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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"

32484 results found.

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

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