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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"

32495 results found.

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

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