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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: precise position from Kyoto images
  2. GRB 030328 Optical Observations
  3. GRB030328: Decay index
  4. GRB 030328: Optical observations
  5. GRB 030328: optical observations
  6. GRB 030329: Optical afterglow fading
  7. GRB 030329 follow-up
  8. GRB 030329: Optical afterglow candidate
  9. GRB 030329: OT candidate
  10. GRB 030329: Optical afterglow candidate
  11. GRB 030328: OT photometry
  12. GRB030328: optical spectroscopy at TNG
  13. GRB030328: optical photometry at the TNG
  14. VLT spectra of GRB 030328
  15. GRB 030328, optical spectroscopy
  16. GRB 030328, optical observations
  17. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  18. GRB 030328: Optical observations
  19. Re: GRB 030328: Finding chart
  20. GRB 030328: Finding chart
  21. GRB 030328: Optical afterglow candidate
  22. GRB030323 optical observations
  23. GRB030324 optical observation
  24. GRB030131, BVRcIc field photometry
  25. Possible GRB030323 localized by INTEGRAL
  26. IPN triangulation of GRB030325 (final analysis)
  27. GRB030323: Detection on 2003/03/24
  28. IPN triangulation of GRB030326 (single small error box)
  29. GRB 030323: SARA Optical Observations
  30. IPN triangulation of GRB030325 (single small error box)
  31. GRB030324, optical observations
  32. GRB030324, optical observations
  33. IPN triangulation of GRB030325 (two small error boxes)
  34. GRB 030324: TAROT optical observations
  35. GRB030323: V, R, I photometry
  36. GRB 030324 (HETE #2641): Optical observations
  37. GRB030324, Optical Observations
  38. GRB030323: Upper limits from recent and historical observations.
  39. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  40. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  41. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  42. VLT/FORS2 spectra of GRB 030323
  43. GRB030323, ROTSE-III detection of possible optical counterpart
  44. GRB030323, optical observations
  45. GRB030324, BVRcIc field photometry
  46. GRB030323, possible optical counterpart
  47. GRB030323, BVRcIc field calibration
  48. GRB 030324 optical observations
  49. GRB 030320: Optical Observations
  50. GRB 030324, optical observations
  51. IPN triangulation of GRB030320B (annulus)
  52. IPN triangulation of GRB030320 (small error box)
  53. IPN triangulation of GRB030320
  54. Possible GRB 030320 localized by INTEGRAL
  55. GRB030226, addendum to GCN 1892
  56. IPN upper limit to a GRB associated with SN2003L
  57. IPN triangulation of GRB030317 (annulus)
  58. IPN triangulation of GRB030307 (annulus)
  59. GRB 030227: Optical limit at RIKEN
  60. GRB 030226 Optical observations
  61. IPN triangulation of GRB030306 (single small error box - REVISED)
  62. GRB030226: Optical observations at Asiago
  63. IPN triangulation of GRB030306 (single small error box)
  64. IPN triangulation of GRB030306 (two small error boxes)
  65. IPN triangulation of GRB030306 (intense; annulus only so far)
  66. GRB 030226: Optical observations
  67. GRB030226: Analysis of Chandra data
  68. IPN triangulation of GRB030304 (annulus)
  69. GRB 030227: Optical observations
  70. GRB030226, BVRc observations
  71. Chandra detection of the X-ray afterglow of GRB 030226
  72. GRB 030226, further optical/NIR imaging
  73. GRB030227, optical observations
  74. GRB 030226: Ic Observations
  75. GRB030227: Kiso optical upper limit
  76. IPN triangulation of GRB030301 (annulus)
  77. IPN triangulation of GRB030228 (annulus)
  78. GRB030227, BVRcIc field photometry
  79. GRB030226, BVRcIc field calibration
  80. GRB 030227 optical afterglow
  81. 030302: NOT A GRB
  82. 030228: NOT A GRB
  83. GRB 030228, optical observations
  84. GRB 030226: Steep Decline
  85. GRB 030227: Confirmed Optical Afterglow (S1-A)
  86. GRB 030226: R band polarimetric observations
  87. GRB 030226: Optical observations
  88. GRB 030227: fading of candidate optical afterglow 'S1-A'
  89. GRB030227:Optical observations
  90. GRB 20030226: Upper limits from recent and historical observations
  91. GRB 030227, possible optical counterpart of XMM-Newton source
  92. GRB030227 - faint tentative OT candidate
  93. GRB 030226, optical observations
  94. XMM-Newton observation of GRB030227
  95. GRB030227: Kiso optical observations
  96. GRB 030227: Kyoto optical observation
  97. GRB 030226, optical light curve
  98. GRB 030226 spectroscopy
  99. GRB030227: refined INTEGRAL position
  100. GRB030227 localized by INTEGRAL

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