. HETE Trigger #1760 (GRB 010920B?): a new optical source
  93. HETE Trigger #1759 (GRB 010920?) optical observations
  94. BeppoSAX/GRBM detection of GRB 010801
  95. GCN and HETE status
  96. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  97. BeppoSAX/GRBM detection of GRB010728
  98. SGR1900+14 burst seen by HETE: BeppoSAX data
  99. GRB 010629 Optical Observations
  100. SGR1900+14: High Fluence Burst Localized by HETE

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