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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"

35941 results found.

  1. GRB030329 15 GHz radio observation
  2. GRB 030329 RBO V Optical Observations
  3. GRB 030329, optical photometry
  4. GRB030329: Near Infrared Observations
  5. 030331 NOT A GRB
  6. INTEGRAL GRB 030331
  7. GRB 030324: Optical and NIR Observations
  8. GRB 030328, optical photometry
  9. GRB030329: R band light curve by MASTER
  10. GRB030329 - Light curve flattening
  11. GRB 030329: SARA Optical Observations
  12. GRB 030324, optical search
  13. GRB030329 - near contemporaneous optical limits from CONCAM
  14. GRB 030329, optical observations
  15. GRB 030329: Light curve observed during the change of its slope.
  16. GRB030329, BVRcIc field photometry
  17. GRB030329, SPM optical observations
  18. GRB 030329: Optical Decay
  19. Redshift of GRB 030329
  20. GRB030329: ROTSE network observes steepening of decay curve
  21. GRB 030329, optical photometry
  22. GRB 030329: Optical decay and synthesis
  23. GRB 030329: Radio Observations
  24. GRB 030329, optical spectroscopy
  25. GRB 030329: still bright
  26. GRB 030329: Optical pre-Imaging
  27. GRB 030329: visual observations
  28. GRB 030329: Upper limit from 5.6 hours before trigger
  29. GRB030328: R optical observation
  30. GRB 030323: Gemini South VRI obsevations.
  31. GRB030329: Optical observations
  32. GRB 030329, R-band observations, supplement
  33. GRB030329:optical observations by MASTER
  34. GRB 030329: optical observations
  35. GRB 030329, R-band observations
  36. GRB 030329: OT B and R photometry, decline rate
  37. GRB030329: Upper limits from recent and historical observations.
  38. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  39. RXTE detection of GRB 030329 afterglow
  40. GRB 030329: Optical Afterglow Observations
  41. GRB 030329: precise position from Kyoto images
  42. GRB 030328 Optical Observations
  43. GRB 030328: Optical observations
  44. GRB 030328: optical observations
  45. GRB 030329: Optical afterglow fading
  46. GRB 030329 follow-up
  47. GRB 030329: Optical afterglow candidate
  48. GRB 030329: OT candidate
  49. GRB 030329: Optical afterglow candidate
  50. GRB 030328: OT photometry
  51. VLT spectra of GRB 030328
  52. GRB 030328, optical spectroscopy
  53. GRB 030328, optical observations
  54. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  55. GRB 030328: Optical observations
  56. Re: GRB 030328: Finding chart
  57. GRB 030328: Finding chart
  58. GRB 030328: Optical afterglow candidate
  59. GRB030131, BVRcIc field photometry
  60. Possible GRB030323 localized by INTEGRAL
  61. IPN triangulation of GRB030325 (final analysis)
  62. IPN triangulation of GRB030326 (single small error box)
  63. GRB 030323: SARA Optical Observations
  64. IPN triangulation of GRB030325 (single small error box)
  65. GRB030324, optical observations
  66. IPN triangulation of GRB030325 (two small error boxes)
  67. GRB 030324: TAROT optical observations
  68. GRB 030324 (HETE #2641): Optical observations
  69. GRB030324, Optical Observations
  70. GRB030323: Upper limits from recent and historical observations.
  71. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  72. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  73. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  74. VLT/FORS2 spectra of GRB 030323
  75. GRB030323, ROTSE-III detection of possible optical counterpart
  76. GRB030323, optical observations
  77. GRB030324, BVRcIc field photometry
  78. GRB030323, possible optical counterpart
  79. GRB030323, BVRcIc field calibration
  80. GRB 030324 optical observations
  81. GRB 030320: Optical Observations
  82. GRB 030324, optical observations
  83. IPN triangulation of GRB030320B (annulus)
  84. IPN triangulation of GRB030320 (small error box)
  85. IPN triangulation of GRB030320
  86. Possible GRB 030320 localized by INTEGRAL
  87. IPN upper limit to a GRB associated with SN2003L
  88. IPN triangulation of GRB030317 (annulus)
  89. IPN triangulation of GRB030307 (annulus)
  90. GRB 030227: Optical limit at RIKEN
  91. GRB 030226 Optical observations
  92. IPN triangulation of GRB030306 (single small error box - REVISED)
  93. GRB030226: Optical observations at Asiago
  94. IPN triangulation of GRB030306 (single small error box)
  95. IPN triangulation of GRB030306 (two small error boxes)
  96. IPN triangulation of GRB030306 (intense; annulus only so far)
  97. GRB 030226: Optical observations
  98. IPN triangulation of GRB030304 (annulus)
  99. GRB 030227: Optical observations
  100. GRB030226, BVRc observations

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