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

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