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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"

35952 results found.

  1. GRB 030227: Optical limit at RIKEN
  2. GRB 030226 Optical observations
  3. IPN triangulation of GRB030306 (single small error box - REVISED)
  4. GRB030226: Optical observations at Asiago
  5. IPN triangulation of GRB030306 (single small error box)
  6. IPN triangulation of GRB030306 (two small error boxes)
  7. IPN triangulation of GRB030306 (intense; annulus only so far)
  8. GRB 030226: Optical observations
  9. IPN triangulation of GRB030304 (annulus)
  10. GRB 030227: Optical observations
  11. GRB030226, BVRc observations
  12. Chandra detection of the X-ray afterglow of GRB 030226
  13. GRB 030226, further optical/NIR imaging
  14. GRB030227, optical observations
  15. GRB 030226: Ic Observations
  16. GRB030227: Kiso optical upper limit
  17. IPN triangulation of GRB030301 (annulus)
  18. IPN triangulation of GRB030228 (annulus)
  19. GRB030227, BVRcIc field photometry
  20. GRB030226, BVRcIc field calibration
  21. GRB 030227 optical afterglow
  22. 030302: NOT A GRB
  23. 030228: NOT A GRB
  24. GRB 030228, optical observations
  25. GRB 030226: Steep Decline
  26. GRB 030227: Confirmed Optical Afterglow (S1-A)
  27. GRB 030226: R band polarimetric observations
  28. GRB 030226: Optical observations
  29. GRB 030227: fading of candidate optical afterglow 'S1-A'
  30. GRB030227:Optical observations
  31. GRB 20030226: Upper limits from recent and historical observations
  32. GRB 030227, possible optical counterpart of XMM-Newton source
  33. GRB030227 - faint tentative OT candidate
  34. GRB 030226, optical observations
  35. GRB030227: Kiso optical observations
  36. GRB 030227: Kyoto optical observation
  37. GRB 030226, optical light curve
  38. GRB 030226 spectroscopy
  39. Possible break in the GRB 030226 light curve
  40. GRB 030226 : Predicted light curve
  41. IPN triangulation of GRB030225 (annulus)
  42. GRB 030226: Confirmed decay index
  43. GRB030226: ESI spectroscopy
  44. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  45. GRB 030226 simultaneous optical observations
  46. Two absorption systems in GRB 030226
  47. GRB 030226, optical observations
  48. GRB 030226 Optical Spectra and R,I,z' Imaging
  49. GRB 030226, optical observations
  50. GRB 030226: Optical afterglow
  51. GRB 030217: Optical Observations at 4, 5, and 6 Days
  52. IPN triangulation of GRB030223 (annulus)
  53. IPN triangulation of GRB030220 (annulus)
  54. GRB: Non-Referencing of GCN Circulars.
  55. IPN triangulation of GRB030218 (annulus)
  56. IPN triangulation of GRB030217 (small error box)
  57. IPN triangulation of GRB030215C (annulus)
  58. IPN triangulation of GRB030217 (annulus)
  59. IPN triangulation of GRB030216 (annulus)
  60. IPN triangulation of GRB030215A and GRB030215B (annuli)
  61. GRB030115, WSRT radio observations - correction to GCN 1864
  62. GRB 030131: marginal optical detection
  63. GRB030115, WSRT radio observations
  64. IPN triangulation of GRB030206 (annulus)
  65. IPN triangulation of GRB030208 (annulus)
  66. GRB 030204: Optical Observations
  67. GRB030204 field photometry
  68. GRB020819: Kiso R and I band observations
  69. GRB 030204: Correction to GCN 1856
  70. GRB 030115: Optical Observations
  71. GRB 030204, optical observations
  72. IPN triangulation of GRB030204 (small error box)
  73. IPN triangulation of GRB030202 (annulus)
  74. GRB 030131, optical observations
  75. GRB030131: Kiso optical limit for corrected position
  76. GRB030131: Optical limits for corrected position
  77. GRB 030131: afterglow candidate
  78. GRB 030115, late-time optical observations
  79. GRB030131: corrected INTEGRAL position
  80. Type Ic SN2003L (SN/GRB?), optical spectrum
  81. GRB030131: Kiso Observations
  82. GRB 020819: Host galaxy at Radio Position
  83. IPN triangulation of GRB030131 - CORRECTION
  84. GRB 020819: afterglow candidate
  85. IPN triangulation of GRB030131
  86. GRB 030131 optical observations
  87. GRB 030131 optical observations
  88. A long GRB detected by INTEGRAL
  89. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  90. Type Ic SN2003L (SN/GRB?) Radio Observations
  91. IPN triangulation of GRB030127 (annulus)
  92. GRB030115 submm upper limit
  93. IPN triangulation of GRB030119 (two large error boxes)
  94. GRB 030115: Further IR observations with IRSF/SIRIUS
  95. IPN triangulation of GRB030117 (two large error boxes)
  96. Publicizing GRB Discoveries - A Message from NASA HQ
  97. GRB 030115: Radio detection of IR candidate
  98. GRB 030115, simultaneous observations by BOOTES-1
  99. GRB 030115: IR observations with IRSF/SIRIUS
  100. IPN triangulation of GRB030115C (large error box)

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