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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. GRB 030329 RBO V Optical Observations
  2. GRB 030329, optical photometry
  3. GRB030329: Near Infrared Observations
  4. 030331 NOT A GRB
  5. INTEGRAL GRB 030331
  6. GRB 030324: Optical and NIR Observations
  7. GRB 030328, optical photometry
  8. GRB030329: R band light curve by MASTER
  9. GRB030329 - Light curve flattening
  10. GRB 030329: SARA Optical Observations
  11. GRB 030324, optical search
  12. GRB030329 - near contemporaneous optical limits from CONCAM
  13. GRB030329: R and B observations
  14. GRB 030329, optical observations
  15. GRB030329: Optical observations
  16. GRB030328: X-ray Fading and Spectrum Measured with Chandra
  17. GRB030329a: detection by Konus-Wind
  18. GRB030329b: detection by Konus-Wind and Helicon-CoronasF
  19. GRB 030329: Light curve observed during the change of its slope.
  20. GRB030329, BVRcIc field photometry
  21. GRB030329, SPM optical observations
  22. GRB 030329: Optical Decay
  23. Redshift of GRB 030329
  24. GRB030329: ROTSE network observes steepening of decay curve
  25. GRB 030329, optical photometry
  26. GRB 030329: Optical decay and synthesis
  27. GRB030329 optical observations
  28. GRB030329: optical spectroscopy with the TNG
  29. GRB 030329: Radio Observations
  30. GRB 030329, optical spectroscopy
  31. GRB 030329: still bright
  32. GRB 030329: Optical pre-Imaging
  33. GRB 030329: visual observations
  34. GRB 030329: Upper limit from 5.6 hours before trigger
  35. GRB030328: R optical observation
  36. GRB030328: X-ray Afterglow Observed with Chandra
  37. GRB 030323: Gemini South VRI obsevations.
  38. GRB030329: Optical observations
  39. GRB 030329, R-band observations, supplement
  40. GRB030329 optical observations
  41. GRB030329:optical observations by MASTER
  42. GRB 030329: optical observations
  43. GRB 030329, R-band observations
  44. GRB 030329: OT B and R photometry, decline rate
  45. GRB030329: Upper limits from recent and historical observations.
  46. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  47. RXTE detection of GRB 030329 afterglow
  48. GRB 030329: Optical Afterglow Observations
  49. GRB 030329: precise position from Kyoto images
  50. GRB 030328 Optical Observations
  51. GRB030328: Decay index
  52. GRB 030328: Optical observations
  53. GRB 030328: optical observations
  54. GRB 030329: Optical afterglow fading
  55. GRB 030329 follow-up
  56. GRB 030329: Optical afterglow candidate
  57. GRB 030329: OT candidate
  58. GRB 030329: Optical afterglow candidate
  59. GRB 030328: OT photometry
  60. GRB030328: optical spectroscopy at TNG
  61. GRB030328: optical photometry at the TNG
  62. VLT spectra of GRB 030328
  63. GRB 030328, optical spectroscopy
  64. GRB 030328, optical observations
  65. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  66. GRB 030328: Optical observations
  67. Re: GRB 030328: Finding chart
  68. GRB 030328: Finding chart
  69. GRB 030328: Optical afterglow candidate
  70. GRB030323 optical observations
  71. GRB030324 optical observation
  72. GRB030131, BVRcIc field photometry
  73. Possible GRB030323 localized by INTEGRAL
  74. IPN triangulation of GRB030325 (final analysis)
  75. GRB030323: Detection on 2003/03/24
  76. IPN triangulation of GRB030326 (single small error box)
  77. GRB 030323: SARA Optical Observations
  78. IPN triangulation of GRB030325 (single small error box)
  79. GRB030324, optical observations
  80. GRB030324, optical observations
  81. IPN triangulation of GRB030325 (two small error boxes)
  82. GRB 030324: TAROT optical observations
  83. GRB030323: V, R, I photometry
  84. GRB 030324 (HETE #2641): Optical observations
  85. GRB030324, Optical Observations
  86. GRB030323: Upper limits from recent and historical observations.
  87. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  88. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  89. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  90. VLT/FORS2 spectra of GRB 030323
  91. GRB030323, ROTSE-III detection of possible optical counterpart
  92. GRB030323, optical observations
  93. GRB030324, BVRcIc field photometry
  94. GRB030323, possible optical counterpart
  95. GRB030323, BVRcIc field calibration
  96. GRB 030324 optical observations
  97. GRB 030320: Optical Observations
  98. GRB 030324, optical observations
  99. IPN triangulation of GRB030320B (annulus)
  100. IPN triangulation of GRB030320 (small error box)

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