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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"

32490 results found.

  1. GRB 030227: Confirmed Optical Afterglow (S1-A)
  2. GRB 030226: R band polarimetric observations
  3. GRB 030226: Optical observations
  4. GRB 030227: fading of candidate optical afterglow 'S1-A'
  5. GRB030227:Optical observations
  6. GRB 20030226: Upper limits from recent and historical observations
  7. GRB 030227, possible optical counterpart of XMM-Newton source
  8. GRB030227 - faint tentative OT candidate
  9. GRB 030226, optical observations
  10. XMM-Newton observation of GRB030227
  11. GRB 030227: Kyoto optical observation
  12. GRB 030226, optical light curve
  13. GRB 030226 spectroscopy
  14. Possible break in the GRB 030226 light curve
  15. GRB030226: optical observation
  16. GRB 030226: Confirmed decay index
  17. GRB030226: ESI spectroscopy
  18. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  19. Two absorption systems in GRB 030226
  20. GRB 030226, optical observations
  21. GRB030226: optical observations and refined redshift
  22. GRB 030226, optical observations
  23. GRB 030226: Optical afterglow
  24. GRB 030217: Optical Observations at 4, 5, and 6 Days
  25. GRB: Non-Referencing of GCN Circulars.
  26. GRB030217: optical observations
  27. IPN triangulation of GRB030217 (small error box)
  28. GRB030115, WSRT radio observations - correction to GCN 1864
  29. GRB 030131: marginal optical detection
  30. GCN/INTEGRAL Mistake Fixed
  31. GRB 030204: Optical Observations
  32. GRB030204 field photometry
  33. GRB020819: Kiso R and I band observations
  34. GRB 030204: Correction to GCN 1856
  35. GRB030131: Candidate Optical Afterglow
  36. GRB 030115: Optical Observations
  37. GRB 030204, optical observations
  38. GRB 030131, optical observations
  39. GRB030131: Kiso optical limit for corrected position
  40. GRB030131: Optical limits for corrected position
  41. GRB 030131: afterglow candidate
  42. GRB 030115, late-time optical observations
  43. Type Ic SN2003L (SN/GRB?), optical spectrum
  44. GRB 020819: Host galaxy at Radio Position
  45. IPN triangulation of GRB030131 - CORRECTION
  46. IPN triangulation of GRB030131
  47. GRB030131: Optical limit
  48. GRB 030131 optical observations
  49. GRB030131: refined position
  50. GRB 030131 optical observations
  51. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  52. GRB030115 submm upper limit
  53. GRB 030115: Further IR observations with IRSF/SIRIUS
  54. Publicizing GRB Discoveries - A Message from NASA HQ
  55. GRB 030115, simultaneous observations by BOOTES-1
  56. GRB 030115: IR observations with IRSF/SIRIUS
  57. GRB030115: R-band counterpart of IR candidate
  58. GRB030115, afterglow candidate
  59. GRB 021211: R-band observations at late-time
  60. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  61. IPN triangulation of GRB030115B (small error box)
  62. GRB 030115 : Possible IR counterpart
  63. GRB 030115: Radio Observations
  64. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  65. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  66. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  67. Distribution of INTEGRAL SPI-ACS triggers
  68. GRB030115: TAROT optical observations
  69. GRB 021211: VLT spectrum
  70. GRB 030115: APO Optical Observations
  71. GRB 030115, no optical candidate
  72. GRB 030115, optical observations
  73. GRB 030115, optical candidate
  74. IPN triangulation of GRB030109 (annulus)
  75. IPN triangulation of GRB030105 (large error box)
  76. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  77. Coronas-F -Wind triangulation of GRB030102
  78. IPN triangulation of GRB030102 (annulus)
  79. VLT spectroscopy of the probable host of GRB 021211
  80. GRB021226
  81. GRB 021211: Probable Host and Underlying Supernova
  82. GRB 021226 registration by Helicon/Coronas-F
  83. GRB 021112: Evidence for Another Dark Optical Afterglow
  84. GRB 021219: OSN optical observations
  85. GRB021219: Radio Observations
  86. GRB021219, optical observations
  87. IPN triangulation of GRB021219 - CORRECTION
  88. IPN triangulation of GRB021219
  89. GRB021219, optical observation by MASTER
  90. GRB021219: Correction to GCN 1766
  91. VLT spectra of GRB 021211 revisited
  92. GRB021219: a long GRB localized by INTEGRAL
  93. GRB021211: APO optical observations
  94. IPN detection of continued activity from SGR1806-20
  95. XRF 020903 : HST observations
  96. GRB 021201: Optical Observations
  97. GRB 021211, optical observations
  98. GRB 021211: CTIO observations
  99. GRB021211: Measurement of Early Time Afterglow
  100. VLT spectrum of GRB 021211

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