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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"

35360 results found.

  1. GRB 030324, optical observations
  2. IPN triangulation of GRB030320B (annulus)
  3. IPN triangulation of GRB030320 (small error box)
  4. IPN triangulation of GRB030320
  5. Possible GRB 030320 localized by INTEGRAL
  6. IPN upper limit to a GRB associated with SN2003L
  7. IPN triangulation of GRB030317 (annulus)
  8. IPN triangulation of GRB030307 (annulus)
  9. GRB 030227: Optical limit at RIKEN
  10. GRB 030226 Optical observations
  11. IPN triangulation of GRB030306 (single small error box - REVISED)
  12. GRB030226: Optical observations at Asiago
  13. IPN triangulation of GRB030306 (single small error box)
  14. IPN triangulation of GRB030306 (two small error boxes)
  15. IPN triangulation of GRB030306 (intense; annulus only so far)
  16. GRB 030226: Optical observations
  17. IPN triangulation of GRB030304 (annulus)
  18. GRB 030227: Optical observations
  19. GRB030226, BVRc observations
  20. Chandra detection of the X-ray afterglow of GRB 030226
  21. GRB 030226, further optical/NIR imaging
  22. GRB030227, optical observations
  23. GRB 030226: Ic Observations
  24. GRB030227: Kiso optical upper limit
  25. IPN triangulation of GRB030301 (annulus)
  26. IPN triangulation of GRB030228 (annulus)
  27. GRB030227, BVRcIc field photometry
  28. GRB030226, BVRcIc field calibration
  29. GRB 030227 optical afterglow
  30. 030302: NOT A GRB
  31. 030228: NOT A GRB
  32. GRB 030228, optical observations
  33. GRB 030226: Steep Decline
  34. GRB 030227: Confirmed Optical Afterglow (S1-A)
  35. GRB 030226: R band polarimetric observations
  36. GRB 030226: Optical observations
  37. GRB 030227: fading of candidate optical afterglow 'S1-A'
  38. GRB030227:Optical observations
  39. GRB 20030226: Upper limits from recent and historical observations
  40. GRB 030227, possible optical counterpart of XMM-Newton source
  41. GRB030227 - faint tentative OT candidate
  42. GRB 030226, optical observations
  43. GRB030227: Kiso optical observations
  44. GRB 030227: Kyoto optical observation
  45. GRB 030226, optical light curve
  46. GRB 030226 spectroscopy
  47. Possible break in the GRB 030226 light curve
  48. GRB 030226 : Predicted light curve
  49. IPN triangulation of GRB030225 (annulus)
  50. GRB 030226: Confirmed decay index
  51. GRB030226: ESI spectroscopy
  52. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  53. GRB 030226 simultaneous optical observations
  54. Two absorption systems in GRB 030226
  55. GRB 030226, optical observations
  56. GRB 030226 Optical Spectra and R,I,z' Imaging
  57. GRB 030226, optical observations
  58. GRB 030226: Optical afterglow
  59. GRB 030217: Optical Observations at 4, 5, and 6 Days
  60. IPN triangulation of GRB030223 (annulus)
  61. IPN triangulation of GRB030220 (annulus)
  62. GRB: Non-Referencing of GCN Circulars.
  63. IPN triangulation of GRB030218 (annulus)
  64. IPN triangulation of GRB030217 (small error box)
  65. IPN triangulation of GRB030215C (annulus)
  66. IPN triangulation of GRB030217 (annulus)
  67. IPN triangulation of GRB030216 (annulus)
  68. IPN triangulation of GRB030215A and GRB030215B (annuli)
  69. GRB030115, WSRT radio observations - correction to GCN 1864
  70. GRB 030131: marginal optical detection
  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. GRB 030115: Optical Observations
  79. GRB 030204, optical observations
  80. IPN triangulation of GRB030204 (small error box)
  81. IPN triangulation of GRB030202 (annulus)
  82. GRB 030131, optical observations
  83. GRB030131: Kiso optical limit for corrected position
  84. GRB030131: Optical limits for corrected position
  85. GRB 030131: afterglow candidate
  86. GRB 030115, late-time optical observations
  87. GRB030131: corrected INTEGRAL position
  88. Type Ic SN2003L (SN/GRB?), optical spectrum
  89. GRB030131: Kiso Observations
  90. GRB 020819: Host galaxy at Radio Position
  91. IPN triangulation of GRB030131 - CORRECTION
  92. GRB 020819: afterglow candidate
  93. IPN triangulation of GRB030131
  94. GRB 030131 optical observations
  95. GRB 030131 optical observations
  96. A long GRB detected by INTEGRAL
  97. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  98. Type Ic SN2003L (SN/GRB?) Radio Observations
  99. IPN triangulation of GRB030127 (annulus)
  100. GRB030115 submm upper limit

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