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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"

32489 results found.

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

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