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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"

45431 results found.

  1. GRB030323: Upper limits from recent and historical observations.
  2. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  3. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  4. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  5. VLT/FORS2 spectra of GRB 030323
  6. GRB030323, ROTSE-III detection of possible optical counterpart
  7. GRB030323, optical observations
  8. GRB030324, BVRcIc field photometry
  9. GRB030323, possible optical counterpart
  10. GRB030323, BVRcIc field calibration
  11. GRB 030324 optical observations
  12. GRB 030320: Optical Observations
  13. GRB 030324, optical observations
  14. IPN triangulation of GRB030320B (annulus)
  15. IPN triangulation of GRB030320 (small error box)
  16. IPN triangulation of GRB030320
  17. Possible GRB 030320 localized by INTEGRAL
  18. GRB030226, addendum to GCN 1892
  19. IPN upper limit to a GRB associated with SN2003L
  20. IPN triangulation of GRB030317 (annulus)
  21. IPN triangulation of GRB030307 (annulus)
  22. GRB 030227: Optical limit at RIKEN
  23. GRB 030226 Optical observations
  24. IPN triangulation of GRB030306 (single small error box - REVISED)
  25. GRB030226: Optical observations at Asiago
  26. IPN triangulation of GRB030306 (single small error box)
  27. IPN triangulation of GRB030306 (two small error boxes)
  28. IPN triangulation of GRB030306 (intense; annulus only so far)
  29. GRB 030226: Optical observations
  30. GRB030226: Analysis of Chandra data
  31. IPN triangulation of GRB030304 (annulus)
  32. GRB 030227: Optical observations
  33. GRB030226, BVRc observations
  34. Chandra detection of the X-ray afterglow of GRB 030226
  35. GRB 030226, further optical/NIR imaging
  36. GRB030227, optical observations
  37. GRB 030226: Ic Observations
  38. GRB030227: Kiso optical upper limit
  39. IPN triangulation of GRB030301 (annulus)
  40. IPN triangulation of GRB030228 (annulus)
  41. GRB030227, BVRcIc field photometry
  42. GRB030226, BVRcIc field calibration
  43. 030302: NOT A GRB
  44. 030228: NOT A GRB
  45. GRB 030228, optical observations
  46. GRB 030226: Steep Decline
  47. GRB 030227: Confirmed Optical Afterglow (S1-A)
  48. GRB 030226: R band polarimetric observations
  49. GRB 030226: Optical observations
  50. GRB 030227: fading of candidate optical afterglow 'S1-A'
  51. GRB030227:Optical observations
  52. GRB 20030226: Upper limits from recent and historical observations
  53. GRB 030227, possible optical counterpart of XMM-Newton source
  54. GRB030227 - faint tentative OT candidate
  55. GRB 030226, optical observations
  56. XMM-Newton observation of GRB030227
  57. GRB030227: Kiso optical observations
  58. GRB 030227: Kyoto optical observation
  59. GRB 030226, optical light curve
  60. GRB 030226 spectroscopy
  61. GRB030227: refined INTEGRAL position
  62. GRB030227 localized by INTEGRAL
  63. Possible break in the GRB 030226 light curve
  64. GRB 030226 : Predicted light curve
  65. GRB030226: optical observation
  66. IPN triangulation of GRB030225 (annulus)
  67. GRB 030226: Confirmed decay index
  68. GRB030226: ESI spectroscopy
  69. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  70. GRB 030226 simultaneous optical observations
  71. Two absorption systems in GRB 030226
  72. GRB 030226, optical observations
  73. GRB030226: optical observations and refined redshift
  74. GRB030226: Optical decay index
  75. GRB 030226 Optical Spectra and R,I,z' Imaging
  76. GRB 030226, optical observations
  77. GRB 030226: Optical afterglow
  78. GRB030226: Candidate optical afterglow
  79. GRB 030217: Optical Observations at 4, 5, and 6 Days
  80. IPN triangulation of GRB030223 (annulus)
  81. IPN triangulation of GRB030220 (annulus)
  82. GRB: Non-Referencing of GCN Circulars.
  83. IPN triangulation of GRB030218 (annulus)
  84. GRB030217: optical observations
  85. IPN triangulation of GRB030217 (small error box)
  86. IPN triangulation of GRB030215C (annulus)
  87. IPN triangulation of GRB030217 (annulus)
  88. IPN triangulation of GRB030216 (annulus)
  89. IPN triangulation of GRB030215A and GRB030215B (annuli)
  90. GRB030115, WSRT radio observations - correction to GCN 1864
  91. GRB 030131: marginal optical detection
  92. GCN/INTEGRAL Mistake Fixed
  93. GRB030115, WSRT radio observations
  94. IPN triangulation of GRB030206 (annulus)
  95. IPN triangulation of GRB030208 (annulus)
  96. GRB 030204: Optical Observations
  97. GRB030204 field photometry
  98. GRB020819: Kiso R and I band observations
  99. GRB030131: Candidate Optical Afterglow
  100. GRB 030115: Optical Observations

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