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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"
  1. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  2. VLT/FORS2 spectra of GRB 030323
  3. GRB030323, ROTSE-III detection of possible optical counterpart
  4. GRB030323, optical observations
  5. GRB030324, BVRcIc field photometry
  6. GRB030323, possible optical counterpart
  7. GRB030323, BVRcIc field calibration
  8. GRB 030324 optical observations
  9. GRB 030320: Optical Observations
  10. GRB 030324, optical observations
  11. IPN triangulation of GRB030320B (annulus)
  12. IPN triangulation of GRB030320 (small error box)
  13. IPN triangulation of GRB030320
  14. Possible GRB 030320 localized by INTEGRAL
  15. GRB030226, addendum to GCN 1892
  16. IPN upper limit to a GRB associated with SN2003L
  17. IPN triangulation of GRB030317 (annulus)
  18. IPN triangulation of GRB030307 (annulus)
  19. GRB 030227: Optical limit at RIKEN
  20. GRB 030226 Optical observations
  21. IPN triangulation of GRB030306 (single small error box - REVISED)
  22. GRB030226: Optical observations at Asiago
  23. IPN triangulation of GRB030306 (single small error box)
  24. IPN triangulation of GRB030306 (two small error boxes)
  25. IPN triangulation of GRB030306 (intense; annulus only so far)
  26. GRB 030226: Optical observations
  27. GRB030226: Analysis of Chandra data
  28. IPN triangulation of GRB030304 (annulus)
  29. GRB 030227: Optical observations
  30. GRB030226, BVRc observations
  31. Chandra detection of the X-ray afterglow of GRB 030226
  32. GRB 030226, further optical/NIR imaging
  33. GRB030227, optical observations
  34. GRB 030226: Ic Observations
  35. GRB030227: Kiso optical upper limit
  36. IPN triangulation of GRB030301 (annulus)
  37. IPN triangulation of GRB030228 (annulus)
  38. GRB030227, BVRcIc field photometry
  39. GRB030226, BVRcIc field calibration
  40. GRB 030227 optical afterglow
  41. 030302: NOT A GRB
  42. 030228: NOT A GRB
  43. GRB 030228, optical observations
  44. GRB 030226: Steep Decline
  45. GRB 030227: Confirmed Optical Afterglow (S1-A)
  46. GRB 030226: R band polarimetric observations
  47. GRB 030226: Optical observations
  48. GRB 030227: fading of candidate optical afterglow 'S1-A'
  49. GRB030227:Optical observations
  50. GRB 20030226: Upper limits from recent and historical observations
  51. GRB 030227, possible optical counterpart of XMM-Newton source
  52. GRB030227 - faint tentative OT candidate
  53. GRB 030226, optical observations
  54. XMM-Newton observation of GRB030227
  55. GRB030227: Kiso optical observations
  56. GRB 030227: Kyoto optical observation
  57. GRB 030226, optical light curve
  58. GRB 030226 spectroscopy
  59. GRB030227: refined INTEGRAL position
  60. GRB030227 localized by INTEGRAL
  61. Possible break in the GRB 030226 light curve
  62. GRB 030226 : Predicted light curve
  63. GRB030226: optical observation
  64. IPN triangulation of GRB030225 (annulus)
  65. GRB 030226: Confirmed decay index
  66. GRB030226: ESI spectroscopy
  67. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  68. GRB 030226 simultaneous optical observations
  69. Two absorption systems in GRB 030226
  70. GRB 030226, optical observations
  71. GRB030226: optical observations and refined redshift
  72. GRB030226: Optical decay index
  73. GRB 030226 Optical Spectra and R,I,z' Imaging
  74. GRB 030226, optical observations
  75. GRB 030226: Optical afterglow
  76. GRB030226: Candidate optical afterglow
  77. GRB 030217: Optical Observations at 4, 5, and 6 Days
  78. IPN triangulation of GRB030223 (annulus)
  79. IPN triangulation of GRB030220 (annulus)
  80. GRB: Non-Referencing of GCN Circulars.
  81. IPN triangulation of GRB030218 (annulus)
  82. GRB030217: optical observations
  83. IPN triangulation of GRB030217 (small error box)
  84. IPN triangulation of GRB030215C (annulus)
  85. IPN triangulation of GRB030217 (annulus)
  86. IPN triangulation of GRB030216 (annulus)
  87. IPN triangulation of GRB030215A and GRB030215B (annuli)
  88. GRB030115, WSRT radio observations - correction to GCN 1864
  89. GRB 030131: marginal optical detection
  90. GCN/INTEGRAL Mistake Fixed
  91. GRB030115, WSRT radio observations
  92. IPN triangulation of GRB030206 (annulus)
  93. IPN triangulation of GRB030208 (annulus)
  94. GRB 030204: Optical Observations
  95. GRB030204 field photometry
  96. GRB020819: Kiso R and I band observations
  97. GRB 030204: Correction to GCN 1856
  98. GRB030131: Candidate Optical Afterglow
  99. GRB 030115: Optical Observations
  100. GRB 030204, optical observations

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