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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"

37524 results found.

  1. GRB 030329: Optical Decay
  2. Redshift of GRB 030329
  3. GRB030329: ROTSE network observes steepening of decay curve
  4. GRB 030329, optical photometry
  5. GRB 030329: Optical decay and synthesis
  6. GRB 030329: Radio Observations
  7. GRB 030329, optical spectroscopy
  8. GRB 030329: still bright
  9. GRB 030329: Optical pre-Imaging
  10. GRB 030329: visual observations
  11. GRB 030329: Upper limit from 5.6 hours before trigger
  12. GRB030328: R optical observation
  13. GRB 030323: Gemini South VRI obsevations.
  14. GRB030329: Optical observations
  15. GRB 030329, R-band observations, supplement
  16. GRB030329:optical observations by MASTER
  17. GRB 030329: optical observations
  18. GRB 030329, R-band observations
  19. GRB 030329: OT B and R photometry, decline rate
  20. GRB030329: Upper limits from recent and historical observations.
  21. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  22. RXTE detection of GRB 030329 afterglow
  23. GRB 030329: Optical Afterglow Observations
  24. GRB 030329: precise position from Kyoto images
  25. GRB 030328 Optical Observations
  26. GRB 030328: Optical observations
  27. GRB 030328: optical observations
  28. GRB 030329: Optical afterglow fading
  29. GRB 030329 follow-up
  30. GRB 030329: Optical afterglow candidate
  31. GRB 030329: OT candidate
  32. GRB 030329: Optical afterglow candidate
  33. GRB 030328: OT photometry
  34. VLT spectra of GRB 030328
  35. GRB 030328, optical spectroscopy
  36. GRB 030328, optical observations
  37. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  38. GRB 030328: Optical observations
  39. Re: GRB 030328: Finding chart
  40. GRB 030328: Finding chart
  41. GRB 030328: Optical afterglow candidate
  42. GRB030131, BVRcIc field photometry
  43. Possible GRB030323 localized by INTEGRAL
  44. IPN triangulation of GRB030325 (final analysis)
  45. IPN triangulation of GRB030326 (single small error box)
  46. GRB 030323: SARA Optical Observations
  47. IPN triangulation of GRB030325 (single small error box)
  48. GRB030324, optical observations
  49. IPN triangulation of GRB030325 (two small error boxes)
  50. GRB 030324: TAROT optical observations
  51. GRB 030324 (HETE #2641): Optical observations
  52. GRB030324, Optical Observations
  53. GRB030323: Upper limits from recent and historical observations.
  54. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  55. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  56. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  57. VLT/FORS2 spectra of GRB 030323
  58. GRB030323, ROTSE-III detection of possible optical counterpart
  59. GRB030323, optical observations
  60. GRB030324, BVRcIc field photometry
  61. GRB030323, possible optical counterpart
  62. GRB030323, BVRcIc field calibration
  63. GRB 030324 optical observations
  64. GRB 030320: Optical Observations
  65. GRB 030324, optical observations
  66. IPN triangulation of GRB030320B (annulus)
  67. IPN triangulation of GRB030320 (small error box)
  68. IPN triangulation of GRB030320
  69. Possible GRB 030320 localized by INTEGRAL
  70. IPN upper limit to a GRB associated with SN2003L
  71. IPN triangulation of GRB030317 (annulus)
  72. IPN triangulation of GRB030307 (annulus)
  73. GRB 030227: Optical limit at RIKEN
  74. GRB 030226 Optical observations
  75. IPN triangulation of GRB030306 (single small error box - REVISED)
  76. GRB030226: Optical observations at Asiago
  77. IPN triangulation of GRB030306 (single small error box)
  78. IPN triangulation of GRB030306 (two small error boxes)
  79. IPN triangulation of GRB030306 (intense; annulus only so far)
  80. GRB 030226: Optical observations
  81. IPN triangulation of GRB030304 (annulus)
  82. GRB 030227: Optical observations
  83. GRB030226, BVRc observations
  84. Chandra detection of the X-ray afterglow of GRB 030226
  85. GRB 030226, further optical/NIR imaging
  86. GRB030227, optical observations
  87. GRB 030226: Ic Observations
  88. GRB030227: Kiso optical upper limit
  89. IPN triangulation of GRB030301 (annulus)
  90. IPN triangulation of GRB030228 (annulus)
  91. GRB030227, BVRcIc field photometry
  92. GRB030226, BVRcIc field calibration
  93. GRB 030227 optical afterglow
  94. 030302: NOT A GRB
  95. 030228: NOT A GRB
  96. GRB 030228, optical observations
  97. GRB 030226: Steep Decline
  98. GRB 030227: Confirmed Optical Afterglow (S1-A)
  99. GRB 030226: R band polarimetric observations
  100. GRB 030226: Optical observations

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