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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"

35957 results found.

  1. GRB030329 - OT rebrightens
  2. GRB 030329: SARA Optical Observations
  3. AAVSO V & R observations of GRB030329
  4. IPN triangulation of GRB030331 (annulus)
  5. GRB 030329: optical observations
  6. IPN triangulation of GRB030329b (large error box)
  7. GRB 030329: beginning of the new fading phase in optical band
  8. GRB 030329, optical spectroscopy
  9. GRB 030329: fading X-ray afterglow with RXTE
  10. GRB 030329: optical photometry
  11. Photometry of GRB030329 - Constant OT Magnitude
  12. GRB 030329, R-band observations
  13. GRB 030329, R-band light curve
  14. GRB 030329: further optical observations
  15. GRB030329 - OT brightens
  16. GRB 030329: OT observations at Kanazawa
  17. GRB030329 15 GHz radio observation
  18. GRB 030329 RBO V Optical Observations
  19. GRB 030329, optical photometry
  20. GRB030329: Near Infrared Observations
  21. 030331 NOT A GRB
  22. INTEGRAL GRB 030331
  23. GRB 030324: Optical and NIR Observations
  24. GRB 030328, optical photometry
  25. GRB030329: R band light curve by MASTER
  26. GRB030329 - Light curve flattening
  27. GRB 030329: SARA Optical Observations
  28. GRB 030324, optical search
  29. GRB030329 - near contemporaneous optical limits from CONCAM
  30. GRB 030329, optical observations
  31. GRB 030329: Light curve observed during the change of its slope.
  32. GRB030329, BVRcIc field photometry
  33. GRB030329, SPM optical observations
  34. GRB 030329: Optical Decay
  35. Redshift of GRB 030329
  36. GRB030329: ROTSE network observes steepening of decay curve
  37. GRB 030329, optical photometry
  38. GRB 030329: Optical decay and synthesis
  39. GRB 030329: Radio Observations
  40. GRB 030329, optical spectroscopy
  41. GRB 030329: still bright
  42. GRB 030329: Optical pre-Imaging
  43. GRB 030329: visual observations
  44. GRB 030329: Upper limit from 5.6 hours before trigger
  45. GRB030328: R optical observation
  46. GRB 030323: Gemini South VRI obsevations.
  47. GRB030329: Optical observations
  48. GRB 030329, R-band observations, supplement
  49. GRB030329:optical observations by MASTER
  50. GRB 030329: optical observations
  51. GRB 030329, R-band observations
  52. GRB 030329: OT B and R photometry, decline rate
  53. GRB030329: Upper limits from recent and historical observations.
  54. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  55. RXTE detection of GRB 030329 afterglow
  56. GRB 030329: Optical Afterglow Observations
  57. GRB 030329: precise position from Kyoto images
  58. GRB 030328 Optical Observations
  59. GRB 030328: Optical observations
  60. GRB 030328: optical observations
  61. GRB 030329: Optical afterglow fading
  62. GRB 030329 follow-up
  63. GRB 030329: Optical afterglow candidate
  64. GRB 030329: OT candidate
  65. GRB 030329: Optical afterglow candidate
  66. GRB 030328: OT photometry
  67. VLT spectra of GRB 030328
  68. GRB 030328, optical spectroscopy
  69. GRB 030328, optical observations
  70. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  71. GRB 030328: Optical observations
  72. Re: GRB 030328: Finding chart
  73. GRB 030328: Finding chart
  74. GRB 030328: Optical afterglow candidate
  75. GRB030131, BVRcIc field photometry
  76. Possible GRB030323 localized by INTEGRAL
  77. IPN triangulation of GRB030325 (final analysis)
  78. IPN triangulation of GRB030326 (single small error box)
  79. GRB 030323: SARA Optical Observations
  80. IPN triangulation of GRB030325 (single small error box)
  81. GRB030324, optical observations
  82. IPN triangulation of GRB030325 (two small error boxes)
  83. GRB 030324: TAROT optical observations
  84. GRB 030324 (HETE #2641): Optical observations
  85. GRB030324, Optical Observations
  86. GRB030323: Upper limits from recent and historical observations.
  87. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  88. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  89. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  90. VLT/FORS2 spectra of GRB 030323
  91. GRB030323, ROTSE-III detection of possible optical counterpart
  92. GRB030323, optical observations
  93. GRB030324, BVRcIc field photometry
  94. GRB030323, possible optical counterpart
  95. GRB030323, BVRcIc field calibration
  96. GRB 030324 optical observations
  97. GRB 030320: Optical Observations
  98. GRB 030324, optical observations
  99. IPN triangulation of GRB030320B (annulus)
  100. IPN triangulation of GRB030320 (small error box)

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