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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"

24357 results found.

  1. GRB030328: X-ray Afterglow Observed with Chandra
  2. GRB030329:optical observations by MASTER
  3. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  4. GRB 030328: Optical observations
  5. GRB030328: optical spectroscopy at TNG
  6. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  7. GRB030324, optical observations
  8. GRB030324, optical observations
  9. GRB 030324: TAROT optical observations
  10. GRB030323: V, R, I photometry
  11. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  12. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  13. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  14. VLT/FORS2 spectra of GRB 030323
  15. IPN triangulation of GRB030320
  16. Possible GRB 030320 localized by INTEGRAL
  17. GRB030226, addendum to GCN 1892
  18. IPN upper limit to a GRB associated with SN2003L
  19. GRB030226: Optical observations at Asiago
  20. IPN triangulation of GRB030306 (two small error boxes)
  21. IPN triangulation of GRB030306 (intense; annulus only so far)
  22. GRB 030226: Optical observations
  23. GRB030226: Analysis of Chandra data
  24. GRB 030227: Optical observations
  25. GRB030226, BVRc observations
  26. Chandra detection of the X-ray afterglow of GRB 030226
  27. GRB 030226, further optical/NIR imaging
  28. GRB 030226: Ic Observations
  29. GRB030227: Kiso optical upper limit
  30. GRB 030227 optical afterglow
  31. 030302: NOT A GRB
  32. 030228: NOT A GRB
  33. GRB 030226: Steep Decline
  34. GRB 030227: Confirmed Optical Afterglow (S1-A)
  35. GRB 030226: Optical observations
  36. GRB030227:Optical observations
  37. GRB 030227, possible optical counterpart of XMM-Newton source
  38. GRB030227: Kiso optical observations
  39. GRB 030226, optical light curve
  40. GRB030227: refined INTEGRAL position
  41. GRB030227 localized by INTEGRAL
  42. Possible break in the GRB 030226 light curve
  43. GRB 030226 : Predicted light curve
  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 Spectra and R,I,z' Imaging
  48. GRB: Non-Referencing of GCN Circulars.
  49. GRB 030131: marginal optical detection
  50. GRB 030204: Optical Observations
  51. GRB030131: Candidate Optical Afterglow
  52. GRB 030204, optical observations
  53. GRB 030131, optical observations
  54. GRB030131: Kiso optical limit for corrected position
  55. GRB030131: Optical limits for corrected position
  56. GRB 030115, late-time optical observations
  57. GRB030131: corrected INTEGRAL position
  58. GRB030131: Kiso Observations
  59. GRB 020819: Host galaxy at Radio Position
  60. IPN triangulation of GRB030131
  61. GRB030131: Optical limit
  62. GRB030131: refined position
  63. A long GRB detected by INTEGRAL
  64. IPN triangulation of GRB030119 (two large error boxes)
  65. IPN triangulation of GRB030117 (two large error boxes)
  66. Publicizing GRB Discoveries - A Message from NASA HQ
  67. GRB 030115, simultaneous observations by BOOTES-1
  68. GRB030115: R-band counterpart of IR candidate
  69. GRB 021211: R-band observations at late-time
  70. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  71. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  72. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  73. GRB 021211: VLT spectrum
  74. Information about where HETE will be pointing
  75. IPN triangulation of GRB030105 (large error box)
  76. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  77. VLT spectroscopy of the probable host of GRB 021211
  78. IPN triangulation of GRB030101 (two large error boxes)
  79. GRB021219, optical observations
  80. GRB021219, optical observation by MASTER
  81. XRF 020903 : HST observations
  82. GRB 021211: CTIO observations
  83. GRB021211: Measurement of Early Time Afterglow
  84. VLT spectrum of GRB 021211
  85. IPN triangulation of GRB021211B (two large error boxes)
  86. GRB 021211: early break in light curve
  87. GRB021204: Kiso Observations
  88. GRB 021211, R- and I-band observations
  89. GRB021211, OT at 108 s
  90. GRB021211 (HETE2493), OT at 143 sec
  91. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  92. GRB 021204: Optical Observations at RIKEN
  93. IPN detection of renewed activity from SGR1806-20
  94. GRB 021201: BOOTES simultaneous optical observations
  95. Radio Catalog of GRB Afterglows
  96. GRB021004, late time optical observations
  97. GRB021004 Chandra Observation
  98. IPN triangulation of GRB021119 (large error box)
  99. IPN BURST POSITION
  100. IPN triangulation of GRB021125 (INTEGRAL BURST)

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