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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"

35993 results found.

  1. GRB 030329: Optical afterglow candidate
  2. GRB 030328: OT photometry
  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. GRB030131, BVRcIc field photometry
  12. Possible GRB030323 localized by INTEGRAL
  13. IPN triangulation of GRB030325 (final analysis)
  14. IPN triangulation of GRB030326 (single small error box)
  15. GRB 030323: SARA Optical Observations
  16. IPN triangulation of GRB030325 (single small error box)
  17. GRB030324, optical observations
  18. IPN triangulation of GRB030325 (two small error boxes)
  19. GRB 030324: TAROT optical observations
  20. GRB 030324 (HETE #2641): Optical observations
  21. GRB030324, Optical Observations
  22. GRB030323: Upper limits from recent and historical observations.
  23. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  24. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  25. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  26. VLT/FORS2 spectra of GRB 030323
  27. GRB030323, ROTSE-III detection of possible optical counterpart
  28. GRB030323, optical observations
  29. GRB030324, BVRcIc field photometry
  30. GRB030323, possible optical counterpart
  31. GRB030323, BVRcIc field calibration
  32. GRB 030324 optical observations
  33. GRB 030320: Optical Observations
  34. GRB 030324, optical observations
  35. IPN triangulation of GRB030320B (annulus)
  36. IPN triangulation of GRB030320 (small error box)
  37. IPN triangulation of GRB030320
  38. Possible GRB 030320 localized by INTEGRAL
  39. IPN upper limit to a GRB associated with SN2003L
  40. IPN triangulation of GRB030317 (annulus)
  41. IPN triangulation of GRB030307 (annulus)
  42. GRB 030227: Optical limit at RIKEN
  43. GRB 030226 Optical observations
  44. IPN triangulation of GRB030306 (single small error box - REVISED)
  45. GRB030226: Optical observations at Asiago
  46. IPN triangulation of GRB030306 (single small error box)
  47. IPN triangulation of GRB030306 (two small error boxes)
  48. IPN triangulation of GRB030306 (intense; annulus only so far)
  49. GRB 030226: Optical observations
  50. IPN triangulation of GRB030304 (annulus)
  51. GRB 030227: Optical observations
  52. GRB030226, BVRc observations
  53. Chandra detection of the X-ray afterglow of GRB 030226
  54. GRB 030226, further optical/NIR imaging
  55. GRB030227, optical observations
  56. GRB 030226: Ic Observations
  57. GRB030227: Kiso optical upper limit
  58. IPN triangulation of GRB030301 (annulus)
  59. IPN triangulation of GRB030228 (annulus)
  60. GRB030227, BVRcIc field photometry
  61. GRB030226, BVRcIc field calibration
  62. GRB 030227 optical afterglow
  63. 030302: NOT A GRB
  64. 030228: NOT A GRB
  65. GRB 030228, optical observations
  66. GRB 030226: Steep Decline
  67. GRB 030227: Confirmed Optical Afterglow (S1-A)
  68. GRB 030226: R band polarimetric observations
  69. GRB 030226: Optical observations
  70. GRB 030227: fading of candidate optical afterglow 'S1-A'
  71. GRB030227:Optical observations
  72. GRB 20030226: Upper limits from recent and historical observations
  73. GRB 030227, possible optical counterpart of XMM-Newton source
  74. GRB030227 - faint tentative OT candidate
  75. GRB 030226, optical observations
  76. GRB030227: Kiso optical observations
  77. GRB 030227: Kyoto optical observation
  78. GRB 030226, optical light curve
  79. GRB 030226 spectroscopy
  80. Possible break in the GRB 030226 light curve
  81. GRB 030226 : Predicted light curve
  82. IPN triangulation of GRB030225 (annulus)
  83. GRB 030226: Confirmed decay index
  84. GRB030226: ESI spectroscopy
  85. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  86. GRB 030226 simultaneous optical observations
  87. Two absorption systems in GRB 030226
  88. GRB 030226, optical observations
  89. GRB 030226 Optical Spectra and R,I,z' Imaging
  90. GRB 030226, optical observations
  91. GRB 030226: Optical afterglow
  92. GRB 030217: Optical Observations at 4, 5, and 6 Days
  93. IPN triangulation of GRB030223 (annulus)
  94. IPN triangulation of GRB030220 (annulus)
  95. GRB: Non-Referencing of GCN Circulars.
  96. IPN triangulation of GRB030218 (annulus)
  97. IPN triangulation of GRB030217 (small error box)
  98. IPN triangulation of GRB030215C (annulus)
  99. IPN triangulation of GRB030217 (annulus)
  100. IPN triangulation of GRB030216 (annulus)

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