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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"
  1. GRB030329, optical observation
  2. GRB030329, new UBVRcIc field photometry
  3. GRB 030329, light curve and SN prediction
  4. GRB030329: optical observations at Tokyo Tech
  5. GRB 030329: optical observations
  6. GRB030329: multiple re-brightening phases
  7. GRB 030329, BRI photometry
  8. GRB030328: Full Observation, X-ray Fading and Spectrum Measured
  9. GRB 030329 , SPM optical observations
  10. GRB030329: Optical observations at Teramo
  11. GRB 030329: Radio observations at GMRT
  12. GRB030329: more 15GHz observations
  13. Further AAVSO V,B,R observations of GRB030329
  14. GRB 030329: Additional Mt. Laguna Optical Observations
  15. GRB 030329: SARA Optical Observations
  16. GRB 030329: Observations with ANDICAM
  17. GRB030329: Optical observations
  18. GRB030329: further optical photometry and evidence for a light curve discontinuity
  19. GRB 030329: Correction to GCN 2056
  20. GRB 030329: fitting parameters and re-brightening
  21. GRB 030329: KAIT optical photometry
  22. GRB030329 Further RBO Optical Observations
  23. triangulation of GRB 030331 (single error box)
  24. GRB030329 - OT rebrightens
  25. GRB 030329: SARA Optical Observations
  26. AAVSO V & R observations of GRB030329
  27. IPN triangulation of GRB030331 (annulus)
  28. GRB 030329: optical observations
  29. IPN triangulation of GRB030329b (large error box)
  30. GRB 030329: beginning of the new fading phase in optical band
  31. GRB 030329, optical spectroscopy
  32. GRB 030329: fading X-ray afterglow with RXTE
  33. GRB 030329: optical photometry
  34. GRB030329: Optical observations
  35. Photometry of GRB030329 - Constant OT Magnitude
  36. GRB 030329, R-band observations
  37. GRB 030329, R-band light curve
  38. GRB 030329: further optical observations
  39. GRB030329 - OT brightens
  40. GRB 030329: OT observations at Kanazawa
  41. GRB030329 15 GHz radio observation
  42. GRB 030329 RBO V Optical Observations
  43. GRB 030329, optical photometry
  44. GRB030329: Near Infrared Observations
  45. 030331 NOT A GRB
  46. INTEGRAL GRB 030331
  47. GRB 030324: Optical and NIR Observations
  48. GRB 030328, optical photometry
  49. GRB030329: R band light curve by MASTER
  50. GRB030329 - Light curve flattening
  51. GRB 030329: SARA Optical Observations
  52. GRB 030324, optical search
  53. GRB030329 - near contemporaneous optical limits from CONCAM
  54. GRB030329: R and B observations
  55. GRB 030329, optical observations
  56. GRB030329: Optical observations
  57. GRB030328: X-ray Fading and Spectrum Measured with Chandra
  58. GRB030329a: detection by Konus-Wind
  59. GRB030329b: detection by Konus-Wind and Helicon-CoronasF
  60. GRB 030329: Light curve observed during the change of its slope.
  61. GRB030329, BVRcIc field photometry
  62. GRB030329, SPM optical observations
  63. GRB 030329: Optical Decay
  64. Redshift of GRB 030329
  65. GRB030329: ROTSE network observes steepening of decay curve
  66. GRB 030329, optical photometry
  67. GRB 030329: Optical decay and synthesis
  68. GRB030329 optical observations
  69. GRB030329: optical spectroscopy with the TNG
  70. GRB 030329: Radio Observations
  71. GRB 030329, optical spectroscopy
  72. GRB 030329: still bright
  73. GRB 030329: Optical pre-Imaging
  74. GRB 030329: visual observations
  75. GRB 030329: Upper limit from 5.6 hours before trigger
  76. GRB030328: R optical observation
  77. GRB030328: X-ray Afterglow Observed with Chandra
  78. GRB 030323: Gemini South VRI obsevations.
  79. GRB030329: Optical observations
  80. GRB 030329, R-band observations, supplement
  81. GRB030329 optical observations
  82. GRB030329:optical observations by MASTER
  83. GRB 030329: optical observations
  84. GRB 030329, R-band observations
  85. GRB 030329: OT B and R photometry, decline rate
  86. GRB030329: Upper limits from recent and historical observations.
  87. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  88. RXTE detection of GRB 030329 afterglow
  89. GRB 030329: Optical Afterglow Observations
  90. GRB 030329: precise position from Kyoto images
  91. GRB 030328 Optical Observations
  92. GRB030328: Decay index
  93. GRB 030328: Optical observations
  94. GRB 030328: optical observations
  95. GRB 030329: Optical afterglow fading
  96. GRB 030329 follow-up
  97. GRB 030329: Optical afterglow candidate
  98. GRB 030329: OT candidate
  99. GRB 030329: Optical afterglow candidate
  100. GRB 030328: OT photometry

Advanced

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