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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. IPN triangulation of GRB030306 (single small error box - REVISED)
  2. GRB030226: Optical observations at Asiago
  3. IPN triangulation of GRB030306 (single small error box)
  4. IPN triangulation of GRB030306 (two small error boxes)
  5. IPN triangulation of GRB030306 (intense; annulus only so far)
  6. GRB 030226: Optical observations
  7. GRB030226: Analysis of Chandra data
  8. IPN triangulation of GRB030304 (annulus)
  9. GRB 030227: Optical observations
  10. GRB030226, BVRc observations
  11. Chandra detection of the X-ray afterglow of GRB 030226
  12. GRB 030226, further optical/NIR imaging
  13. GRB030227, optical observations
  14. GRB 030226: Ic Observations
  15. GRB030227: Kiso optical upper limit
  16. IPN triangulation of GRB030301 (annulus)
  17. IPN triangulation of GRB030228 (annulus)
  18. GRB030227, BVRcIc field photometry
  19. GRB030226, BVRcIc field calibration
  20. GRB 030227 optical afterglow
  21. 030302: NOT A GRB
  22. 030228: NOT A GRB
  23. GRB 030228, optical observations
  24. GRB 030226: Steep Decline
  25. GRB 030227: Confirmed Optical Afterglow (S1-A)
  26. GRB 030226: R band polarimetric observations
  27. GRB 030226: Optical observations
  28. GRB 030227: fading of candidate optical afterglow 'S1-A'
  29. GRB030227:Optical observations
  30. GRB 20030226: Upper limits from recent and historical observations
  31. GRB 030227, possible optical counterpart of XMM-Newton source
  32. GRB030227 - faint tentative OT candidate
  33. GRB 030226, optical observations
  34. XMM-Newton observation of GRB030227
  35. GRB030227: Kiso optical observations
  36. GRB 030227: Kyoto optical observation
  37. GRB 030226, optical light curve
  38. GRB 030226 spectroscopy
  39. GRB030227: refined INTEGRAL position
  40. GRB030227 localized by INTEGRAL
  41. Possible break in the GRB 030226 light curve
  42. GRB 030226 : Predicted light curve
  43. GRB030226: optical observation
  44. IPN triangulation of GRB030225 (annulus)
  45. GRB 030226: Confirmed decay index
  46. GRB030226: ESI spectroscopy
  47. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  48. GRB 030226 simultaneous optical observations
  49. Two absorption systems in GRB 030226
  50. GRB 030226, optical observations
  51. GRB030226: optical observations and refined redshift
  52. GRB030226: Optical decay index
  53. GRB 030226 Optical Spectra and R,I,z' Imaging
  54. GRB 030226, optical observations
  55. GRB 030226: Optical afterglow
  56. GRB030226: Candidate optical afterglow
  57. GRB 030217: Optical Observations at 4, 5, and 6 Days
  58. IPN triangulation of GRB030223 (annulus)
  59. IPN triangulation of GRB030220 (annulus)
  60. GRB: Non-Referencing of GCN Circulars.
  61. IPN triangulation of GRB030218 (annulus)
  62. GRB030217: optical observations
  63. IPN triangulation of GRB030217 (small error box)
  64. IPN triangulation of GRB030215C (annulus)
  65. IPN triangulation of GRB030217 (annulus)
  66. IPN triangulation of GRB030216 (annulus)
  67. IPN triangulation of GRB030215A and GRB030215B (annuli)
  68. GRB030115, WSRT radio observations - correction to GCN 1864
  69. GRB 030131: marginal optical detection
  70. GCN/INTEGRAL Mistake Fixed
  71. GRB030115, WSRT radio observations
  72. IPN triangulation of GRB030206 (annulus)
  73. IPN triangulation of GRB030208 (annulus)
  74. GRB 030204: Optical Observations
  75. GRB030204 field photometry
  76. GRB020819: Kiso R and I band observations
  77. GRB 030204: Correction to GCN 1856
  78. GRB030131: Candidate Optical Afterglow
  79. GRB 030115: Optical Observations
  80. GRB 030204, optical observations
  81. IPN triangulation of GRB030204 (small error box)
  82. IPN triangulation of GRB030202 (annulus)
  83. GRB 030131, optical observations
  84. GRB030131: Kiso optical limit for corrected position
  85. GRB030131: Optical limits for corrected position
  86. GRB 030131: afterglow candidate
  87. GRB 030115, late-time optical observations
  88. GRB030131: corrected INTEGRAL position
  89. Type Ic SN2003L (SN/GRB?), optical spectrum
  90. GRB030131: Kiso Observations
  91. GRB 020819: Host galaxy at Radio Position
  92. IPN triangulation of GRB030131 - CORRECTION
  93. GRB 020819: afterglow candidate
  94. IPN triangulation of GRB030131
  95. GRB030131: Optical limit
  96. GRB 030131 optical observations
  97. GRB030131: refined position
  98. GRB 030131 optical observations
  99. A long GRB detected by INTEGRAL
  100. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m

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