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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"

35956 results found.

  1. Possible GRB 030320 localized by INTEGRAL
  2. IPN upper limit to a GRB associated with SN2003L
  3. IPN triangulation of GRB030317 (annulus)
  4. IPN triangulation of GRB030307 (annulus)
  5. GRB 030227: Optical limit at RIKEN
  6. GRB 030226 Optical observations
  7. IPN triangulation of GRB030306 (single small error box - REVISED)
  8. GRB030226: Optical observations at Asiago
  9. IPN triangulation of GRB030306 (single small error box)
  10. IPN triangulation of GRB030306 (two small error boxes)
  11. IPN triangulation of GRB030306 (intense; annulus only so far)
  12. GRB 030226: Optical observations
  13. IPN triangulation of GRB030304 (annulus)
  14. GRB 030227: Optical observations
  15. GRB030226, BVRc observations
  16. Chandra detection of the X-ray afterglow of GRB 030226
  17. GRB 030226, further optical/NIR imaging
  18. GRB030227, optical observations
  19. GRB 030226: Ic Observations
  20. GRB030227: Kiso optical upper limit
  21. IPN triangulation of GRB030301 (annulus)
  22. IPN triangulation of GRB030228 (annulus)
  23. GRB030227, BVRcIc field photometry
  24. GRB030226, BVRcIc field calibration
  25. GRB 030227 optical afterglow
  26. 030302: NOT A GRB
  27. 030228: NOT A GRB
  28. GRB 030228, optical observations
  29. GRB 030226: Steep Decline
  30. GRB 030227: Confirmed Optical Afterglow (S1-A)
  31. GRB 030226: R band polarimetric observations
  32. GRB 030226: Optical observations
  33. GRB 030227: fading of candidate optical afterglow 'S1-A'
  34. GRB030227:Optical observations
  35. GRB 20030226: Upper limits from recent and historical observations
  36. GRB 030227, possible optical counterpart of XMM-Newton source
  37. GRB030227 - faint tentative OT candidate
  38. GRB 030226, optical observations
  39. GRB030227: Kiso optical observations
  40. GRB 030227: Kyoto optical observation
  41. GRB 030226, optical light curve
  42. GRB 030226 spectroscopy
  43. Possible break in the GRB 030226 light curve
  44. GRB 030226 : Predicted light curve
  45. IPN triangulation of GRB030225 (annulus)
  46. GRB 030226: Confirmed decay index
  47. GRB030226: ESI spectroscopy
  48. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  49. GRB 030226 simultaneous optical observations
  50. Two absorption systems in GRB 030226
  51. GRB 030226, optical observations
  52. GRB 030226 Optical Spectra and R,I,z' Imaging
  53. GRB 030226, optical observations
  54. GRB 030226: Optical afterglow
  55. GRB 030217: Optical Observations at 4, 5, and 6 Days
  56. IPN triangulation of GRB030223 (annulus)
  57. IPN triangulation of GRB030220 (annulus)
  58. GRB: Non-Referencing of GCN Circulars.
  59. IPN triangulation of GRB030218 (annulus)
  60. IPN triangulation of GRB030217 (small error box)
  61. IPN triangulation of GRB030215C (annulus)
  62. IPN triangulation of GRB030217 (annulus)
  63. IPN triangulation of GRB030216 (annulus)
  64. IPN triangulation of GRB030215A and GRB030215B (annuli)
  65. GRB030115, WSRT radio observations - correction to GCN 1864
  66. GRB 030131: marginal optical detection
  67. GRB030115, WSRT radio observations
  68. IPN triangulation of GRB030206 (annulus)
  69. IPN triangulation of GRB030208 (annulus)
  70. GRB 030204: Optical Observations
  71. GRB030204 field photometry
  72. GRB020819: Kiso R and I band observations
  73. GRB 030204: Correction to GCN 1856
  74. GRB 030115: Optical Observations
  75. GRB 030204, optical observations
  76. IPN triangulation of GRB030204 (small error box)
  77. IPN triangulation of GRB030202 (annulus)
  78. GRB 030131, optical observations
  79. GRB030131: Kiso optical limit for corrected position
  80. GRB030131: Optical limits for corrected position
  81. GRB 030131: afterglow candidate
  82. GRB 030115, late-time optical observations
  83. GRB030131: corrected INTEGRAL position
  84. Type Ic SN2003L (SN/GRB?), optical spectrum
  85. GRB030131: Kiso Observations
  86. GRB 020819: Host galaxy at Radio Position
  87. IPN triangulation of GRB030131 - CORRECTION
  88. GRB 020819: afterglow candidate
  89. IPN triangulation of GRB030131
  90. GRB 030131 optical observations
  91. GRB 030131 optical observations
  92. A long GRB detected by INTEGRAL
  93. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  94. Type Ic SN2003L (SN/GRB?) Radio Observations
  95. IPN triangulation of GRB030127 (annulus)
  96. GRB030115 submm upper limit
  97. IPN triangulation of GRB030119 (two large error boxes)
  98. GRB 030115: Further IR observations with IRSF/SIRIUS
  99. IPN triangulation of GRB030117 (two large error boxes)
  100. Publicizing GRB Discoveries - A Message from NASA HQ

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