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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"

32801 results found.

  1. GRB 030329: Optical afterglow fading
  2. GRB 030329 follow-up
  3. GRB 030329: Optical afterglow candidate
  4. GRB 030329: OT candidate
  5. GRB 030329: Optical afterglow candidate
  6. GRB 030328: OT photometry
  7. VLT spectra of GRB 030328
  8. GRB 030328, optical spectroscopy
  9. GRB 030328, optical observations
  10. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  11. GRB 030328: Optical observations
  12. Re: GRB 030328: Finding chart
  13. GRB 030328: Finding chart
  14. GRB 030328: Optical afterglow candidate
  15. GRB030131, BVRcIc field photometry
  16. Possible GRB030323 localized by INTEGRAL
  17. IPN triangulation of GRB030325 (final analysis)
  18. IPN triangulation of GRB030326 (single small error box)
  19. GRB 030323: SARA Optical Observations
  20. IPN triangulation of GRB030325 (single small error box)
  21. GRB030324, optical observations
  22. IPN triangulation of GRB030325 (two small error boxes)
  23. GRB 030324: TAROT optical observations
  24. GRB 030324 (HETE #2641): Optical observations
  25. GRB030324, Optical Observations
  26. GRB030323: Upper limits from recent and historical observations.
  27. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  28. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  29. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  30. VLT/FORS2 spectra of GRB 030323
  31. GRB030323, ROTSE-III detection of possible optical counterpart
  32. GRB030323, optical observations
  33. GRB030324, BVRcIc field photometry
  34. GRB030323, possible optical counterpart
  35. GRB030323, BVRcIc field calibration
  36. GRB 030324 optical observations
  37. GRB 030320: Optical Observations
  38. GRB 030324, optical observations
  39. IPN triangulation of GRB030320B (annulus)
  40. IPN triangulation of GRB030320 (small error box)
  41. IPN triangulation of GRB030320
  42. Possible GRB 030320 localized by INTEGRAL
  43. IPN upper limit to a GRB associated with SN2003L
  44. IPN triangulation of GRB030317 (annulus)
  45. IPN triangulation of GRB030307 (annulus)
  46. GRB 030227: Optical limit at RIKEN
  47. GRB 030226 Optical observations
  48. IPN triangulation of GRB030306 (single small error box - REVISED)
  49. GRB030226: Optical observations at Asiago
  50. IPN triangulation of GRB030306 (single small error box)
  51. IPN triangulation of GRB030306 (two small error boxes)
  52. IPN triangulation of GRB030306 (intense; annulus only so far)
  53. GRB 030226: Optical observations
  54. IPN triangulation of GRB030304 (annulus)
  55. GRB 030227: Optical observations
  56. GRB030226, BVRc observations
  57. Chandra detection of the X-ray afterglow of GRB 030226
  58. GRB 030226, further optical/NIR imaging
  59. GRB030227, optical observations
  60. GRB 030226: Ic Observations
  61. GRB030227: Kiso optical upper limit
  62. IPN triangulation of GRB030301 (annulus)
  63. IPN triangulation of GRB030228 (annulus)
  64. GRB030227, BVRcIc field photometry
  65. GRB030226, BVRcIc field calibration
  66. GRB 030227 optical afterglow
  67. 030302: NOT A GRB
  68. 030228: NOT A GRB
  69. GRB 030228, optical observations
  70. GRB 030226: Steep Decline
  71. GRB 030227: Confirmed Optical Afterglow (S1-A)
  72. GRB 030226: R band polarimetric observations
  73. GRB 030226: Optical observations
  74. GRB 030227: fading of candidate optical afterglow 'S1-A'
  75. GRB030227:Optical observations
  76. GRB 20030226: Upper limits from recent and historical observations
  77. GRB 030227, possible optical counterpart of XMM-Newton source
  78. GRB030227 - faint tentative OT candidate
  79. GRB 030226, optical observations
  80. GRB030227: Kiso optical observations
  81. GRB 030227: Kyoto optical observation
  82. GRB 030226, optical light curve
  83. GRB 030226 spectroscopy
  84. Possible break in the GRB 030226 light curve
  85. GRB 030226 : Predicted light curve
  86. IPN triangulation of GRB030225 (annulus)
  87. GRB 030226: Confirmed decay index
  88. GRB030226: ESI spectroscopy
  89. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  90. GRB 030226 simultaneous optical observations
  91. Two absorption systems in GRB 030226
  92. GRB 030226, optical observations
  93. GRB 030226 Optical Spectra and R,I,z' Imaging
  94. GRB 030226, optical observations
  95. GRB 030226: Optical afterglow
  96. GRB 030217: Optical Observations at 4, 5, and 6 Days
  97. IPN triangulation of GRB030223 (annulus)
  98. IPN triangulation of GRB030220 (annulus)
  99. GRB: Non-Referencing of GCN Circulars.
  100. IPN triangulation of GRB030218 (annulus)

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