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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"

32481 results found.

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

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