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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"

15993 results found.

  1. GRB 030328: Optical observations
  2. GRB 030328: optical observations
  3. GRB 030329: Optical afterglow fading
  4. GRB 030329: Optical afterglow candidate
  5. GRB 030329: Optical afterglow candidate
  6. GRB030328: optical spectroscopy at TNG
  7. GRB030328: optical photometry at the TNG
  8. VLT spectra of GRB 030328
  9. GRB 030328, optical spectroscopy
  10. GRB 030328, optical observations
  11. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  12. GRB 030328: Optical observations
  13. GRB 030328: Finding chart
  14. GRB 030328: Optical afterglow candidate
  15. GRB030323 optical observations
  16. GRB030324 optical observation
  17. GRB030323: Detection on 2003/03/24
  18. GRB 030323: SARA Optical Observations
  19. GRB030324, optical observations
  20. GRB030324, optical observations
  21. GRB 030324: TAROT optical observations
  22. GRB 030324 (HETE #2641): Optical observations
  23. GRB030324, Optical Observations
  24. GRB030323: Upper limits from recent and historical observations.
  25. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  26. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  27. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  28. GRB030323, ROTSE-III detection of possible optical counterpart
  29. GRB030323, optical observations
  30. GRB030323, possible optical counterpart
  31. GRB 030324 optical observations
  32. GRB 030320: Optical Observations
  33. GRB 030324, optical observations
  34. GRB 030227: Optical limit at RIKEN
  35. GRB 030226 Optical observations
  36. GRB030226: Optical observations at Asiago
  37. GRB 030226: Optical observations
  38. GRB 030227: Optical observations
  39. GRB030226, BVRc observations
  40. Chandra detection of the X-ray afterglow of GRB 030226
  41. GRB 030226, further optical/NIR imaging
  42. GRB030227, optical observations
  43. GRB 030226: Ic Observations
  44. GRB030227: Kiso optical upper limit
  45. GRB030227, BVRcIc field photometry
  46. GRB030226, BVRcIc field calibration
  47. GRB 030227 optical afterglow
  48. GRB 030228, optical observations
  49. GRB 030226: Steep Decline
  50. GRB 030227: Confirmed Optical Afterglow (S1-A)
  51. GRB 030226: R band polarimetric observations
  52. GRB 030226: Optical observations
  53. GRB 030227: fading of candidate optical afterglow 'S1-A'
  54. GRB030227:Optical observations
  55. GRB 20030226: Upper limits from recent and historical observations
  56. GRB 030227, possible optical counterpart of XMM-Newton source
  57. GRB030227 - faint tentative OT candidate
  58. GRB 030226, optical observations
  59. GRB030227: Kiso optical observations
  60. GRB 030227: Kyoto optical observation
  61. GRB 030226, optical light curve
  62. GRB 030226 spectroscopy
  63. GRB 030226 : Predicted light curve
  64. GRB030226: optical observation
  65. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  66. GRB 030226 simultaneous optical observations
  67. GRB 030226, optical observations
  68. GRB030226: optical observations and refined redshift
  69. GRB030226: Optical decay index
  70. GRB 030226 Optical Spectra and R,I,z' Imaging
  71. GRB 030226, optical observations
  72. GRB 030226: Optical afterglow
  73. GRB030226: Candidate optical afterglow
  74. GRB 030217: Optical Observations at 4, 5, and 6 Days
  75. GRB030217: optical observations
  76. GRB 030131: marginal optical detection
  77. GRB 030204: Optical Observations
  78. GRB030131: Candidate Optical Afterglow
  79. GRB 030115: Optical Observations
  80. GRB 030204, optical observations
  81. GRB 030131, optical observations
  82. GRB030131: Kiso optical limit for corrected position
  83. GRB030131: Optical limits for corrected position
  84. GRB 030115, late-time optical observations
  85. Type Ic SN2003L (SN/GRB?), optical spectrum
  86. GRB 020819: Host galaxy at Radio Position
  87. GRB 020819: afterglow candidate
  88. GRB030131: Optical limit
  89. GRB 030131 optical observations
  90. GRB 030131 optical observations
  91. Type Ic SN2003L (SN/GRB?) Radio Observations
  92. GRB 030115, simultaneous observations by BOOTES-1
  93. GRB030115: R-band counterpart of IR candidate
  94. GRB 021211: R-band observations at late-time
  95. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  96. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  97. GRB030115: TAROT optical observations
  98. GRB 030115: APO Optical Observations
  99. GRB 030115, no optical candidate
  100. GRB 030115, optical observations

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