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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"

36784 results found.

  1. GRB 030328: Optical afterglow candidate
  2. GRB030131, BVRcIc field photometry
  3. Possible GRB030323 localized by INTEGRAL
  4. IPN triangulation of GRB030325 (final analysis)
  5. IPN triangulation of GRB030326 (single small error box)
  6. GRB 030323: SARA Optical Observations
  7. IPN triangulation of GRB030325 (single small error box)
  8. GRB030324, optical observations
  9. IPN triangulation of GRB030325 (two small error boxes)
  10. GRB 030324: TAROT optical observations
  11. GRB 030324 (HETE #2641): Optical observations
  12. GRB030324, Optical Observations
  13. GRB030323: Upper limits from recent and historical observations.
  14. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  15. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  16. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  17. VLT/FORS2 spectra of GRB 030323
  18. GRB030323, ROTSE-III detection of possible optical counterpart
  19. GRB030323, optical observations
  20. GRB030324, BVRcIc field photometry
  21. GRB030323, possible optical counterpart
  22. GRB030323, BVRcIc field calibration
  23. GRB 030324 optical observations
  24. GRB 030320: Optical Observations
  25. GRB 030324, optical observations
  26. IPN triangulation of GRB030320B (annulus)
  27. IPN triangulation of GRB030320 (small error box)
  28. IPN triangulation of GRB030320
  29. Possible GRB 030320 localized by INTEGRAL
  30. IPN upper limit to a GRB associated with SN2003L
  31. IPN triangulation of GRB030317 (annulus)
  32. IPN triangulation of GRB030307 (annulus)
  33. GRB 030227: Optical limit at RIKEN
  34. GRB 030226 Optical observations
  35. IPN triangulation of GRB030306 (single small error box - REVISED)
  36. GRB030226: Optical observations at Asiago
  37. IPN triangulation of GRB030306 (single small error box)
  38. IPN triangulation of GRB030306 (two small error boxes)
  39. IPN triangulation of GRB030306 (intense; annulus only so far)
  40. GRB 030226: Optical observations
  41. IPN triangulation of GRB030304 (annulus)
  42. GRB 030227: Optical observations
  43. GRB030226, BVRc observations
  44. Chandra detection of the X-ray afterglow of GRB 030226
  45. GRB 030226, further optical/NIR imaging
  46. GRB030227, optical observations
  47. GRB 030226: Ic Observations
  48. GRB030227: Kiso optical upper limit
  49. IPN triangulation of GRB030301 (annulus)
  50. IPN triangulation of GRB030228 (annulus)
  51. GRB030227, BVRcIc field photometry
  52. GRB030226, BVRcIc field calibration
  53. GRB 030227 optical afterglow
  54. 030302: NOT A GRB
  55. 030228: NOT A GRB
  56. GRB 030228, optical observations
  57. GRB 030226: Steep Decline
  58. GRB 030227: Confirmed Optical Afterglow (S1-A)
  59. GRB 030226: R band polarimetric observations
  60. GRB 030226: Optical observations
  61. GRB 030227: fading of candidate optical afterglow 'S1-A'
  62. GRB030227:Optical observations
  63. GRB 20030226: Upper limits from recent and historical observations
  64. GRB 030227, possible optical counterpart of XMM-Newton source
  65. GRB030227 - faint tentative OT candidate
  66. GRB 030226, optical observations
  67. GRB030227: Kiso optical observations
  68. GRB 030227: Kyoto optical observation
  69. GRB 030226, optical light curve
  70. GRB 030226 spectroscopy
  71. Possible break in the GRB 030226 light curve
  72. GRB 030226 : Predicted light curve
  73. IPN triangulation of GRB030225 (annulus)
  74. GRB 030226: Confirmed decay index
  75. GRB030226: ESI spectroscopy
  76. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  77. GRB 030226 simultaneous optical observations
  78. Two absorption systems in GRB 030226
  79. GRB 030226, optical observations
  80. GRB 030226 Optical Spectra and R,I,z' Imaging
  81. GRB 030226, optical observations
  82. GRB 030226: Optical afterglow
  83. GRB 030217: Optical Observations at 4, 5, and 6 Days
  84. IPN triangulation of GRB030223 (annulus)
  85. IPN triangulation of GRB030220 (annulus)
  86. GRB: Non-Referencing of GCN Circulars.
  87. IPN triangulation of GRB030218 (annulus)
  88. IPN triangulation of GRB030217 (small error box)
  89. IPN triangulation of GRB030215C (annulus)
  90. IPN triangulation of GRB030217 (annulus)
  91. IPN triangulation of GRB030216 (annulus)
  92. IPN triangulation of GRB030215A and GRB030215B (annuli)
  93. GRB030115, WSRT radio observations - correction to GCN 1864
  94. GRB 030131: marginal optical detection
  95. GRB030115, WSRT radio observations
  96. IPN triangulation of GRB030206 (annulus)
  97. IPN triangulation of GRB030208 (annulus)
  98. GRB 030204: Optical Observations
  99. GRB030204 field photometry
  100. GRB020819: Kiso R and I band observations

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