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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: OT candidate
  2. GRB 030329: Optical afterglow candidate
  3. GRB 030328: OT photometry
  4. GRB030328: optical spectroscopy at TNG
  5. GRB030328: optical photometry at the TNG
  6. VLT spectra of GRB 030328
  7. GRB 030328, optical spectroscopy
  8. GRB 030328, optical observations
  9. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  10. GRB 030328: Optical observations
  11. Re: GRB 030328: Finding chart
  12. GRB 030328: Finding chart
  13. GRB 030328: Optical afterglow candidate
  14. GRB030323 optical observations
  15. GRB030324 optical observation
  16. GRB030131, BVRcIc field photometry
  17. Possible GRB030323 localized by INTEGRAL
  18. IPN triangulation of GRB030325 (final analysis)
  19. GRB030323: Detection on 2003/03/24
  20. IPN triangulation of GRB030326 (single small error box)
  21. GRB 030323: SARA Optical Observations
  22. IPN triangulation of GRB030325 (single small error box)
  23. GRB030324, optical observations
  24. GRB030324, optical observations
  25. IPN triangulation of GRB030325 (two small error boxes)
  26. GRB 030324: TAROT optical observations
  27. GRB030323: V, R, I photometry
  28. GRB 030324 (HETE #2641): Optical observations
  29. GRB030324, Optical Observations
  30. GRB030323: Upper limits from recent and historical observations.
  31. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  32. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  33. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  34. VLT/FORS2 spectra of GRB 030323
  35. GRB030323, ROTSE-III detection of possible optical counterpart
  36. GRB030323, optical observations
  37. GRB030324, BVRcIc field photometry
  38. GRB030323, possible optical counterpart
  39. GRB030323, BVRcIc field calibration
  40. GRB 030324 optical observations
  41. GRB 030320: Optical Observations
  42. GRB 030324, optical observations
  43. IPN triangulation of GRB030320B (annulus)
  44. IPN triangulation of GRB030320 (small error box)
  45. IPN triangulation of GRB030320
  46. Possible GRB 030320 localized by INTEGRAL
  47. GRB030226, addendum to GCN 1892
  48. IPN upper limit to a GRB associated with SN2003L
  49. IPN triangulation of GRB030317 (annulus)
  50. IPN triangulation of GRB030307 (annulus)
  51. GRB 030227: Optical limit at RIKEN
  52. GRB 030226 Optical observations
  53. IPN triangulation of GRB030306 (single small error box - REVISED)
  54. GRB030226: Optical observations at Asiago
  55. IPN triangulation of GRB030306 (single small error box)
  56. IPN triangulation of GRB030306 (two small error boxes)
  57. IPN triangulation of GRB030306 (intense; annulus only so far)
  58. GRB 030226: Optical observations
  59. GRB030226: Analysis of Chandra data
  60. IPN triangulation of GRB030304 (annulus)
  61. GRB 030227: Optical observations
  62. GRB030226, BVRc observations
  63. Chandra detection of the X-ray afterglow of GRB 030226
  64. GRB 030226, further optical/NIR imaging
  65. GRB030227, optical observations
  66. GRB 030226: Ic Observations
  67. GRB030227: Kiso optical upper limit
  68. IPN triangulation of GRB030301 (annulus)
  69. IPN triangulation of GRB030228 (annulus)
  70. GRB030227, BVRcIc field photometry
  71. GRB030226, BVRcIc field calibration
  72. GRB 030227 optical afterglow
  73. 030302: NOT A GRB
  74. 030228: NOT A GRB
  75. GRB 030228, optical observations
  76. GRB 030226: Steep Decline
  77. GRB 030227: Confirmed Optical Afterglow (S1-A)
  78. GRB 030226: R band polarimetric observations
  79. GRB 030226: Optical observations
  80. GRB 030227: fading of candidate optical afterglow 'S1-A'
  81. GRB030227:Optical observations
  82. GRB 20030226: Upper limits from recent and historical observations
  83. GRB 030227, possible optical counterpart of XMM-Newton source
  84. GRB030227 - faint tentative OT candidate
  85. GRB 030226, optical observations
  86. XMM-Newton observation of GRB030227
  87. GRB030227: Kiso optical observations
  88. GRB 030227: Kyoto optical observation
  89. GRB 030226, optical light curve
  90. GRB 030226 spectroscopy
  91. GRB030227: refined INTEGRAL position
  92. GRB030227 localized by INTEGRAL
  93. Possible break in the GRB 030226 light curve
  94. GRB 030226 : Predicted light curve
  95. GRB030226: optical observation
  96. IPN triangulation of GRB030225 (annulus)
  97. GRB 030226: Confirmed decay index
  98. GRB030226: ESI spectroscopy
  99. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  100. GRB 030226 simultaneous optical observations

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