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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"

32512 results found.

  1. GRB 030320: Optical Observations
  2. IPN triangulation of GRB030320 (small error box)
  3. IPN triangulation of GRB030320
  4. GRB030226, addendum to GCN 1892
  5. IPN upper limit to a GRB associated with SN2003L
  6. GRB 030227: Optical limit at RIKEN
  7. GRB 030226 Optical observations
  8. IPN triangulation of GRB030306 (single small error box - REVISED)
  9. GRB030226: Optical observations at Asiago
  10. IPN triangulation of GRB030306 (two small error boxes)
  11. GRB 030226: Optical observations
  12. GRB030226: Analysis of Chandra data
  13. GRB 030227: Optical observations
  14. GRB030226, BVRc observations
  15. Chandra detection of the X-ray afterglow of GRB 030226
  16. GRB 030226, further optical/NIR imaging
  17. GRB 030226: Ic Observations
  18. GRB030227: Kiso optical upper limit
  19. GRB030227, BVRcIc field photometry
  20. GRB030226, BVRcIc field calibration
  21. GRB 030227 optical afterglow
  22. GRB 030226: Steep Decline
  23. GRB 030227: Confirmed Optical Afterglow (S1-A)
  24. GRB 030226: R band polarimetric observations
  25. GRB 030226: Optical observations
  26. GRB 030227: fading of candidate optical afterglow 'S1-A'
  27. GRB030227:Optical observations
  28. GRB 20030226: Upper limits from recent and historical observations
  29. GRB 030227, possible optical counterpart of XMM-Newton source
  30. GRB030227 - faint tentative OT candidate
  31. GRB 030226, optical observations
  32. XMM-Newton observation of GRB030227
  33. GRB 030227: Kyoto optical observation
  34. GRB 030226, optical light curve
  35. GRB 030226 spectroscopy
  36. Possible break in the GRB 030226 light curve
  37. GRB030226: optical observation
  38. GRB 030226: Confirmed decay index
  39. GRB030226: ESI spectroscopy
  40. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  41. Two absorption systems in GRB 030226
  42. GRB 030226, optical observations
  43. GRB030226: optical observations and refined redshift
  44. GRB 030226, optical observations
  45. GRB 030226: Optical afterglow
  46. GRB 030217: Optical Observations at 4, 5, and 6 Days
  47. GRB: Non-Referencing of GCN Circulars.
  48. GRB030217: optical observations
  49. IPN triangulation of GRB030217 (small error box)
  50. GRB030115, WSRT radio observations - correction to GCN 1864
  51. GRB 030131: marginal optical detection
  52. GCN/INTEGRAL Mistake Fixed
  53. GRB 030204: Optical Observations
  54. GRB030204 field photometry
  55. GRB020819: Kiso R and I band observations
  56. GRB 030204: Correction to GCN 1856
  57. GRB030131: Candidate Optical Afterglow
  58. GRB 030115: Optical Observations
  59. GRB 030204, optical observations
  60. GRB 030131, optical observations
  61. GRB030131: Kiso optical limit for corrected position
  62. GRB030131: Optical limits for corrected position
  63. GRB 030131: afterglow candidate
  64. GRB 030115, late-time optical observations
  65. Type Ic SN2003L (SN/GRB?), optical spectrum
  66. GRB 020819: Host galaxy at Radio Position
  67. IPN triangulation of GRB030131 - CORRECTION
  68. IPN triangulation of GRB030131
  69. GRB030131: Optical limit
  70. GRB 030131 optical observations
  71. GRB030131: refined position
  72. GRB 030131 optical observations
  73. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  74. GRB030115 submm upper limit
  75. GRB 030115: Further IR observations with IRSF/SIRIUS
  76. Publicizing GRB Discoveries - A Message from NASA HQ
  77. GRB 030115, simultaneous observations by BOOTES-1
  78. GRB 030115: IR observations with IRSF/SIRIUS
  79. GRB030115: R-band counterpart of IR candidate
  80. GRB030115, afterglow candidate
  81. GRB 021211: R-band observations at late-time
  82. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  83. IPN triangulation of GRB030115B (small error box)
  84. GRB 030115 : Possible IR counterpart
  85. GRB 030115: Radio Observations
  86. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  87. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  88. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  89. Distribution of INTEGRAL SPI-ACS triggers
  90. GRB030115: TAROT optical observations
  91. GRB 021211: VLT spectrum
  92. GRB 030115: APO Optical Observations
  93. GRB 030115, no optical candidate
  94. GRB 030115, optical observations
  95. GRB 030115, optical candidate
  96. IPN triangulation of GRB030109 (annulus)
  97. IPN triangulation of GRB030105 (large error box)
  98. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  99. Coronas-F -Wind triangulation of GRB030102
  100. IPN triangulation of GRB030102 (annulus)

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