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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"

37146 results found.

  1. GRB 030329: Optical afterglow candidate
  2. GRB 030329: OT candidate
  3. GRB 030329: Optical afterglow candidate
  4. GRB 030328: OT photometry
  5. VLT spectra of GRB 030328
  6. GRB 030328, optical spectroscopy
  7. GRB 030328, optical observations
  8. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  9. GRB 030328: Optical observations
  10. Re: GRB 030328: Finding chart
  11. GRB 030328: Finding chart
  12. GRB 030328: Optical afterglow candidate
  13. GRB030131, BVRcIc field photometry
  14. Possible GRB030323 localized by INTEGRAL
  15. IPN triangulation of GRB030325 (final analysis)
  16. IPN triangulation of GRB030326 (single small error box)
  17. GRB 030323: SARA Optical Observations
  18. IPN triangulation of GRB030325 (single small error box)
  19. GRB030324, optical observations
  20. GRB030324, optical observations
  21. IPN triangulation of GRB030325 (two small error boxes)
  22. GRB 030324: TAROT optical observations
  23. GRB 030324 (HETE #2641): Optical observations
  24. GRB030324, Optical Observations
  25. GRB030323: Upper limits from recent and historical observations.
  26. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  27. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  28. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  29. VLT/FORS2 spectra of GRB 030323
  30. GRB030323, ROTSE-III detection of possible optical counterpart
  31. GRB030323, optical observations
  32. GRB030324, BVRcIc field photometry
  33. GRB030323, possible optical counterpart
  34. GRB030323, BVRcIc field calibration
  35. GRB 030324 optical observations
  36. GRB 030320: Optical Observations
  37. GRB 030324, optical observations
  38. IPN triangulation of GRB030320B (annulus)
  39. IPN triangulation of GRB030320 (small error box)
  40. IPN triangulation of GRB030320
  41. Possible GRB 030320 localized by INTEGRAL
  42. IPN upper limit to a GRB associated with SN2003L
  43. IPN triangulation of GRB030317 (annulus)
  44. IPN triangulation of GRB030307 (annulus)
  45. GRB 030227: Optical limit at RIKEN
  46. GRB 030226 Optical observations
  47. IPN triangulation of GRB030306 (single small error box - REVISED)
  48. GRB030226: Optical observations at Asiago
  49. IPN triangulation of GRB030306 (single small error box)
  50. IPN triangulation of GRB030306 (two small error boxes)
  51. IPN triangulation of GRB030306 (intense; annulus only so far)
  52. GRB 030226: Optical observations
  53. IPN triangulation of GRB030304 (annulus)
  54. GRB 030227: Optical observations
  55. GRB030226, BVRc observations
  56. Chandra detection of the X-ray afterglow of GRB 030226
  57. GRB 030226, further optical/NIR imaging
  58. GRB030227, optical observations
  59. GRB 030226: Ic Observations
  60. GRB030227: Kiso optical upper limit
  61. IPN triangulation of GRB030301 (annulus)
  62. IPN triangulation of GRB030228 (annulus)
  63. GRB030227, BVRcIc field photometry
  64. GRB030226, BVRcIc field calibration
  65. GRB 030227 optical afterglow
  66. 030302: NOT A GRB
  67. 030228: NOT A GRB
  68. GRB 030228, optical observations
  69. GRB 030226: Steep Decline
  70. GRB 030227: Confirmed Optical Afterglow (S1-A)
  71. GRB 030226: R band polarimetric observations
  72. GRB 030226: Optical observations
  73. GRB 030227: fading of candidate optical afterglow 'S1-A'
  74. GRB030227:Optical observations
  75. GRB 20030226: Upper limits from recent and historical observations
  76. GRB 030227, possible optical counterpart of XMM-Newton source
  77. GRB030227 - faint tentative OT candidate
  78. GRB 030226, optical observations
  79. GRB030227: Kiso optical observations
  80. GRB 030227: Kyoto optical observation
  81. GRB 030226, optical light curve
  82. GRB 030226 spectroscopy
  83. Possible break in the GRB 030226 light curve
  84. GRB 030226 : Predicted light curve
  85. IPN triangulation of GRB030225 (annulus)
  86. GRB 030226: Confirmed decay index
  87. GRB030226: ESI spectroscopy
  88. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  89. GRB 030226 simultaneous optical observations
  90. Two absorption systems in GRB 030226
  91. GRB 030226, optical observations
  92. GRB 030226 Optical Spectra and R,I,z' Imaging
  93. GRB 030226, optical observations
  94. GRB 030226: Optical afterglow
  95. GRB 030217: Optical Observations at 4, 5, and 6 Days
  96. IPN triangulation of GRB030223 (annulus)
  97. IPN triangulation of GRB030220 (annulus)
  98. GRB: Non-Referencing of GCN Circulars.
  99. IPN triangulation of GRB030218 (annulus)
  100. IPN triangulation of GRB030217 (small error box)

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